james kain / Mbed 2 deprecated GPS_Incremental

JEK changes enabling proper recording of IMU/GPS datastrams - 02-APR-2013

Dependencies:   mbed

Fork of GPS_Incremental by Dan Matthews

PCMessaging.h@6:2a8486283198, 2013-04-02 (annotated)

Committer:
jekain314
Date:
Tue Apr 02 15:22:37 2013 +0000
Revision:
6:2a8486283198
Child:
7:2e20e4cf53e6
JEK changes enabling proper recording of IMU/GPS datastreams to the SD-card

Who changed what in which revision?

UserRevisionLine numberNew contents of line
jekain314 6:2a8486283198 1 //these are defines for the messages that are sent from the PC across the USB
jekain314 6:2a8486283198 2 //these messages produce reactions on the mbed
jekain314 6:2a8486283198 3 const unsigned char STATUS_MSG =0;
jekain314 6:2a8486283198 4 const unsigned char POSVEL_MSG =1;
jekain314 6:2a8486283198 5 const unsigned char STARTDATA_MSG =2;
jekain314 6:2a8486283198 6 const unsigned char STOPDATA_MSG =3;
jekain314 6:2a8486283198 7 const unsigned char STARTSTREAM_MSG =4;
jekain314 6:2a8486283198 8 const unsigned char STOPSTREAM_MSG =5;
jekain314 6:2a8486283198 9 const unsigned char STARTLOGINFO_MSG =6;
jekain314 6:2a8486283198 10 const unsigned char STOPLOGINFO_MSG =7;
jekain314 6:2a8486283198 11
jekain314 6:2a8486283198 12 const double DEGREES_TO_RADIANS = acos(-1.0)/180.0;
jekain314 6:2a8486283198 13 const double eccen = 0.0818191908426; //WGS84 earth eccentricity
jekain314 6:2a8486283198 14 const double earthRadius = 6378137; //WGS84 earthRadius in meters
jekain314 6:2a8486283198 15
jekain314 6:2a8486283198 16 char serBuf[128];
jekain314 6:2a8486283198 17 int serBufChars=0;
jekain314 6:2a8486283198 18
jekain314 6:2a8486283198 19 //flags to control the PC command actions
jekain314 6:2a8486283198 20 bool sendPosVel =false;
jekain314 6:2a8486283198 21 bool sendStatus =false;
jekain314 6:2a8486283198 22 bool sendRecData =false;
jekain314 6:2a8486283198 23 bool streamPos =false;
jekain314 6:2a8486283198 24 bool sendStreamPos =false;
jekain314 6:2a8486283198 25 bool logMsgInfo =false;
jekain314 6:2a8486283198 26 bool sendLogMsgInfo =false;
jekain314 6:2a8486283198 27 bool recordData =false;
jekain314 6:2a8486283198 28
jekain314 6:2a8486283198 29
jekain314 6:2a8486283198 30 const unsigned char numMessages = 8; //number of potential messages
jekain314 6:2a8486283198 31 char msgList[numMessages][32]; //text array storing the command messages from the PC
jekain314 6:2a8486283198 32 char minMessageSize = 10; //minimum size of a text message
jekain314 6:2a8486283198 33 unsigned char CR = 0x0d; //ASCII Carriage Return
jekain314 6:2a8486283198 34 unsigned char LF = 0x0a; //ASCII Line Feed
jekain314 6:2a8486283198 35
jekain314 6:2a8486283198 36 void setUpMessages(void)
jekain314 6:2a8486283198 37 {
jekain314 6:2a8486283198 38 //set up the ASCII text records that are candidates to be passed from the PC
jekain314 6:2a8486283198 39 sprintf(msgList[STATUS_MSG], "WMsg STATUS");
jekain314 6:2a8486283198 40 sprintf(msgList[POSVEL_MSG], "WMsg POSVEL");
jekain314 6:2a8486283198 41 sprintf(msgList[STARTDATA_MSG], "WMsg RECORDDATA Y");
jekain314 6:2a8486283198 42 sprintf(msgList[STOPDATA_MSG], "WMsg RECORDDATA N");
jekain314 6:2a8486283198 43 sprintf(msgList[STARTSTREAM_MSG], "WMsg POSSTREAM Y");
jekain314 6:2a8486283198 44 sprintf(msgList[STOPSTREAM_MSG], "WMsg POSSTREAM N");
jekain314 6:2a8486283198 45 sprintf(msgList[STARTLOGINFO_MSG], "WMsg LOGINFO Y");
jekain314 6:2a8486283198 46 sprintf(msgList[STOPLOGINFO_MSG], "WMsg LOGINFO N");
jekain314 6:2a8486283198 47 //message length is from 10 to 16 chars
jekain314 6:2a8486283198 48
jekain314 6:2a8486283198 49 toPC.printf(" finished setting up messages \n");
jekain314 6:2a8486283198 50 }
jekain314 6:2a8486283198 51
jekain314 6:2a8486283198 52 void readFromPC()
jekain314 6:2a8486283198 53 {
jekain314 6:2a8486283198 54 //The received commands only occur at the initialization stage -- time is not that critical there.
