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#include <inttypes.h>
#include "ubx.h"
#include "timer0.h"
#include "uart0.h"
// ------------------------------------------------------------------------------------------------
// defines
#define DAYS_FROM_JAN01YEAR0001_TO_JAN6_1980 722819 // the year 0 does not exist!
#define DAYS_PER_YEAR 365
#define DAYS_PER_LEAPYEAR 366
#define DAYS_PER_4YEARS 1461 //((3 * DAYS_PER_YEAR) + DAYS_PER_LEAPYEAR) // years dividable by 4 are leap years
#define DAYS_PER_100YEARS 36524 //((25 * DAYS_PER_4YEARS) - 1) // years dividable by 100 are no leap years
#define DAYS_PER_400YEARS 146097 //((4 * DAYS_PER_100YEARS) + 1L) // but years dividable by 400 are leap years
#define SECONDS_PER_MINUTE 60
#define MINUTES_PER_HOUR 60
#define HOURS_PER_DAY 24
#define DAYS_PER_WEEK 7
#define SECONDS_PER_HOUR 3600 //(SECONDS_PER_MINUTE * MINUTES_PER_HOUR)
#define SECONDS_PER_DAY 86400 //(SECONDS_PER_HOUR * HOURS_PER_DAY)
#define SECONDS_PER_WEEK 604800 //(SECONDS_PER_DAY * DAYS_PER_WEEK)
// days per month in normal and leap years
const uint32_t Leap[ 13 ] = { 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 };
const uint32_t Normal[ 13 ] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
#define LEAP_SECONDS_FROM_1980 15 // the last one was on the Dec 31th 2008
// message sync bytes
#define UBX_SYNC1_CHAR 0xB5
#define UBX_SYNC2_CHAR 0x62
// protocoll identifier
#define UBX_CLASS_NAV 0x01
// message id
#define UBX_ID_POSLLH 0x02
#define UBX_ID_SOL 0x06
#define UBX_ID_VELNED 0x12
// ------------------------------------------------------------------------------------------------
// typedefs
// ubx parser state
typedef enum
{
UBXSTATE_IDLE,
UBXSTATE_SYNC1,
UBXSTATE_SYNC2,
UBXSTATE_CLASS,
UBXSTATE_LEN1,
UBXSTATE_LEN2,
UBXSTATE_DATA,
UBXSTATE_CKA,
UBXSTATE_CKB
} ubxState_t;
typedef struct
{
uint32_t itow; // ms GPS Millisecond Time of Week
int32_t frac; // ns remainder of rounded ms above
int16_t week; // GPS week
uint8_t GPSfix; // GPSfix Type, range 0..6
uint8_t Flags; // Navigation Status Flags
int32_t ECEF_X; // cm ECEF X coordinate
int32_t ECEF_Y; // cm ECEF Y coordinate
int32_t ECEF_Z; // cm ECEF Z coordinate
int32_t PAcc; // cm 3D Position Accuracy Estimate
int32_t ECEFVX; // cm/s ECEF X velocity
int32_t ECEFVY; // cm/s ECEF Y velocity
int32_t ECEFVZ; // cm/s ECEF Z velocity
uint32_t SAcc; // cm/s Speed Accuracy Estimate
uint16_t PDOP; // 0.01 Position DOP
uint8_t res1; // reserved
uint8_t numSV; // Number of SVs used in navigation solution
uint32_t res2; // reserved
uint8_t Status; // invalid/newdata/processed
} __attribute__((packed)) ubx_nav_sol_t;
typedef struct
{
uint32_t itow; // ms GPS Millisecond Time of Week
int32_t VEL_N; // cm/s NED north velocity
int32_t VEL_E; // cm/s NED east velocity
int32_t VEL_D; // cm/s NED down velocity
int32_t Speed; // cm/s Speed (3-D)
int32_t GSpeed; // cm/s Ground Speed (2-D)
int32_t Heading; // 1e-05 deg Heading 2-D
uint32_t SAcc; // cm/s Speed Accuracy Estimate
uint32_t CAcc; // deg Course / Heading Accuracy Estimate
uint8_t Status; // invalid/newdata/processed
