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AP_GPS: check for corret GPS solution rates in flight and fix 

if the GPS is giving us data at less than 300ms intervals then re-send
the configuration messages to try to kick it into the right rates

Pair-Programmed-With: Randy Mackay <rmackay9@yahoo.com>
This commit is contained in:
Andrew Tridgell 2013-10-02 12:32:32 +10:00
parent e672b61bbb
commit 34f7f88190
2 changed files with 78 additions and 7 deletions
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75
libraries/AP_GPS/AP_GPS_UBLOX.cpp
View File

@ -64,6 +64,45 @@ AP_GPS_UBLOX::init(AP_HAL::UARTDriver *s, enum GPS_Engine_Setting nav_setting)
_new_speed = false;
}
/*
send the next step of rate updates to the GPS. This reconfigures the
GPS on the fly to have the right message rates. It needs to be
careful to only send a message if there is sufficient buffer space
available on the serial port to avoid it blocking the CPU
*/
void
AP_GPS_UBLOX::send_next_rate_update(void)
{
if (_port->txspace() < sizeof(struct ubx_header)+sizeof(struct ubx_cfg_nav_rate)+2) {
// not enough space - do it next time
return;
}
switch (rate_update_step) {
case 0:
_configure_navigation_rate(200);
break;
case 1:
_configure_message_rate(CLASS_NAV, MSG_POSLLH, 1);
break;
case 2:
_configure_message_rate(CLASS_NAV, MSG_STATUS, 1);
break;
case 3:
_configure_message_rate(CLASS_NAV, MSG_SOL, 1);
break;
case 4:
_configure_message_rate(CLASS_NAV, MSG_VELNED, 1);
break;
}
rate_update_step++;
if (rate_update_step > 4) {
need_rate_update = false;
rate_update_step = 0;
}
}
// Process bytes available from the stream
//
// The stream is assumed to contain only messages we recognise. If it
@ -80,6 +119,10 @@ AP_GPS_UBLOX::read(void)
int16_t numc;
bool parsed = false;
if (need_rate_update) {
send_next_rate_update();
}
numc = _port->available();
for (int16_t i = 0; i < numc; i++) { // Process bytes received
@ -299,6 +342,17 @@ AP_GPS_UBLOX::_parse_gps(void)
if (_new_position && _new_speed) {
_new_speed = _new_position = false;
_fix_count++;
uint32_t new_fix_time = hal.scheduler->millis();
if (!need_rate_update && new_fix_time - _last_fix_time > 300 && _fix_count % 20 == 0) {
// the GPS is running slow. It possibly browned out and
// restarted with incorrect parameters. We will slowly
// send out new parameters to fix it
need_rate_update = true;
rate_update_step = 0;
}
_last_fix_time = new_fix_time;
if (_fix_count == 100) {
// ask for nav settings every 20 seconds
Debug("Asking for engine setting\n");
@ -365,13 +419,25 @@ AP_GPS_UBLOX::_configure_message_rate(uint8_t msg_class, uint8_t msg_id, uint8_t
_send_message(CLASS_CFG, MSG_CFG_SET_RATE, &msg, sizeof(msg));
}
/*
* configure a UBlox GPS navigation solution rate of 200ms
*/
void
AP_GPS_UBLOX::_configure_navigation_rate(uint16_t rate_ms)
{
struct ubx_cfg_nav_rate msg;
msg.measure_rate_ms = rate_ms;
msg.nav_rate = 1;
msg.timeref = 0; // UTC time
_send_message(CLASS_CFG, MSG_CFG_RATE, &msg, sizeof(msg));
}
/*
* configure a UBlox GPS for the given message rate
*/
void
AP_GPS_UBLOX::_configure_gps(void)
{
struct ubx_cfg_nav_rate msg;
const unsigned baudrates[4] = {9600U, 19200U, 38400U, 57600U};
// the GPS may be setup for a different baud rate. This ensures
@ -385,11 +451,8 @@ AP_GPS_UBLOX::_configure_gps(void)
}
_port->begin(38400U);
// ask for navigation solutions every 200ms
msg.measure_rate_ms = 200;
msg.nav_rate = 1;
msg.timeref = 0; // UTC time
_send_message(CLASS_CFG, MSG_CFG_RATE, &msg, sizeof(msg));
// ask for nav solutions at 5Hz
_configure_navigation_rate(200);
// ask for the messages we parse to be sent on every navigation solution
_configure_message_rate(CLASS_NAV, MSG_POSLLH, 1);

10
libraries/AP_GPS/AP_GPS_UBLOX.h
View File

@ -51,7 +51,9 @@ public:
_payload_counter(0),
_fix_count(0),
_disable_counter(0),
next_fix(GPS::FIX_NONE)
next_fix(GPS::FIX_NONE),
need_rate_update(false),
rate_update_step(0)
{}
// Methods
@ -219,10 +221,16 @@ private:
// used to update fix between status and position packets
Fix_Status next_fix;
bool need_rate_update;
uint8_t rate_update_step;
uint32_t _last_fix_time;
void _configure_navigation_rate(uint16_t rate_ms);
void _configure_message_rate(uint8_t msg_class, uint8_t msg_id, uint8_t rate);
void _configure_gps(void);
void _update_checksum(uint8_t *data, uint8_t len, uint8_t &ck_a, uint8_t &ck_b);
void _send_message(uint8_t msg_class, uint8_t msg_id, void *msg, uint8_t size);
void send_next_rate_update(void);
};