jekain314 6:2a8486283198 55 //during the real-time action, we will never pass the followong if test ( no characters received)
jekain314 6:2a8486283198 56 if (toPC.readable()) //read a PC serial byte and test it for a command
jekain314 6:2a8486283198 57 {
jekain314 6:2a8486283198 58
jekain314 6:2a8486283198 59 // Read in next character
jekain314 6:2a8486283198 60 char inChar = toPC.getc(); //read char from the USB serial link to the PC
jekain314 6:2a8486283198 61
jekain314 6:2a8486283198 62 //incoming messages will end witb a CR / LF -- disregard these chars
jekain314 6:2a8486283198 63 if (inChar == CR || inChar == LF) return;
jekain314 6:2a8486283198 64
jekain314 6:2a8486283198 65 serBuf[serBufChars++] = inChar; //set this char in a char array
jekain314 6:2a8486283198 66
jekain314 6:2a8486283198 67 //no need to continue if numChars are less than the shortest candidate message
jekain314 6:2a8486283198 68 if (serBufChars < minMessageSize) return;
jekain314 6:2a8486283198 69
jekain314 6:2a8486283198 70 // Append end of string
jekain314 6:2a8486283198 71 //We always assume we have a complete message string and test for this below
jekain314 6:2a8486283198 72 serBuf[serBufChars] = '\0';
jekain314 6:2a8486283198 73
jekain314 6:2a8486283198 74 bool validMessage = false;
jekain314 6:2a8486283198 75
jekain314 6:2a8486283198 76 // Check for valid message -- there are numMessages possible messages
jekain314 6:2a8486283198 77 for (int m = 0; m < numMessages && !validMessage; m++) //check for all messages ...
jekain314 6:2a8486283198 78 {
jekain314 6:2a8486283198 79 //toPC.printf(" \n\n found chars to test %3d %3d %s \n\n\n ", serBufChars, strlen(msgList[m]), serBuf );
jekain314 6:2a8486283198 80
jekain314 6:2a8486283198 81 //check the current partial message against ALL possible messages
jekain314 6:2a8486283198 82 //messages must match in both strength length and text
jekain314 6:2a8486283198 83 if (serBufChars == strlen(msgList[m]) && strncmp(serBuf, msgList[m], serBufChars) == 0 )
jekain314 6:2a8486283198 84 {
jekain314 6:2a8486283198 85
jekain314 6:2a8486283198 86 //toPC.printf( "\n found valid message \n\n");
jekain314 6:2a8486283198 87
jekain314 6:2a8486283198 88 validMessage = true;
jekain314 6:2a8486283198 89 serBufChars = 0; //reset the character count to reset for next message
jekain314 6:2a8486283198 90
jekain314 6:2a8486283198 91 //set programmatic action flags based on the message
jekain314 6:2a8486283198 92 switch(m)
jekain314 6:2a8486283198 93 {
jekain314 6:2a8486283198 94 case STATUS_MSG:
jekain314 6:2a8486283198 95 sendStatus = true; //send a status message back to PC
jekain314 6:2a8486283198 96 break;
jekain314 6:2a8486283198 97 case POSVEL_MSG:
jekain314 6:2a8486283198 98 sendPosVel = true; //send a posvel message back to PC
jekain314 6:2a8486283198 99 break;
jekain314 6:2a8486283198 100 case STARTDATA_MSG: //start the data recording to the SD card
jekain314 6:2a8486283198 101 recordData = true;
jekain314 6:2a8486283198 102 sendRecData = true;
jekain314 6:2a8486283198 103 break;
jekain314 6:2a8486283198 104 case STOPDATA_MSG: //stop the data recording to the SD card
jekain314 6:2a8486283198 105 recordData = false;
jekain314 6:2a8486283198 106 sendRecData = true;
jekain314 6:2a8486283198 107 break;
