From 52c17e74e8b44aada30abe1a816f0a021d87022f Mon Sep 17 00:00:00 2001
From: Adam Shapiro <adam@pointonenav.com>
Date: Mon, 2 Dec 2024 10:22:05 -0500
Subject: [PATCH 01/12] Added missing separator for input wrapper messages.

---
 python/fusion_engine_client/messages/measurements.py | 4 ++++
 src/point_one/fusion_engine/messages/measurements.h  | 4 ++++
 2 files changed, 8 insertions(+)

diff --git a/python/fusion_engine_client/messages/measurements.py b/python/fusion_engine_client/messages/measurements.py
index 2847e8f5..5af26208 100644
--- a/python/fusion_engine_client/messages/measurements.py
+++ b/python/fusion_engine_client/messages/measurements.py
@@ -1391,6 +1391,10 @@ def to_numpy(cls, messages: Sequence['RawHeadingOutput']):
         result.update(MeasurementDetails.to_numpy([m.details for m in messages]))
         return result
 
+################################################################################
+# Binary Sensor Data Definitions
+################################################################################
+
 
 class InputDataWrapperMessage(MessagePayload):
     """!
diff --git a/src/point_one/fusion_engine/messages/measurements.h b/src/point_one/fusion_engine/messages/measurements.h
index f414293e..8d7e832e 100644
--- a/src/point_one/fusion_engine/messages/measurements.h
+++ b/src/point_one/fusion_engine/messages/measurements.h
@@ -1261,6 +1261,10 @@ struct P1_ALIGNAS(4) RawHeadingOutput : public MessagePayload {
   float baseline_distance_m = NAN;
 };
 
+////////////////////////////////////////////////////////////////////////////////
+// Binary Sensor Data Definitions
+////////////////////////////////////////////////////////////////////////////////
+
 /**
  * @brief A block of incoming sensor data whose definition depends on the value
  *        of @ ref data_type. (@ref MessageType::INPUT_DATA_WRAPPER).

From 23d1e382118db8c6f338af8c54d2fb49d9fc6573 Mon Sep 17 00:00:00 2001
From: Adam Shapiro <adam@pointonenav.com>
Date: Mon, 2 Dec 2024 10:30:17 -0500
Subject: [PATCH 02/12] Renamed HeadingOutput -> GNSSHeadingOutput.

This distinguishes between a vehicle body heading (orientation) _measurement_
computed from two GNSS antennas, which is a sensor input to the navigation
engine, and the YPR vehicle body orientation being estimated by the navigation
engine (reported in PoseMessage).
---
 .../fusion_engine_client/analysis/analyzer.py | 19 +++---
 python/fusion_engine_client/messages/defs.py  |  4 +-
 .../messages/measurements.py                  | 28 ++++----
 .../fusion_engine/messages/configuration.h    |  2 +-
 src/point_one/fusion_engine/messages/defs.h   | 17 ++---
 .../fusion_engine/messages/measurements.h     | 66 +++++++++++--------
 6 files changed, 74 insertions(+), 62 deletions(-)

diff --git a/python/fusion_engine_client/analysis/analyzer.py b/python/fusion_engine_client/analysis/analyzer.py
index 3ef47a18..17078158 100755
--- a/python/fusion_engine_client/analysis/analyzer.py
+++ b/python/fusion_engine_client/analysis/analyzer.py
@@ -1943,20 +1943,20 @@ def _plot_imu_data(self, message_cls, filename, figure_title):
 
         self._add_figure(name=filename, figure=figure, title=figure_title)
 
-    def plot_heading_measurements(self):
+    def plot_gnss_heading_measurements(self):
         """!
-        @brief Generate time series plots for heading (degrees) and baseline distance (meters) data.
+        @brief Generate time series plots for GNSS heading (degrees) and baseline distance (meters) data.
         """
         if self.output_dir is None:
             return
 
         # Read the heading measurement data.
-        result = self.reader.read(message_types=[RawHeadingOutput, HeadingOutput], **self.params)
-        raw_heading_data = result[RawHeadingOutput.MESSAGE_TYPE]
-        heading_data = result[HeadingOutput.MESSAGE_TYPE]
+        result = self.reader.read(message_types=[RawGNSSHeadingOutput, GNSSHeadingOutput], **self.params)
+        raw_heading_data = result[RawGNSSHeadingOutput.MESSAGE_TYPE]
+        heading_data = result[GNSSHeadingOutput.MESSAGE_TYPE]
 
         if (len(heading_data.p1_time) == 0) and (len(raw_heading_data.p1_time) == 0):
-            self.logger.info('No heading measurement data available. Skipping plot.')
+            self.logger.info('No GNSS heading measurement data available. Skipping plot.')
             return
 
         # Note that we read the pose data after heading, that way we don't bother reading pose data from disk if there's
@@ -1987,7 +1987,6 @@ def plot_heading_measurements(self):
 
         fig.update_layout(title='Heading Plots', legend_traceorder='normal', modebar_add=['v1hovermode'])
 
-
         # Display the navigation engine's heading estimate, if available, for comparison with the heading sensor
         # measurement.
         if primary_pose_data is not None:
@@ -2003,7 +2002,7 @@ def plot_heading_measurements(self):
                         customdata=primary_pose_data.p1_time,
                         mode='lines',
                         line={'color': 'yellow'},
-                        name='Primary Device Heading Estimate',
+                        name='Navigation Engine Heading Estimate',
                         hovertemplate='<b>Time</b>: %{x:.3f} sec (%{customdata:.3f} sec)'
                                       '<br><b>Heading</b>: %{y:.2f} deg'
                     ),
@@ -2188,7 +2187,7 @@ def plot_heading_measurements(self):
                 row=3, col=1
             )
 
-        self._add_figure(name='heading_measurement', figure=fig, title='Measurements: Heading')
+        self._add_figure(name='gnss_heading_measurement', figure=fig, title='Measurements: GNSS Heading')
 
     def plot_system_status_profiling(self):
         """!
@@ -3004,7 +3003,7 @@ def main(args=None):
 
         # By default, we always plot heading measurements (i.e., output from a secondary heading device like an
         # LG69T-AH), separate from other sensor measurements controlled by --measurements.
-        analyzer.plot_heading_measurements()
+        analyzer.plot_gnss_heading_measurements()
 
         if truth_lla_deg is not None:
             analyzer.plot_stationary_position_error(truth_lla_deg)
diff --git a/python/fusion_engine_client/messages/defs.py b/python/fusion_engine_client/messages/defs.py
index 8fcfb0c2..49429d9d 100644
--- a/python/fusion_engine_client/messages/defs.py
+++ b/python/fusion_engine_client/messages/defs.py
@@ -99,9 +99,9 @@ class MessageType(IntEnum):
 
     # Sensor measurement messages.
     IMU_OUTPUT = 11000
-    RAW_HEADING_OUTPUT = 11001
+    RAW_GNSS_HEADING_OUTPUT = 11001
     RAW_IMU_OUTPUT = 11002
-    HEADING_OUTPUT = 11003
+    GNSS_HEADING_OUTPUT = 11003
     IMU_INPUT = 11004
 
     # Vehicle measurement messages.
diff --git a/python/fusion_engine_client/messages/measurements.py b/python/fusion_engine_client/messages/measurements.py
index 5af26208..ac6dd533 100644
--- a/python/fusion_engine_client/messages/measurements.py
+++ b/python/fusion_engine_client/messages/measurements.py
@@ -1165,15 +1165,15 @@ def to_numpy(cls, messages):
         return result
 
 ################################################################################
-# Heading Sensor Definitions
+# GNSS Heading Sensor Definitions
 ################################################################################
 
 
-class HeadingOutput(MessagePayload):
+class GNSSHeadingOutput(MessagePayload):
     """!
-    @brief Heading sensor measurement output with heading bias corrections applied.
+    @brief Multi-antenna GNSS heading sensor measurement output with offset corrections applied.
     """
-    MESSAGE_TYPE = MessageType.HEADING_OUTPUT
+    MESSAGE_TYPE = MessageType.GNSS_HEADING_OUTPUT
     MESSAGE_VERSION = 0
 
     _STRUCT = struct.Struct('<B3xL3ff')
@@ -1188,13 +1188,13 @@ def __init__(self):
         self.flags = 0
 
         ##
-        # The measured YPR vector (in degrees), resolved in the ENU frame, after applying horizontal (yaw) and vertical
-        # (pitch) bias corrections.
+        # The measured vehicle body orientation (in degrees), after applying horizontal (yaw) and vertical (pitch)
+        # offset corrections.
         self.ypr_deg = np.full((3,), np.nan)
 
         ##
         # The heading angle (in degrees) with respect to true north, pointing from the primary antenna to the secondary
-        # antenna, after applying bias corrections.
+        # antenna, after applying offset corrections.
         #
         # @note
         # Reported in the range [0, 360).
@@ -1249,7 +1249,7 @@ def __repr__(self):
 
     def __str__(self):
         return f"""\
-Heading Output @ {str(self.details.p1_time)}
+GNSS Heading Output @ {str(self.details.p1_time)}
   Solution Type: {self.solution_type}
   YPR (ENU) (deg): {self.ypr_deg[0]:.2f}, {self.ypr_deg[1]:.2f}, {self.ypr_deg[2]:.2f}
   Heading (deg): {self.heading_true_north_deg:.2f}"""
@@ -1259,7 +1259,7 @@ def calcsize(cls) -> int:
         return cls._STRUCT.size + MeasurementDetails.calcsize()
 
     @classmethod
-    def to_numpy(cls, messages: Sequence['HeadingOutput']):
+    def to_numpy(cls, messages: Sequence['GNSSHeadingOutput']):
         result = {
             'solution_type': np.array([int(m.solution_type) for m in messages], dtype=int),
             'flags': np.array([int(m.flags) for m in messages], dtype=np.uint32),
@@ -1270,11 +1270,11 @@ def to_numpy(cls, messages: Sequence['HeadingOutput']):
         return result
 
 
-class RawHeadingOutput(MessagePayload):
+class RawGNSSHeadingOutput(MessagePayload):
     """!
-    @brief Raw (uncorrected) heading sensor measurement output.
+    @brief Raw (uncorrected) GNSS heading sensor measurement output.
     """
-    MESSAGE_TYPE = MessageType.RAW_HEADING_OUTPUT
+    MESSAGE_TYPE = MessageType.RAW_GNSS_HEADING_OUTPUT
     MESSAGE_VERSION = 0
 
