forked from ArduPilot/pymavlink
-
Notifications
You must be signed in to change notification settings - Fork 0
/
mavextra.py
1318 lines (1123 loc) · 51.2 KB
/
mavextra.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
#!/usr/bin/env python
'''
useful extra functions for use by mavlink clients
Copyright Andrew Tridgell 2011
Released under GNU GPL version 3 or later
'''
from __future__ import print_function
from __future__ import absolute_import
from builtins import object
from math import *
try:
# in case numpy isn't installed
from .quaternion import Quaternion
except:
pass
try:
# rotmat doesn't work on Python3.2 yet
from .rotmat import Vector3, Matrix3
except Exception:
pass
def kmh(mps):
'''convert m/s to Km/h'''
return mps*3.6
def altitude(SCALED_PRESSURE, ground_pressure=None, ground_temp=None):
'''calculate barometric altitude'''
from . import mavutil
self = mavutil.mavfile_global
if ground_pressure is None:
if self.param('GND_ABS_PRESS', None) is None:
return 0
ground_pressure = self.param('GND_ABS_PRESS', 1)
if ground_temp is None:
ground_temp = self.param('GND_TEMP', 0)
scaling = ground_pressure / (SCALED_PRESSURE.press_abs*100.0)
temp = ground_temp + 273.15
return log(scaling) * temp * 29271.267 * 0.001
def altitude2(SCALED_PRESSURE, ground_pressure=None, ground_temp=None):
'''calculate barometric altitude'''
from . import mavutil
self = mavutil.mavfile_global
if ground_pressure is None:
if self.param('GND_ABS_PRESS', None) is None:
return 0
ground_pressure = self.param('GND_ABS_PRESS', 1)
if ground_temp is None:
ground_temp = self.param('GND_TEMP', 0)
scaling = SCALED_PRESSURE.press_abs*100.0 / ground_pressure
temp = ground_temp + 273.15
return 153.8462 * temp * (1.0 - exp(0.190259 * log(scaling)))
def mag_heading(RAW_IMU, ATTITUDE, declination=None, SENSOR_OFFSETS=None, ofs=None):
'''calculate heading from raw magnetometer'''
if declination is None:
from . import mavutil
declination = degrees(mavutil.mavfile_global.param('COMPASS_DEC', 0))
mag_x = RAW_IMU.xmag
mag_y = RAW_IMU.ymag
mag_z = RAW_IMU.zmag
if SENSOR_OFFSETS is not None and ofs is not None:
mag_x += ofs[0] - SENSOR_OFFSETS.mag_ofs_x
mag_y += ofs[1] - SENSOR_OFFSETS.mag_ofs_y
mag_z += ofs[2] - SENSOR_OFFSETS.mag_ofs_z
# go via a DCM matrix to match the APM calculation
dcm_matrix = rotation(ATTITUDE)
cos_pitch_sq = 1.0-(dcm_matrix.c.x*dcm_matrix.c.x)
headY = mag_y * dcm_matrix.c.z - mag_z * dcm_matrix.c.y
headX = mag_x * cos_pitch_sq - dcm_matrix.c.x * (mag_y * dcm_matrix.c.y + mag_z * dcm_matrix.c.z)
heading = degrees(atan2(-headY,headX)) + declination
if heading < 0:
heading += 360
return heading
def mag_heading_motors(RAW_IMU, ATTITUDE, declination, SENSOR_OFFSETS, ofs, SERVO_OUTPUT_RAW, motor_ofs):
'''calculate heading from raw magnetometer'''
ofs = get_motor_offsets(SERVO_OUTPUT_RAW, ofs, motor_ofs)
if declination is None:
from . import mavutil
declination = degrees(mavutil.mavfile_global.param('COMPASS_DEC', 0))
mag_x = RAW_IMU.xmag
mag_y = RAW_IMU.ymag
mag_z = RAW_IMU.zmag
if SENSOR_OFFSETS is not None and ofs is not None:
mag_x += ofs[0] - SENSOR_OFFSETS.mag_ofs_x
mag_y += ofs[1] - SENSOR_OFFSETS.mag_ofs_y
mag_z += ofs[2] - SENSOR_OFFSETS.mag_ofs_z
headX = mag_x*cos(ATTITUDE.pitch) + mag_y*sin(ATTITUDE.roll)*sin(ATTITUDE.pitch) + mag_z*cos(ATTITUDE.roll)*sin(ATTITUDE.pitch)
headY = mag_y*cos(ATTITUDE.roll) - mag_z*sin(ATTITUDE.roll)
heading = degrees(atan2(-headY,headX)) + declination
if heading < 0:
heading += 360
return heading
def mag_field(RAW_IMU, SENSOR_OFFSETS=None, ofs=None):