jekain314 6:2a8486283198 108 case STARTSTREAM_MSG:
jekain314 6:2a8486283198 109 case STOPSTREAM_MSG:
jekain314 6:2a8486283198 110 streamPos = (m == STARTSTREAM_MSG);
jekain314 6:2a8486283198 111 sendStreamPos = true;
jekain314 6:2a8486283198 112 break;
jekain314 6:2a8486283198 113 case STARTLOGINFO_MSG:
jekain314 6:2a8486283198 114 case STOPLOGINFO_MSG:
jekain314 6:2a8486283198 115 logMsgInfo = (m == STARTLOGINFO_MSG);
jekain314 6:2a8486283198 116 sendLogMsgInfo = true;
jekain314 6:2a8486283198 117 break;
jekain314 6:2a8486283198 118 } //end Switch statement
jekain314 6:2a8486283198 119 break;
jekain314 6:2a8486283198 120 } //end test for a valid message
jekain314 6:2a8486283198 121 } //end message text loop
jekain314 6:2a8486283198 122 } //end pc.readable
jekain314 6:2a8486283198 123 };
jekain314 6:2a8486283198 124
jekain314 6:2a8486283198 125 void earthCoefficients(double latitudeRad, double longitudeRad, double height, double &latRateFac, double &lonRateFac)
jekain314 6:2a8486283198 126 {
jekain314 6:2a8486283198 127 //compute the lat and lon factors for use in the interpolation of the lat and lon between 1 sec epochs
jekain314 6:2a8486283198 128 //latRateFac & lonRateFac multiplied by Vnorth or VEast to get latRate and lonRate
jekain314 6:2a8486283198 129 //see this document (page 32) www.fas.org/spp/military/program/nav/basicnav.pdf
jekain314 6:2a8486283198 130
jekain314 6:2a8486283198 131 double eccenSinLat = eccen * sin(latitudeRad);
jekain314 6:2a8486283198 132 double temp1 = 1.0 - eccenSinLat*eccenSinLat;
jekain314 6:2a8486283198 133 double temp2 = sqrt(temp1);
jekain314 6:2a8486283198 134 double r_meridian = earthRadius * ( 1.0 - eccen*eccen)/ (temp1 * temp2);
jekain314 6:2a8486283198 135 double r_normal = earthRadius / temp2;
jekain314 6:2a8486283198 136
jekain314 6:2a8486283198 137 //divide Vnorth by latRateFac to get the latitude rate in deg per sec
jekain314 6:2a8486283198 138 latRateFac = (r_meridian + height)* DEGREES_TO_RADIANS;
jekain314 6:2a8486283198 139
jekain314 6:2a8486283198 140 //divide VEast by lonRateFac to get the longitude rate in deg per sec
jekain314 6:2a8486283198 141 lonRateFac = (r_normal + height) * cos(latitudeRad)* DEGREES_TO_RADIANS;
jekain314 6:2a8486283198 142 }
jekain314 6:2a8486283198 143
jekain314 6:2a8486283198 144 void sendPosVelMessageToPC(OEM615BESTPOS posMsg, OEM615BESTVEL velMsg)
jekain314 6:2a8486283198 145 {
jekain314 6:2a8486283198 146 //north and east velocity from the horizontal speed and heading
jekain314 6:2a8486283198 147 //velMsg may not be the "current" message --- but is the one also associated with a position message
jekain314 6:2a8486283198 148 double nVel = velMsg.horizontalSpeed*cos(velMsg.heading*DEGREES_TO_RADIANS);
jekain314 6:2a8486283198 149 double eVel = velMsg.horizontalSpeed*sin(velMsg.heading*DEGREES_TO_RADIANS);
jekain314 6:2a8486283198 150
jekain314 6:2a8486283198 151 double latRateFac;
jekain314 6:2a8486283198 152 double lonRateFac;
jekain314 6:2a8486283198 153
jekain314 6:2a8486283198 154 earthCoefficients( posMsg.latitude*DEGREES_TO_RADIANS,
jekain314 6:2a8486283198 155 posMsg.longitude*DEGREES_TO_RADIANS,
jekain314 6:2a8486283198 156 posMsg.height,
jekain314 6:2a8486283198 157 latRateFac, lonRateFac);
jekain314 6:2a8486283198 158