     _STRUCT = struct.Struct('<B3xL3f3fff')
@@ -1367,7 +1367,7 @@ def __repr__(self):
 
     def __str__(self):
         return f"""\
-Raw Heading Output @ {str(self.details.p1_time)}
+Raw GNSS Heading Output @ {str(self.details.p1_time)}
   Solution Type: {self.solution_type}
   Relative position (ENU) (m): {self.relative_position_enu_m[0]:.2f}, {self.relative_position_enu_m[1]:.2f}, {self.relative_position_enu_m[2]:.2f}
   Position std (ENU) (m): {self.position_std_enu_m[0]:.2f}, {self.position_std_enu_m[1]:.2f}, {self.position_std_enu_m[2]:.2f}
@@ -1379,7 +1379,7 @@ def calcsize(cls) -> int:
         return cls._STRUCT.size + MeasurementDetails.calcsize()
 
     @classmethod
-    def to_numpy(cls, messages: Sequence['RawHeadingOutput']):
+    def to_numpy(cls, messages: Sequence['RawGNSSHeadingOutput']):
         result = {
             'solution_type': np.array([int(m.solution_type) for m in messages], dtype=int),
             'flags': np.array([int(m.flags) for m in messages], dtype=np.uint32),
diff --git a/src/point_one/fusion_engine/messages/configuration.h b/src/point_one/fusion_engine/messages/configuration.h
index f73cee94..b3bb010f 100644
--- a/src/point_one/fusion_engine/messages/configuration.h
+++ b/src/point_one/fusion_engine/messages/configuration.h
@@ -1222,7 +1222,7 @@ struct P1_ALIGNAS(4) HardwareTickConfig {
  * If one value is NOT set, the system will not output the corrected
  * heading message.
  *
- * @ref HeadingOutput
+ * @ref GNSSHeadingOutput
  */
 struct P1_ALIGNAS(4) HeadingBias {
   /**
diff --git a/src/point_one/fusion_engine/messages/defs.h b/src/point_one/fusion_engine/messages/defs.h
index 26e964a4..7e7df482 100644
--- a/src/point_one/fusion_engine/messages/defs.h
+++ b/src/point_one/fusion_engine/messages/defs.h
@@ -47,9 +47,9 @@ enum class MessageType : uint16_t {
 
   // Sensor measurement messages.
   IMU_OUTPUT = 11000, ///< @ref IMUOutput
-  RAW_HEADING_OUTPUT = 11001, ///< @ref RawHeadingOutput
+  RAW_GNSS_HEADING_OUTPUT = 11001, ///< @ref RawGNSSHeadingOutput
   RAW_IMU_OUTPUT = 11002, ///< @ref RawIMUOutput
-  HEADING_OUTPUT = 11003, ///< @ref HeadingOutput
+  GNSS_HEADING_OUTPUT = 11003, ///< @ref GNSSHeadingOutput
   IMU_INPUT = 11004, ///< @ref IMUInput
 
   // Vehicle measurement messages.
@@ -151,14 +151,14 @@ P1_CONSTEXPR_FUNC const char* to_string(MessageType type) {
     case MessageType::IMU_OUTPUT:
       return "IMU Output";
 
-    case MessageType::RAW_HEADING_OUTPUT:
-      return "Raw heading output";
+    case MessageType::RAW_GNSS_HEADING_OUTPUT:
+      return "Raw GNSS Heading Output";
 
     case MessageType::RAW_IMU_OUTPUT:
       return "Raw IMU Output";
 
-    case MessageType::HEADING_OUTPUT:
-      return "Heading Output";
+    case MessageType::GNSS_HEADING_OUTPUT:
+      return "GNSS Heading Output";
 
     case MessageType::IMU_INPUT:
       return "IMU Input";
@@ -320,6 +320,7 @@ P1_CONSTEXPR_FUNC bool IsCommand(MessageType message_type) {
     case MessageType::GET_MESSAGE_RATE:
     case MessageType::STA5635_COMMAND:
       return true;
+
     case MessageType::INVALID:
     case MessageType::POSE:
     case MessageType::GNSS_INFO:
@@ -329,9 +330,9 @@ P1_CONSTEXPR_FUNC bool IsCommand(MessageType message_type) {
     case MessageType::RELATIVE_ENU_POSITION:
     case MessageType::SYSTEM_STATUS:
     case MessageType::IMU_OUTPUT:
-    case MessageType::RAW_HEADING_OUTPUT:
+    case MessageType::RAW_GNSS_HEADING_OUTPUT:
     case MessageType::RAW_IMU_OUTPUT:
-    case MessageType::HEADING_OUTPUT:
+    case MessageType::GNSS_HEADING_OUTPUT:
     case MessageType::IMU_INPUT:
     case MessageType::DEPRECATED_WHEEL_SPEED_MEASUREMENT:
     case MessageType::DEPRECATED_VEHICLE_SPEED_MEASUREMENT:
diff --git a/src/point_one/fusion_engine/messages/measurements.h b/src/point_one/fusion_engine/messages/measurements.h
index 8d7e832e..22b1e113 100644
--- a/src/point_one/fusion_engine/messages/measurements.h
+++ b/src/point_one/fusion_engine/messages/measurements.h
@@ -1138,19 +1138,29 @@ struct P1_ALIGNAS(4) DeprecatedVehicleSpeedMeasurement : public MessagePayload {
 ////////////////////////////////////////////////////////////////////////////////
 
 /**
- * @brief Heading sensor measurement output with heading bias corrections
- *        applied (@ref MessageType::HEADING_OUTPUT, version 1.0).
+ * @brief Multi-antenna GNSS heading sensor measurement output with offset
+ *        corrections applied (@ref MessageType::GNSS_HEADING_OUTPUT, version
+ *        1.0).
  * @ingroup measurement_messages
  *
- * This message is an output from the device contaning heading sensor
- * measurements after applying user-specified horizontal and vertical bias
- * corrections to account for the orientation of the primary and secondary GNSS
- * antennas.
+ * This message is an output from the device contaning heading/orientation
+ * measurements generated using multiple GNSS antennas/receivers. On supported
+ * devices, the device will measure vehicle yaw (heading) and pitch based on the
+ * relative positions of two GNSS antennas. When more than two antennas are
+ * present, the device may additionally measure roll angle.
  *
- * See also @ref RawHeadingOutput.
+ * @note
+ * This message contains vehicle body angle measurements generated from GNSS
+ * measurements. These measurements inputs to the navigation engine, not the
+ * filtered output from engine. They may be less accurate than the vehicle body
+ * orientation estimate in @ref PoseMessage.
+ *
+ * The measurements in this message have user-specified corrections applied for
+ * the horizontal and vertical offsets between the two GNSS antennas. See also
+ * @ref RawGNSSHeadingOutput.
  */
-struct P1_ALIGNAS(4) HeadingOutput : public MessagePayload {
-  static constexpr MessageType MESSAGE_TYPE = MessageType::HEADING_OUTPUT;
+struct P1_ALIGNAS(4) GNSSHeadingOutput : public MessagePayload {
+  static constexpr MessageType MESSAGE_TYPE = MessageType::GNSS_HEADING_OUTPUT;
   static constexpr uint8_t MESSAGE_VERSION = 0;
 
   /**
@@ -1171,25 +1181,22 @@ struct P1_ALIGNAS(4) HeadingOutput : public MessagePayload {
   uint32_t flags = 0;
 
   /**
-   * The measured YPR vector (in degrees), resolved in the ENU frame.
+   * The measured vehicle body orientation (in degrees).
    *
    * YPR is defined as an intrinsic Euler-321 rotation, i.e., yaw, pitch, then
-   * roll.
+   * roll with respect to the local ENU tangent plane. See @ref
+   * PoseMessage::ypr_deg for a complete rotation definition.
    *
-   * @note
-   * This field contains the measured attitude information (@ref
-   * RawHeadingOutput) from a secondary heading device after applying @ref
-   * ConfigType::HEADING_BIAS configuration settings for yaw (horizontal) and
-   * pitch (vertical) offsets between the primary and secondary GNSS antennas.
-   * If either bias value is not specified, the corresponding measurement values
-   * will be set to `NAN`.
+   * If any angles are not available, they will be set to `NAN`. For
+   * dual-antenna systems, the device will measure yaw and pitch, but not roll.
    */
   float ypr_deg[3] = {NAN, NAN, NAN};
 
   /**
    * The heading angle (in degrees) with respect to true north, pointing from
-   * the primary antenna to the secondary  antenna, after applying bias
-   * corrections.
+   * the primary antenna to the secondary antenna.
+   *
+   * The reported angle includes the user-specified heading offset correction.
    *
    * @note
    * Reported in the range [0, 360).
@@ -1198,17 +1205,22 @@ struct P1_ALIGNAS(4) HeadingOutput : public MessagePayload {
 };
 
 /**
- * @brief Raw (uncorrected) heading sensor measurement output (@ref
- *        MessageType::RAW_HEADING_OUTPUT, version 1.0).
+ * @brief Raw (uncorrected) GNSS heading sensor measurement output (@ref
+ *        MessageType::RAW_GNSS_HEADING_OUTPUT, version 1.0).
  * @ingroup measurement_messages
  *
- * This message is an output from the device contaning raw heading sensor
- * measurements that have not been corrected for mounting angle biases.
+ * This message is an output from the device contaning raw orientation
+ * measurements generated using multiple GNSS antennas/receivers that have not
+ * been corrected for horizontal/vertical offsets between the antennas. Here,
+ * orientation is represented as the vector from a primary GNSS antenna to a
+ * secondary GNSS antenna.
  *
- * See also @ref HeadingOutput.
+ * For vehicle body angle measurements, and for measurements corrected for
+ * horizontal/vertical offsets, see @ref GNSSHeadingOutput.
  */
-struct P1_ALIGNAS(4) RawHeadingOutput : public MessagePayload {
-  static constexpr MessageType MESSAGE_TYPE = MessageType::RAW_HEADING_OUTPUT;
+struct P1_ALIGNAS(4) RawGNSSHeadingOutput : public MessagePayload {
+  static constexpr MessageType MESSAGE_TYPE =
+      MessageType::RAW_GNSS_HEADING_OUTPUT;
   static constexpr uint8_t MESSAGE_VERSION = 0;
 
   /**

From 43a633c05a69714a22a86c668b964a381987322e Mon Sep 17 00:00:00 2001
From: Adam Shapiro <adam@pointonenav.com>
Date: Mon, 2 Dec 2024 11:56:30 -0500
Subject: [PATCH 03/12] Minor P1 time description cleanup.

