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LibrePilot/flight/Modules/GPS/GPS.c
Stacey Sheldon 5f8760a55c com: Move buffering out of USART/HID layer and into COM layer
This allows the spektrum and sbus receiver drivers to bind
directly to the usart layer using a properly exported API
rather than overriding the interrupt handler.

Bytes are now pushed directly from the usart layer into the
com layer without any buffering.  The com layer performs all
of the buffering.

A further benefit from this approach is that we can put all
blocking/non-blocking behaviour into the COM layer and not
in the underlying drivers.

Misc related changes:
 - Remove obsolete .handler field from irq configs
 - Adapt all users of PIOS_COM_* functions to new API
 - Fixup callers of PIOS_USB_HID_Init()
2011-07-27 19:45:38 -04:00

426 lines
12 KiB
C

/**
******************************************************************************
* @addtogroup OpenPilotModules OpenPilot Modules
* @{
* @addtogroup GSPModule GPS Module
* @brief Process GPS information
* @{
*
* @file GPS.c
* @author The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
* @brief GPS module, handles GPS and NMEA stream
* @see The GNU Public License (GPL) Version 3
*
*****************************************************************************/
/*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
// ****************
#include "openpilot.h"
#include "GPS.h"
#include <stdbool.h>
#ifdef ENABLE_GPS_BINARY_GTOP
#include "GTOP_BIN.h"
#endif
#if defined(ENABLE_GPS_ONESENTENCE_GTOP) || defined(ENABLE_GPS_NMEA)
#include "NMEA.h"
#endif
#include "gpsposition.h"
#include "homelocation.h"
#include "gpstime.h"
#include "WorldMagModel.h"
#include "CoordinateConversions.h"
// ****************
// Private functions
static void gpsTask(void *parameters);
#ifdef PIOS_GPS_SETS_HOMELOCATION
static void setHomeLocation(GPSPositionData * gpsData);
static float GravityAccel(float latitude, float longitude, float altitude);
#endif
// ****************
// Private constants
//#define FULL_COLD_RESTART // uncomment this to tell the GPS to do a FULL COLD restart
//#define DISABLE_GPS_THRESHOLD //
#define GPS_TIMEOUT_MS 500
#define GPS_COMMAND_RESEND_TIMEOUT_MS 2000
#ifdef PIOS_GPS_SETS_HOMELOCATION
// Unfortunately need a good size stack for the WMM calculation
#ifdef ENABLE_GPS_BINARY_GTOP
#define STACK_SIZE_BYTES 800
#else
#define STACK_SIZE_BYTES 800
#endif
#else
#ifdef ENABLE_GPS_BINARY_GTOP
#define STACK_SIZE_BYTES 440
#else
#define STACK_SIZE_BYTES 440
#endif
#endif
#define TASK_PRIORITY (tskIDLE_PRIORITY + 1)
// ****************
// Private variables
static uint32_t gpsPort;
static xTaskHandle gpsTaskHandle;
#ifndef ENABLE_GPS_BINARY_GTOP
static char gps_rx_buffer[128];
#endif
static uint32_t timeOfLastCommandMs;
static uint32_t timeOfLastUpdateMs;
static uint32_t numUpdates;
static uint32_t numChecksumErrors;
static uint32_t numParsingErrors;
// ****************
/**
* Initialise the gps module
* \return -1 if initialisation failed
* \return 0 on success
*/
int32_t GPSStart(void)
{
// Start gps task
xTaskCreate(gpsTask, (signed char *)"GPS", STACK_SIZE_BYTES/4, NULL, TASK_PRIORITY, &gpsTaskHandle);
TaskMonitorAdd(TASKINFO_RUNNING_GPS, gpsTaskHandle);
return 0;
}
/**
* Initialise the gps module
* \return -1 if initialisation failed
* \return 0 on success
*/
int32_t GPSInitialize(void)
{
// TODO: Get gps settings object
gpsPort = PIOS_COM_GPS;
return 0;
}
MODULE_INITCALL(GPSInitialize, GPSStart)
// ****************
/**
* Main gps task. It does not return.
*/
static void gpsTask(void *parameters)
{
portTickType xDelay = 100 / portTICK_RATE_MS;
uint32_t timeNowMs = xTaskGetTickCount() * portTICK_RATE_MS;;