} __attribute__((packed)) ubx_nav_velned_t;
typedef struct
{
uint32_t itow; // ms GPS Millisecond Time of Week
int32_t LON; // 1e-07 deg Longitude
int32_t LAT; // 1e-07 deg Latitude
int32_t HEIGHT; // mm Height above Ellipsoid
int32_t HMSL; // mm Height above mean sea level
uint32_t Hacc; // mm Horizontal Accuracy Estimate
uint32_t Vacc; // mm Vertical Accuracy Estimate
uint8_t Status; // invalid/newdata/processed
} __attribute__((packed)) ubx_nav_posllh_t;
//------------------------------------------------------------------------------------
// global variables
// local buffers for the incomming ubx messages
volatile ubx_nav_sol_t UbxSol = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0, INVALID};
volatile ubx_nav_posllh_t UbxPosLlh = {0,0,0,0,0,0,0, INVALID};
volatile ubx_nav_velned_t UbxVelNed = {0,0,0,0,0,0,0,0,0, INVALID};
uint16_t CheckGPSOkay = 0;
// shared buffer
gps_data_t GPSData = {{0,0,0,INVALID},0,0,0,0,0,0,0, INVALID};
//------------------------------------------------------------------------------------
// functions
uint8_t IsLeapYear(uint16_t year)
{
if((year%400 == 0) || ( (year%4 == 0) && (year%100 != 0) ) ) return 1;
else return 0;
}
/********************************************************/
/* Calculates the UTC Time from the GPS week and tow */
/********************************************************/
void SetGPSTime(DateTime_t * pTimeStruct)
{
uint32_t Days, Seconds, Week;
uint16_t YearPart;
uint32_t * MonthDayTab = 0;
uint8_t i;
// if GPS data show valid time data
if((UbxSol.Status != INVALID) && (UbxSol.Flags & FLAG_WKNSET) && (UbxSol.Flags & FLAG_TOWSET) )
{
Seconds = UbxSol.itow / 1000L;
Week = (uint32_t)UbxSol.week;
// correct leap seconds since 1980
if(Seconds < LEAP_SECONDS_FROM_1980)
{
Week--;
Seconds = SECONDS_PER_WEEK - LEAP_SECONDS_FROM_1980 + Seconds;
}
else Seconds -= LEAP_SECONDS_FROM_1980;
Days = DAYS_FROM_JAN01YEAR0001_TO_JAN6_1980;
Days += (Week * DAYS_PER_WEEK);
Days += Seconds / SECONDS_PER_DAY; // seperate days from GPS seconds of week
pTimeStruct->Year = 1;
YearPart = (uint16_t)(Days / DAYS_PER_400YEARS);
pTimeStruct->Year += YearPart * 400;
Days = Days % DAYS_PER_400YEARS;
YearPart = (uint16_t)(Days / DAYS_PER_100YEARS);
pTimeStruct->Year += YearPart * 100;
Days = Days % DAYS_PER_100YEARS;
YearPart = (uint16_t)(Days / DAYS_PER_4YEARS);
pTimeStruct->Year += YearPart * 4;
Days = Days % DAYS_PER_4YEARS;
if(Days < (3* DAYS_PER_YEAR)) YearPart = (uint16_t)(Days / DAYS_PER_YEAR);
else YearPart = 3;
pTimeStruct->Year += YearPart;
// calculate remaining days of year
Days -= (uint32_t)(YearPart * DAYS_PER_YEAR);
Days += 1;
// check if current year is a leap year
if(IsLeapYear(pTimeStruct->Year)) MonthDayTab = (uint32_t*)Leap;
else MonthDayTab = (uint32_t*)Normal;
// seperate month and day from days of year
for ( i = 0; i < 12; i++ )
{
if ( (MonthDayTab[i]< Days) && (Days <= MonthDayTab[i+1]) )
{
pTimeStruct->Month = i+1;
pTimeStruct->Day = Days - MonthDayTab[i];
i = 12;
}
}
Seconds = Seconds % SECONDS_PER_DAY; // remaining seconds of current day
pTimeStruct->Hour = (uint8_t)(Seconds / SECONDS_PER_HOUR);