---
 src/point_one/fusion_engine/messages/device.h   | 5 -----
 src/point_one/fusion_engine/messages/solution.h | 8 +-------
 2 files changed, 1 insertion(+), 12 deletions(-)

diff --git a/src/point_one/fusion_engine/messages/device.h b/src/point_one/fusion_engine/messages/device.h
index 56c3e497..d4fdda71 100644
--- a/src/point_one/fusion_engine/messages/device.h
+++ b/src/point_one/fusion_engine/messages/device.h
@@ -286,11 +286,6 @@ struct P1_ALIGNAS(4) EventNotificationMessage : public MessagePayload {
  * @brief System status information (@ref
  *        MessageType::SYSTEM_STATUS, version 1.0).
  * @ingroup device_status
- *
- * @note
- * All data is timestamped using the Point One Time, which is a monotonic
- * timestamp referenced to the start of the device. Corresponding messages (@ref
- * SystemStatusMessage) may be associated using their @ref p1_time values.
  */
 
 struct P1_ALIGNAS(4) SystemStatusMessage : public MessagePayload {
diff --git a/src/point_one/fusion_engine/messages/solution.h b/src/point_one/fusion_engine/messages/solution.h
index 02dc1a01..0aac8e73 100644
--- a/src/point_one/fusion_engine/messages/solution.h
+++ b/src/point_one/fusion_engine/messages/solution.h
@@ -32,7 +32,7 @@ namespace messages {
  * @ingroup solution_messages
  *
  * @note
- * All data is timestamped using the Point One Time, which is a monotonic
+ * All data is timestamped using Point One (P1) time, which is a monotonic
  * timestamp referenced to the start of the device. Corresponding messages (@ref
  * GNSSInfoMessage, @ref GNSSSatelliteMessage, etc.) may be associated using
  * their @ref p1_time values.
@@ -502,12 +502,6 @@ struct P1_ALIGNAS(4) CalibrationStatusMessage : public MessagePayload {
  * @brief Relative ENU position to base station (@ref
  *        MessageType::RELATIVE_ENU_POSITION, version 1.1).
  * @ingroup solution_messages
- *
- * @note
- * All data is timestamped using the Point One Time, which is a monotonic
- * timestamp referenced to the start of the device. Corresponding messages (@ref
- * PoseMessage, @ref GNSSSatelliteMessage, etc.) may be associated using
- * their @ref p1_time values.
  */
 struct P1_ALIGNAS(4) RelativeENUPositionMessage : public MessagePayload {
   static constexpr MessageType MESSAGE_TYPE =

From 702ebd077c5c24796db3a71afb468ec3062a719f Mon Sep 17 00:00:00 2001
From: Adam Shapiro <adam@pointonenav.com>
Date: Mon, 2 Dec 2024 12:00:02 -0500
Subject: [PATCH 04/12] Added a note about RelativeENUPositionMessage vs
 GNSSHeadingOutput.

---
 python/fusion_engine_client/messages/solution.py | 6 ++++++
 src/point_one/fusion_engine/messages/solution.h  | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/python/fusion_engine_client/messages/solution.py b/python/fusion_engine_client/messages/solution.py
index efaafa18..c607ebc5 100644
--- a/python/fusion_engine_client/messages/solution.py
+++ b/python/fusion_engine_client/messages/solution.py
@@ -813,6 +813,12 @@ def to_numpy(cls, messages: Sequence['CalibrationStatus']):
 class RelativeENUPositionMessage(MessagePayload):
     """!
     @brief Relative ENU position to base station.
+
+    @note
+    This message represents the relationship between the navigation engine's
+    position solution and a nearby RTK base station. It is not used to convey
+    unfiltered vehicle body orientation measurements generated using multiple
+    GNSS antennas. See @ref GNSSHeadingOutput instead.
     """
     MESSAGE_TYPE = MessageType.RELATIVE_ENU_POSITION
     MESSAGE_VERSION = 0
diff --git a/src/point_one/fusion_engine/messages/solution.h b/src/point_one/fusion_engine/messages/solution.h
index 0aac8e73..956da115 100644
--- a/src/point_one/fusion_engine/messages/solution.h
+++ b/src/point_one/fusion_engine/messages/solution.h
@@ -502,6 +502,12 @@ struct P1_ALIGNAS(4) CalibrationStatusMessage : public MessagePayload {
  * @brief Relative ENU position to base station (@ref
  *        MessageType::RELATIVE_ENU_POSITION, version 1.1).
  * @ingroup solution_messages
+ *
+ * @note
+ * This message represents the relationship between the navigation engine's
+ * position solution and a nearby RTK base station. It is not used to convey
+ * unfiltered vehicle body orientation measurements generated using multiple
+ * GNSS antennas. See @ref GNSSHeadingOutput instead.
  */
 struct P1_ALIGNAS(4) RelativeENUPositionMessage : public MessagePayload {
   static constexpr MessageType MESSAGE_TYPE =

From 29df29537812c74e609e0830e5275a7a6043524e Mon Sep 17 00:00:00 2001
From: Adam Shapiro <adam@pointonenav.com>
Date: Mon, 2 Dec 2024 17:18:39 -0500
Subject: [PATCH 05/12] Renamed GNSSHeadingOutput -> GNSSAttitudeOutput.

---
 .../fusion_engine_client/analysis/analyzer.py | 24 +++++++-------
 python/fusion_engine_client/messages/defs.py  |  4 +--
 .../messages/measurements.py                  | 22 ++++++-------
 .../fusion_engine_client/messages/solution.py |  2 +-
 .../fusion_engine/messages/configuration.h    |  2 +-
 src/point_one/fusion_engine/messages/defs.h   | 17 +++++-----
 .../fusion_engine/messages/measurements.h     | 32 +++++++++----------
 .../fusion_engine/messages/solution.h         |  2 +-
 8 files changed, 53 insertions(+), 52 deletions(-)

diff --git a/python/fusion_engine_client/analysis/analyzer.py b/python/fusion_engine_client/analysis/analyzer.py
index 17078158..3f4eb570 100755
--- a/python/fusion_engine_client/analysis/analyzer.py
+++ b/python/fusion_engine_client/analysis/analyzer.py
@@ -1943,24 +1943,24 @@ def _plot_imu_data(self, message_cls, filename, figure_title):
 
         self._add_figure(name=filename, figure=figure, title=figure_title)
 
-    def plot_gnss_heading_measurements(self):
+    def plot_gnss_attitude_measurements(self):
         """!
-        @brief Generate time series plots for GNSS heading (degrees) and baseline distance (meters) data.
+        @brief Generate time series plots for GNSS attitude (degrees) and baseline distance (meters) data.
         """
         if self.output_dir is None:
             return
 
-        # Read the heading measurement data.
-        result = self.reader.read(message_types=[RawGNSSHeadingOutput, GNSSHeadingOutput], **self.params)
-        raw_heading_data = result[RawGNSSHeadingOutput.MESSAGE_TYPE]
-        heading_data = result[GNSSHeadingOutput.MESSAGE_TYPE]
+        # Read the attitude measurement data.
+        result = self.reader.read(message_types=[RawGNSSAttitudeOutput, GNSSAttitudeOutput], **self.params)
+        raw_heading_data = result[RawGNSSAttitudeOutput.MESSAGE_TYPE]
+        heading_data = result[GNSSAttitudeOutput.MESSAGE_TYPE]
 
         if (len(heading_data.p1_time) == 0) and (len(raw_heading_data.p1_time) == 0):
-            self.logger.info('No GNSS heading measurement data available. Skipping plot.')
+            self.logger.info('No GNSS attitude measurement data available. Skipping plot.')
             return
 
-        # Note that we read the pose data after heading, that way we don't bother reading pose data from disk if there's
-        # no heading data in the log.
+        # Note that we read the pose data after attitude, that way we don't bother reading pose data from disk if
+        # there's no heading data in the log.
         result = self.reader.read(message_types=[PoseMessage], source_ids=self.default_source_id, **self.params)
         primary_pose_data = result[PoseMessage.MESSAGE_TYPE]
 
@@ -2187,7 +2187,7 @@ def plot_gnss_heading_measurements(self):
                 row=3, col=1
             )
 
-        self._add_figure(name='gnss_heading_measurement', figure=fig, title='Measurements: GNSS Heading')
+        self._add_figure(name='gnss_attitude_measurement', figure=fig, title='Measurements: GNSS Attitude')
 
     def plot_system_status_profiling(self):
         """!
@@ -3001,9 +3001,9 @@ def main(args=None):
         analyzer.plot_gnss_corrections_status()
         analyzer.plot_dop()
 
-        # By default, we always plot heading measurements (i.e., output from a secondary heading device like an
+        # By default, we always plot attitude measurements (i.e., output from a secondary GNSS attitude sensor like an
         # LG69T-AH), separate from other sensor measurements controlled by --measurements.
-        analyzer.plot_gnss_heading_measurements()
+        analyzer.plot_gnss_attitude_measurements()
 
         if truth_lla_deg is not None:
             analyzer.plot_stationary_position_error(truth_lla_deg)
diff --git a/python/fusion_engine_client/messages/defs.py b/python/fusion_engine_client/messages/defs.py
index 49429d9d..23bd6904 100644
--- a/python/fusion_engine_client/messages/defs.py
+++ b/python/fusion_engine_client/messages/defs.py
@@ -99,9 +99,9 @@ class MessageType(IntEnum):
 
     # Sensor measurement messages.
     IMU_OUTPUT = 11000
-    RAW_GNSS_HEADING_OUTPUT = 11001
+    RAW_GNSS_ATTITUDE_OUTPUT = 11001
     RAW_IMU_OUTPUT = 11002
-    GNSS_HEADING_OUTPUT = 11003
+    GNSS_ATTITUDE_OUTPUT = 11003
     IMU_INPUT = 11004
 
     # Vehicle measurement messages.
diff --git a/python/fusion_engine_client/messages/measurements.py b/python/fusion_engine_client/messages/measurements.py
index ac6dd533..bf831924 100644
--- a/python/fusion_engine_client/messages/measurements.py
+++ b/python/fusion_engine_client/messages/measurements.py
@@ -1169,11 +1169,11 @@ def to_numpy(cls, messages):
 ################################################################################
 
 
-class GNSSHeadingOutput(MessagePayload):
+class GNSSAttitudeOutput(MessagePayload):
     """!
-    @brief Multi-antenna GNSS heading sensor measurement output with offset corrections applied.
+    @brief Multi-antenna GNSS attitude sensor measurement output with offset corrections applied.
     """
-    MESSAGE_TYPE = MessageType.GNSS_HEADING_OUTPUT
+    MESSAGE_TYPE = MessageType.GNSS_ATTITUDE_OUTPUT
     MESSAGE_VERSION = 0
 
