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GPS: add NS and EW velocity computation, which some real-world devices display.

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jmt 2010-03-27 11:37:06 +00:00 • committed by Tim Moore
parent 4265b2e241
commit 40e383451b
2 changed files with 29 additions and 1 deletions
src/Instrumentation
gps.cxxgps.hxx

26
src/Instrumentation/gps.cxx
View file

@ -249,6 +249,8 @@ GPS::init ()
_trip_odometer_node = _gpsNode->getChild("trip-odometer", 0, true);
_true_bug_error_node = _gpsNode->getChild("true-bug-error-deg", 0, true);
_magnetic_bug_error_node = _gpsNode->getChild("magnetic-bug-error-deg", 0, true);
_eastWestVelocity = _gpsNode->getChild("ew-velocity-msec", 0, true);
_northSouthVelocity = _gpsNode->getChild("ns-velocity-msec", 0, true);
// waypoints
SGPropertyNode *wp_node = _gpsNode->getChild("wp", 0, true);
@ -420,6 +422,7 @@ GPS::clearOutput()
_indicated_pos = SGGeod();
_last_vertical_speed = 0.0;
_last_true_track = 0.0;
_lastEWVelocity = _lastNSVelocity = 0.0;
_raim_node->setDoubleValue(0.0);
_indicated_pos = SGGeod();
@ -431,6 +434,8 @@ GPS::clearOutput()
_tracking_bug_node->setDoubleValue(0);
_true_bug_error_node->setDoubleValue(0);
_magnetic_bug_error_node->setDoubleValue(0);
_northSouthVelocity->setDoubleValue(0.0);
_eastWestVelocity->setDoubleValue(0.0);
}
void
@ -545,9 +550,28 @@ GPS::updateBasicData(double dt)
double vertical_speed_mpm = ((_indicated_pos.getElevationM() - _last_pos.getElevationM()) * 60 / dt);
_last_vertical_speed = vertical_speed_mpm * SG_METER_TO_FEET;
speed_kt = fgGetLowPass(_last_speed_kts, speed_kt, dt/20.0);
speed_kt = fgGetLowPass(_last_speed_kts, speed_kt, dt/10.0);
_last_speed_kts = speed_kt;
SGGeod g = _indicated_pos;
g.setLongitudeDeg(_last_pos.getLongitudeDeg());
double northSouthM = SGGeodesy::distanceM(_last_pos, g);
northSouthM = copysign(northSouthM, _indicated_pos.getLatitudeDeg() - _last_pos.getLatitudeDeg());
double nsMSec = fgGetLowPass(_lastNSVelocity, northSouthM / dt, dt/2.0);
_lastNSVelocity = nsMSec;
_northSouthVelocity->setDoubleValue(nsMSec);
g = _indicated_pos;
g.setLatitudeDeg(_last_pos.getLatitudeDeg());
double eastWestM = SGGeodesy::distanceM(_last_pos, g);
eastWestM = copysign(eastWestM, _indicated_pos.getLongitudeDeg() - _last_pos.getLongitudeDeg());
double ewMSec = fgGetLowPass(_lastEWVelocity, eastWestM / dt, dt/2.0);
_lastEWVelocity = ewMSec;
_eastWestVelocity->setDoubleValue(ewMSec);
double odometer = _odometer_node->getDoubleValue();
_odometer_node->setDoubleValue(odometer + distance_m * SG_METER_TO_NM);
odometer = _trip_odometer_node->getDoubleValue();

4
src/Instrumentation/gps.hxx
View file

@ -333,6 +333,8 @@ private:
SGPropertyNode_ptr _trip_odometer_node;
SGPropertyNode_ptr _true_bug_error_node;
SGPropertyNode_ptr _magnetic_bug_error_node;
SGPropertyNode_ptr _eastWestVelocity;
SGPropertyNode_ptr _northSouthVelocity;
SGPropertyNode_ptr _ref_navaid_id_node;
SGPropertyNode_ptr _ref_navaid_bearing_node;
@ -358,6 +360,8 @@ private:
double _last_speed_kts;
double _last_true_track;
double _last_vertical_speed;
double _lastEWVelocity;
double _lastNSVelocity;
std::string _mode;
GPSListener* _listener;