Seconds = Seconds % SECONDS_PER_HOUR; // remaining seconds of current hour
pTimeStruct->Min = (uint8_t)(Seconds / SECONDS_PER_MINUTE);
Seconds = Seconds % SECONDS_PER_MINUTE; // remaining seconds of current minute
pTimeStruct->Sec = (uint8_t)(Seconds);
pTimeStruct->mSec = (uint16_t)(UbxSol.itow % 1000L);
pTimeStruct->Valid = 1;
}
else
{
pTimeStruct->Valid = 0;
}
}
/********************************************************/
/* Initialize UBX Parser */
/********************************************************/
void UBX_Init(void)
{
// mark msg buffers invalid
UbxSol.Status = INVALID;
UbxPosLlh.Status = INVALID;
UbxVelNed.Status = INVALID;
GPSData.Status = INVALID;
}
/********************************************************/
/* Upate GPS data stcructure */
/********************************************************/
void Update_GPSData (void)
{
static uint16_t Ubx_Timeout = 0;
static uint8_t Msg_Count = 0;
// the timeout is used to detect the delay between two message sets
// and is used for synchronisation so that always a set is collected
// that belongs together
// _______NAVSOL|POSLLH|VELNED|___________________NAVSOL|POSLLH|VELNED|_____________
// | 8ms | 8ms | 184 ms | | |
// msg_count: 0 1 2 0 1 2
if(CheckDelay(Ubx_Timeout)) Msg_Count = 0;
else Msg_Count++;
Ubx_Timeout = SetDelay(100); // reset ubx msg timeout
// if a new set of ubx messages was collected
if((Msg_Count >= 2))
{ // if set is complete
if((UbxSol.Status == NEWDATA) && (UbxPosLlh.Status == NEWDATA) && (UbxVelNed.Status == NEWDATA))
{
CheckGPSOkay++;
// update GPS data only if the status is INVALID or PROCESSED and the last ubx message was received within less than 100 ms
if(GPSData.Status != NEWDATA) // if last data were processed
{ // wait for new data at all neccesary ubx messages
GPSData.Status = INVALID;
// NAV SOL
GPSData.Flags = UbxSol.Flags;
GPSData.NumOfSats = UbxSol.numSV;
GPSData.SatFix = UbxSol.GPSfix;
GPSData.Position_Accuracy = UbxSol.PAcc;
GPSData.Speed_Accuracy = UbxSol.SAcc;
SetGPSTime(&SystemTime); // update system time
// NAV POSLLH
GPSData.Position.Status = INVALID;
GPSData.Position.Longitude = UbxPosLlh.LON;
GPSData.Position.Latitude = UbxPosLlh.LAT;
GPSData.Position.Altitude = UbxPosLlh.HMSL;
GPSData.Position.Status = NEWDATA;
// NAV VELNED
GPSData.Speed_East = UbxVelNed.VEL_E;
GPSData.Speed_North = UbxVelNed.VEL_N;
GPSData.Speed_Top = -UbxVelNed.VEL_D;
GPSData.Speed_Ground = UbxVelNed.GSpeed;
GPSData.Heading = UbxVelNed.Heading;
GPSData.Status = NEWDATA; // new data available
} // EOF if(GPSData.Status != NEWDATA)
} // EOF all ubx messages received
// set state to collect new data
UbxSol.Status = PROCESSED; // ready for new data
UbxPosLlh.Status = PROCESSED; // ready for new data
UbxVelNed.Status = PROCESSED; // ready for new data
}
}
/********************************************************/
/* UBX Parser */
/********************************************************/
void UBX_Parser(uint8_t c)
{
static ubxState_t ubxState = UBXSTATE_IDLE;
static uint16_t msglen;
static uint8_t cka, ckb;
static uint8_t *ubxP, *ubxEp, *ubxSp; // pointers to data currently transfered
//state machine