     _STRUCT = struct.Struct('<B3xL3ff')
@@ -1249,7 +1249,7 @@ def __repr__(self):
 
     def __str__(self):
         return f"""\
-GNSS Heading Output @ {str(self.details.p1_time)}
+GNSS Attitude Output @ {str(self.details.p1_time)}
   Solution Type: {self.solution_type}
   YPR (ENU) (deg): {self.ypr_deg[0]:.2f}, {self.ypr_deg[1]:.2f}, {self.ypr_deg[2]:.2f}
   Heading (deg): {self.heading_true_north_deg:.2f}"""
@@ -1259,7 +1259,7 @@ def calcsize(cls) -> int:
         return cls._STRUCT.size + MeasurementDetails.calcsize()
 
     @classmethod
-    def to_numpy(cls, messages: Sequence['GNSSHeadingOutput']):
+    def to_numpy(cls, messages: Sequence['GNSSAttitudeOutput']):
         result = {
             'solution_type': np.array([int(m.solution_type) for m in messages], dtype=int),
             'flags': np.array([int(m.flags) for m in messages], dtype=np.uint32),
@@ -1270,11 +1270,11 @@ def to_numpy(cls, messages: Sequence['GNSSHeadingOutput']):
         return result
 
 
-class RawGNSSHeadingOutput(MessagePayload):
+class RawGNSSAttitudeOutput(MessagePayload):
     """!
-    @brief Raw (uncorrected) GNSS heading sensor measurement output.
+    @brief Raw (uncorrected) GNSS attitude sensor measurement output.
     """
-    MESSAGE_TYPE = MessageType.RAW_GNSS_HEADING_OUTPUT
+    MESSAGE_TYPE = MessageType.RAW_GNSS_ATTITUDE_OUTPUT
     MESSAGE_VERSION = 0
 
     _STRUCT = struct.Struct('<B3xL3f3fff')
@@ -1283,7 +1283,7 @@ def __init__(self):
         ## Measurement timestamps, if available. See @ref measurement_messages.
         self.details = MeasurementDetails()
 
-        ## Set to @ref SolutionType::RTKFixed when heading is available, or @ref SolutionType::Invalid otherwise.
+        ## Set to @ref SolutionType::RTKFixed when attitude is available, or @ref SolutionType::Invalid otherwise.
         self.solution_type = SolutionType.Invalid
         ## A bitmask of flags associated with the solution.
         self.flags = 0
@@ -1367,7 +1367,7 @@ def __repr__(self):
 
     def __str__(self):
         return f"""\
-Raw GNSS Heading Output @ {str(self.details.p1_time)}
+Raw GNSS Attitude Output @ {str(self.details.p1_time)}
   Solution Type: {self.solution_type}
   Relative position (ENU) (m): {self.relative_position_enu_m[0]:.2f}, {self.relative_position_enu_m[1]:.2f}, {self.relative_position_enu_m[2]:.2f}
   Position std (ENU) (m): {self.position_std_enu_m[0]:.2f}, {self.position_std_enu_m[1]:.2f}, {self.position_std_enu_m[2]:.2f}
@@ -1379,7 +1379,7 @@ def calcsize(cls) -> int:
         return cls._STRUCT.size + MeasurementDetails.calcsize()
 
     @classmethod
-    def to_numpy(cls, messages: Sequence['RawGNSSHeadingOutput']):
+    def to_numpy(cls, messages: Sequence['RawGNSSAttitudeOutput']):
         result = {
             'solution_type': np.array([int(m.solution_type) for m in messages], dtype=int),
             'flags': np.array([int(m.flags) for m in messages], dtype=np.uint32),
diff --git a/python/fusion_engine_client/messages/solution.py b/python/fusion_engine_client/messages/solution.py
index c607ebc5..e6b910be 100644
--- a/python/fusion_engine_client/messages/solution.py
+++ b/python/fusion_engine_client/messages/solution.py
@@ -818,7 +818,7 @@ class RelativeENUPositionMessage(MessagePayload):
     This message represents the relationship between the navigation engine's
     position solution and a nearby RTK base station. It is not used to convey
     unfiltered vehicle body orientation measurements generated using multiple
-    GNSS antennas. See @ref GNSSHeadingOutput instead.
+    GNSS antennas. See @ref GNSSAttitudeOutput instead.
     """
     MESSAGE_TYPE = MessageType.RELATIVE_ENU_POSITION
     MESSAGE_VERSION = 0
diff --git a/src/point_one/fusion_engine/messages/configuration.h b/src/point_one/fusion_engine/messages/configuration.h
index b3bb010f..042160d6 100644
--- a/src/point_one/fusion_engine/messages/configuration.h
+++ b/src/point_one/fusion_engine/messages/configuration.h
@@ -1222,7 +1222,7 @@ struct P1_ALIGNAS(4) HardwareTickConfig {
  * If one value is NOT set, the system will not output the corrected
  * heading message.
  *
- * @ref GNSSHeadingOutput
+ * @ref GNSSAttitudeOutput
  */
 struct P1_ALIGNAS(4) HeadingBias {
   /**
diff --git a/src/point_one/fusion_engine/messages/defs.h b/src/point_one/fusion_engine/messages/defs.h
index 7e7df482..bcf22dd1 100644
--- a/src/point_one/fusion_engine/messages/defs.h
+++ b/src/point_one/fusion_engine/messages/defs.h
@@ -47,9 +47,10 @@ enum class MessageType : uint16_t {
 
   // Sensor measurement messages.
   IMU_OUTPUT = 11000, ///< @ref IMUOutput
-  RAW_GNSS_HEADING_OUTPUT = 11001, ///< @ref RawGNSSHeadingOutput
+  RAW_GNSS_ATTITUDE_OUTPUT = 11001, ///< @ref RawGNSSAttitudeOutput
   RAW_IMU_OUTPUT = 11002, ///< @ref RawIMUOutput
-  GNSS_HEADING_OUTPUT = 11003, ///< @ref GNSSHeadingOutput
+  // TODO Change the numbers
+  GNSS_ATTITUDE_OUTPUT = 11003, ///< @ref GNSSAttitudeOutput
   IMU_INPUT = 11004, ///< @ref IMUInput
 
   // Vehicle measurement messages.
@@ -151,14 +152,14 @@ P1_CONSTEXPR_FUNC const char* to_string(MessageType type) {
     case MessageType::IMU_OUTPUT:
       return "IMU Output";
 
-    case MessageType::RAW_GNSS_HEADING_OUTPUT:
-      return "Raw GNSS Heading Output";
+    case MessageType::RAW_GNSS_ATTITUDE_OUTPUT:
+      return "Raw GNSS Attitude Output";
 
     case MessageType::RAW_IMU_OUTPUT:
       return "Raw IMU Output";
 
-    case MessageType::GNSS_HEADING_OUTPUT:
-      return "GNSS Heading Output";
+    case MessageType::GNSS_ATTITUDE_OUTPUT:
+      return "GNSS Attitude Output";
 
     case MessageType::IMU_INPUT:
       return "IMU Input";
@@ -330,9 +331,9 @@ P1_CONSTEXPR_FUNC bool IsCommand(MessageType message_type) {
     case MessageType::RELATIVE_ENU_POSITION:
     case MessageType::SYSTEM_STATUS:
     case MessageType::IMU_OUTPUT:
-    case MessageType::RAW_GNSS_HEADING_OUTPUT:
+    case MessageType::RAW_GNSS_ATTITUDE_OUTPUT:
     case MessageType::RAW_IMU_OUTPUT:
-    case MessageType::GNSS_HEADING_OUTPUT:
+    case MessageType::GNSS_ATTITUDE_OUTPUT:
     case MessageType::IMU_INPUT:
     case MessageType::DEPRECATED_WHEEL_SPEED_MEASUREMENT:
     case MessageType::DEPRECATED_VEHICLE_SPEED_MEASUREMENT:
diff --git a/src/point_one/fusion_engine/messages/measurements.h b/src/point_one/fusion_engine/messages/measurements.h
index 22b1e113..d7f74bb0 100644
--- a/src/point_one/fusion_engine/messages/measurements.h
+++ b/src/point_one/fusion_engine/messages/measurements.h
@@ -1134,20 +1134,20 @@ struct P1_ALIGNAS(4) DeprecatedVehicleSpeedMeasurement : public MessagePayload {
 };
 
 ////////////////////////////////////////////////////////////////////////////////
-// Heading Sensor Definitions
+// Attitude Sensor Definitions
 ////////////////////////////////////////////////////////////////////////////////
 
 /**
- * @brief Multi-antenna GNSS heading sensor measurement output with offset
- *        corrections applied (@ref MessageType::GNSS_HEADING_OUTPUT, version
+ * @brief Multi-antenna GNSS attitude sensor measurement output with offset
+ *        corrections applied (@ref MessageType::GNSS_ATTITUDE_OUTPUT, version
  *        1.0).
  * @ingroup measurement_messages
  *
- * This message is an output from the device contaning heading/orientation
- * measurements generated using multiple GNSS antennas/receivers. On supported
- * devices, the device will measure vehicle yaw (heading) and pitch based on the
- * relative positions of two GNSS antennas. When more than two antennas are
- * present, the device may additionally measure roll angle.
+ * This message is an output from the device contaning orientation measurements
+ * generated using multiple GNSS antennas/receivers. On supported devices, the
+ * device will measure vehicle yaw (heading) and pitch based on the relative
+ * positions of two GNSS antennas. When more than two antennas are present, the
+ * device may additionally measure roll angle.
  *
  * @note
  * This message contains vehicle body angle measurements generated from GNSS
@@ -1157,10 +1157,10 @@ struct P1_ALIGNAS(4) DeprecatedVehicleSpeedMeasurement : public MessagePayload {
  *
  * The measurements in this message have user-specified corrections applied for
  * the horizontal and vertical offsets between the two GNSS antennas. See also
- * @ref RawGNSSHeadingOutput.
+ * @ref RawGNSSAttitudeOutput.
  */
-struct P1_ALIGNAS(4) GNSSHeadingOutput : public MessagePayload {
-  static constexpr MessageType MESSAGE_TYPE = MessageType::GNSS_HEADING_OUTPUT;
+struct P1_ALIGNAS(4) GNSSAttitudeOutput : public MessagePayload {
+  static constexpr MessageType MESSAGE_TYPE = MessageType::GNSS_ATTITUDE_OUTPUT;
   static constexpr uint8_t MESSAGE_VERSION = 0;
 
   /**
@@ -1205,8 +1205,8 @@ struct P1_ALIGNAS(4) GNSSHeadingOutput : public MessagePayload {
 };
 
