diff --git a/src/mintpy/asc_desc2horz_vert.py b/src/mintpy/asc_desc2horz_vert.py
index 4585781e4..832d6e5d2 100644
--- a/src/mintpy/asc_desc2horz_vert.py
+++ b/src/mintpy/asc_desc2horz_vert.py
@@ -31,7 +31,7 @@ def get_overlap_lalo(atr_list):
     return S, N, W, E
 
 
-def get_design_matrix4east_north_up(los_inc_angle, los_az_angle, obs_direction):
+def get_design_matrix4east_north_up(los_inc_angle, los_az_angle, obs_direction=None):
     """Design matrix G to convert multi-track range/azimuth displacement into east/north/up direction.
     Parameters: los_inc_angle - 1D np.ndarray in size of (num_obs,) in float32, LOS incidence angle in degree
                 los_az_angle  - 1D np.ndarray in size of (num_obs,) in float32, LOS azimuth   angle in degree
@@ -41,6 +41,14 @@ def get_design_matrix4east_north_up(los_inc_angle, los_az_angle, obs_direction):
     num_obs = los_inc_angle.shape[0]
     G = np.zeros((num_obs, 3), dtype=np.float32)
 
+    # obs_direction: default value
+    if not obs_direction:
+        obs_direction = ['range'] * num_obs
+
+    # obs_direction: check var type
+    if not isinstance(obs_direction, (list, np.ndarray)):
+        raise ValueError(f'input obs_direction ({obs_direction}) is NOT a list or numpy.ndarray!')
+
     for i, (inc_angle, az_angle, obs_dir) in enumerate(zip(los_inc_angle, los_az_angle, obs_direction)):
         # calculate the unit vector
         if obs_dir == 'range':
diff --git a/src/mintpy/prep_gamma.py b/src/mintpy/prep_gamma.py
index 196c8edff..d0c09b825 100644
--- a/src/mintpy/prep_gamma.py
+++ b/src/mintpy/prep_gamma.py
@@ -179,7 +179,7 @@ def extract_metadata4interferogram(fname, sensor_name=None):
         rg_pixel_size = float(atr['RANGE_PIXEL_SIZE']) / float(atr['RLOOKS'])
         rg_fact = rg_resolution / rg_pixel_size
 
-        antenna_length = sensor.SENSOR_DICT[sensor_name]['antenna_length']
+        antenna_length = sensor.SENSOR_DICT[sensor_name.lower()]['antenna_length']
         az_resolution = antenna_length / 2
         az_pixel_size = float(atr['AZIMUTH_PIXEL_SIZE']) / float(atr['ALOOKS'])
         az_fact = az_resolution / az_pixel_size
@@ -341,7 +341,7 @@ def prep_gamma(inps):
     for fname in inps.file:
         # interferograms
         if inps.file_ext in ['.unw', '.cor', '.int']:
-            extract_metadata4interferogram(fname, sensor_name=inps.sensor.lower())
+            extract_metadata4interferogram(fname, sensor_name=inps.sensor)
 
         # geometry - geo
         elif inps.file_ext.endswith(('to_rdc', '2_rdc', '2rdc')) or fname.endswith('.utm.dem'):
diff --git a/src/mintpy/utils/arg_utils.py b/src/mintpy/utils/arg_utils.py
index 503f4ca7e..d8ffdaa25 100644
--- a/src/mintpy/utils/arg_utils.py
+++ b/src/mintpy/utils/arg_utils.py
@@ -344,6 +344,8 @@ def add_map_argument(parser):
                       action='store_false', help='do not display scale bar.')
     mapg.add_argument('--scalebar-pad','--sbar-pad', dest='scalebar_pad', type=float, default=0.05,
                       help='scale bar label pad in ratio of scalebar width (default: %(default)s).')
+    mapg.add_argument('--scalebar-lw','--scalebar-linewidth', dest='scalebar_linewidth', type=float,
+                      default=2.0, help='scale bar symbol line width (default: %(default)s).')
     return parser
 
 
diff --git a/src/mintpy/utils/map.py b/src/mintpy/utils/map.py
index c21d86806..db49e7af7 100644
--- a/src/mintpy/utils/map.py
+++ b/src/mintpy/utils/map.py
@@ -114,7 +114,8 @@ def auto_lalo_sequence(geo_box, lalo_step=None, lalo_max_num=4, step_candidate=[
 
 ############################################  Scale Bar  #############################################
 
-def draw_scalebar(ax, geo_box, unit='degrees', loc=[0.2, 0.2, 0.1], labelpad=0.05, font_size=12, color='k'):
+def draw_scalebar(ax, geo_box, unit='degrees', loc=[0.2, 0.2, 0.1], labelpad=0.05, font_size=12,
+                  color='k', linewidth=2):
     """draw a simple map scale from x1,y to x2,y in map projection coordinates, label it with actual distance
     ref_link: http://matplotlib.1069221.n5.nabble.com/basemap-scalebar-td14133.html
     Parameters: ax       : matplotlib.pyplot.axes object
@@ -165,9 +166,10 @@ def draw_scalebar(ax, geo_box, unit='degrees', loc=[0.2, 0.2, 0.1], labelpad=0.0
     lon1 = lon_c + length_disp / 2.0
 
     ## plot scale bar
-    ax.plot([lon0, lon1], [lat_c, lat_c], color=color)
-    ax.plot([lon0, lon0], [lat_c, lat_c + 0.1*length_disp], color=color)
-    ax.plot([lon1, lon1], [lat_c, lat_c + 0.1*length_disp], color=color)
+    kwargs = dict(color=color, linewidth=linewidth)
+    ax.plot([lon0, lon1], [lat_c, lat_c], **kwargs)
+    ax.plot([lon0, lon0], [lat_c, lat_c + 0.1*length_disp], **kwargs)
+    ax.plot([lon1, lon1], [lat_c, lat_c + 0.1*length_disp], **kwargs)
 
     ## plot scale bar label
     unit = 'm'
diff --git a/src/mintpy/view.py b/src/mintpy/view.py
index e3ef94a0e..aee29a3b8 100644
--- a/src/mintpy/view.py
+++ b/src/mintpy/view.py
@@ -570,6 +570,7 @@ def plot_slice(ax, data, metadata, inps):
                 loc=inps.scalebar,
                 labelpad=inps.scalebar_pad,
                 font_size=inps.font_size,
+                linewidth=inps.scalebar_linewidth,
             )
 
         # Lat Lon labels