make simulator protocol match the one that Foreflight uses

main/xplane.go

@@ -1,10 +1,15 @@
 /*
 	Copyright (c) 2018 Thorsten Biermann
+	Copyright (c) 2013 Adrian Batzill
 	Distributable under the terms of The "BSD New" License
 	that can be found in the LICENSE file, herein included
 	as part of this header.
 
 	xplane.go: Routines for generating X-Plane data feed
+
+	Seems to be mostly undocumented, so instead of reverse engineering x-plane, we use this:
+	https://www.foreflight.com/support/network-gps/
+	Seems to be very similar, but the XATT message is cut short. It seems to work with most software though?
 */
 
 package main
@@ -15,18 +20,19 @@ import (
 )
 
 func convertKnotsToXPlaneSpeed(knots float32) float32 {
-	return knots / 1.945
+	return knots / 1.94384 // meters per second
 }
 
 func createXPlaneGpsMsg(latDeg float32, lonDeg float32, altMslFt float32, trackDeg float32, speedKt float32) []byte {
 	// example: XGPS1,-122.298432,47.450756,420.9961,349.7547,57.9145
-	return []byte(fmt.Sprintf("XGPS1,%.6f,%.6f,%.4f,%.4f,%.4f", lonDeg, latDeg, convertFeetToMeters(altMslFt), trackDeg, convertKnotsToXPlaneSpeed(speedKt)))
+	return []byte(fmt.Sprintf("XGPSStratux,%.6f,%.6f,%.4f,%.4f,%.4f", lonDeg+0.5, latDeg, convertFeetToMeters(altMslFt), trackDeg, convertKnotsToXPlaneSpeed(speedKt)))
 }
 
 func createXPlaneAttitudeMsg(headingDeg float32, pitchDeg float32, rollDeg float32) []byte {
 	// example: XATT1,345.1,-1.1,-12.5,0.1374,0.0954,-0.0444,-17.0,-1.2,-65.0,-0.01,1.63,0.02
 	// TODO find out what the remaining parameters are for
-	return []byte(fmt.Sprintf("XATT1,%.1f,%.1f,%.1f,%.4f,%.4f,%.4f,%.1f,%.1f,%.1f,%.2f,%.2f,%.2f", headingDeg, pitchDeg, rollDeg, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0))
+	//return []byte(fmt.Sprintf("XATT1,%.1f,%.1f,%.1f,%.4f,%.4f,%.4f,%.1f,%.1f,%.1f,%.2f,%.2f,%.2f", headingDeg, pitchDeg, rollDeg, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0))
+	return []byte(fmt.Sprintf("XATTStratux,%.1f,%.1f,%.1f", headingDeg, pitchDeg, rollDeg))
 }
 
 func createXPlaneTrafficMsg(targetId uint32, latDeg float32, lonDeg float32, altFt int32, hSpeedKt uint32, vSpeedFpm int32, onGround bool, trackDeg uint32, callSign string) []byte {
@@ -44,5 +50,5 @@ func createXPlaneTrafficMsg(targetId uint32, latDeg float32, lonDeg float32, alt
 	regEx, _ := regexp.Compile("[^a-zA-Z0-9]+")
 	cleanCallSign := regEx.ReplaceAllString(callSign, "")
 
-	return []byte(fmt.Sprintf("XTRA1,%d,%.6f,%.6f,%d,%d,%d,%d,%d,%s", targetId, latDeg, lonDeg, altFt, vSpeedFpm, airborneValue, trackDeg, hSpeedKt, cleanCallSign))
+	return []byte(fmt.Sprintf("XTRAFFICStratux,%d,%.6f,%.6f,%d,%d,%d,%d,%d,%s", targetId, latDeg, lonDeg, altFt, vSpeedFpm, airborneValue, trackDeg, hSpeedKt, cleanCallSign))
 }