'''calculate magnetic field strength from raw magnetometer'''
mag_x = RAW_IMU.xmag
mag_y = RAW_IMU.ymag
mag_z = RAW_IMU.zmag
if SENSOR_OFFSETS is not None and ofs is not None:
mag_x += ofs[0] - SENSOR_OFFSETS.mag_ofs_x
mag_y += ofs[1] - SENSOR_OFFSETS.mag_ofs_y
mag_z += ofs[2] - SENSOR_OFFSETS.mag_ofs_z
return sqrt(mag_x**2 + mag_y**2 + mag_z**2)
def mag_field_df(MAG, ofs=None):
'''calculate magnetic field strength from raw magnetometer (dataflash version)'''
mag = Vector3(MAG.MagX, MAG.MagY, MAG.MagZ)
offsets = Vector3(MAG.OfsX, MAG.OfsY, MAG.OfsZ)
if ofs is not None:
mag = (mag - offsets) + Vector3(ofs[0], ofs[1], ofs[2])
return mag.length()
def get_motor_offsets(SERVO_OUTPUT_RAW, ofs, motor_ofs):
'''calculate magnetic field strength from raw magnetometer'''
from . import mavutil
self = mavutil.mavfile_global
m = SERVO_OUTPUT_RAW
motor_pwm = m.servo1_raw + m.servo2_raw + m.servo3_raw + m.servo4_raw
motor_pwm *= 0.25
rc3_min = self.param('RC3_MIN', 1100)
rc3_max = self.param('RC3_MAX', 1900)
motor = (motor_pwm - rc3_min) / (rc3_max - rc3_min)
if motor > 1.0:
motor = 1.0
if motor < 0.0:
motor = 0.0
motor_offsets0 = motor_ofs[0] * motor
motor_offsets1 = motor_ofs[1] * motor
motor_offsets2 = motor_ofs[2] * motor
ofs = (ofs[0] + motor_offsets0, ofs[1] + motor_offsets1, ofs[2] + motor_offsets2)
return ofs
def mag_field_motors(RAW_IMU, SENSOR_OFFSETS, ofs, SERVO_OUTPUT_RAW, motor_ofs):
'''calculate magnetic field strength from raw magnetometer'''
mag_x = RAW_IMU.xmag
mag_y = RAW_IMU.ymag
mag_z = RAW_IMU.zmag
ofs = get_motor_offsets(SERVO_OUTPUT_RAW, ofs, motor_ofs)
if SENSOR_OFFSETS is not None and ofs is not None:
mag_x += ofs[0] - SENSOR_OFFSETS.mag_ofs_x
mag_y += ofs[1] - SENSOR_OFFSETS.mag_ofs_y
mag_z += ofs[2] - SENSOR_OFFSETS.mag_ofs_z
return sqrt(mag_x**2 + mag_y**2 + mag_z**2)
def angle_diff(angle1, angle2):
'''show the difference between two angles in degrees'''
ret = angle1 - angle2
if ret > 180:
ret -= 360;
if ret < -180:
ret += 360
return ret
average_data = {}
def average(var, key, N):
'''average over N points'''
global average_data
if not key in average_data:
average_data[key] = [var]*N
return var
average_data[key].pop(0)
average_data[key].append(var)
return sum(average_data[key])/N
derivative_data = {}
def second_derivative_5(var, key):
'''5 point 2nd derivative'''
global derivative_data
from . import mavutil
tnow = mavutil.mavfile_global.timestamp
if not key in derivative_data:
derivative_data[key] = (tnow, [var]*5)
return 0
(last_time, data) = derivative_data[key]
data.pop(0)
data.append(var)
derivative_data[key] = (tnow, data)
h = (tnow - last_time)
# N=5 2nd derivative from
# http://www.holoborodko.com/pavel/numerical-methods/numerical-derivative/smooth-low-noise-differentiators/
ret = ((data[4] + data[0]) - 2*data[2]) / (4*h**2)
return ret
def second_derivative_9(var, key):
'''9 point 2nd derivative'''
global derivative_data
from . import mavutil
tnow = mavutil.mavfile_global.timestamp
if not key in derivative_data:
derivative_data[key] = (tnow, [var]*9)
return 0
(last_time, data) = derivative_data[key]
data.pop(0)
data.append(var)
derivative_data[key] = (tnow, data)
h = (tnow - last_time)
# N=5 2nd derivative from
# http://www.holoborodko.com/pavel/numerical-methods/numerical-derivative/smooth-low-noise-differentiators/
f = data
ret = ((f[8] + f[0]) + 4*(f[7] + f[1]) + 4*(f[6]+f[2]) - 4*(f[5]+f[3]) - 10*f[4])/(64*h**2)
return ret
lowpass_data = {}
def lowpass(var, key, factor):
'''a simple lowpass filter'''
