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2039 - 1
// Navigation with a GPS directly attached to the FC's UART1.
2
 
3
#include <inttypes.h>
4
#include <stdlib.h>
5
#include <stddef.h>
6
//#include "mymath.h"
7
//#include "timer0.h"
8
//#include "uart1.h"
9
//#include "rc.h"
10
//#include "eeprom.h"
11
#include "ubx.h"
12
#include "configuration.h"
13
#include "controlMixer.h"
14
#include "output.h"
15
#include "isqrt.h"
16
#include "attitude.h"
17
#include "dongfangMath.h"
18
 
19
typedef enum {
20
  GPS_FLIGHT_MODE_UNDEF,
21
  GPS_FLIGHT_MODE_FREE,
22
  GPS_FLIGHT_MODE_AID,
23
  GPS_FLIGHT_MODE_HOME,
24
} FlightMode_t;
25
 
26
#define GPS_POSINTEGRAL_LIMIT 32000
27
#define GPS_STICK_LIMIT         45              // limit of gps stick control to avoid critical flight attitudes
28
#define GPS_P_LIMIT                     25
29
 
30
typedef struct {
31
  int32_t longitude;
32
  int32_t latitude;
33
  int32_t altitude;
34
  Status_t status;
35
} GPS_Pos_t;
36
 
37
// GPS coordinates for hold position
38
GPS_Pos_t holdPosition = { 0, 0, 0, INVALID };
39
// GPS coordinates for home position
40
GPS_Pos_t homePosition = { 0, 0, 0, INVALID };
41
// the current flight mode
42
FlightMode_t flightMode = GPS_FLIGHT_MODE_UNDEF;
43
 
44
// ---------------------------------------------------------------------------------
45
void GPS_updateFlightMode(void) {
46
  static FlightMode_t flightModeOld = GPS_FLIGHT_MODE_UNDEF;
47
 
48
  if (controlMixer_getSignalQuality() <= SIGNAL_BAD
49
      || MKFlags & MKFLAG_EMERGENCY_FLIGHT) {
50
    flightMode = GPS_FLIGHT_MODE_FREE;
51
  } else {
52
    if (dynamicParams.directGPSMode < 50)
53
      flightMode = GPS_FLIGHT_MODE_AID;
54
    else if (dynamicParams.directGPSMode < 180)
55
      flightMode = GPS_FLIGHT_MODE_FREE;
56
    else
57
      flightMode = GPS_FLIGHT_MODE_HOME;
58
  }
59
 
60
  if (flightMode != flightModeOld) {
61
    beep(100);
62
    flightModeOld = flightMode;
63
  }
64
}
65
 
66
// ---------------------------------------------------------------------------------
67
// This function defines a good GPS signal condition
68
uint8_t GPS_isSignalOK(void) {
69
  static uint8_t GPSFix = 0;
70
  if ((GPSInfo.status != INVALID) && (GPSInfo.satfix == SATFIX_3D)
71
      && (GPSInfo.flags & FLAG_GPSFIXOK)
72
      && ((GPSInfo.satnum >= staticParams.GPSMininumSatellites) || GPSFix)) {
73
    GPSFix = 1;
74
    return 1;
75
  } else
76
    return (0);
77
}
78
 
79
// ---------------------------------------------------------------------------------
80
// rescale xy-vector length to  limit
81
uint8_t GPS_limitXY(int32_t *x, int32_t *y, int32_t limit) {
82
  int32_t len;
83
  len = isqrt32(*x * *x + *y * *y);
84
  if (len > limit) {
85
    // normalize control vector components to the limit
86
    *x = (*x * limit) / len;
87
    *y = (*y * limit) / len;
88
    return 1;
89
  }
90
  return 0;
91
}
92
 
93
// checks nick and roll sticks for manual control
94
uint8_t GPS_isManuallyControlled(int16_t* naviSticks) {
95
  if (naviSticks[CONTROL_PITCH] < staticParams.naviStickThreshold
96
      && naviSticks[CONTROL_ROLL] < staticParams.naviStickThreshold)
97
    return 0;
98
  else
99
    return 1;
100
}
101
 
