Removed "airspeed" field from Airspeed UAVO. Now everything is done either with true airspeed or calibrated airspeed

flight/Modules/Airspeed/revolution/airspeed.c

@@ -79,6 +79,8 @@
 
 #define F_PI 3.141526535897932f
 #define DEG2RAD (F_PI/180.0f)
+#define T0 288.15f
+#define BARO_TEMPERATURE_OFFSET 5
 
 // Private types
 
@@ -211,12 +213,18 @@ static void airspeedTask(void *parameters)
 			baro_airspeedGet(&airspeedData, &lastSysTime, airspeedSensorType, airspeedADCPin);
 			
 			//Calculate true airspeed, not taking into account compressibility effects
-			#define T0 288.15f
 			float baroTemperature;
 			
 			BaroAltitudeTemperatureGet(&baroTemperature);
-			baroTemperature-=5; //Do this just because we suspect that the board heats up relative to its surroundings. THIS IS BAD(tm)
+			baroTemperature-=BARO_TEMPERATURE_OFFSET; //Do this just because we suspect that the board heats up relative to its surroundings. THIS IS BAD(tm)
-			airspeed_tas_baro=airspeedData.CAS * sqrtf((baroTemperature+273.15)/T0) + airspeedErrInt * GPS_AIRSPEED_BIAS_KI;
+ #ifdef GPS_AIRSPEED_PRESENT
+			//GPS present, so use baro sensor to filter TAS
+			airspeed_tas_baro=airspeedData.CalibratedAirspeed * sqrtf((baroTemperature+273.15)/T0) + airspeedErrInt * GPS_AIRSPEED_BIAS_KI;
+ #else
+			//No GPS, so TAS comes only from baro sensor
+			airspeedData.TrueAirspeed=airspeedData.CalibratedAirspeed * sqrtf((baroTemperature+273.15)/T0) + airspeedErrInt * GPS_AIRSPEED_BIAS_KI;
+ #endif			
+			
 		}
 		else
 #endif
@@ -266,6 +274,13 @@ static void airspeedTask(void *parameters)
 							
 				//There's already an airspeed sensor, so instead correct it for bias with P correction. The I correction happened earlier in the function.
 				airspeedData.TrueAirspeed = airspeed_tas_baro + airspeedErr * GPS_AIRSPEED_BIAS_KP;
+				
+				
+				/* Note: 
+				      This would be a good place to change the airspeed calibration, so that it matches the GPS computed values. However,
+				      this might be a bad idea, as their are two degrees of freedom here: temperature and sensor calibration. I don't 
+				      know how to control for temperature bias.
+				 */
 			}
 			else
  #endif
@@ -274,18 +289,22 @@ static void airspeedTask(void *parameters)
 				//case, filter the airspeed for smoother output
 				float alpha=gpsSamplePeriod_ms/(gpsSamplePeriod_ms + GPS_AIRSPEED_TIME_CONSTANT_MS); //Low pass filter.
 				airspeedData.TrueAirspeed=v_air_GPS*(alpha) + airspeedData.TrueAirspeed*(1.0f-alpha);
+				
+				//Calculate calibrated airspeed from GPS, since we're not getting it from a discrete airspeed sensor
+				float baroTemperature;
+				BaroAltitudeTemperatureGet(&baroTemperature);
+				baroTemperature-=BARO_TEMPERATURE_OFFSET; //Do this just because we suspect that the board heats up relative to its surroundings. THIS IS BAD(tm)
+				airspeedData.CalibratedAirspeed =airspeedData.TrueAirspeed / sqrtf((baroTemperature+273.15)/T0);
 			}			
 		}
+ #ifdef BARO_AIRSPEED_PRESENT
+		else if (airspeedData.BaroConnected==BAROAIRSPEED_BAROCONNECTED_TRUE){
+			//No GPS velocity estimate this loop, so filter data with baro airspeed
+			float alpha=gpsSamplePeriod_ms/(gpsSamplePeriod_ms + GPS_AIRSPEED_TIME_CONSTANT_MS); //Low pass filter.
+			airspeedData.TrueAirspeed=airspeedData.TrueAirspeed*(alpha) + airspeedData.TrueAirspeed*(1.0f-alpha);
+		}
+ #endif
 #endif
-		
-		//Legacy UAVO support, this needs to be removed in favor of using TAS and CAS, as appropriate.
-		if (airspeedData.BaroConnected==BAROAIRSPEED_BAROCONNECTED_FALSE){ //If we only have a GPS, use GPS data as airspeed...
-			airspeedData.Airspeed=airspeedData.TrueAirspeed;
-		}
-		else{                            //...otherwise, use the only baro airspeed because we still don't trust true airspeed calculations
-			airspeedData.Airspeed=airspeedData.CAS;
-		}
-			
 		//Set the UAVO
 		BaroAirspeedSet(&airspeedData);
 			

