fly316/PX4-Autopilot
7
0
Fork 0
mirror of https://gitee.com/mirrors_PX4/PX4-Autopilot.git synced 2026-04-14 10:07:39 +08:00
Code Issues Packages Projects Releases Wiki Activity

Restructered the parsing/configuring, MTK working

Browse Source
This commit is contained in:
Julian Oes 2013-02-07 14:48:00 -08:00
parent d36eb8a3fc
commit a88b9f4eef
5 changed files with 313 additions and 302 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

239
apps/drivers/gps/gps.cpp
View File

@ -53,7 +53,6 @@
#include <stdio.h>
#include <math.h>
#include <unistd.h>
#include <termios.h>
#include <fcntl.h>
#include <nuttx/arch.h>
@ -71,7 +70,7 @@
#include <uORB/topics/vehicle_gps_position.h>
#include "ubx.h"
//#include "ubx.h"
#include "mtk.h"
#define SEND_BUFFER_LENGTH 100
@ -113,10 +112,8 @@ private:
int _serial_fd; ///< serial interface to GPS
unsigned _baudrate; ///< current baudrate
char _port[20]; ///< device / serial port path
const unsigned _baudrates_to_try[NUMBER_OF_TRIES]; ///< try different baudrates that GPS could be set to
const gps_driver_mode_t _modes_to_try[NUMBER_OF_TRIES]; ///< try different modes
volatile int _task; //< worker task
bool _config_needed; ///< flag to signal that configuration of GPS is needed
bool _healthy; ///< flag to signal if the GPS is ok
bool _baudrate_changed; ///< flag to signal that the baudrate with the GPS has changed
bool _mode_changed; ///< flag that the GPS mode has changed
gps_driver_mode_t _mode; ///< current mode
@ -171,11 +168,9 @@ GPS *g_dev;
GPS::GPS(const char* uart_path) :
CDev("gps", GPS_DEVICE_PATH),
_task_should_exit(false),
_baudrates_to_try({9600, 38400, 57600, 115200, 38400}),
_modes_to_try({GPS_DRIVER_MODE_UBX, GPS_DRIVER_MODE_UBX, GPS_DRIVER_MODE_UBX, GPS_DRIVER_MODE_UBX, GPS_DRIVER_MODE_MTK}),
_config_needed(true),
_baudrate_changed(false),
_healthy(false),
_mode_changed(false),
_mode(GPS_DRIVER_MODE_MTK),
_Helper(nullptr),
_report_pub(-1),
_rate(0.0f)
@ -250,20 +245,6 @@ GPS::ioctl(struct file *filp, int cmd, unsigned long arg)
return ret;
}
void
GPS::config()
{
_Helper->configure(_serial_fd, _baudrate_changed, _baudrate);
/* Sometimes the baudrate needs to be changed, for instance UBX with factory settings are changed
* from 9600 to 38400
*/
if (_baudrate_changed) {
set_baudrate(_baudrate);
_baudrate_changed = false;
}
}
void
GPS::task_main_trampoline(void *arg)
{
@ -276,10 +257,7 @@ GPS::task_main()
log("starting");
/* open the serial port */
_serial_fd = ::open(_port, O_RDWR); //TODO make the device dynamic depending on startup parameters
/* buffer to read from the serial port */
uint8_t buf[32];
_serial_fd = ::open(_port, O_RDWR);
if (_serial_fd < 0) {
log("failed to open serial port: %s err: %d", _port, errno);
@ -288,151 +266,65 @@ GPS::task_main()
_exit(1);
}
/* poll descriptor */
pollfd fds[1];
fds[0].fd = _serial_fd;
fds[0].events = POLLIN;
/* lock against the ioctl handler */
lock();
unsigned try_i = 0;
_baudrate = _baudrates_to_try[try_i];