 /**
- * @brief Raw (uncorrected) GNSS heading sensor measurement output (@ref
- *        MessageType::RAW_GNSS_HEADING_OUTPUT, version 1.0).
+ * @brief Raw (uncorrected) GNSS attitude sensor measurement output (@ref
+ *        MessageType::RAW_GNSS_ATTITUDE_OUTPUT, version 1.0).
  * @ingroup measurement_messages
  *
  * This message is an output from the device contaning raw orientation
@@ -1216,11 +1216,11 @@ struct P1_ALIGNAS(4) GNSSHeadingOutput : public MessagePayload {
  * secondary GNSS antenna.
  *
  * For vehicle body angle measurements, and for measurements corrected for
- * horizontal/vertical offsets, see @ref GNSSHeadingOutput.
+ * horizontal/vertical offsets, see @ref GNSSAttitudeOutput.
  */
-struct P1_ALIGNAS(4) RawGNSSHeadingOutput : public MessagePayload {
+struct P1_ALIGNAS(4) RawGNSSAttitudeOutput : public MessagePayload {
   static constexpr MessageType MESSAGE_TYPE =
-      MessageType::RAW_GNSS_HEADING_OUTPUT;
+      MessageType::RAW_GNSS_ATTITUDE_OUTPUT;
   static constexpr uint8_t MESSAGE_VERSION = 0;
 
   /**
diff --git a/src/point_one/fusion_engine/messages/solution.h b/src/point_one/fusion_engine/messages/solution.h
index 956da115..f66422d8 100644
--- a/src/point_one/fusion_engine/messages/solution.h
+++ b/src/point_one/fusion_engine/messages/solution.h
@@ -507,7 +507,7 @@ struct P1_ALIGNAS(4) CalibrationStatusMessage : public MessagePayload {
  * This message represents the relationship between the navigation engine's
  * position solution and a nearby RTK base station. It is not used to convey
  * unfiltered vehicle body orientation measurements generated using multiple
- * GNSS antennas. See @ref GNSSHeadingOutput instead.
+ * GNSS antennas. See @ref GNSSAttitudeOutput instead.
  */
 struct P1_ALIGNAS(4) RelativeENUPositionMessage : public MessagePayload {
   static constexpr MessageType MESSAGE_TYPE =

From 92b3b5b63a6c78cbe91dae34c91db932d25a93c3 Mon Sep 17 00:00:00 2001
From: Adam Shapiro <adam@pointonenav.com>
Date: Mon, 2 Dec 2024 18:27:02 -0500
Subject: [PATCH 06/12] Added Python yaw/heading helper functions.

---
 python/fusion_engine_client/messages/defs.py | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/python/fusion_engine_client/messages/defs.py b/python/fusion_engine_client/messages/defs.py
index 23bd6904..63e53ad8 100644
--- a/python/fusion_engine_client/messages/defs.py
+++ b/python/fusion_engine_client/messages/defs.py
@@ -785,3 +785,11 @@ def PackedDataToBuffer(packed_data: bytes, buffer: Optional[bytes] = None, offse
         return buffer
     else:
         return len(packed_data)
+
+
+def yaw_to_heading(yaw_deg: Union[float, np.ndarray]):
+    return 90.0 - yaw_deg
+
+
+def heading_to_yaw(heading_deg: Union[float, np.ndarray]):
+    return 90.0 - heading_deg

From aebbc45542390786254caaac5476fcb9b20aa473 Mon Sep 17 00:00:00 2001
From: Adam Shapiro <adam@pointonenav.com>
Date: Mon, 2 Dec 2024 18:28:15 -0500
Subject: [PATCH 07/12] Redefined GNSS attitude messages and deprecated old
 IDs.

- Removed redundant heading convenience fields (compute from the ENU vector or
yaw)
- Added YPR std dev
- Added baseline distance std dev
- Compute heading angle as needed in Analyzer
---
 .../fusion_engine_client/analysis/analyzer.py | 14 ++--
 python/fusion_engine_client/messages/defs.py  |  6 +-
 .../messages/measurements.py                  | 64 ++++++++++---------
 src/point_one/fusion_engine/messages/defs.h   | 27 +++++---
 .../fusion_engine/messages/measurements.h     | 30 ++++-----
 5 files changed, 78 insertions(+), 63 deletions(-)

diff --git a/python/fusion_engine_client/analysis/analyzer.py b/python/fusion_engine_client/analysis/analyzer.py
index 3f4eb570..c9e68878 100755
--- a/python/fusion_engine_client/analysis/analyzer.py
+++ b/python/fusion_engine_client/analysis/analyzer.py
@@ -2012,10 +2012,11 @@ def plot_gnss_attitude_measurements(self):
         # Corrected heading plot
         if len(heading_data.p1_time) > 0:
             heading_time = heading_data.p1_time - float(self.t0)
+            heading_deg = 90.0 - heading_data.ypr_deg[0, :]
             fig.add_trace(
                 go.Scatter(
                     x=heading_time,
-                    y=heading_data.heading_true_north_deg,
+                    y=heading_deg,
                     customdata=heading_data.p1_time,
                     mode='markers',
                     marker={'size': 2, "color": "green"},
@@ -2030,6 +2031,9 @@ def plot_gnss_attitude_measurements(self):
         # Uncorrected heading plot
         if len(raw_heading_data.p1_time) > 0:
             raw_heading_time = raw_heading_data.p1_time - float(self.t0)
+            raw_heading_deg = np.degrees(np.arctan2(raw_heading_data.relative_position_enu_m[1, :],
+                                                    raw_heading_data.relative_position_enu_m[0, :]))
+
             # Compute heading uncertainty envelop.
             denom = raw_heading_data.relative_position_enu_m[0]**2 + raw_heading_data.relative_position_enu_m[1]**2
             dh_e = raw_heading_data.relative_position_enu_m[0] / denom
@@ -2047,7 +2051,7 @@ def plot_gnss_attitude_measurements(self):
             fig.add_trace(
                 go.Scatter(
                     x=raw_heading_time,
-                    y=raw_heading_data.heading_true_north_deg,
+                    y=raw_heading_deg,
                     customdata=raw_heading_data.p1_time,
                     mode='markers',
                     marker={'size': 2, "color": "red"},
@@ -2058,12 +2062,12 @@ def plot_gnss_attitude_measurements(self):
                 ),
                 row=1, col=1
             )
-            idx = ~np.isnan(raw_heading_data.heading_true_north_deg)
+            idx = ~np.isnan(raw_heading_deg)
 
             fig.add_trace(
                 go.Scatter(
                     x=raw_heading_time[idx],
-                    y=raw_heading_data.heading_true_north_deg[idx] + envelope[idx],
+                    y=raw_heading_deg[idx] + envelope[idx],
                     mode='lines',
                     marker={'size': 2, "color": "red"},
                     line=dict(width=0),
@@ -2077,7 +2081,7 @@ def plot_gnss_attitude_measurements(self):
             fig.add_trace(
                 go.Scatter(
                     x=raw_heading_time[idx],
-                    y=raw_heading_data.heading_true_north_deg[idx] - envelope[idx],
+                    y=raw_heading_deg[idx] - envelope[idx],
                     mode='lines',
                     marker={'size': 2, "color": "red"},
                     line=dict(width=0),
diff --git a/python/fusion_engine_client/messages/defs.py b/python/fusion_engine_client/messages/defs.py
index 63e53ad8..bc4ec613 100644
--- a/python/fusion_engine_client/messages/defs.py
+++ b/python/fusion_engine_client/messages/defs.py
@@ -99,10 +99,12 @@ class MessageType(IntEnum):
 
     # Sensor measurement messages.
     IMU_OUTPUT = 11000
-    RAW_GNSS_ATTITUDE_OUTPUT = 11001
+    DEPRECATED_RAW_HEADING_OUTPUT = 11001
     RAW_IMU_OUTPUT = 11002
-    GNSS_ATTITUDE_OUTPUT = 11003
+    DEPRECATED_HEADING_OUTPUT = 11003
     IMU_INPUT = 11004
+    GNSS_ATTITUDE_OUTPUT = 11005
+    RAW_GNSS_ATTITUDE_OUTPUT = 11006
 
     # Vehicle measurement messages.
     DEPRECATED_WHEEL_SPEED_MEASUREMENT = 11101
diff --git a/python/fusion_engine_client/messages/measurements.py b/python/fusion_engine_client/messages/measurements.py
index bf831924..e45ce835 100644
--- a/python/fusion_engine_client/messages/measurements.py
+++ b/python/fusion_engine_client/messages/measurements.py
@@ -1,3 +1,4 @@
+import math
 import struct
 from typing import Sequence
 
@@ -1176,7 +1177,7 @@ class GNSSAttitudeOutput(MessagePayload):
     MESSAGE_TYPE = MessageType.GNSS_ATTITUDE_OUTPUT
     MESSAGE_VERSION = 0
 
-    _STRUCT = struct.Struct('<B3xL3ff')
+    _STRUCT = struct.Struct('<B3xI3f3f')
 
     def __init__(self):
         ## Measurement timestamps, if available. See @ref measurement_messages.
@@ -1184,6 +1185,7 @@ def __init__(self):
 
         ## Set to @ref SolutionType::RTKFixed when heading is available, or @ref SolutionType::Invalid otherwise.
         self.solution_type = SolutionType.Invalid
+
         ## A bitmask of flags associated with the solution
         self.flags = 0
 
@@ -1193,12 +1195,8 @@ def __init__(self):
         self.ypr_deg = np.full((3,), np.nan)
 
         ##
-        # The heading angle (in degrees) with respect to true north, pointing from the primary antenna to the secondary
-        # antenna, after applying offset corrections.
-        #
-        # @note
-        # Reported in the range [0, 360).
-        self.heading_true_north_deg = np.nan
+        # The standard deviation of the orientation measurement (in degrees).
+        self.ypr_std_deg = np.full((3,), np.nan)
 
     def pack(self, buffer: bytes = None, offset: int = 0, return_buffer: bool = True) -> (bytes, int):
         if buffer is None:
@@ -1216,7 +1214,9 @@ def pack(self, buffer: bytes = None, offset: int = 0, return_buffer: bool = True
             self.ypr_deg[0],
             self.ypr_deg[1],
             self.ypr_deg[2],
-            self.heading_true_north_deg)
+            self.ypr_std_deg[0],
+            self.ypr_std_deg[1],
+            self.ypr_std_deg[2])
         offset += self._STRUCT.size
 
         if return_buffer:
@@ -1234,7 +1234,9 @@ def unpack(self, buffer: bytes, offset: int = 0, message_version: int = MessageP
          self.ypr_deg[0],
          self.ypr_deg[1],
          self.ypr_deg[2],
-         self.heading_true_north_deg) = \
+         self.ypr_std_deg[0],
+         self.ypr_std_deg[1],
+         self.ypr_std_deg[2]) = \
             self._STRUCT.unpack_from(buffer, offset)
         offset += self._STRUCT.size
 