global lowpass_data
if not key in lowpass_data:
lowpass_data[key] = var
else:
lowpass_data[key] = factor*lowpass_data[key] + (1.0 - factor)*var
return lowpass_data[key]
last_diff = {}
def diff(var, key):
'''calculate differences between values'''
global last_diff
ret = 0
if not key in last_diff:
last_diff[key] = var
return 0
ret = var - last_diff[key]
last_diff[key] = var
return ret
last_delta = {}
def delta(var, key, tusec=None):
'''calculate slope'''
global last_delta
if tusec is not None:
tnow = tusec * 1.0e-6
else:
from . import mavutil
tnow = mavutil.mavfile_global.timestamp
ret = 0
if key in last_delta:
(last_v, last_t, last_ret) = last_delta[key]
if last_t == tnow:
return last_ret
if tnow == last_t:
ret = 0
else:
ret = (var - last_v) / (tnow - last_t)
last_delta[key] = (var, tnow, ret)
return ret
def delta_angle(var, key, tusec=None):
'''calculate slope of an angle'''
global last_delta
if tusec is not None:
tnow = tusec * 1.0e-6
else:
from . import mavutil
tnow = mavutil.mavfile_global.timestamp
dv = 0
ret = 0
if key in last_delta:
(last_v, last_t, last_ret) = last_delta[key]
if last_t == tnow:
return last_ret
if tnow == last_t:
ret = 0
else:
dv = var - last_v
if dv > 180:
dv -= 360
if dv < -180:
dv += 360
ret = dv / (tnow - last_t)
last_delta[key] = (var, tnow, ret)
return ret
def roll_estimate(RAW_IMU,GPS_RAW_INT=None,ATTITUDE=None,SENSOR_OFFSETS=None, ofs=None, mul=None,smooth=0.7):
'''estimate roll from accelerometer'''
rx = RAW_IMU.xacc * 9.81 / 1000.0
ry = RAW_IMU.yacc * 9.81 / 1000.0
rz = RAW_IMU.zacc * 9.81 / 1000.0
if ATTITUDE is not None and GPS_RAW_INT is not None:
ry -= ATTITUDE.yawspeed * GPS_RAW_INT.vel*0.01
rz += ATTITUDE.pitchspeed * GPS_RAW_INT.vel*0.01
if SENSOR_OFFSETS is not None and ofs is not None:
rx += SENSOR_OFFSETS.accel_cal_x
ry += SENSOR_OFFSETS.accel_cal_y
rz += SENSOR_OFFSETS.accel_cal_z
rx -= ofs[0]
ry -= ofs[1]
rz -= ofs[2]
if mul is not None:
rx *= mul[0]
ry *= mul[1]
rz *= mul[2]
return lowpass(degrees(-asin(ry/sqrt(rx**2+ry**2+rz**2))),'_roll',smooth)
def pitch_estimate(RAW_IMU, GPS_RAW_INT=None,ATTITUDE=None, SENSOR_OFFSETS=None, ofs=None, mul=None, smooth=0.7):
'''estimate pitch from accelerometer'''
rx = RAW_IMU.xacc * 9.81 / 1000.0
ry = RAW_IMU.yacc * 9.81 / 1000.0
rz = RAW_IMU.zacc * 9.81 / 1000.0
if ATTITUDE is not None and GPS_RAW_INT is not None:
ry -= ATTITUDE.yawspeed * GPS_RAW_INT.vel*0.01
rz += ATTITUDE.pitchspeed * GPS_RAW_INT.vel*0.01
if SENSOR_OFFSETS is not None and ofs is not None:
rx += SENSOR_OFFSETS.accel_cal_x
ry += SENSOR_OFFSETS.accel_cal_y
rz += SENSOR_OFFSETS.accel_cal_z
rx -= ofs[0]
ry -= ofs[1]
rz -= ofs[2]
if mul is not None:
rx *= mul[0]
ry *= mul[1]
rz *= mul[2]
return lowpass(degrees(asin(rx/sqrt(rx**2+ry**2+rz**2))),'_pitch',smooth)
def rotation(ATTITUDE):
'''return the current DCM rotation matrix'''
r = Matrix3()
r.from_euler(ATTITUDE.roll, ATTITUDE.pitch, ATTITUDE.yaw)
return r
def mag_rotation(RAW_IMU, inclination, declination):
'''return an attitude rotation matrix that is consistent with the current mag
vector'''
m_body = Vector3(RAW_IMU.xmag, RAW_IMU.ymag, RAW_IMU.zmag)
m_earth = Vector3(m_body.length(), 0, 0)
r = Matrix3()
r.from_euler(0, -radians(inclination), radians(declination))
m_earth = r * m_earth
r.from_two_vectors(m_earth, m_body)
return r
def mag_yaw(RAW_IMU, inclination, declination):
'''estimate yaw from mag'''
m = mag_rotation(RAW_IMU, inclination, declination)
(r, p, y) = m.to_euler()
y = degrees(y)
if y < 0:
y += 360
return y