_mode = _modes_to_try[try_i];
_mode_changed = true;
set_baudrate(_baudrate);
uint64_t time_before_configuration = hrt_absolute_time();
uint64_t last_rate_measurement = hrt_absolute_time();
unsigned last_rate_count = 0;
bool pos_updated;
bool config_needed_res;
/* loop handling received serial bytes and also configuring in between */
while (!_task_should_exit) {
/* If a configuration does not finish in the config timeout, change the baudrate */
if (_config_needed && time_before_configuration + CONFIG_TIMEOUT < hrt_absolute_time()) {
/* loop through possible modes/baudrates */
try_i = (try_i + 1) % NUMBER_OF_TRIES;
_baudrate = _baudrates_to_try[try_i];
set_baudrate(_baudrate);
if (_mode != _modes_to_try[try_i]) {
_mode_changed = true;
}
_mode = _modes_to_try[try_i];
if (_Helper != nullptr) {
_Helper->reset();
}
time_before_configuration = hrt_absolute_time();
if (_Helper != nullptr) {
delete(_Helper);
/* set to zero to ensure parser is not used while not instantiated */
_Helper = nullptr;
}
if (_mode_changed) {
if (_Helper != nullptr) {
delete(_Helper);
/* set to zero to ensure parser is not used while not instantiated */
_Helper = nullptr;
}
switch (_mode) {
case GPS_DRIVER_MODE_UBX:
_Helper = new UBX();
break;
switch (_mode) {
// case GPS_DRIVER_MODE_UBX:
// _Helper = new UBX();
// break;
case GPS_DRIVER_MODE_MTK:
printf("try new mtk\n");
_Helper = new MTK();
break;
case GPS_DRIVER_MODE_NMEA:
//_Helper = new NMEA();
//_Helper = new NMEA(); //TODO: add NMEA
break;
default:
break;
}
_mode_changed = false;
}
/* during configuration, the timeout should be small, so that we can send config messages in between parsing,
* but during normal operation, it should never timeout because updates should arrive with 5Hz */
int poll_timeout;
if (_config_needed) {
poll_timeout = 50;
} else {
poll_timeout = 400;
}
/* sleep waiting for data, but no more than the poll timeout */
// XXX unlock/lock makes sense?
unlock();
int ret = ::poll(fds, sizeof(fds) / sizeof(fds[0]), poll_timeout);
lock();
if (_Helper->configure(_serial_fd, _baudrate) == 0) {
while (_Helper->receive(_serial_fd, _report) > 0 && !_task_should_exit) {
/* opportunistic publishing - else invalid data would end up on the bus */
if (_report_pub > 0) {
orb_publish(ORB_ID(vehicle_gps_position), _report_pub, &_report);
} else {
_report_pub = orb_advertise(ORB_ID(vehicle_gps_position), &_report);
}
/* this would be bad... */
if (ret < 0) {
log("poll error %d", errno);
} else if (ret == 0) {
/* no response from the GPS */
if (_config_needed == false) {
_config_needed = true;
warnx("GPS module timeout");
_Helper->reset();
}
config();
} else if (ret > 0) {
/* if we have new data from GPS, go handle it */
if (fds[0].revents & POLLIN) {
int count;
last_rate_count++;
/*
* We are here because poll says there is some data, so this
* won't block even on a blocking device. If more bytes are
* available, we'll go back to poll() again...