GPSPositionData GpsData;
#ifdef ENABLE_GPS_BINARY_GTOP
GTOP_BIN_init();
#else
uint8_t rx_count = 0;
bool start_flag = false;
bool found_cr = false;
int32_t gpsRxOverflow = 0;
#endif
#ifdef FULL_COLD_RESTART
// tell the GPS to do a FULL COLD restart
PIOS_COM_SendStringNonBlocking(gpsPort, "$PMTK104*37\r\n");
timeOfLastCommandMs = timeNowMs;
while (timeNowMs - timeOfLastCommandMs < 300) // delay for 300ms to let the GPS sort itself out
{
vTaskDelay(xDelay); // Block task until next update
timeNowMs = xTaskGetTickCount() * portTICK_RATE_MS;;
}
#endif
#ifdef DISABLE_GPS_THRESHOLD
PIOS_COM_SendStringNonBlocking(gpsPort, "$PMTK397,0*23\r\n");
#endif
#ifdef ENABLE_GPS_BINARY_GTOP
// switch to GTOP binary mode
PIOS_COM_SendStringNonBlocking(gpsPort ,"$PGCMD,21,1*6F\r\n");
#endif
#ifdef ENABLE_GPS_ONESENTENCE_GTOP
// switch to single sentence mode
PIOS_COM_SendStringNonBlocking(gpsPort, "$PGCMD,21,2*6C\r\n");
#endif
#ifdef ENABLE_GPS_NMEA
// switch to NMEA mode
PIOS_COM_SendStringNonBlocking(gpsPort, "$PGCMD,21,3*6D\r\n");
#endif
numUpdates = 0;
numChecksumErrors = 0;
numParsingErrors = 0;
timeOfLastUpdateMs = timeNowMs;
timeOfLastCommandMs = timeNowMs;
// Loop forever
while (1)
{
#ifdef ENABLE_GPS_BINARY_GTOP
// GTOP BINARY GPS mode
while (PIOS_COM_ReceiveBufferUsed(gpsPort) > 0)
{
uint8_t c;
PIOS_COM_ReceiveBuffer(gpsPort, &c, 1, 0);
if (GTOP_BIN_update_position(c, &numChecksumErrors, &numParsingErrors) >= 0)
{
numUpdates++;
timeNowMs = xTaskGetTickCount() * portTICK_RATE_MS;
timeOfLastUpdateMs = timeNowMs;
timeOfLastCommandMs = timeNowMs;
}
}
#else
// NMEA or SINGLE-SENTENCE GPS mode
// This blocks the task until there is something on the buffer
while (PIOS_COM_ReceiveBufferUsed(gpsPort) > 0)
{
uint8_t c;
PIOS_COM_ReceiveBuffer(gpsPort, &c, 1, 0);
// detect start while acquiring stream
if (!start_flag && (c == '$'))
{
start_flag = true;
found_cr = false;
rx_count = 0;
}
else
if (!start_flag)
continue;
if (rx_count >= sizeof(gps_rx_buffer))
{
// The buffer is already full and we haven't found a valid NMEA sentence.
// Flush the buffer and note the overflow event.
gpsRxOverflow++;
start_flag = false;
found_cr = false;
rx_count = 0;
}
else
{
gps_rx_buffer[rx_count] = c;
rx_count++;
}
// look for ending '\r\n' sequence
if (!found_cr && (c == '\r') )
found_cr = true;
else
if (found_cr && (c != '\n') )
found_cr = false; // false end flag
else
if (found_cr && (c == '\n') )
{
// The NMEA functions require a zero-terminated string
// As we detected \r\n, the string as for sure 2 bytes long, we will also strip the \r\n
gps_rx_buffer[rx_count-2] = 0;
// prepare to parse next sentence
start_flag = false;
found_cr = false;
rx_count = 0;
// Our rxBuffer must look like this now:
// [0] = '$'
// ... = zero or more bytes of sentence payload
// [end_pos - 1] = '\r'
// [end_pos] = '\n'
//
// Prepare to consume the sentence from the buffer
// Validate the checksum over the sentence
if (!NMEA_checksum(&gps_rx_buffer[1]))
{ // Invalid checksum. May indicate dropped characters on Rx.
//PIOS_DEBUG_PinHigh(2);
++numChecksumErrors;
//PIOS_DEBUG_PinLow(2);
}
else
{ // Valid checksum, use this packet to update the GPS position
if (!NMEA_update_position(&gps_rx_buffer[1])) {
//PIOS_DEBUG_PinHigh(2);
++numParsingErrors;
//PIOS_DEBUG_PinLow(2);
}
else
++numUpdates;
timeNowMs = xTaskGetTickCount() * portTICK_RATE_MS;
timeOfLastUpdateMs = timeNowMs;
timeOfLastCommandMs = timeNowMs;
}
}
}
#endif
// Check for GPS timeout
timeNowMs = xTaskGetTickCount() * portTICK_RATE_MS;
if ((timeNowMs - timeOfLastUpdateMs) >= GPS_TIMEOUT_MS)
{ // we have not received any valid GPS sentences for a while.
// either the GPS is not plugged in or a hardware problem or the GPS has locked up.