def mag_pitch(RAW_IMU, inclination, declination):
'''estimate pithc from mag'''
m = mag_rotation(RAW_IMU, inclination, declination)
(r, p, y) = m.to_euler()
return degrees(p)
def mag_roll(RAW_IMU, inclination, declination):
'''estimate roll from mag'''
m = mag_rotation(RAW_IMU, inclination, declination)
(r, p, y) = m.to_euler()
return degrees(r)
def gravity(RAW_IMU, SENSOR_OFFSETS=None, ofs=None, mul=None, smooth=0.7):
'''estimate pitch from accelerometer'''
if hasattr(RAW_IMU, 'xacc'):
rx = RAW_IMU.xacc * 9.81 / 1000.0
ry = RAW_IMU.yacc * 9.81 / 1000.0
rz = RAW_IMU.zacc * 9.81 / 1000.0
else:
rx = RAW_IMU.AccX
ry = RAW_IMU.AccY
rz = RAW_IMU.AccZ
if SENSOR_OFFSETS is not None and ofs is not None:
rx += SENSOR_OFFSETS.accel_cal_x
ry += SENSOR_OFFSETS.accel_cal_y
rz += SENSOR_OFFSETS.accel_cal_z
rx -= ofs[0]
ry -= ofs[1]
rz -= ofs[2]
if mul is not None:
rx *= mul[0]
ry *= mul[1]
rz *= mul[2]
return sqrt(rx**2+ry**2+rz**2)
def pitch_sim(SIMSTATE, GPS_RAW):
'''estimate pitch from SIMSTATE accels'''
xacc = SIMSTATE.xacc - lowpass(delta(GPS_RAW.v,"v")*6.6, "v", 0.9)
zacc = SIMSTATE.zacc
zacc += SIMSTATE.ygyro * GPS_RAW.v;
if xacc/zacc >= 1:
return 0
if xacc/zacc <= -1:
return -0
return degrees(-asin(xacc/zacc))
def distance_two(GPS_RAW1, GPS_RAW2, horizontal=True):
'''distance between two points'''
if hasattr(GPS_RAW1, 'Lat'):
lat1 = radians(GPS_RAW1.Lat)
lat2 = radians(GPS_RAW2.Lat)
lon1 = radians(GPS_RAW1.Lng)
lon2 = radians(GPS_RAW2.Lng)
alt1 = GPS_RAW1.Alt
alt2 = GPS_RAW2.Alt
elif hasattr(GPS_RAW1, 'cog'):
lat1 = radians(GPS_RAW1.lat)*1.0e-7
lat2 = radians(GPS_RAW2.lat)*1.0e-7
lon1 = radians(GPS_RAW1.lon)*1.0e-7
lon2 = radians(GPS_RAW2.lon)*1.0e-7
alt1 = GPS_RAW1.alt*0.001
alt2 = GPS_RAW2.alt*0.001
else:
lat1 = radians(GPS_RAW1.lat)
lat2 = radians(GPS_RAW2.lat)
lon1 = radians(GPS_RAW1.lon)
lon2 = radians(GPS_RAW2.lon)
alt1 = GPS_RAW1.alt*0.001
alt2 = GPS_RAW2.alt*0.001
dLat = lat2 - lat1
dLon = lon2 - lon1
a = sin(0.5*dLat)**2 + sin(0.5*dLon)**2 * cos(lat1) * cos(lat2)
c = 2.0 * atan2(sqrt(a), sqrt(1.0-a))
ground_dist = 6371 * 1000 * c
if horizontal:
return ground_dist
return sqrt(ground_dist**2 + (alt2-alt1)**2)
first_fix = None
def distance_home(GPS_RAW):
'''distance from first fix point'''
global first_fix
if (hasattr(GPS_RAW, 'fix_type') and GPS_RAW.fix_type < 2) or \
(hasattr(GPS_RAW, 'Status') and GPS_RAW.Status < 2):
return 0
if first_fix is None:
first_fix = GPS_RAW
return 0
return distance_two(GPS_RAW, first_fix)
def sawtooth(ATTITUDE, amplitude=2.0, period=5.0):
'''sawtooth pattern based on uptime'''
mins = (ATTITUDE.usec * 1.0e-6)/60
p = fmod(mins, period*2)
if p < period:
return amplitude * (p/period)
return amplitude * (period - (p-period))/period
def rate_of_turn(speed, bank):
'''return expected rate of turn in degrees/s for given speed in m/s and
bank angle in degrees'''
if abs(speed) < 2 or abs(bank) > 80:
return 0
ret = degrees(9.81*tan(radians(bank))/speed)
return ret
def wingloading(bank):
'''return expected wing loading factor for a bank angle in radians'''
return 1.0/cos(bank)
def airspeed(VFR_HUD, ratio=None, used_ratio=None, offset=None):
'''recompute airspeed with a different ARSPD_RATIO'''
from . import mavutil
mav = mavutil.mavfile_global
if ratio is None:
ratio = 1.9936 # APM default
if used_ratio is None:
if 'ARSPD_RATIO' in mav.params:
used_ratio = mav.params['ARSPD_RATIO']
else:
print("no ARSPD_RATIO in mav.params")
used_ratio = ratio
if hasattr(VFR_HUD,'airspeed'):
airspeed = VFR_HUD.airspeed
else:
airspeed = VFR_HUD.Airspeed