102
// set given position to current gps position
103
uint8_t GPS_setCurrPosition(GPS_Pos_t * pGPSPos) {
104
  uint8_t retval = 0;
105
  if (pGPSPos == NULL)
106
    return (retval); // bad pointer
107
 
108
  if (GPS_isSignalOK()) { // is GPS signal condition is fine
109
    pGPSPos->longitude = GPSInfo.longitude;
110
    pGPSPos->latitude = GPSInfo.latitude;
111
    pGPSPos->altitude = GPSInfo.altitude;
112
    pGPSPos->status = NEWDATA;
113
    retval = 1;
114
  } else { // bad GPS signal condition
115
    pGPSPos->status = INVALID;
116
    retval = 0;
117
  }
118
  return (retval);
119
}
120
 
121
// clear position
122
uint8_t GPS_clearPosition(GPS_Pos_t * pGPSPos) {
123
  uint8_t retval = 0;
124
  if (pGPSPos == NULL)
125
    return retval; // bad pointer
126
  else {
127
    pGPSPos->longitude = 0;
128
    pGPSPos->latitude = 0;
129
    pGPSPos->altitude = 0;
130
    pGPSPos->status = INVALID;
131
    retval = 1;
132
  }
133
  return (retval);
134
}
135
 
136
// calculates the GPS control stick values from the deviation to target position
137
// if the pointer to the target positin is NULL or is the target position invalid
138
// then the P part of the controller is deactivated.
139
void GPS_PIDController(GPS_Pos_t *pTargetPos, int16_t* sticks) {
140
  static int32_t PID_Nick, PID_Roll;
141
  int32_t coscompass, sincompass;
142
  int32_t GPSPosDev_North, GPSPosDev_East; // Position deviation in cm
143
  int32_t P_North = 0, D_North = 0, P_East = 0, D_East = 0, I_North = 0,
144
      I_East = 0;
145
  int32_t PID_North = 0, PID_East = 0;
146
  static int32_t cos_target_latitude = 1;
147
  static int32_t GPSPosDevIntegral_North = 0, GPSPosDevIntegral_East = 0;
148
  static GPS_Pos_t *pLastTargetPos = 0;
149
 
150
  // if GPS data and Compass are ok
151
  if (GPS_isSignalOK() && (compassHeading >= 0)) {
152
    if (pTargetPos != NULL) // if there is a target position
153
        {
154
      if (pTargetPos->status != INVALID) // and the position data are valid
155
          {
156
        // if the target data are updated or the target pointer has changed
157
        if ((pTargetPos->status != PROCESSED)
158
            || (pTargetPos != pLastTargetPos)) {
159
          // reset error integral
160
          GPSPosDevIntegral_North = 0;
161
          GPSPosDevIntegral_East = 0;
162
          // recalculate latitude projection
163
          cos_target_latitude = int_cos((int16_t) (pTargetPos->latitude / 10000000L));
164
          // remember last target pointer
165
          pLastTargetPos = pTargetPos;
166
          // mark data as processed
167
          pTargetPos->status = PROCESSED;
168
        }
169
        // calculate position deviation from latitude and longitude differences
170
        GPSPosDev_North = (GPSInfo.latitude - pTargetPos->latitude); // to calculate real cm we would need *111/100 additionally
171
        GPSPosDev_East = (GPSInfo.longitude - pTargetPos->longitude); // to calculate real cm we would need *111/100 additionally
172
        // calculate latitude projection
173
        GPSPosDev_East *= cos_target_latitude;
174
        GPSPosDev_East >>= MATH_UNIT_FACTOR_LOG;
175
      } else { // no valid target position available
176
        // reset error
177
        GPSPosDev_North = 0;
178
        GPSPosDev_East = 0;
179
        // reset error integral
180
        GPSPosDevIntegral_North = 0;
181
        GPSPosDevIntegral_East = 0;
182
      }
183
    } else { // no target position available
184
      // reset error
185
      GPSPosDev_North = 0;
186
      GPSPosDev_East = 0;
187
      // reset error integral
188
      GPSPosDevIntegral_North = 0;
189
      GPSPosDevIntegral_East = 0;
190
    }
191
 