jekain314 6:2a8486283198 159 //commented calculations are for a spherical earth (Chris's original computation)
jekain314 6:2a8486283198 160 // For the 1 second deltas with which we are dealing
jekain314 6:2a8486283198 161 // This calculation should be close enough for now
jekain314 6:2a8486283198 162 // Approximately 1 nautical mile / minute latitude, 60 minutes/degree, 1852 meters/nautical mile
jekain314 6:2a8486283198 163 //double latMetersPerDeg = 60.0*1852.0;
jekain314 6:2a8486283198 164 // longitude separation is approximately equal to latitude separation * cosine of latitude
jekain314 6:2a8486283198 165 //double lonMetersPerDeg = latMetersPerDeg*cos(posMsg.latitude*DEGREES_TO_RADIANS);
jekain314 6:2a8486283198 166
jekain314 6:2a8486283198 167 // Elapsed time since last known GPS position
jekain314 6:2a8486283198 168 //PPSTimeOffset is a result of possibly missing a prior GPS position message
jekain314 6:2a8486283198 169 // timeFromPPS.read() is always the time from the moset recent 1PPS
jekain314 6:2a8486283198 170 double elTime = (double)PPSTimeOffset + timeFromPPS.read();
jekain314 6:2a8486283198 171
jekain314 6:2a8486283198 172 // Position time -- GPSTime is the time of the last valid GPS position message
jekain314 6:2a8486283198 173 double posTime = GPSTime + elTime;
jekain314 6:2a8486283198 174
jekain314 6:2a8486283198 175 //toPC.printf(" elTime = %6.3f PPSimeOffset = %6.3f \n", elTime, PPSTimeOffset);
jekain314 6:2a8486283198 176 //toPC.printf(" latRateFac = %10.3f lonRateFac = %10.3f \n", latRateFac, lonRateFac);
jekain314 6:2a8486283198 177 //toPC.printf(" latRateFac = %10.3f lonRateFac = %10.3f \n", latMetersPerDeg, lonMetersPerDeg);
jekain314 6:2a8486283198 178
jekain314 6:2a8486283198 179 // Estimated position based on previous position and velocity
jekain314 6:2a8486283198 180 // posMsg is the last time when the BESTVEL and BESTPOS messages had identical times
jekain314 6:2a8486283198 181 //double latPos = posMsg.latitude + (nVel/latMetersPerDeg)*elTime;
jekain314 6:2a8486283198 182 //double lonPos = posMsg.longitude + (eVel/lonMetersPerDeg)*elTime;
jekain314 6:2a8486283198 183
jekain314 6:2a8486283198 184 double latPos = posMsg.latitude + (nVel/latRateFac)*elTime;
jekain314 6:2a8486283198 185 double lonPos = posMsg.longitude + (eVel/lonRateFac)*elTime;
jekain314 6:2a8486283198 186 double htPos = posMsg.height + velMsg.verticalSpeed/(60*1852)*elTime;
jekain314 6:2a8486283198 187
jekain314 6:2a8486283198 188 toPC.printf("WMsg POSVEL %5.3lf %1d %s %8.5lf %9.5lf %4.3lf %4.3lf %4.3lf %4.3lf\n",
jekain314 6:2a8486283198 189 posTime,
jekain314 6:2a8486283198 190 posMsg.numSolSV,
jekain314 6:2a8486283198 191 posMsg.solStatus,
jekain314 6:2a8486283198 192 latPos,
jekain314 6:2a8486283198 193 lonPos,
jekain314 6:2a8486283198 194 htPos,
jekain314 6:2a8486283198 195 nVel,
jekain314 6:2a8486283198 196 eVel,
jekain314 6:2a8486283198 197 velMsg.verticalSpeed
jekain314 6:2a8486283198 198 );
jekain314 6:2a8486283198 199 }
jekain314 6:2a8486283198 200
jekain314 6:2a8486283198 201 void processPCmessages(FILE* &fpNav, OEM615BESTPOS posMsg, OEM615BESTVEL velMsg)
jekain314 6:2a8486283198 202 {
jekain314 6:2a8486283198 203
jekain314 6:2a8486283198 204 //we should put the below stuff into the readPC() procedure.