*/
count = ::read(_serial_fd, buf, sizeof(buf));
/* measure update rate every 5 seconds */
if (hrt_absolute_time() - last_rate_measurement > 5000000) {
_rate = last_rate_count / ((float)((hrt_absolute_time() - last_rate_measurement)) / 1000000.0f);
last_rate_measurement = hrt_absolute_time();
last_rate_count = 0;
}
/* pass received bytes to the packet decoder */
int j;
for (j = 0; j < count; j++) {
pos_updated = false;
config_needed_res = _config_needed;
_Helper->parse(buf[j], &_report, config_needed_res, pos_updated);
if (pos_updated) {
/* opportunistic publishing - else invalid data would end up on the bus */
if (_report_pub > 0) {
orb_publish(ORB_ID(vehicle_gps_position), _report_pub, &_report);
} else {
_report_pub = orb_advertise(ORB_ID(vehicle_gps_position), &_report);
}
last_rate_count++;
/* measure update rate every 5 seconds */
if (hrt_absolute_time() - last_rate_measurement > 5000000) {
_rate = last_rate_count / ((float)((hrt_absolute_time() - last_rate_measurement)) / 1000000.0f);
last_rate_measurement = hrt_absolute_time();
last_rate_count = 0;
}
}
if (config_needed_res == true && _config_needed == false) {
/* the parser told us that an error happened and reconfiguration is needed */
_config_needed = true;
warnx("GPS module lost");
_Helper->reset();
config();
} else if (config_needed_res == true && _config_needed == true) {
/* we are still configuring */
config();
} else if (config_needed_res == false && _config_needed == true) {
/* the parser is happy, stop configuring */
warnx("GPS module found");
_config_needed = false;
}
if (!_healthy) {
warnx("module found");
_healthy = true;
}
}
if (_healthy) {
warnx("module lost");
_healthy = false;
_rate = 0.0f;
}
}
lock();
}
debug("exiting");
@ -443,59 +335,12 @@ GPS::task_main()
_exit(0);
}
int
GPS::set_baudrate(unsigned baud)
{
/* process baud rate */
int speed;
switch (baud) {
case 9600: speed = B9600; break;
case 19200: speed = B19200; break;
case 38400: speed = B38400; break;
case 57600: speed = B57600; break;
case 115200: speed = B115200; break;
default:
warnx("ERROR: Unsupported baudrate: %d\n", baud);
return -EINVAL;
}
struct termios uart_config;
int termios_state;
/* fill the struct for the new configuration */
tcgetattr(_serial_fd, &uart_config);
/* clear ONLCR flag (which appends a CR for every LF) */
uart_config.c_oflag &= ~ONLCR;
/* no parity, one stop bit */
uart_config.c_cflag &= ~(CSTOPB | PARENB);
/* set baud rate */
if ((termios_state = cfsetispeed(&uart_config, speed)) < 0) {
warnx("ERROR setting config: %d (cfsetispeed)\n", termios_state);
return -1;
}
if ((termios_state = cfsetospeed(&uart_config, speed)) < 0) {
warnx("ERROR setting config: %d (cfsetospeed)\n", termios_state);
return -1;
}
if ((termios_state = tcsetattr(_serial_fd, TCSANOW, &uart_config)) < 0) {
warnx("ERROR setting baudrate (tcsetattr)\n");
return -1;
}
/* XXX if resetting the parser here, ensure it does exist (check for null pointer) */
return 0;
}
void
GPS::cmd_reset()
{
_config_needed = true;
//XXX add reset?
}
void
@ -514,7 +359,7 @@ GPS::print_info()
default:
break;
}
warnx("port: %s, baudrate: %d, status: %s", _port, _baudrate, (_config_needed) ? "NOT OK" : "OK");
warnx("port: %s, baudrate: %d, status: %s", _port, _baudrate, (_healthy) ? "OK" : "NOT OK");
if (_report.timestamp_position != 0) {
warnx("position lock: %dD, last update %4.2f seconds ago", (int)_report.fix_type,
(double)((float)(hrt_absolute_time() - _report.timestamp_position) / 1000000.0f));

90
apps/drivers/gps/gps_helper.cpp Normal file
View File

@ -0,0 +1,90 @@
/****************************************************************************
*
* Copyright (C) 2008-2013 PX4 Development Team. All rights reserved.