192
    //Calculate PID-components of the controller
193
 
194
    // D-Part
195
    D_North = ((int32_t) staticParams.naviD * GPSInfo.velnorth) / 512;
196
    D_East = ((int32_t) staticParams.naviD * GPSInfo.veleast) / 512;
197
 
198
    // P-Part
199
    P_North = ((int32_t) staticParams.naviP * GPSPosDev_North) / 2048;
200
    P_East = ((int32_t) staticParams.naviP * GPSPosDev_East) / 2048;
201
 
202
    // I-Part
203
    I_North = ((int32_t) staticParams.naviI * GPSPosDevIntegral_North)
204
        / 8192;
205
    I_East = ((int32_t) staticParams.naviI * GPSPosDevIntegral_East) / 8192;
206
 
207
    // combine P & I
208
    PID_North = P_North + I_North;
209
    PID_East = P_East + I_East;
210
    if (!GPS_limitXY(&PID_North, &PID_East, GPS_P_LIMIT)) {
211
      GPSPosDevIntegral_North += GPSPosDev_North / 16;
212
      GPSPosDevIntegral_East += GPSPosDev_East / 16;
213
      GPS_limitXY(&GPSPosDevIntegral_North, &GPSPosDevIntegral_East,
214
          GPS_POSINTEGRAL_LIMIT);
215
    }
216
 
217
    // combine PI- and D-Part
218
    PID_North += D_North;
219
    PID_East += D_East;
220
 
221
    // scale combination with gain.
222
    // dongfang: Lets not do that. P I and D can be scaled instead.
223
    // PID_North = (PID_North * (int32_t) staticParams.NaviGpsGain) / 100;
224
    // PID_East = (PID_East * (int32_t) staticParams.NaviGpsGain) / 100;
225
 
226
    // GPS to nick and roll settings
227
    // A positive nick angle moves head downwards (flying forward).
228
    // A positive roll angle tilts left side downwards (flying left).
229
    // If compass heading is 0 the head of the copter is in north direction.
230
    // A positive nick angle will fly to north and a positive roll angle will fly to west.
231
    // In case of a positive north deviation/velocity the
232
    // copter should fly to south (negative nick).
233
    // In case of a positive east position deviation and a positive east velocity the
234
    // copter should fly to west (positive roll).
235
    // The influence of the GPSStickNick and GPSStickRoll variable is contrarily to the stick values
236
    // in the flight.c. Therefore a positive north deviation/velocity should result in a positive
237
    // GPSStickNick and a positive east deviation/velocity should result in a negative GPSStickRoll.
238
 
239
    coscompass = int_cos(yawGyroHeading / GYRO_DEG_FACTOR_YAW);
240
    sincompass = int_sin(yawGyroHeading / GYRO_DEG_FACTOR_YAW);
241
    PID_Nick = (coscompass * PID_North + sincompass * PID_East) >> MATH_UNIT_FACTOR_LOG;
242
    PID_Roll = (sincompass * PID_North - coscompass * PID_East) >> MATH_UNIT_FACTOR_LOG;
243
 
244
    // limit resulting GPS control vector
245
    GPS_limitXY(&PID_Nick, &PID_Roll, GPS_STICK_LIMIT);
246
 
247
    sticks[CONTROL_PITCH] += (int16_t) PID_Nick;
248
    sticks[CONTROL_ROLL] += (int16_t) PID_Roll;
249
  } else { // invalid GPS data or bad compass reading
250
    // reset error integral
251
    GPSPosDevIntegral_North = 0;
252
    GPSPosDevIntegral_East = 0;
253
  }
254
}
255
 
256
void navigation_periodicTask(int16_t* sticks) {
257
  static uint8_t GPS_P_Delay = 0;
258
  static uint16_t beep_rythm = 0;
259
 