flight/Modules/Airspeed/revolution/baro_airspeed.c

@@ -151,10 +151,10 @@ void baro_airspeedGet(BaroAirspeedData *baroAirspeedData, portTickType *lastSysT
 		}
 		//Filter CAS
 		float alpha=SAMPLING_DELAY_MS_MPXV/(SAMPLING_DELAY_MS_MPXV + ANALOG_BARO_AIRSPEED_TIME_CONSTANT_MS); //Low pass filter.
-		float filteredAirspeed = calibratedAirspeed*(alpha) + baroAirspeedData->CAS*(1.0f-alpha);
+		float filteredAirspeed = calibratedAirspeed*(alpha) + baroAirspeedData->CalibratedAirspeed*(1.0f-alpha);
 		
 		//Set two values, one for the UAVO airspeed sensor reading, and the other for the GPS corrected one
-		baroAirspeedData->CAS = filteredAirspeed;
+		baroAirspeedData->CalibratedAirspeed = filteredAirspeed;
 #else
 		//Whoops, no sensor defined in pios_config.h. Revert to GPS.
 		baroAirspeedData->BaroConnected = BAROAIRSPEED_BAROCONNECTED_FALSE;
@@ -179,7 +179,7 @@ void baro_airspeedGet(BaroAirspeedData *baroAirspeedData, portTickType *lastSysT
 		baroAirspeedData->SensorValue = PIOS_ETASV3_ReadAirspeed();
 		if (baroAirspeedData->SensorValue==-1) {
 			baroAirspeedData->BaroConnected = BAROAIRSPEED_BAROCONNECTED_FALSE;
-			baroAirspeedData->Airspeed = 0;
+			baroAirspeedData->CalibratedAirspeed = 0;
 			BaroAirspeedSet(&baroAirspeedData);
 			return;
 		}
@@ -204,7 +204,7 @@ void baro_airspeedGet(BaroAirspeedData *baroAirspeedData, portTickType *lastSysT
 		float calibratedAirspeed = ETS_AIRSPEED_SCALE * sqrtf((float)abs(baroAirspeedData->SensorValue - airspeedSettingsData.ZeroPoint)); //Is this calibrated or indicated airspeed?
 		
 		baroAirspeedData->BaroConnected = BAROAIRSPEED_BAROCONNECTED_TRUE;
-		baroAirspeedData->CAS = calibratedAirspeed;
+		baroAirspeedData->CalibratedAirspeed = calibratedAirspeed;
 #else
 		//Whoops, no EagleTree sensor defined in pios_config.h. Declare it unconnected...
 		baroAirspeedData->BaroConnected = BAROAIRSPEED_BAROCONNECTED_FALSE;

flight/Modules/FixedWingPathFollower/fixedwingpathfollower.c

@@ -363,7 +363,7 @@ static uint8_t updateFixedDesiredAttitude()
 	