@@ -1244,15 +1246,16 @@ def unpack(self, buffer: bytes, offset: int = 0, message_version: int = MessageP
 
     def __repr__(self):
         result = super().__repr__()[:-1]
-        result += f', solution_type={self.solution_type}, heading={self.heading_true_north_deg:.1f} deg]'
+        ypr_str = '(%.1f, %.1f, %.1f)' % tuple(self.ypr_deg)
+        result += f', solution_type={self.solution_type}, ypr={ypr_str} deg]'
         return result
 
     def __str__(self):
         return f"""\
 GNSS Attitude Output @ {str(self.details.p1_time)}
   Solution Type: {self.solution_type}
-  YPR (ENU) (deg): {self.ypr_deg[0]:.2f}, {self.ypr_deg[1]:.2f}, {self.ypr_deg[2]:.2f}
-  Heading (deg): {self.heading_true_north_deg:.2f}"""
+  YPR (deg): {self.ypr_deg[0]:.2f}, {self.ypr_deg[1]:.2f}, {self.ypr_deg[2]:.2f}
+  YPR std (deg): {self.ypr_std_deg[0]:.2f}, {self.ypr_std_deg[1]:.2f}, {self.ypr_std_deg[2]:.2f}"""
 
     @classmethod
     def calcsize(cls) -> int:
@@ -1264,7 +1267,7 @@ def to_numpy(cls, messages: Sequence['GNSSAttitudeOutput']):
             'solution_type': np.array([int(m.solution_type) for m in messages], dtype=int),
             'flags': np.array([int(m.flags) for m in messages], dtype=np.uint32),
             'ypr_deg': np.array([m.ypr_deg for m in messages]).T,
-            'heading_true_north_deg': np.array([m.heading_true_north_deg for m in messages], dtype=float),
+            'ypr_std_deg': np.array([m.ypr_std_deg for m in messages]).T,
         }
         result.update(MeasurementDetails.to_numpy([m.details for m in messages]))
         return result
@@ -1292,23 +1295,23 @@ def __init__(self):
         # The position of the secondary GNSS antenna relative to the primary antenna (in meters), resolved with respect
         # to the local ENU tangent plane: east, north, up.
         self.relative_position_enu_m = np.full((3,), np.nan)
+
         ##
         # The position standard deviation (in meters), resolved with respect to the
         # local ENU tangent plane: east, north, up.
         self.position_std_enu_m = np.full((3,), np.nan)
 
-        ##
-        # The heading between the primary device antenna and the secondary (in degrees) with
-        # respect to true north.
-        #
-        # @note
-        # Reported in the range [0, 360).
-        self.heading_true_north_deg = np.nan
-
         ##
         # The estimated distance between primary and secondary antennas (in meters).
         self.baseline_distance_m = np.nan
 
+        ##
+        # The standard deviation of the baseline distance estimate (in meters).
+        self.baseline_distance_std_m = np.nan
+
+    def get_heading_deg(self):
+        return math.degrees(math.atan2(self.relative_position_enu_m[1], self.relative_position_enu_m[0]))
+
     def pack(self, buffer: bytes = None, offset: int = 0, return_buffer: bool = True) -> (bytes, int):
         if buffer is None:
             buffer = bytearray(self.calcsize())
@@ -1329,8 +1332,8 @@ def pack(self, buffer: bytes = None, offset: int = 0, return_buffer: bool = True
             self.position_std_enu_m[0],
             self.position_std_enu_m[1],
             self.position_std_enu_m[2],
-            self.heading_true_north_deg,
-            self.baseline_distance_m)
+            self.baseline_distance_m,
+            self.baseline_distance_std_m)
         offset += self._STRUCT.size
 
         if return_buffer:
@@ -1351,8 +1354,8 @@ def unpack(self, buffer: bytes, offset: int = 0, message_version: int = MessageP
          self.position_std_enu_m[0],
          self.position_std_enu_m[1],
          self.position_std_enu_m[2],
-         self.heading_true_north_deg,
-         self.baseline_distance_m) = self._STRUCT.unpack_from(buffer, offset)
+         self.baseline_distance_m,
+         self.baseline_distance_std_m) = self._STRUCT.unpack_from(buffer, offset)
         offset += self._STRUCT.size
 
         self.solution_type = SolutionType(solution_type_int)
@@ -1361,7 +1364,9 @@ def unpack(self, buffer: bytes, offset: int = 0, message_version: int = MessageP
 
     def __repr__(self):
         result = super().__repr__()[:-1]
-        result += f', solution_type={self.solution_type}, heading={self.heading_true_north_deg:.1f} deg, ' \
+        enu_str = '(%.2f, %.2f, %.3f)' % tuple(self.relative_position_enu_m)
+        heading_deg = self.get_heading_deg()
+        result += f', solution_type={self.solution_type}, enu={enu_str} m, heading={heading_deg:.1f} deg, ' \
                   f'baseline={self.baseline_distance_m} m]'
         return result
 
@@ -1371,8 +1376,9 @@ def __str__(self):
   Solution Type: {self.solution_type}
   Relative position (ENU) (m): {self.relative_position_enu_m[0]:.2f}, {self.relative_position_enu_m[1]:.2f}, {self.relative_position_enu_m[2]:.2f}
   Position std (ENU) (m): {self.position_std_enu_m[0]:.2f}, {self.position_std_enu_m[1]:.2f}, {self.position_std_enu_m[2]:.2f}
-  Heading (deg): {self.heading_true_north_deg:.2f}
-  Baseline distance (m): {self.baseline_distance_m:.2f}"""
+  Heading (deg): {self.get_heading_deg():.2f}
+  Baseline distance (m): {self.baseline_distance_m:.2f}
+  Baseline std (m): {self.baseline_distance_std_m:.2f}"""
 
     @classmethod
     def calcsize(cls) -> int:
@@ -1385,8 +1391,8 @@ def to_numpy(cls, messages: Sequence['RawGNSSAttitudeOutput']):
             'flags': np.array([int(m.flags) for m in messages], dtype=np.uint32),
             'relative_position_enu_m': np.array([m.relative_position_enu_m for m in messages]).T,
             'position_std_enu_m': np.array([m.position_std_enu_m for m in messages]).T,
-            'heading_true_north_deg': np.array([float(m.heading_true_north_deg) for m in messages]),
             'baseline_distance_m': np.array([float(m.baseline_distance_m) for m in messages]),
+            'baseline_distance_std_m': np.array([float(m.baseline_distance_std_m) for m in messages]),
         }
         result.update(MeasurementDetails.to_numpy([m.details for m in messages]))
         return result
diff --git a/src/point_one/fusion_engine/messages/defs.h b/src/point_one/fusion_engine/messages/defs.h
index bcf22dd1..b91c4da7 100644
--- a/src/point_one/fusion_engine/messages/defs.h
+++ b/src/point_one/fusion_engine/messages/defs.h
@@ -47,11 +47,12 @@ enum class MessageType : uint16_t {
 
   // Sensor measurement messages.
   IMU_OUTPUT = 11000, ///< @ref IMUOutput
-  RAW_GNSS_ATTITUDE_OUTPUT = 11001, ///< @ref RawGNSSAttitudeOutput
+  DEPRECATED_RAW_HEADING_OUTPUT = 11001,
   RAW_IMU_OUTPUT = 11002, ///< @ref RawIMUOutput
-  // TODO Change the numbers
-  GNSS_ATTITUDE_OUTPUT = 11003, ///< @ref GNSSAttitudeOutput
+  DEPRECATED_HEADING_OUTPUT = 11003,
   IMU_INPUT = 11004, ///< @ref IMUInput
+  GNSS_ATTITUDE_OUTPUT = 11005, ///< @ref GNSSAttitudeOutput
+  RAW_GNSS_ATTITUDE_OUTPUT = 11006, ///< @ref RawGNSSAttitudeOutput
 
   // Vehicle measurement messages.
   DEPRECATED_WHEEL_SPEED_MEASUREMENT =
@@ -152,18 +153,24 @@ P1_CONSTEXPR_FUNC const char* to_string(MessageType type) {
     case MessageType::IMU_OUTPUT:
       return "IMU Output";
 
-    case MessageType::RAW_GNSS_ATTITUDE_OUTPUT:
-      return "Raw GNSS Attitude Output";
+    case MessageType::DEPRECATED_RAW_HEADING_OUTPUT:
+      return "Raw GNSS Heading Output";
 
     case MessageType::RAW_IMU_OUTPUT:
       return "Raw IMU Output";
 
-    case MessageType::GNSS_ATTITUDE_OUTPUT:
-      return "GNSS Attitude Output";
+    case MessageType::DEPRECATED_HEADING_OUTPUT:
+      return "GNSS Heading Output";
 
     case MessageType::IMU_INPUT:
       return "IMU Input";
 
+    case MessageType::GNSS_ATTITUDE_OUTPUT:
+      return "GNSS Attitude Output";
+
+    case MessageType::RAW_GNSS_ATTITUDE_OUTPUT:
+      return "Raw GNSS Attitude Output";
+
     case MessageType::DEPRECATED_WHEEL_SPEED_MEASUREMENT:
       return "Wheel Speed Measurement";
 
@@ -331,10 +338,12 @@ P1_CONSTEXPR_FUNC bool IsCommand(MessageType message_type) {
     case MessageType::RELATIVE_ENU_POSITION:
     case MessageType::SYSTEM_STATUS:
     case MessageType::IMU_OUTPUT:
-    case MessageType::RAW_GNSS_ATTITUDE_OUTPUT:
+    case MessageType::DEPRECATED_RAW_HEADING_OUTPUT:
     case MessageType::RAW_IMU_OUTPUT:
-    case MessageType::GNSS_ATTITUDE_OUTPUT:
+    case MessageType::DEPRECATED_HEADING_OUTPUT:
     case MessageType::IMU_INPUT:
+    case MessageType::GNSS_ATTITUDE_OUTPUT:
+    case MessageType::RAW_GNSS_ATTITUDE_OUTPUT:
     case MessageType::DEPRECATED_WHEEL_SPEED_MEASUREMENT:
     case MessageType::DEPRECATED_VEHICLE_SPEED_MEASUREMENT:
     case MessageType::WHEEL_TICK_INPUT:
diff --git a/src/point_one/fusion_engine/messages/measurements.h b/src/point_one/fusion_engine/messages/measurements.h
index d7f74bb0..a1e766e7 100644
--- a/src/point_one/fusion_engine/messages/measurements.h
+++ b/src/point_one/fusion_engine/messages/measurements.h
@@ -1189,19 +1189,17 @@ struct P1_ALIGNAS(4) GNSSAttitudeOutput : public MessagePayload {
    *
    * If any angles are not available, they will be set to `NAN`. For
    * dual-antenna systems, the device will measure yaw and pitch, but not roll.
+   *
+   * Note that yaw is measured from east in a counter-clockwise direction. For
+   * example, north is +90 degrees. Heading with respect to true north can be
+   * computed as `heading = 90.0 - ypr_deg[0]`.
    */
   float ypr_deg[3] = {NAN, NAN, NAN};
 