airspeed_pressure = (airspeed**2) / used_ratio
if offset is not None:
airspeed_pressure += offset
if airspeed_pressure < 0:
airspeed_pressure = 0
airspeed = sqrt(airspeed_pressure * ratio)
return airspeed
def EAS2TAS(ARSP,GPS,BARO,ground_temp=25):
'''EAS2TAS from ARSP.Temp'''
tempK = ground_temp + 273.15 - 0.0065 * GPS.Alt
return sqrt(1.225 / (BARO.Press / (287.26 * tempK)))
def airspeed_ratio(VFR_HUD):
'''recompute airspeed with a different ARSPD_RATIO'''
from . import mavutil
mav = mavutil.mavfile_global
airspeed_pressure = (VFR_HUD.airspeed**2) / ratio
airspeed = sqrt(airspeed_pressure * ratio)
return airspeed
def airspeed_voltage(VFR_HUD, ratio=None):
'''back-calculate the voltage the airspeed sensor must have seen'''
from . import mavutil
mav = mavutil.mavfile_global
if ratio is None:
ratio = 1.9936 # APM default
if 'ARSPD_RATIO' in mav.params:
used_ratio = mav.params['ARSPD_RATIO']
else:
used_ratio = ratio
if 'ARSPD_OFFSET' in mav.params:
offset = mav.params['ARSPD_OFFSET']
else:
return -1
airspeed_pressure = (pow(VFR_HUD.airspeed,2)) / used_ratio
raw = airspeed_pressure + offset
SCALING_OLD_CALIBRATION = 204.8
voltage = 5.0 * raw / 4096
return voltage
def earth_rates(ATTITUDE):
'''return angular velocities in earth frame'''
from math import sin, cos, tan, fabs
p = ATTITUDE.rollspeed
q = ATTITUDE.pitchspeed
r = ATTITUDE.yawspeed
phi = ATTITUDE.roll
theta = ATTITUDE.pitch
psi = ATTITUDE.yaw
phiDot = p + tan(theta)*(q*sin(phi) + r*cos(phi))
thetaDot = q*cos(phi) - r*sin(phi)
if fabs(cos(theta)) < 1.0e-20:
theta += 1.0e-10
psiDot = (q*sin(phi) + r*cos(phi))/cos(theta)
return (phiDot, thetaDot, psiDot)
def roll_rate(ATTITUDE):
'''return roll rate in earth frame'''
(phiDot, thetaDot, psiDot) = earth_rates(ATTITUDE)
return phiDot
def pitch_rate(ATTITUDE):
'''return pitch rate in earth frame'''
(phiDot, thetaDot, psiDot) = earth_rates(ATTITUDE)
return thetaDot
def yaw_rate(ATTITUDE):
'''return yaw rate in earth frame'''
(phiDot, thetaDot, psiDot) = earth_rates(ATTITUDE)
return psiDot
def gps_velocity(GLOBAL_POSITION_INT):
'''return GPS velocity vector'''
return Vector3(GLOBAL_POSITION_INT.vx, GLOBAL_POSITION_INT.vy, GLOBAL_POSITION_INT.vz) * 0.01
def gps_velocity_old(GPS_RAW_INT):
'''return GPS velocity vector'''
return Vector3(GPS_RAW_INT.vel*0.01*cos(radians(GPS_RAW_INT.cog*0.01)),
GPS_RAW_INT.vel*0.01*sin(radians(GPS_RAW_INT.cog*0.01)), 0)
def gps_velocity_body(GPS_RAW_INT, ATTITUDE):
'''return GPS velocity vector in body frame'''
r = rotation(ATTITUDE)
return r.transposed() * Vector3(GPS_RAW_INT.vel*0.01*cos(radians(GPS_RAW_INT.cog*0.01)),
GPS_RAW_INT.vel*0.01*sin(radians(GPS_RAW_INT.cog*0.01)),
-tan(ATTITUDE.pitch)*GPS_RAW_INT.vel*0.01)
def earth_accel(RAW_IMU,ATTITUDE):
'''return earth frame acceleration vector'''
r = rotation(ATTITUDE)
accel = Vector3(RAW_IMU.xacc, RAW_IMU.yacc, RAW_IMU.zacc) * 9.81 * 0.001
return r * accel
def earth_gyro(RAW_IMU,ATTITUDE):
'''return earth frame gyro vector'''
r = rotation(ATTITUDE)
accel = Vector3(degrees(RAW_IMU.xgyro), degrees(RAW_IMU.ygyro), degrees(RAW_IMU.zgyro)) * 0.001
return r * accel
def airspeed_energy_error(NAV_CONTROLLER_OUTPUT, VFR_HUD):
'''return airspeed energy error matching APM internals
This is positive when we are going too slow
'''
aspeed_cm = VFR_HUD.airspeed*100
target_airspeed = NAV_CONTROLLER_OUTPUT.aspd_error + aspeed_cm
airspeed_energy_error = ((target_airspeed*target_airspeed) - (aspeed_cm*aspeed_cm))*0.00005
return airspeed_energy_error
def energy_error(NAV_CONTROLLER_OUTPUT, VFR_HUD):