 //	float groundspeedActual;
 	float groundspeedDesired;
-	float airspeedActual;
+	float calibratedAirspeedActual;
 	float airspeedDesired;
 	float airspeedError;
 	float accelActual;
@@ -401,8 +401,7 @@ static uint8_t updateFixedDesiredAttitude()
 
 	// Current ground speed
 //	groundspeedActual  = sqrtf( velocityActual.East*velocityActual.East + velocityActual.North*velocityActual.North );
-//	airspeedActual     = groundspeedActual + baroAirspeedBias;
+	calibratedAirspeedActual     = baroAirspeed.CalibratedAirspeed;
-	airspeedActual     = baroAirspeed.Airspeed;
 
 	// Desired ground speed
 	groundspeedDesired = sqrtf(velocityDesired.North*velocityDesired.North + velocityDesired.East*velocityDesired.East);
@@ -411,7 +410,7 @@ static uint8_t updateFixedDesiredAttitude()
 							fixedwingpathfollowerSettings.CruiseSpeed);
 
 	// Airspeed error
-	airspeedError = airspeedDesired - airspeedActual;
+	airspeedError = airspeedDesired - calibratedAirspeedActual;
 
 	// Vertical speed error
 	descentspeedDesired = bound (
@@ -429,28 +428,28 @@ static uint8_t updateFixedDesiredAttitude()
 	// Error condition: plane too slow or too fast
 	fixedwingpathfollowerStatus.Errors[FIXEDWINGPATHFOLLOWERSTATUS_ERRORS_HIGHSPEED] = 0;
 	fixedwingpathfollowerStatus.Errors[FIXEDWINGPATHFOLLOWERSTATUS_ERRORS_LOWSPEED] = 0;
-	if ( airspeedActual >  fixedwingpathfollowerSettings.AirSpeedMax) {
+	if ( calibratedAirspeedActual >  fixedwingpathfollowerSettings.AirSpeedMax) {
 		fixedwingpathfollowerStatus.Errors[FIXEDWINGPATHFOLLOWERSTATUS_ERRORS_OVERSPEED] = 1;
 		result = 0;
 	}
-	if ( airspeedActual >  fixedwingpathfollowerSettings.CruiseSpeed * 1.2f) {
+	if ( calibratedAirspeedActual >  fixedwingpathfollowerSettings.CruiseSpeed * 1.2f) {
 		fixedwingpathfollowerStatus.Errors[FIXEDWINGPATHFOLLOWERSTATUS_ERRORS_HIGHSPEED] = 1;
 		result = 0;
 	}
-	if (airspeedActual < fixedwingpathfollowerSettings.BestClimbRateSpeed * 0.8f && 1) { //The next three && 1 are placeholders for UAVOs representing LANDING and TAKEOFF
+	if (calibratedAirspeedActual < fixedwingpathfollowerSettings.BestClimbRateSpeed * 0.8f && 1) { //The next three && 1 are placeholders for UAVOs representing LANDING and TAKEOFF
 		fixedwingpathfollowerStatus.Errors[FIXEDWINGPATHFOLLOWERSTATUS_ERRORS_LOWSPEED] = 1;
 		result = 0;
 	}
-	if (airspeedActual < fixedwingpathfollowerSettings.StallSpeedClean && 1 && 1) { //Where the && 1 represents the UAVO that will control whether the airplane is prepped for landing or not
+	if (calibratedAirspeedActual < fixedwingpathfollowerSettings.StallSpeedClean && 1 && 1) { //Where the && 1 represents the UAVO that will control whether the airplane is prepped for landing or not
 		fixedwingpathfollowerStatus.Errors[FIXEDWINGPATHFOLLOWERSTATUS_ERRORS_STALLSPEED] = 1;
 		result = 0;
 	}
-	if (airspeedActual < fixedwingpathfollowerSettings.StallSpeedDirty && 1) {
+	if (calibratedAirspeedActual < fixedwingpathfollowerSettings.StallSpeedDirty && 1) {
 		fixedwingpathfollowerStatus.Errors[FIXEDWINGPATHFOLLOWERSTATUS_ERRORS_STALLSPEED] = 1;
 		result = 0;
 	}
 	