   /**
-   * The heading angle (in degrees) with respect to true north, pointing from
-   * the primary antenna to the secondary antenna.
-   *
-   * The reported angle includes the user-specified heading offset correction.
-   *
-   * @note
-   * Reported in the range [0, 360).
+   * The standard deviation of the orientation measurement (in degrees).
    */
-  float heading_true_north_deg = NAN;
+  float ypr_std_deg[3] = {NAN, NAN, NAN};
 };
 
 /**
@@ -1253,24 +1251,20 @@ struct P1_ALIGNAS(4) RawGNSSAttitudeOutput : public MessagePayload {
   float relative_position_enu_m[3] = {NAN, NAN, NAN};
 
   /**
-   * The position standard deviation (in meters), resolved with respect to the
-   * local ENU tangent plane: east, north, up.
+   * The standard deviation of the relative position vector (in meters),
+   * resolved with respect to the local ENU tangent plane: east, north, up.
    */
   float position_std_enu_m[3] = {NAN, NAN, NAN};
 
   /**
-   * The measured heading angle (in degrees) with respect to true north,
-   * pointing from the primary antenna to the secondary antenna.
-   *
-   * @note
-   * Reported in the range [0, 360).
+   * The estimated distance between primary and secondary antennas (in meters).
    */
-  float heading_true_north_deg = NAN;
+  float baseline_distance_m = NAN;
 
   /**
-   * The estimated distance between primary and secondary antennas (in meters).
+   * The standard deviation of the baseline distance estimate (in meters).
    */
-  float baseline_distance_m = NAN;
+  float baseline_distance_std_m = NAN;
 };
 
 ////////////////////////////////////////////////////////////////////////////////

From 45df8009386a189a25491f66a2a37cd16d797107 Mon Sep 17 00:00:00 2001
From: Adam Shapiro <adam@pointonenav.com>
Date: Tue, 3 Dec 2024 08:44:31 -0500
Subject: [PATCH 08/12] Include baseline distance in corrected attitude
 message.

---
 .../fusion_engine_client/analysis/analyzer.py | 13 +++++++++
 .../messages/measurements.py                  | 27 +++++++++++++++----
 .../fusion_engine/messages/measurements.h     | 10 +++++++
 3 files changed, 45 insertions(+), 5 deletions(-)

diff --git a/python/fusion_engine_client/analysis/analyzer.py b/python/fusion_engine_client/analysis/analyzer.py
index c9e68878..ac0cbc7c 100755
--- a/python/fusion_engine_client/analysis/analyzer.py
+++ b/python/fusion_engine_client/analysis/analyzer.py
@@ -2028,6 +2028,19 @@ def plot_gnss_attitude_measurements(self):
                 row=1, col=1
             )
 
+            fig.add_trace(
+                go.Scatter(
+                    x=heading_time,
+                    y=heading_data.baseline_distance_m,
+                    customdata=heading_data.p1_time,
+                    marker={'size': 2, "color": "green"},
+                    hovertemplate='<b>Time</b>: %{x:.3f} sec (%{customdata:.3f} sec)'
+                                  '<br><b>Baseline</b>: %{y:.2f} m',
+                    name='Baseline'
+                ),
+                row=2, col=1
+            )
+
         # Uncorrected heading plot
         if len(raw_heading_data.p1_time) > 0:
             raw_heading_time = raw_heading_data.p1_time - float(self.t0)
diff --git a/python/fusion_engine_client/messages/measurements.py b/python/fusion_engine_client/messages/measurements.py
index e45ce835..f95c9dae 100644
--- a/python/fusion_engine_client/messages/measurements.py
+++ b/python/fusion_engine_client/messages/measurements.py
@@ -1177,7 +1177,7 @@ class GNSSAttitudeOutput(MessagePayload):
     MESSAGE_TYPE = MessageType.GNSS_ATTITUDE_OUTPUT
     MESSAGE_VERSION = 0
 
-    _STRUCT = struct.Struct('<B3xI3f3f')
+    _STRUCT = struct.Struct('<B3xI3f3f2f')
 
     def __init__(self):
         ## Measurement timestamps, if available. See @ref measurement_messages.
@@ -1198,6 +1198,14 @@ def __init__(self):
         # The standard deviation of the orientation measurement (in degrees).
         self.ypr_std_deg = np.full((3,), np.nan)
 
+        ##
+        # The estimated distance between primary and secondary antennas (in meters).
+        self.baseline_distance_m = np.nan
+
+        ##
+        # The standard deviation of the baseline distance estimate (in meters).
+        self.baseline_distance_std_m = np.nan
+
     def pack(self, buffer: bytes = None, offset: int = 0, return_buffer: bool = True) -> (bytes, int):
         if buffer is None:
             buffer = bytearray(self.calcsize())
@@ -1216,7 +1224,9 @@ def pack(self, buffer: bytes = None, offset: int = 0, return_buffer: bool = True
             self.ypr_deg[2],
             self.ypr_std_deg[0],
             self.ypr_std_deg[1],
-            self.ypr_std_deg[2])
+            self.ypr_std_deg[2],
+            self.baseline_distance_m,
+            self.baseline_distance_std_m)
         offset += self._STRUCT.size
 
         if return_buffer:
@@ -1236,7 +1246,9 @@ def unpack(self, buffer: bytes, offset: int = 0, message_version: int = MessageP
          self.ypr_deg[2],
          self.ypr_std_deg[0],
          self.ypr_std_deg[1],
-         self.ypr_std_deg[2]) = \
+         self.ypr_std_deg[2],
+         self.baseline_distance_m,
+         self.baseline_distance_std_m) = \
             self._STRUCT.unpack_from(buffer, offset)
         offset += self._STRUCT.size
 
@@ -1247,7 +1259,8 @@ def unpack(self, buffer: bytes, offset: int = 0, message_version: int = MessageP
     def __repr__(self):
         result = super().__repr__()[:-1]
         ypr_str = '(%.1f, %.1f, %.1f)' % tuple(self.ypr_deg)
-        result += f', solution_type={self.solution_type}, ypr={ypr_str} deg]'
+        result += f', solution_type={self.solution_type}, ypr={ypr_str} deg, ' \
+                  f'baseline={self.baseline_distance_m} m]'
         return result
 
     def __str__(self):
@@ -1255,7 +1268,9 @@ def __str__(self):
 GNSS Attitude Output @ {str(self.details.p1_time)}
   Solution Type: {self.solution_type}
   YPR (deg): {self.ypr_deg[0]:.2f}, {self.ypr_deg[1]:.2f}, {self.ypr_deg[2]:.2f}
-  YPR std (deg): {self.ypr_std_deg[0]:.2f}, {self.ypr_std_deg[1]:.2f}, {self.ypr_std_deg[2]:.2f}"""
+  YPR std (deg): {self.ypr_std_deg[0]:.2f}, {self.ypr_std_deg[1]:.2f}, {self.ypr_std_deg[2]:.2f}
+  Baseline distance (m): {self.baseline_distance_m:.2f}
+  Baseline std (m): {self.baseline_distance_std_m:.2f}"""
 
     @classmethod
     def calcsize(cls) -> int:
@@ -1268,6 +1283,8 @@ def to_numpy(cls, messages: Sequence['GNSSAttitudeOutput']):
             'flags': np.array([int(m.flags) for m in messages], dtype=np.uint32),
             'ypr_deg': np.array([m.ypr_deg for m in messages]).T,
             'ypr_std_deg': np.array([m.ypr_std_deg for m in messages]).T,
+            'baseline_distance_m': np.array([float(m.baseline_distance_m) for m in messages]),
+            'baseline_distance_std_m': np.array([float(m.baseline_distance_std_m) for m in messages]),
         }
         result.update(MeasurementDetails.to_numpy([m.details for m in messages]))
         return result
diff --git a/src/point_one/fusion_engine/messages/measurements.h b/src/point_one/fusion_engine/messages/measurements.h
index a1e766e7..5076cfef 100644
--- a/src/point_one/fusion_engine/messages/measurements.h
+++ b/src/point_one/fusion_engine/messages/measurements.h
@@ -1200,6 +1200,16 @@ struct P1_ALIGNAS(4) GNSSAttitudeOutput : public MessagePayload {
    * The standard deviation of the orientation measurement (in degrees).
    */
   float ypr_std_deg[3] = {NAN, NAN, NAN};
+
+  /**
+   * The estimated distance between primary and secondary antennas (in meters).
+   */
+  float baseline_distance_m = NAN;
+
+  /**
+   * The standard deviation of the baseline distance estimate (in meters).
+   */
+  float baseline_distance_std_m = NAN;
 };
 
 /**

From c117cd84674edd253dab599d59ba028fed108b4d Mon Sep 17 00:00:00 2001
From: Adam Shapiro <adam@pointonenav.com>
Date: Tue, 3 Dec 2024 10:00:45 -0500
Subject: [PATCH 09/12] Removed baseline distance from RawGNSSAttitudeOutput.