jekain314 6:2a8486283198 205 //only do these actions in response to a command so no need for the tests w/o an inoput byte from the PC
jekain314 6:2a8486283198 206 //perform the activities as a response to the commands
jekain314 6:2a8486283198 207 if (sendPosVel) //true if we want to return a position solution
jekain314 6:2a8486283198 208 {
jekain314 6:2a8486283198 209 sendPosVel=false; //set to true if a POSVEL is requested from the PC
jekain314 6:2a8486283198 210 sendPosVelMessageToPC(posMsg, velMsg);
jekain314 6:2a8486283198 211 }
jekain314 6:2a8486283198 212
jekain314 6:2a8486283198 213 //all this does is assess the GPS convergence -- really available in the above
jekain314 6:2a8486283198 214 if (sendStatus) //send the status message to the PC
jekain314 6:2a8486283198 215 {
jekain314 6:2a8486283198 216 sendStatus=false;
jekain314 6:2a8486283198 217 char solReady = 'N';
jekain314 6:2a8486283198 218 //solStatus
jekain314 6:2a8486283198 219 if (posMsg.solStatus == 0) //see description of solution status in OEMV615.h
jekain314 6:2a8486283198 220 {
jekain314 6:2a8486283198 221 solReady = 'Y';
jekain314 6:2a8486283198 222 }
jekain314 6:2a8486283198 223 toPC.printf("WMsg STATUS %5.3lf %c\n",
jekain314 6:2a8486283198 224 GPSTime,
jekain314 6:2a8486283198 225 solReady
jekain314 6:2a8486283198 226 );
jekain314 6:2a8486283198 227 }
jekain314 6:2a8486283198 228
jekain314 6:2a8486283198 229 //should just record ALL the data -- can pick over it in the post-processing
jekain314 6:2a8486283198 230 if (sendRecData) //begin to (or stop) record the serial data
jekain314 6:2a8486283198 231 {
jekain314 6:2a8486283198 232 sendRecData=false;
jekain314 6:2a8486283198 233 char recChar = 'N';
jekain314 6:2a8486283198 234 if (recordData)
jekain314 6:2a8486283198 235 {
jekain314 6:2a8486283198 236 if ((fpNav == NULL))
jekain314 6:2a8486283198 237 {
jekain314 6:2a8486283198 238 fpNav = fopen("/sd/Data/NAV.bin", "wb");
jekain314 6:2a8486283198 239 //toPC.printf("\n opened the SD card file recordData=%10d \n\n", fpNav);
jekain314 6:2a8486283198 240 }
jekain314 6:2a8486283198 241 if (fpNav != NULL)
jekain314 6:2a8486283198 242 {
jekain314 6:2a8486283198 243 recChar = 'Y';
jekain314 6:2a8486283198 244 }
jekain314 6:2a8486283198 245 else
jekain314 6:2a8486283198 246 {
jekain314 6:2a8486283198 247 toPC.printf(" Could not open the SD card \n\n");
jekain314 6:2a8486283198 248 }
jekain314 6:2a8486283198 249 }
jekain314 6:2a8486283198 250 else
jekain314 6:2a8486283198 251 {
jekain314 6:2a8486283198 252 if (fpNav != NULL)
jekain314 6:2a8486283198 253 {
jekain314 6:2a8486283198 254 toPC.printf(" closing the SD card file \n\n");
jekain314 6:2a8486283198 255 fclose(fpNav);
jekain314 6:2a8486283198 256 recordData = false;
jekain314 6:2a8486283198 257 fpNav = NULL;
jekain314 6:2a8486283198 258 }
jekain314 6:2a8486283198 259 }
jekain314 6:2a8486283198 260 toPC.printf("WMsg RECORDDATA %c\n",
jekain314 6:2a8486283198 261 recChar
jekain314 6:2a8486283198 262 );
jekain314 6:2a8486283198 263 }
jekain314 6:2a8486283198 264
jekain314 6:2a8486283198 265 if (sendStreamPos) //stream the position data to the PC
jekain314 6:2a8486283198 266 {
jekain314 6:2a8486283198 267 sendStreamPos=false;
jekain314 6:2a8486283198 268 char streamChar = 'N';
jekain314 6:2a8486283198 269 if (streamPos)
jekain314 6:2a8486283198 270 {
jekain314 6:2a8486283198 271 streamChar = 'Y';
jekain314 6:2a8486283198 272 }
jekain314 6:2a8486283198 273 toPC.printf("WMsg POSSTREAM %c\n",
jekain314 6:2a8486283198 274 streamChar
jekain314 6:2a8486283198 275 );
jekain314 6:2a8486283198 276 }
jekain314 6:2a8486283198 277
jekain314 6:2a8486283198 278 //not sure this is ever used ..
jekain314 6:2a8486283198 279 if (sendLogMsgInfo) //send log info to the PC
jekain314 6:2a8486283198 280 {
jekain314 6:2a8486283198 281 sendLogMsgInfo=false;
jekain314 6:2a8486283198 282 char logChar = 'N';
jekain314 6:2a8486283198 283 if (logMsgInfo)
jekain314 6:2a8486283198 284 {
jekain314 6:2a8486283198 285 logChar = 'Y';
jekain314 6:2a8486283198 286 }
jekain314 6:2a8486283198 287 toPC.printf("WMsg LOGINFO %c\n",
jekain314 6:2a8486283198 288 logChar
jekain314 6:2a8486283198 289 );
jekain314 6:2a8486283198 290 }
jekain314 6:2a8486283198 291
jekain314 6:2a8486283198 292
jekain314 6:2a8486283198 293 }