'''return energy error matching APM internals
This is positive when we are too low or going too slow
'''
aspeed_energy_error = airspeed_energy_error(NAV_CONTROLLER_OUTPUT, VFR_HUD)
alt_error = NAV_CONTROLLER_OUTPUT.alt_error*100
energy_error = aspeed_energy_error + alt_error*0.098
return energy_error
def rover_turn_circle(SERVO_OUTPUT_RAW):
'''return turning circle (diameter) in meters for steering_angle in degrees
'''
# this matches Toms slash
max_wheel_turn = 35
wheelbase = 0.335
wheeltrack = 0.296
steering_angle = max_wheel_turn * (SERVO_OUTPUT_RAW.servo1_raw - 1500) / 400.0
theta = radians(steering_angle)
return (wheeltrack/2) + (wheelbase/sin(theta))
def rover_yaw_rate(VFR_HUD, SERVO_OUTPUT_RAW):
'''return yaw rate in degrees/second given steering_angle and speed'''
max_wheel_turn=35
speed = VFR_HUD.groundspeed
# assume 1100 to 1900 PWM on steering
steering_angle = max_wheel_turn * (SERVO_OUTPUT_RAW.servo1_raw - 1500) / 400.0
if abs(steering_angle) < 1.0e-6 or abs(speed) < 1.0e-6:
return 0
d = rover_turn_circle(SERVO_OUTPUT_RAW)
c = pi * d
t = c / speed
rate = 360.0 / t
return rate
def rover_lat_accel(VFR_HUD, SERVO_OUTPUT_RAW):
'''return lateral acceleration in m/s/s'''
speed = VFR_HUD.groundspeed
yaw_rate = rover_yaw_rate(VFR_HUD, SERVO_OUTPUT_RAW)
accel = radians(yaw_rate) * speed
return accel
def demix1(servo1, servo2, gain=0.5):
'''de-mix a mixed servo output'''
s1 = servo1 - 1500
s2 = servo2 - 1500
out1 = (s1+s2)*gain
out2 = (s1-s2)*gain
return out1+1500
def demix2(servo1, servo2, gain=0.5):
'''de-mix a mixed servo output'''
s1 = servo1 - 1500
s2 = servo2 - 1500
out1 = (s1+s2)*gain
out2 = (s1-s2)*gain
return out2+1500
def mixer(servo1, servo2, mixtype=1, gain=0.5):
'''mix two servos'''
s1 = servo1 - 1500
s2 = servo2 - 1500
v1 = (s1-s2)*gain
v2 = (s1+s2)*gain
if mixtype == 2:
v2 = -v2
elif mixtype == 3:
v1 = -v1
elif mixtype == 4:
v1 = -v1
v2 = -v2
if v1 > 600:
v1 = 600
elif v1 < -600:
v1 = -600
if v2 > 600:
v2 = 600
elif v2 < -600:
v2 = -600
return (1500+v1,1500+v2)
def mix1(servo1, servo2, mixtype=1, gain=0.5):
'''de-mix a mixed servo output'''
(v1,v2) = mixer(servo1, servo2, mixtype=mixtype, gain=gain)
return v1
def mix2(servo1, servo2, mixtype=1, gain=0.5):
'''de-mix a mixed servo output'''
(v1,v2) = mixer(servo1, servo2, mixtype=mixtype, gain=gain)
return v2
def wrap_180(angle):
if angle > 180:
angle -= 360.0
if angle < -180:
angle += 360.0
return angle
def wrap_360(angle):
if angle > 360:
angle -= 360.0
if angle < 0:
angle += 360.0
return angle
class DCM_State(object):
'''DCM state object'''
def __init__(self, roll, pitch, yaw):
self.dcm = Matrix3()
self.dcm2 = Matrix3()
self.dcm.from_euler(radians(roll), radians(pitch), radians(yaw))
self.dcm2.from_euler(radians(roll), radians(pitch), radians(yaw))
self.mag = Vector3()
self.gyro = Vector3()
self.accel = Vector3()
self.gps = None
self.rate = 50.0
self.kp = 0.2
self.kp_yaw = 0.3
self.omega_P = Vector3()
self.omega_P_yaw = Vector3()
self.omega_I = Vector3() # (-0.00199045287445, -0.00653007719666, -0.00714212376624)
self.omega_I_sum = Vector3()
self.omega_I_sum_time = 0
self.omega = Vector3()
self.ra_sum = Vector3()
self.last_delta_angle = Vector3()
self.last_velocity = Vector3()
(self.roll, self.pitch, self.yaw) = self.dcm.to_euler()
(self.roll2, self.pitch2, self.yaw2) = self.dcm2.to_euler()
def update(self, gyro, accel, mag, GPS):
if self.gyro != gyro or self.accel != accel:
delta_angle = old_div((gyro+self.omega_I), self.rate)
self.dcm.rotate(delta_angle)