-	if (airspeedActual<1e-6) {
+	if (calibratedAirspeedActual<1e-6) {
 		// prevent division by zero, abort without controlling anything. This guidance mode is not suited for takeoff or touchdown, or handling stationary planes
 		// also we cannot handle planes flying backwards, lets just wait until the nose drops
 		fixedwingpathfollowerStatus.Errors[FIXEDWINGPATHFOLLOWERSTATUS_ERRORS_LOWSPEED] = 1;
@@ -555,7 +554,7 @@ static uint8_t updateFixedDesiredAttitude()
 	 */
 	// compute desired acceleration
 	if(0){
-		accelDesired = bound( (airspeedError/airspeedActual) * fixedwingpathfollowerSettings.SpeedP[FIXEDWINGPATHFOLLOWERSETTINGS_SPEEDP_KP],
+		accelDesired = bound( (airspeedError/calibratedAirspeedActual) * fixedwingpathfollowerSettings.SpeedP[FIXEDWINGPATHFOLLOWERSETTINGS_SPEEDP_KP],
 			-fixedwingpathfollowerSettings.SpeedP[FIXEDWINGPATHFOLLOWERSETTINGS_SPEEDP_MAX],
 			fixedwingpathfollowerSettings.SpeedP[FIXEDWINGPATHFOLLOWERSETTINGS_SPEEDP_MAX]);
 		fixedwingpathfollowerStatus.Error[FIXEDWINGPATHFOLLOWERSTATUS_ERROR_SPEED] = airspeedError;
@@ -579,7 +578,7 @@ static uint8_t updateFixedDesiredAttitude()
 		fixedwingpathfollowerStatus.ErrorInt[FIXEDWINGPATHFOLLOWERSTATUS_ERRORINT_ACCEL] = accelIntegral;
 		fixedwingpathfollowerStatus.Command[FIXEDWINGPATHFOLLOWERSTATUS_COMMAND_ACCEL] = accelCommand;
 		
-		pitchCommand= -accelCommand + bound ( (-descentspeedError/airspeedActual) * fixedwingpathfollowerSettings.VerticalToPitchCrossFeed[FIXEDWINGPATHFOLLOWERSETTINGS_VERTICALTOPITCHCROSSFEED_KP],
+		pitchCommand= -accelCommand + bound ( (-descentspeedError/calibratedAirspeedActual) * fixedwingpathfollowerSettings.VerticalToPitchCrossFeed[FIXEDWINGPATHFOLLOWERSETTINGS_VERTICALTOPITCHCROSSFEED_KP],
 			-fixedwingpathfollowerSettings.VerticalToPitchCrossFeed[FIXEDWINGPATHFOLLOWERSETTINGS_VERTICALTOPITCHCROSSFEED_MAX],
 			fixedwingpathfollowerSettings.VerticalToPitchCrossFeed[FIXEDWINGPATHFOLLOWERSETTINGS_VERTICALTOPITCHCROSSFEED_MAX]
 			);
@@ -715,7 +714,7 @@ static void baroAirspeedUpdatedCb(UAVObjEvent * ev)
 		float groundspeed = sqrtf(velocityActual.East*velocityActual.East + velocityActual.North*velocityActual.North );
 
 		
-		baroAirspeedBias = baroAirspeed.Airspeed - groundspeed;
+		baroAirspeedBias = baroAirspeed.TrueAirspeed - groundspeed;
 	}
 
 }

flight/Modules/PathPlanner/pathplanner.c

@@ -485,7 +485,7 @@ static uint8_t conditionAboveSpeed() {
 		BaroAirspeedData baroAirspeed;
 		BaroAirspeedGet (&baroAirspeed);
 		if (baroAirspeed.BaroConnected == BAROAIRSPEED_BAROCONNECTED_TRUE) {
-			velocity = baroAirspeed.Airspeed;
+			velocity = baroAirspeed.TrueAirspeed;
 		}
 	}
 

ground/openpilotgcs/src/plugins/hitlnew/fgsimulator.cpp

@@ -311,7 +311,7 @@ void FGSimulator::processUpdate(const QByteArray& inp)
     out.altitude = altitude;
     out.groundspeed = groundspeed;
 