* Author: Thomas Gubler <thomasgubler@student.ethz.ch>
* Julian Oes <joes@student.ethz.ch>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name PX4 nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
#include <termios.h>
#include <errno.h>
#include <systemlib/err.h>
#include "gps_helper.h"
/* @file gps_helper.cpp */
int
GPS_Helper::set_baudrate(const int &fd, unsigned baud)
{
/* process baud rate */
int speed;
switch (baud) {
case 9600: speed = B9600; break;
case 19200: speed = B19200; break;
case 38400: speed = B38400; break;
case 57600: speed = B57600; break;
case 115200: speed = B115200; break;
default:
warnx("ERROR: Unsupported baudrate: %d\n", baud);
return -EINVAL;
}
struct termios uart_config;
int termios_state;
/* fill the struct for the new configuration */
tcgetattr(fd, &uart_config);
/* clear ONLCR flag (which appends a CR for every LF) */
uart_config.c_oflag &= ~ONLCR;
/* no parity, one stop bit */
uart_config.c_cflag &= ~(CSTOPB | PARENB);
/* set baud rate */
if ((termios_state = cfsetispeed(&uart_config, speed)) < 0) {
warnx("ERROR setting config: %d (cfsetispeed)\n", termios_state);
return -1;
}
if ((termios_state = cfsetospeed(&uart_config, speed)) < 0) {
warnx("ERROR setting config: %d (cfsetospeed)\n", termios_state);
return -1;
}
if ((termios_state = tcsetattr(fd, TCSANOW, &uart_config)) < 0) {
warnx("ERROR setting baudrate (tcsetattr)\n");
return -1;
}
/* XXX if resetting the parser here, ensure it does exist (check for null pointer) */
return 0;
}

11
apps/drivers/gps/gps_helper.h
View File

@ -33,17 +33,20 @@
*
****************************************************************************/
/* @file U-Blox protocol definitions */
/* @file gps_helper.h */
#ifndef GPS_HELPER_H
#define GPS_HELPER_H
#include <uORB/uORB.h>
#include <uORB/topics/vehicle_gps_position.h>
class GPS_Helper
{
public:
virtual void reset(void) = 0;
virtual void configure(const int &fd, bool &baudrate_changed, unsigned &baudrate) = 0;
virtual void parse(uint8_t, struct vehicle_gps_position_s*, bool &config_needed, bool &pos_updated) = 0;
virtual int configure(const int &fd, unsigned &baud) = 0;
virtual int receive(const int &fd, struct vehicle_gps_position_s &gps_position) = 0;
int set_baudrate(const int &fd, unsigned baud);
};
#endif /* GPS_HELPER_H */

240
apps/drivers/gps/mtk.cpp
View File

@ -37,85 +37,143 @@
#include <unistd.h>
#include <stdio.h>
#include <poll.h>
#include <math.h>
#include <string.h>
#include <assert.h>
#include <systemlib/err.h>
#include <uORB/uORB.h>
#include <uORB/topics/vehicle_gps_position.h>
#include <drivers/drv_hrt.h>
#include "mtk.h"
MTK::MTK() :
_config_sent(false),
_mtk_revision(0)
{
decodeInit();
decode_init();
}
MTK::~MTK()
{
}
void
MTK::reset()
int
MTK::configure(const int &fd, unsigned &baudrate)
{
/* set baudrate first */
if (GPS_Helper::set_baudrate(fd, MTK_BAUDRATE) != 0)
return -1;
}
baudrate = MTK_BAUDRATE;
void
MTK::configure(const int &fd, bool &baudrate_changed, unsigned &baudrate)
{
if (_config_sent == false) {
/* Write config messages, don't wait for an answer */
if (strlen(MTK_OUTPUT_5HZ) != write(fd, MTK_OUTPUT_5HZ, strlen(MTK_OUTPUT_5HZ))) {
warnx("mtk: config write failed");
return -1;
}
usleep(10000);