This is just the norm of the ENU vector contained in the message, so it's
redundant.
---
 python/fusion_engine_client/analysis/analyzer.py  |  5 +++--
 .../fusion_engine_client/messages/measurements.py | 15 ++++-----------
 .../fusion_engine/messages/measurements.h         | 10 ----------
 3 files changed, 7 insertions(+), 23 deletions(-)

diff --git a/python/fusion_engine_client/analysis/analyzer.py b/python/fusion_engine_client/analysis/analyzer.py
index ac0cbc7c..0d084c75 100755
--- a/python/fusion_engine_client/analysis/analyzer.py
+++ b/python/fusion_engine_client/analysis/analyzer.py
@@ -2046,6 +2046,7 @@ def plot_gnss_attitude_measurements(self):
             raw_heading_time = raw_heading_data.p1_time - float(self.t0)
             raw_heading_deg = np.degrees(np.arctan2(raw_heading_data.relative_position_enu_m[1, :],
                                                     raw_heading_data.relative_position_enu_m[0, :]))
+            raw_baseline_distance_m = np.linalg.norm(raw_heading_data.relative_position_enu_m, axis=0)
 
             # Compute heading uncertainty envelop.
             denom = raw_heading_data.relative_position_enu_m[0]**2 + raw_heading_data.relative_position_enu_m[1]**2
@@ -2058,7 +2059,7 @@ def plot_gnss_attitude_measurements(self):
             )
 
             envelope = np.arctan(
-                (2 * heading_std / raw_heading_data.baseline_distance_m)
+                (2 * heading_std / raw_baseline_distance_m)
             )
             envelope *= 180. / np.pi
             fig.add_trace(
@@ -2147,7 +2148,7 @@ def plot_gnss_attitude_measurements(self):
             fig.add_trace(
                 go.Scatter(
                     x=raw_heading_time,
-                    y=raw_heading_data.baseline_distance_m,
+                    y=raw_baseline_distance_m,
                     customdata=raw_heading_data.p1_time,
                     marker={'size': 2, "color": "red"},
                     hovertemplate='<b>Time</b>: %{x:.3f} sec (%{customdata:.3f} sec)'
diff --git a/python/fusion_engine_client/messages/measurements.py b/python/fusion_engine_client/messages/measurements.py
index f95c9dae..6708f1bb 100644
--- a/python/fusion_engine_client/messages/measurements.py
+++ b/python/fusion_engine_client/messages/measurements.py
@@ -1297,7 +1297,7 @@ class RawGNSSAttitudeOutput(MessagePayload):
     MESSAGE_TYPE = MessageType.RAW_GNSS_ATTITUDE_OUTPUT
     MESSAGE_VERSION = 0
 
-    _STRUCT = struct.Struct('<B3xL3f3fff')
+    _STRUCT = struct.Struct('<B3xL3f3f')
 
     def __init__(self):
         ## Measurement timestamps, if available. See @ref measurement_messages.
@@ -1370,9 +1370,7 @@ def unpack(self, buffer: bytes, offset: int = 0, message_version: int = MessageP
          self.relative_position_enu_m[2],
          self.position_std_enu_m[0],
          self.position_std_enu_m[1],
-         self.position_std_enu_m[2],
-         self.baseline_distance_m,
-         self.baseline_distance_std_m) = self._STRUCT.unpack_from(buffer, offset)
+         self.position_std_enu_m[2]) = self._STRUCT.unpack_from(buffer, offset)
         offset += self._STRUCT.size
 
         self.solution_type = SolutionType(solution_type_int)
@@ -1383,8 +1381,7 @@ def __repr__(self):
         result = super().__repr__()[:-1]
         enu_str = '(%.2f, %.2f, %.3f)' % tuple(self.relative_position_enu_m)
         heading_deg = self.get_heading_deg()
-        result += f', solution_type={self.solution_type}, enu={enu_str} m, heading={heading_deg:.1f} deg, ' \
-                  f'baseline={self.baseline_distance_m} m]'
+        result += f', solution_type={self.solution_type}, enu={enu_str} m, heading={heading_deg:.1f} deg]'
         return result
 
     def __str__(self):
@@ -1393,9 +1390,7 @@ def __str__(self):
   Solution Type: {self.solution_type}
   Relative position (ENU) (m): {self.relative_position_enu_m[0]:.2f}, {self.relative_position_enu_m[1]:.2f}, {self.relative_position_enu_m[2]:.2f}
   Position std (ENU) (m): {self.position_std_enu_m[0]:.2f}, {self.position_std_enu_m[1]:.2f}, {self.position_std_enu_m[2]:.2f}
-  Heading (deg): {self.get_heading_deg():.2f}
-  Baseline distance (m): {self.baseline_distance_m:.2f}
-  Baseline std (m): {self.baseline_distance_std_m:.2f}"""
+  Heading (deg): {self.get_heading_deg():.2f}"""
 
     @classmethod
     def calcsize(cls) -> int:
@@ -1408,8 +1403,6 @@ def to_numpy(cls, messages: Sequence['RawGNSSAttitudeOutput']):
             'flags': np.array([int(m.flags) for m in messages], dtype=np.uint32),
             'relative_position_enu_m': np.array([m.relative_position_enu_m for m in messages]).T,
             'position_std_enu_m': np.array([m.position_std_enu_m for m in messages]).T,
-            'baseline_distance_m': np.array([float(m.baseline_distance_m) for m in messages]),
-            'baseline_distance_std_m': np.array([float(m.baseline_distance_std_m) for m in messages]),
         }
         result.update(MeasurementDetails.to_numpy([m.details for m in messages]))
         return result
diff --git a/src/point_one/fusion_engine/messages/measurements.h b/src/point_one/fusion_engine/messages/measurements.h
index 5076cfef..d25ad09a 100644
--- a/src/point_one/fusion_engine/messages/measurements.h
+++ b/src/point_one/fusion_engine/messages/measurements.h
@@ -1265,16 +1265,6 @@ struct P1_ALIGNAS(4) RawGNSSAttitudeOutput : public MessagePayload {
    * resolved with respect to the local ENU tangent plane: east, north, up.
    */
   float position_std_enu_m[3] = {NAN, NAN, NAN};
-
-  /**
-   * The estimated distance between primary and secondary antennas (in meters).
-   */
-  float baseline_distance_m = NAN;
-
-  /**
-   * The standard deviation of the baseline distance estimate (in meters).
-   */
-  float baseline_distance_std_m = NAN;
 };
 
 ////////////////////////////////////////////////////////////////////////////////

From 29ac75c0feaed93be4ff3029a30371fd81b00b80 Mon Sep 17 00:00:00 2001
From: Adam Shapiro <adam@pointonenav.com>
Date: Tue, 3 Dec 2024 10:27:40 -0500
Subject: [PATCH 10/12] Added get_gps_time() helper function.

---
 python/fusion_engine_client/messages/defs.py | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/python/fusion_engine_client/messages/defs.py b/python/fusion_engine_client/messages/defs.py
index bc4ec613..84fab7dc 100644
--- a/python/fusion_engine_client/messages/defs.py
+++ b/python/fusion_engine_client/messages/defs.py
@@ -589,6 +589,13 @@ def get_p1_time(self) -> Timestamp:
         else:
             return getattr(self, 'p1_time', None)
 
+    def get_gps_time(self) -> Timestamp:
+        measurement_details = getattr(self, 'details', None)
+        if isinstance(measurement_details, MeasurementDetails):
+            if measurement_details.measurement_time_source == SystemTimeSource.GPS_TIME:
+                return measurement_details.measurement_time
+        return getattr(self, 'gps_time', None)
+
     def get_system_time_ns(self) -> float:
         measurement_details = getattr(self, 'details', None)
         if isinstance(measurement_details, MeasurementDetails):

From aebb1a4ba7f5b589e2cad6e7d15acda3109cd3f1 Mon Sep 17 00:00:00 2001
From: Adam Shapiro <adam@pointonenav.com>
Date: Tue, 3 Dec 2024 10:31:26 -0500
Subject: [PATCH 11/12] Add gps_time numpy element if measurements are
 timestamped in GPS time.

---
 python/fusion_engine_client/messages/measurement_details.py | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/python/fusion_engine_client/messages/measurement_details.py b/python/fusion_engine_client/messages/measurement_details.py
index ac17b288..08280f9e 100644
--- a/python/fusion_engine_client/messages/measurement_details.py
+++ b/python/fusion_engine_client/messages/measurement_details.py
@@ -131,6 +131,12 @@ def to_numpy(cls, messages):
             'p1_time': p1_time,
         }
 
+        idx = time_source == SystemTimeSource.GPS_TIME
+        if np.any(idx):
+            gps_time = np.full_like(time_source, np.nan)
+            gps_time[idx] = measurement_time[idx]
+            result['gps_time'] = gps_time
+
         idx = time_source == SystemTimeSource.TIMESTAMPED_ON_RECEPTION
         if np.any(idx):
             system_time = np.full_like(time_source, np.nan)

From 064ae6806aec3ad7cdc7bc957a8808d4ef26a556 Mon Sep 17 00:00:00 2001
From: Adam Shapiro <adam@pointonenav.com>
Date: Tue, 3 Dec 2024 10:32:25 -0500
Subject: [PATCH 12/12] Include GPS time in GNSSAttitudeOutput string if
 available.

---
 .../messages/measurements.py                   | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/python/fusion_engine_client/messages/measurements.py b/python/fusion_engine_client/messages/measurements.py
index 6708f1bb..cc6382d5 100644
--- a/python/fusion_engine_client/messages/measurements.py
+++ b/python/fusion_engine_client/messages/measurements.py
@@ -1264,8 +1264,17 @@ def __repr__(self):
         return result
 
     def __str__(self):
+        gps_time = self.get_gps_time()
+        if gps_time is not None:
+            gps_str = f'{str(gps_time).replace("GPS: ", "")}'
+            utc_str = f'{datetime_to_string(gps_time.as_utc())}'
+        else:
+            gps_str = 'None'
+            utc_str = 'None'
         return f"""\
 GNSS Attitude Output @ {str(self.details.p1_time)}
+  GPS time: {gps_str}
+  UTC time: {utc_str}
   Solution Type: {self.solution_type}
   YPR (deg): {self.ypr_deg[0]:.2f}, {self.ypr_deg[1]:.2f}, {self.ypr_deg[2]:.2f}
   YPR std (deg): {self.ypr_std_deg[0]:.2f}, {self.ypr_std_deg[1]:.2f}, {self.ypr_std_deg[2]:.2f}
@@ -1385,8 +1394,17 @@ def __repr__(self):
         return result
 
     def __str__(self):
+        gps_time = self.get_gps_time()
+        if gps_time is not None:
+            gps_str = f'{str(gps_time).replace("GPS: ", "")}'
+            utc_str = f'{datetime_to_string(gps_time.as_utc())}'
+        else:
+            gps_str = 'None'
+            utc_str = 'None'
         return f"""\
 Raw GNSS Attitude Output @ {str(self.details.p1_time)}
+  GPS time: {gps_str}
+  UTC time: {utc_str}
   Solution Type: {self.solution_type}
   Relative position (ENU) (m): {self.relative_position_enu_m[0]:.2f}, {self.relative_position_enu_m[1]:.2f}, {self.relative_position_enu_m[2]:.2f}
   Position std (ENU) (m): {self.position_std_enu_m[0]:.2f}, {self.position_std_enu_m[1]:.2f}, {self.position_std_enu_m[2]:.2f}