-    out.airspeed = airspeed;
+    out.calibratedAirspeed = airspeed;
 
 
     // Update BaroAltitude object

ground/openpilotgcs/src/plugins/hitlnew/hitlnoisegeneration.cpp

@@ -72,6 +72,6 @@ Noise HitlNoiseGeneration::generateNoise(){
     noise.accelData.y=0;
     noise.accelData.z=0;
 
-    noise.baroAirspeed.Airspeed=0;
+    noise.baroAirspeed.CalibratedAirspeed=0;
 
 }

ground/openpilotgcs/src/plugins/hitlnew/il2simulator.cpp

@@ -273,7 +273,7 @@ void IL2Simulator::processUpdate(const QByteArray& inp)
     out.longitude = settings.longitude.toFloat() * 1e7;
     out.groundspeed = current.groundspeed;
 
-    out.airspeed = current.ias;
+    out.calibratedAirspeed = current.ias;
 
     out.dstN=current.Y;
     out.dstE=current.X;

ground/openpilotgcs/src/plugins/hitlnew/simulator.cpp

@@ -414,7 +414,7 @@ void Simulator::updateUAVOs(Output2OP out){
     // Update BaroAirspeed object
     BaroAirspeed::DataFields baroAirspeedData;
     memset(&baroAirspeedData, 0, sizeof(BaroAirspeed::DataFields));
-    baroAirspeedData.Airspeed = out.airspeed + noise.baroAirspeed.Airspeed;
+    baroAirspeedData.CalibratedAirspeed = out.calibratedAirspeed + noise.baroAirspeed.CalibratedAirspeed;
     baroAirspeed->setData(baroAirspeedData);
 
     //Update gyroscope sensor data

ground/openpilotgcs/src/plugins/hitlnew/simulator.h

@@ -118,7 +118,7 @@ struct Output2OP{
     float altitude;
     float heading;
     float groundspeed; //[m/s]
-    float airspeed;    //[m/s]
+    float calibratedAirspeed;    //[m/s]
     float pitch;
     float roll;
     float pressure;

ground/openpilotgcs/src/plugins/hitlnew/xplanesimulator.cpp

@@ -301,7 +301,7 @@ void XplaneSimulator::processUpdate(const QByteArray& dataBuf)
         out.altitude = altitude;
         out.groundspeed = groundspeed_ktgs*1.15*1.6089/3.6; //Convert from [kts] to [m/s]
 
-        out.airspeed = airspeed_keas*1.15*1.6089/3.6;  //Convert from [kts] to [m/s]
+        out.calibratedAirspeed = airspeed_keas*1.15*1.6089/3.6;  //Convert from [kts] to [m/s]
 
         // Update BaroAltitude object
         out.temperature = temperature;

shared/uavobjectdefinition/baroairspeed.xml

@@ -3,8 +3,7 @@
         <description>The raw data from the dynamic pressure sensor with pressure, temperature and airspeed.</description>
         <field name="BaroConnected" units="" type="enum" elements="1" options="False,True"/>
         <field name="SensorValue" units="raw" type="uint16" elements="1"/>
-        <field name="Airspeed" units="m/s" type="float" elements="1"/>
+        <field name="CalibratedAirspeed" units="m/s" type="float" elements="1"/>
-        <field name="CAS" units="m/s" type="float" elements="1"/>
         <field name="GPSAirspeed" units="m/s" type="float" elements="1"/>
         <field name="TrueAirspeed" units="m/s" type="float" elements="1"/>
         <access gcs="readwrite" flight="readwrite"/>