if (strlen(MTK_OUTPUT_5HZ) != write(fd, MTK_OUTPUT_5HZ, strlen(MTK_OUTPUT_5HZ)))
warnx("mtk: config write failed");
usleep(10000);
if (strlen(MTK_SET_BINARY) != write(fd, MTK_SET_BINARY, strlen(MTK_SET_BINARY))) {
warnx("mtk: config write failed");
return -1;
}
usleep(10000);
if (strlen(MTK_SET_BINARY) != write(fd, MTK_SET_BINARY, strlen(MTK_SET_BINARY)))
warnx("mtk: config write failed");
usleep(10000);
if (strlen(SBAS_ON) != write(fd, SBAS_ON, strlen(SBAS_ON))) {
warnx("mtk: config write failed");
return -1;
}
usleep(10000);
if (strlen(SBAS_ON) != write(fd, SBAS_ON, strlen(SBAS_ON)))
warnx("mtk: config write failed");
usleep(10000);
if (strlen(WAAS_ON) != write(fd, WAAS_ON, strlen(WAAS_ON))) {
warnx("mtk: config write failed");
return -1;
}
usleep(10000);
if (strlen(WAAS_ON) != write(fd, WAAS_ON, strlen(WAAS_ON)))
warnx("mtk: config write failed");
usleep(10000);
if (strlen(MTK_NAVTHRES_OFF) != write(fd, MTK_NAVTHRES_OFF, strlen(MTK_NAVTHRES_OFF)))
warnx("mtk: config write failed");
_config_sent = true;
if (strlen(MTK_NAVTHRES_OFF) != write(fd, MTK_NAVTHRES_OFF, strlen(MTK_NAVTHRES_OFF))) {
warnx("mtk: config write failed");
return -1;
}
return;
return 0;
}
int
MTK::receive(const int &fd, struct vehicle_gps_position_s &gps_position)
{
/* poll descriptor */
pollfd fds[1];
fds[0].fd = fd;
fds[0].events = POLLIN;
uint8_t buf[32];
gps_mtk_packet_t packet;
int j = 0;
ssize_t count = 0;
while (true) {
/* first read whatever is left */
if (j < count) {
/* pass received bytes to the packet decoder */
while (j < count) {
if (parse_char(buf[j], packet) > 0) {
handle_message(packet, gps_position);
return 1;
}
j++;
}
/* everything is read */
j = count = 0;
}
/* then poll for new data */
int ret = ::poll(fds, sizeof(fds) / sizeof(fds[0]), MTK_TIMEOUT_5HZ);
if (ret < 0) {
/* something went wrong when polling */
return -1;
} else if (ret == 0) {
/* Timeout */
return -1;
} else if (ret > 0) {
/* if we have new data from GPS, go handle it */
if (fds[0].revents & POLLIN) {
/*
* We are here because poll says there is some data, so this
* won't block even on a blocking device. If more bytes are
* available, we'll go back to poll() again...
*/
count = ::read(fd, buf, sizeof(buf));
}
}
}
}
void
MTK::decodeInit(void)
MTK::decode_init(void)
{
_rx_ck_a = 0;
_rx_ck_b = 0;
_rx_count = 0;
_decode_state = MTK_DECODE_UNINIT;
}
void
MTK::parse(uint8_t b, struct vehicle_gps_position_s *gps_position, bool &config_needed, bool &pos_updated)
int
MTK::parse_char(uint8_t b, gps_mtk_packet_t &packet)
{
int ret = 0;
if (_decode_state == MTK_DECODE_UNINIT) {
if (b == MTK_SYNC1_V16) {
_decode_state = MTK_DECODE_GOT_CK_A;
config_needed = false;
_mtk_revision = 16;
} else if (b == MTK_SYNC1_V19) {
_decode_state = MTK_DECODE_GOT_CK_A;
config_needed = false;
_mtk_revision = 19;
}
@ -125,78 +183,82 @@ MTK::parse(uint8_t b, struct vehicle_gps_position_s *gps_position, bool &config_
} else {
// Second start symbol was wrong, reset state machine
decodeInit();
decode_init();
}
} else if (_decode_state == MTK_DECODE_GOT_CK_B) {
// Add to checksum
if (_rx_count < 33)
addByteToChecksum(b);
add_byte_to_checksum(b);
// Fill packet buffer
_rx_buffer[_rx_count] = b;
((uint8_t*)(&packet))[_rx_count] = b;
_rx_count++;
/* Packet size minus checksum */
if (_rx_count >= 35) {