260
  GPS_updateFlightMode();
261
 
262
  // store home position if start of flight flag is set
263
  if (MKFlags & MKFLAG_CALIBRATE) {
264
    if (GPS_setCurrPosition(&homePosition))
265
      beep(700);
266
  }
267
 
268
  switch (GPSInfo.status) {
269
  case INVALID: // invalid gps data
270
    if (flightMode != GPS_FLIGHT_MODE_FREE) {
271
      beep(100); // beep if signal is neccesary
272
    }
273
    break;
274
  case PROCESSED: // if gps data are already processed do nothing
275
    // downcount timeout
276
    if (GPSTimeout)
277
      GPSTimeout--;
278
    // if no new data arrived within timeout set current data invalid
279
    // and therefore disable GPS
280
    else {
281
      GPSInfo.status = INVALID;
282
    }
283
    break;
284
  case NEWDATA: // new valid data from gps device
285
    // if the gps data quality is good
286
    beep_rythm++;
287
    if (GPS_isSignalOK()) {
288
      switch (flightMode) { // check what's to do
289
      case GPS_FLIGHT_MODE_FREE:
290
        // update hold position to current gps position
291
        GPS_setCurrPosition(&holdPosition); // can get invalid if gps signal is bad
292
        // disable gps control
293
        break;
294
 
295
      case GPS_FLIGHT_MODE_AID:
296
        if (holdPosition.status != INVALID) {
297
          if (GPS_isManuallyControlled(sticks)) { // MK controlled by user
298
            // update hold point to current gps position
299
            GPS_setCurrPosition(&holdPosition);
300
            // disable gps control
301
            GPS_P_Delay = 0;
302
          } else { // GPS control active
303
            if (GPS_P_Delay < 7) {
304
              // delayed activation of P-Part for 8 cycles (8*0.25s = 2s)
305
              GPS_P_Delay++;
306
              GPS_setCurrPosition(&holdPosition); // update hold point to current gps position
307
              GPS_PIDController(NULL, sticks); // activates only the D-Part
308
            } else
309
              GPS_PIDController(&holdPosition, sticks); // activates the P&D-Part
310
          }
311
        } else // invalid Hold Position
312
        { // try to catch a valid hold position from gps data input
313
          GPS_setCurrPosition(&holdPosition);
314
        }
315
        break;
316
 
317
      case GPS_FLIGHT_MODE_HOME:
318
        if (homePosition.status != INVALID) {
319
          // update hold point to current gps position
320
          // to avoid a flight back if home comming is deactivated
321
          GPS_setCurrPosition(&holdPosition);
322
          if (GPS_isManuallyControlled(sticks)) // MK controlled by user
323
          {
324
          } else {// GPS control active
325
            GPS_PIDController(&homePosition, sticks);
326
          }
327
        } else {
328
          // bad home position
329
          beep(50); // signal invalid home position
330
          // try to hold at least the position as a fallback option
331
 
332
          if (holdPosition.status != INVALID) {
333
            if (GPS_isManuallyControlled(sticks)) {
334
              // MK controlled by user
335
            } else {
336
              // GPS control active
337
              GPS_PIDController(&holdPosition, sticks);
338
            }
339
          } else { // try to catch a valid hold position
340
            GPS_setCurrPosition(&holdPosition);
341
          }
342
        }
343
        break; // eof TSK_HOME
344
      default: // unhandled task
345
        break; // eof default
346
      } // eof switch GPS_Task
347
    } // eof gps data quality is good
348
    else // gps data quality is bad
349
    { // disable gps control
350
      if (flightMode != GPS_FLIGHT_MODE_FREE) {
351
        // beep if signal is not sufficient
352
        if (!(GPSInfo.flags & FLAG_GPSFIXOK) && !(beep_rythm % 5))
353
          beep(100);
354
        else if (GPSInfo.satnum < staticParams.GPSMininumSatellites
355
            && !(beep_rythm % 5))
356
          beep(10);
357
      }
358
    }
359
    // set current data as processed to avoid further calculations on the same gps data
360
    GPSInfo.status = PROCESSED;
361
    break;
362
  } // eof GPSInfo.status
363
}
364