switch (ubxState) // ubx message parser
{
case UBXSTATE_IDLE: // check 1st sync byte
if (c == UBX_SYNC1_CHAR) ubxState = UBXSTATE_SYNC1;
else ubxState = UBXSTATE_IDLE; // out of synchronization
break;
case UBXSTATE_SYNC1: // check 2nd sync byte
if (c == UBX_SYNC2_CHAR) ubxState = UBXSTATE_SYNC2;
else ubxState = UBXSTATE_IDLE; // out of synchronization
break;
case UBXSTATE_SYNC2: // check msg class to be NAV
if (c == UBX_CLASS_NAV) ubxState = UBXSTATE_CLASS;
else ubxState = UBXSTATE_IDLE; // unsupported message class
break;
case UBXSTATE_CLASS: // check message identifier
switch(c)
{
case UBX_ID_POSLLH: // geodetic position
ubxP = (uint8_t *)&UbxPosLlh; // data start pointer
ubxEp = (uint8_t *)(&UbxPosLlh + 1); // data end pointer
ubxSp = (uint8_t *)&UbxPosLlh.Status; // status pointer
break;
case UBX_ID_SOL: // navigation solution
ubxP = (uint8_t *)&UbxSol; // data start pointer
ubxEp = (uint8_t *)(&UbxSol + 1); // data end pointer
ubxSp = (uint8_t *)&UbxSol.Status; // status pointer
break;
case UBX_ID_VELNED: // velocity vector in tangent plane
ubxP = (uint8_t *)&UbxVelNed; // data start pointer
ubxEp = (uint8_t *)(&UbxVelNed + 1); // data end pointer
ubxSp = (uint8_t *)&UbxVelNed.Status; // status pointer
break;
default: // unsupported identifier
ubxState = UBXSTATE_IDLE;
break;
}
if (ubxState != UBXSTATE_IDLE)
{
ubxState = UBXSTATE_LEN1;
cka = UBX_CLASS_NAV + c;
ckb = UBX_CLASS_NAV + cka;
}
break;
case UBXSTATE_LEN1: // 1st message length byte
msglen = (uint16_t)c; // lowbyte first
cka += c;
ckb += cka;
ubxState = UBXSTATE_LEN2;
break;
case UBXSTATE_LEN2: // 2nd message length byte
msglen += ((uint16_t)c)<<8; // high byte last
cka += c;
ckb += cka;
// if the old data are not processed so far then break parsing now
// to avoid writing new data in ISR during reading by another function
if ( *ubxSp == NEWDATA )
{
ubxState = UBXSTATE_IDLE;
Update_GPSData(); //update GPS info respectively
}
else // data invalid or allready processd
{
*ubxSp = INVALID; // mark invalid during buffer filling
ubxState = UBXSTATE_DATA;
}
break;
case UBXSTATE_DATA: // collecting data
if (ubxP < ubxEp)
{
*ubxP++ = c; // copy curent data byte if any space is left
cka += c;
ckb += cka;
if (--msglen == 0) ubxState = UBXSTATE_CKA; // switch to next state if all data was read
}
else // rx buffer overrun
{
ubxState = UBXSTATE_IDLE;
}
break;
case UBXSTATE_CKA:
if (c == cka) ubxState = UBXSTATE_CKB;
else
{
*ubxSp = INVALID;
ubxState = UBXSTATE_IDLE;
}
break;
case UBXSTATE_CKB:
if (c == ckb)
{
*ubxSp = NEWDATA; // new data are valid
Update_GPSData(); //update GPS info respectively
}
else
{ // if checksum not match then set data invalid
*ubxSp = INVALID;
}
ubxState = UBXSTATE_IDLE; // ready to parse new data
break;
default: // unknown ubx state
ubxState = UBXSTATE_IDLE;
break;
}
DebugOut.Analog[9] = GPSData.Speed_North;
DebugOut.Analog[10] = GPSData.Speed_East;
DebugOut.Analog[11] = GPSData.Speed_Top;
DebugOut.Analog[12] = GPSData.NumOfSats;
DebugOut.Analog[13] = GPSData.Position.Longitude;
DebugOut.Analog[14] = GPSData.Position.Latitude;
DebugOut.Analog[15] = GPSData.Position.Altitude;
}