type_gps_mtk_packet *packet = (type_gps_mtk_packet *) _rx_buffer;;
/* Check if checksum is valid */
if (_rx_ck_a == packet->ck_a && _rx_ck_b == packet->ck_b) {
if (_mtk_revision == 16) {
gps_position->lat = packet->latitude * 10; // from degrees*1e6 to degrees*1e7
gps_position->lon = packet->longitude * 10; // from degrees*1e6 to degrees*1e7
} else if (_mtk_revision == 19) {
gps_position->lat = packet->latitude; // both degrees*1e7
gps_position->lon = packet->longitude; // both degrees*1e7
} else {
warnx("mtk: unknown revision");
}
gps_position->alt = (int32_t)(packet->msl_altitude * 10); // from cm to mm
gps_position->fix_type = packet->fix_type;
gps_position->eph_m = packet->hdop; // XXX: Check this because eph_m is in m and hdop is without unit
gps_position->epv_m = 0.0; //unknown in mtk custom mode
gps_position->vel_m_s = ((float)packet->ground_speed)*1e-2f; // from cm/s to m/s
gps_position->cog_rad = ((float)packet->heading) * M_DEG_TO_RAD_F * 1e-2f; //from deg *100 to rad
gps_position->satellites_visible = packet->satellites;
/* convert time and date information to unix timestamp */
struct tm timeinfo; //TODO: test this conversion
uint32_t timeinfo_conversion_temp;
timeinfo.tm_mday = packet->date * 1e-4;
timeinfo_conversion_temp = packet->date - timeinfo.tm_mday * 1e4;
timeinfo.tm_mon = timeinfo_conversion_temp * 1e-2 - 1;
timeinfo.tm_year = (timeinfo_conversion_temp - (timeinfo.tm_mon + 1) * 1e2) + 100;
timeinfo.tm_hour = packet->utc_time * 1e-7;
timeinfo_conversion_temp = packet->utc_time - timeinfo.tm_hour * 1e7;
timeinfo.tm_min = timeinfo_conversion_temp * 1e-5;
timeinfo_conversion_temp -= timeinfo.tm_min * 1e5;
timeinfo.tm_sec = timeinfo_conversion_temp * 1e-3;
timeinfo_conversion_temp -= timeinfo.tm_sec * 1e3;
time_t epoch = mktime(&timeinfo);
gps_position->time_gps_usec = epoch * 1e6; //TODO: test this
gps_position->time_gps_usec += timeinfo_conversion_temp * 1e3;
gps_position->timestamp_position = gps_position->timestamp_time = hrt_absolute_time();
pos_updated = true;
/* Packet size minus checksum, XXX ? */
if (_rx_count >= sizeof(packet)) {
/* Compare checksum */
if (_rx_ck_a == packet.ck_a && _rx_ck_b == packet.ck_b) {
ret = 1;
} else {
warnx("mtk Checksum invalid, 0x%x, 0x%x instead of 0x%x, 0x%x", _rx_ck_a, packet->ck_a, _rx_ck_b, packet->ck_b);
warnx("MTK Checksum invalid");
ret = -1;
}
// Reset state machine to decode next packet
decodeInit();
decode_init();
}
}
return ret;
}
void
MTK::handle_message(gps_mtk_packet_t &packet, struct vehicle_gps_position_s &gps_position)
{
if (_mtk_revision == 16) {
gps_position.lat = packet.latitude * 10; // from degrees*1e6 to degrees*1e7
gps_position.lon = packet.longitude * 10; // from degrees*1e6 to degrees*1e7
} else if (_mtk_revision == 19) {
gps_position.lat = packet.latitude; // both degrees*1e7
gps_position.lon = packet.longitude; // both degrees*1e7
} else {
warnx("mtk: unknown revision");
gps_position.lat = 0;
gps_position.lon = 0;
}
gps_position.alt = (int32_t)(packet.msl_altitude * 10); // from cm to mm
gps_position.fix_type = packet.fix_type;
gps_position.eph_m = packet.hdop; // XXX: Check this because eph_m is in m and hdop is without unit
gps_position.epv_m = 0.0; //unknown in mtk custom mode