GPSPositionGet(&GpsData);
GpsData.Status = GPSPOSITION_STATUS_NOGPS;
GPSPositionSet(&GpsData);
AlarmsSet(SYSTEMALARMS_ALARM_GPS, SYSTEMALARMS_ALARM_ERROR);
if ((timeNowMs - timeOfLastCommandMs) >= GPS_COMMAND_RESEND_TIMEOUT_MS)
{ // resend the command .. just incase the gps has only just been plugged in or the gps did not get our last command
timeOfLastCommandMs = timeNowMs;
#ifdef ENABLE_GPS_BINARY_GTOP
GTOP_BIN_init();
// switch to binary mode
PIOS_COM_SendStringNonBlocking(gpsPort,"$PGCMD,21,1*6F\r\n");
#endif
#ifdef ENABLE_GPS_ONESENTENCE_GTOP
// switch to single sentence mode
PIOS_COM_SendStringNonBlocking(gpsPort,"$PGCMD,21,2*6C\r\n");
#endif
#ifdef ENABLE_GPS_NMEA
// switch to NMEA mode
PIOS_COM_SendStringNonBlocking(gpsPort,"$PGCMD,21,3*6D\r\n");
#endif
#ifdef DISABLE_GPS_TRESHOLD
PIOS_COM_SendStringNonBlocking(gpsPort,"$PMTK397,0*23\r\n");
#endif
}
}
else
{ // we appear to be receiving GPS sentences OK, we've had an update
GPSPositionGet(&GpsData);
#ifdef PIOS_GPS_SETS_HOMELOCATION
HomeLocationData home;
HomeLocationGet(&home);
if ((GpsData.Status == GPSPOSITION_STATUS_FIX3D) && (home.Set == HOMELOCATION_SET_FALSE))
setHomeLocation(&GpsData);
#endif
//criteria for GPS-OK taken from this post...
//http://forums.openpilot.org/topic/1523-professors-insgps-in-svn/page__view__findpost__p__5220
if ((GpsData.PDOP < 3.5) && (GpsData.Satellites >= 7))
AlarmsClear(SYSTEMALARMS_ALARM_GPS);
else
if (GpsData.Status == GPSPOSITION_STATUS_FIX3D)
AlarmsSet(SYSTEMALARMS_ALARM_GPS, SYSTEMALARMS_ALARM_WARNING);
else
AlarmsSet(SYSTEMALARMS_ALARM_GPS, SYSTEMALARMS_ALARM_CRITICAL);
}
// Block task until next update
vTaskDelay(xDelay);
}
}
#ifdef PIOS_GPS_SETS_HOMELOCATION
/*
* Estimate the acceleration due to gravity for a particular location in LLA
*/
static float GravityAccel(float latitude, float longitude, float altitude)
{
// WGS84 gravity model. The effect of gravity over latitude is strong
// enough to change the estimated accelerometer bias in those apps.
double sinsq = sin((double)latitude);
sinsq *= sinsq;
// Likewise, over the altitude range of a high-altitude balloon, the effect
// due to change in altitude can also affect the model.
return (float)(9.7803267714 * (1 + 0.00193185138639*sinsq) / sqrt(1 - 0.00669437999013*sinsq)
- 3.086e-6*altitude);
}
// ****************
static void setHomeLocation(GPSPositionData * gpsData)
{
HomeLocationData home;
HomeLocationGet(&home);
GPSTimeData gps;
GPSTimeGet(&gps);
if (gps.Year >= 2000)
{
// Store LLA
home.Latitude = gpsData->Latitude;
home.Longitude = gpsData->Longitude;
home.Altitude = gpsData->Altitude + gpsData->GeoidSeparation;
// Compute home ECEF coordinates and the rotation matrix into NED
double LLA[3] = { ((double)home.Latitude) / 10e6, ((double)home.Longitude) / 10e6, ((double)home.Altitude) };
double ECEF[3];
RneFromLLA(LLA, (float (*)[3])home.RNE);
LLA2ECEF(LLA, ECEF);
// TODO: Currently UAVTalk only supports float but these conversions use double
// need to find out if they require that precision and if so extend UAVTAlk
home.ECEF[0] = (int32_t) (ECEF[0] * 100);
home.ECEF[1] = (int32_t) (ECEF[1] * 100);
home.ECEF[2] = (int32_t) (ECEF[2] * 100);
// Compute magnetic flux direction at home location
if (WMM_GetMagVector(LLA[0], LLA[1], LLA[2], gps.Month, gps.Day, gps.Year, &home.Be[0]) >= 0)
{ // calculations appeared to go OK
// Compute local acceleration due to gravity. Vehicles that span a very large
// range of altitude (say, weather balloons) may need to update this during the
// flight.
home.g_e = GravityAccel(LLA[0], LLA[1], LLA[2]);
home.Set = HOMELOCATION_SET_TRUE;
HomeLocationSet(&home);
}
}
}
#endif
// ****************
/**
* @}
* @}
*/