correction = self.last_delta_angle % delta_angle
#print (delta_angle - self.last_delta_angle) * 58.0
corrected_delta = delta_angle + 0.0833333 * correction
self.dcm2.rotate(corrected_delta)
self.last_delta_angle = delta_angle
self.dcm.normalize()
self.dcm2.normalize()
self.gyro = gyro
self.accel = accel
(self.roll, self.pitch, self.yaw) = self.dcm.to_euler()
(self.roll2, self.pitch2, self.yaw2) = self.dcm2.to_euler()
dcm_state = None
def DCM_update(IMU, ATT, MAG, GPS):
'''implement full DCM system'''
global dcm_state
if dcm_state is None:
dcm_state = DCM_State(ATT.Roll, ATT.Pitch, ATT.Yaw)
mag = Vector3(MAG.MagX, MAG.MagY, MAG.MagZ)
gyro = Vector3(IMU.GyrX, IMU.GyrY, IMU.GyrZ)
accel = Vector3(IMU.AccX, IMU.AccY, IMU.AccZ)
accel2 = Vector3(IMU.AccX, IMU.AccY, IMU.AccZ)
dcm_state.update(gyro, accel, mag, GPS)
return dcm_state
class PX4_State(object):
'''PX4 DCM state object'''
def __init__(self, roll, pitch, yaw, timestamp):
self.dcm = Matrix3()
self.dcm.from_euler(radians(roll), radians(pitch), radians(yaw))
self.gyro = Vector3()
self.accel = Vector3()
self.timestamp = timestamp
(self.roll, self.pitch, self.yaw) = self.dcm.to_euler()
def update(self, gyro, accel, timestamp):
if self.gyro != gyro or self.accel != accel:
delta_angle = gyro * (timestamp - self.timestamp)
self.timestamp = timestamp
self.dcm.rotate(delta_angle)
self.dcm.normalize()
self.gyro = gyro
self.accel = accel
(self.roll, self.pitch, self.yaw) = self.dcm.to_euler()
px4_state = None
def PX4_update(IMU, ATT):
'''implement full DCM using PX4 native SD log data'''
global px4_state
if px4_state is None:
px4_state = PX4_State(degrees(ATT.Roll), degrees(ATT.Pitch), degrees(ATT.Yaw), IMU._timestamp)
gyro = Vector3(IMU.GyroX, IMU.GyroY, IMU.GyroZ)
accel = Vector3(IMU.AccX, IMU.AccY, IMU.AccZ)
px4_state.update(gyro, accel, IMU._timestamp)
return px4_state
_downsample_N = 0
def downsample(N):
'''conditional that is true on every Nth sample'''
global _downsample_N
_downsample_N = (_downsample_N + 1) % N
return _downsample_N == 0
def armed(HEARTBEAT):
'''return 1 if armed, 0 if not'''
from . import mavutil
if HEARTBEAT.type == mavutil.mavlink.MAV_TYPE_GCS:
self = mavutil.mavfile_global
if self.motors_armed():
return 1
return 0
if HEARTBEAT.base_mode & mavutil.mavlink.MAV_MODE_FLAG_SAFETY_ARMED:
return 1
return 0
def rotation_df(ATT):
'''return the current DCM rotation matrix'''
r = Matrix3()
r.from_euler(radians(ATT.Roll), radians(ATT.Pitch), radians(ATT.Yaw))
return r
def rotation2(AHRS2):
'''return the current DCM rotation matrix'''
r = Matrix3()
r.from_euler(AHRS2.roll, AHRS2.pitch, AHRS2.yaw)
return r
def earth_accel2(RAW_IMU,ATTITUDE):
'''return earth frame acceleration vector from AHRS2'''
r = rotation2(ATTITUDE)
accel = Vector3(RAW_IMU.xacc, RAW_IMU.yacc, RAW_IMU.zacc) * 9.81 * 0.001
return r * accel
def earth_accel_df(IMU,ATT):
'''return earth frame acceleration vector from df log'''
r = rotation_df(ATT)
accel = Vector3(IMU.AccX, IMU.AccY, IMU.AccZ)
return r * accel
def earth_accel2_df(IMU,IMU2,ATT):
'''return earth frame acceleration vector from df log'''
r = rotation_df(ATT)
accel1 = Vector3(IMU.AccX, IMU.AccY, IMU.AccZ)
accel2 = Vector3(IMU2.AccX, IMU2.AccY, IMU2.AccZ)
accel = 0.5 * (accel1 + accel2)
return r * accel
def gps_velocity_df(GPS):
'''return GPS velocity vector'''
vx = GPS.Spd * cos(radians(GPS.GCrs))
vy = GPS.Spd * sin(radians(GPS.GCrs))
return Vector3(vx, vy, GPS.VZ)
def distance_gps2(GPS, GPS2):
'''distance between two points'''
if GPS.TimeMS != GPS2.TimeMS:
# reject messages not time aligned
return None
return distance_two(GPS, GPS2)
radius_of_earth = 6378100.0 # in meters
def wrap_valid_longitude(lon):
''' wrap a longitude value around to always have a value in the range
[-180, +180) i.e 0 => 0, 1 => 1, -1 => -1, 181 => -179, -181 => 179
'''
return (((lon + 180.0) % 360.0) - 180.0)
def gps_newpos(lat, lon, bearing, distance):
'''extrapolate latitude/longitude given a heading and distance
thanks to http://www.movable-type.co.uk/scripts/latlong.html
'''
import math
lat1 = math.radians(lat)
lon1 = math.radians(lon)
brng = math.radians(bearing)
dr = distance/radius_of_earth
lat2 = math.asin(math.sin(lat1)*math.cos(dr) +
math.cos(lat1)*math.sin(dr)*math.cos(brng))
lon2 = lon1 + math.atan2(math.sin(brng)*math.sin(dr)*math.cos(lat1),
math.cos(dr)-math.sin(lat1)*math.sin(lat2))
return (math.degrees(lat2), wrap_valid_longitude(math.degrees(lon2)))
def gps_offset(lat, lon, east, north):
'''return new lat/lon after moving east/north
by the given number of meters'''
import math
bearing = math.degrees(math.atan2(east, north))
distance = math.sqrt(east**2 + north**2)
return gps_newpos(lat, lon, bearing, distance)
ekf_home = None
def ekf1_pos(EKF1):
'''calculate EKF position when EKF disabled'''
global ekf_home
from . import mavutil
self = mavutil.mavfile_global
if ekf_home is None:
if not 'GPS' in self.messages or self.messages['GPS'].Status != 3:
return None
ekf_home = self.messages['GPS']
(ekf_home.Lat, ekf_home.Lng) = gps_offset(ekf_home.Lat, ekf_home.Lng, -EKF1.PE, -EKF1.PN)
(lat,lon) = gps_offset(ekf_home.Lat, ekf_home.Lng, EKF1.PE, EKF1.PN)
return (lat, lon)
def quat_to_euler(q):
'''
Get Euler angles from a quaternion
:param q: quaternion [w, x, y , z]
:returns: euler angles [roll, pitch, yaw]
'''
quat = Quaternion(q)
return quat.euler
def euler_to_quat(e):
'''
Get quaternion from euler angles
:param e: euler angles [roll, pitch, yaw]
:returns: quaternion [w, x, y , z]
'''
quat = Quaternion(e)
return quat.q
def rotate_quat(attitude, roll, pitch, yaw):
'''
Returns rotated quaternion
:param attitude: quaternion [w, x, y , z]
:param roll: rotation in rad
:param pitch: rotation in rad
:param yaw: rotation in rad
:returns: quaternion [w, x, y , z]
'''
quat = Quaternion(attitude)
rotation = Quaternion([roll, pitch, yaw])
res = rotation * quat
return res.q
def qroll(MSG):
'''return quaternion roll in degrees'''
q = Quaternion([MSG.Q1,MSG.Q2,MSG.Q3,MSG.Q4])
return degrees(q.euler[0])
def qpitch(MSG):
'''return quaternion pitch in degrees'''
q = Quaternion([MSG.Q1,MSG.Q2,MSG.Q3,MSG.Q4])
return degrees(q.euler[1])
def qyaw(MSG):
'''return quaternion yaw in degrees'''
q = Quaternion([MSG.Q1,MSG.Q2,MSG.Q3,MSG.Q4])
return degrees(q.euler[2])
def euler_rotated(MSG, roll, pitch, yaw):
'''return eulers in radians from quaternion for view at given attitude in euler radians'''
rot_view = Matrix3()
rot_view.from_euler(roll, pitch, yaw)
q = Quaternion([MSG.Q1,MSG.Q2,MSG.Q3,MSG.Q4])
dcm = (rot_view * q.dcm.transposed()).transposed()
return dcm.to_euler()
def euler_p90(MSG):
'''return eulers in radians from quaternion for view at pitch 90'''
return euler_rotated(MSG, 0, radians(90), 0);
def qroll_p90(MSG):
'''return quaternion roll in degrees for view at pitch 90'''
return degrees(euler_p90(MSG)[0])
def qpitch_p90(MSG):
'''return quaternion roll in degrees for view at pitch 90'''
return degrees(euler_p90(MSG)[1])
def qyaw_p90(MSG):
'''return quaternion roll in degrees for view at pitch 90'''
return degrees(euler_p90(MSG)[2])