gps_position.vel_m_s = ((float)packet.ground_speed)*1e-2f; // from cm/s to m/s
gps_position.cog_rad = ((float)packet.heading) * M_DEG_TO_RAD_F * 1e-2f; //from deg *100 to rad
gps_position.satellites_visible = packet.satellites;
/* convert time and date information to unix timestamp */
struct tm timeinfo; //TODO: test this conversion
uint32_t timeinfo_conversion_temp;
timeinfo.tm_mday = packet.date * 1e-4;
timeinfo_conversion_temp = packet.date - timeinfo.tm_mday * 1e4;
timeinfo.tm_mon = timeinfo_conversion_temp * 1e-2 - 1;
timeinfo.tm_year = (timeinfo_conversion_temp - (timeinfo.tm_mon + 1) * 1e2) + 100;
timeinfo.tm_hour = packet.utc_time * 1e-7;
timeinfo_conversion_temp = packet.utc_time - timeinfo.tm_hour * 1e7;
timeinfo.tm_min = timeinfo_conversion_temp * 1e-5;
timeinfo_conversion_temp -= timeinfo.tm_min * 1e5;
timeinfo.tm_sec = timeinfo_conversion_temp * 1e-3;
timeinfo_conversion_temp -= timeinfo.tm_sec * 1e3;
time_t epoch = mktime(&timeinfo);
gps_position.time_gps_usec = epoch * 1e6; //TODO: test this
gps_position.time_gps_usec += timeinfo_conversion_temp * 1e3;
gps_position.timestamp_position = gps_position.timestamp_time = hrt_absolute_time();
return;
}
void
MTK::addByteToChecksum(uint8_t b)
MTK::add_byte_to_checksum(uint8_t b)
{
_rx_ck_a = _rx_ck_a + b;
_rx_ck_b = _rx_ck_b + _rx_ck_a;

35
apps/drivers/gps/mtk.h
View File

@ -50,6 +50,9 @@
#define WAAS_ON "$PMTK301,2*2E\r\n"
#define MTK_NAVTHRES_OFF "$PMTK397,0*23\r\n"
#define MTK_TIMEOUT_5HZ 400
#define MTK_BAUDRATE 38400
typedef enum {
MTK_DECODE_UNINIT = 0,
MTK_DECODE_GOT_CK_A = 1,
@ -64,16 +67,16 @@ typedef struct {
int32_t latitude; ///< Latitude in degrees * 10^7
int32_t longitude; ///< Longitude in degrees * 10^7
uint32_t msl_altitude; ///< MSL altitude in meters * 10^2
uint32_t ground_speed; ///< FIXME SPEC UNCLEAR
int32_t heading;
uint8_t satellites;
uint8_t fix_type;
uint32_t ground_speed; ///< velocity in m/s
int32_t heading; ///< heading in degrees * 10^2
uint8_t satellites; ///< number of sattelites used
uint8_t fix_type; ///< fix type: XXX correct for that
uint32_t date;
uint32_t utc_time;
uint16_t hdop;
uint16_t hdop; ///< horizontal dilution of position (without unit)
uint8_t ck_a;
uint8_t ck_b;
} type_gps_mtk_packet;
} gps_mtk_packet_t;
#pragma pack(pop)
@ -84,23 +87,31 @@ class MTK : public GPS_Helper
public:
MTK();
~MTK();
void reset(void);
void configure(const int &fd, bool &baudrate_changed, unsigned &baudrate);
void parse(uint8_t, struct vehicle_gps_position_s*, bool &config_needed, bool &pos_updated);
int receive(const int &fd, struct vehicle_gps_position_s &gps_position);
int configure(const int &fd, unsigned &baudrate);
private:
/**
* Parse the binary MTK packet
*/
int parse_char(uint8_t b, gps_mtk_packet_t &packet);
/**
* Handle the package once it has arrived
*/
void handle_message(gps_mtk_packet_t &packet, struct vehicle_gps_position_s &gps_position);
/**
* Reset the parse state machine for a fresh start
*/
void decodeInit(void);
void decode_init(void);
/**
* While parsing add every byte (except the sync bytes) to the checksum
*/
void addByteToChecksum(uint8_t);
void add_byte_to_checksum(uint8_t);
mtk_decode_state_t _decode_state;
bool _config_sent;
uint8_t _mtk_revision;
uint8_t _rx_buffer[MTK_RECV_BUFFER_SIZE];
unsigned _rx_count;