Add emergency status to traffic msgs; additional UAT statistics; cleanup

main/traffic.go

@@ -97,6 +97,7 @@ type TrafficInfo struct {
 	Speed_valid         bool      // set when speed report received.
 	Vvel                int16     // feet per minute
 	Timestamp           time.Time // timestamp of traffic message, UTC
+	PriorityStatus      uint8     // Emergency or priority code as defined in GDL90 spec, DO-260B (Type 28 msg) and DO-282B
 
 	// Parameters starting at 'Age' are calculated from last message receipt on each call of sendTrafficUpdates().
 	// Mode S transmits position and track in separate messages, and altitude can also be
@@ -348,6 +349,9 @@ func makeTrafficReportMsg(ti TrafficInfo) []byte {
 		msg[19+i] = c
 	}
 
+	//msg[27] is priority / emergency status per GDL90 spec (DO260B and DO282B are same codes)
+	msg[27] = ti.PriorityStatus << 4
+
 	return prepareMessage(msg)
 }
 
@@ -394,68 +398,107 @@ func parseDownlinkReport(s string, signalLevel int) {
 
 	// Extract parameters from Mode Status elements, if available.
 	if msg_type == 1 || msg_type == 3 {
+
 		// Determine UAT message version. This is needed for some capability decoding and is useful for debugging.
-		uat_version = (frame[23] >> 2) % 0x08
+		uat_version = (frame[23] >> 2) & 0x07
-		//log.Printf("%06X: UAT version %v\n",icao_addr,uat_version)
 
 		// Extract emitter category.
-		if msg_type == 1 || msg_type == 3 {
-			v := (uint16(frame[17]) << 8) | (uint16(frame[18]))
-			ti.Emitter_category = uint8((v / 1600) % 40)
 
-			// Decode callsign or Flight Plan ID (i.e. squawk code)
+		v := (uint16(frame[17]) << 8) | (uint16(frame[18]))
-			// If the CSID bit (byte 27, bit 7) is set to 1, all eight characters
+		ti.Emitter_category = uint8((v / 1600) % 40)
-			// encoded in bytes 18-23 represent callsign.
-			// If the CSID bit is set to 0, the first four characters encoded in bytes 18-23
-			// represent the Mode A squawk code.
 
-			csid := (frame[26] >> 1) & 0x01
+		// Decode callsign or Flight Plan ID (i.e. squawk code)
+		// If the CSID bit (byte 27, bit 7) is set to 1, all eight characters
+		// encoded in bytes 18-23 represent callsign.
+		// If the CSID bit is set to 0, the first four characters encoded in bytes 18-23
+		// represent the Mode A squawk code.
 
-			if csid == 1 { // decode as callsign
+		csid := (frame[26] >> 1) & 0x01
-				//log.Printf("CSID == 1. Decoding callsign.\n")
-				base40_alphabet := string("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ  ..")
-				tail := ""
 
-				v := (uint16(frame[17]) << 8) | uint16(frame[18])
+		if csid == 1 { // decode as callsign
-				tail += string(base40_alphabet[(v/40)%40])
+			base40_alphabet := string("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ  ..")
-				tail += string(base40_alphabet[v%40])
+			tail := ""
-				v = (uint16(frame[19]) << 8) | uint16(frame[20])
-				tail += string(base40_alphabet[(v/1600)%40])
-				tail += string(base40_alphabet[(v/40)%40])
-				tail += string(base40_alphabet[v%40])
-				v = (uint16(frame[21]) << 8) | uint16(frame[22])
-				tail += string(base40_alphabet[(v/1600)%40])
-				tail += string(base40_alphabet[(v/40)%40])
-				tail += string(base40_alphabet[v%40])
-				tail = strings.Trim(tail, " ")
-				ti.Tail = tail
-				//log.Printf("Callsign decoded as %s\n",tail)
 
-			} else if uat_version >= 2 { // decode as Mode 3/A code, if UAT version is at least 2
+			v := (uint16(frame[17]) << 8) | uint16(frame[18])
-				//log.Printf("CSID == 0. Decoding Mode 3/A code.\n")
+			tail += string(base40_alphabet[(v/40)%40])
-				v := (uint16(frame[17]) << 8) | uint16(frame[18])
+			tail += string(base40_alphabet[v%40])
-				squawk_a := (v / 40) % 40
+			v = (uint16(frame[19]) << 8) | uint16(frame[20])
-				squawk_b := v % 40
+			tail += string(base40_alphabet[(v/1600)%40])
-				v = (uint16(frame[19]) << 8) | uint16(frame[20])
+			tail += string(base40_alphabet[(v/40)%40])
-				squawk_c := (v / 1600) % 40
+			tail += string(base40_alphabet[v%40])
-				squawk_d := (v / 40) % 40
+			v = (uint16(frame[21]) << 8) | uint16(frame[22])
-				squawk := 1000*squawk_a + 100*squawk_b + 10*squawk_c + squawk_d
+			tail += string(base40_alphabet[(v/1600)%40])
-				ti.Squawk = int(squawk)
+			tail += string(base40_alphabet[(v/40)%40])
-				//log.Printf("Mode 3/A decoded as %d\n",squawk)
+			tail += string(base40_alphabet[v%40])
-			}
+			tail = strings.Trim(tail, " ")
+			ti.Tail = tail
+
+		} else if uat_version >= 2 { // decode as Mode 3/A code, if UAT version is at least 2
+			v := (uint16(frame[17]) << 8) | uint16(frame[18])
+			squawk_a := (v / 40) % 40
+			squawk_b := v % 40
+			v = (uint16(frame[19]) << 8) | uint16(frame[20])
+			squawk_c := (v / 1600) % 40
+			squawk_d := (v / 40) % 40
+			squawk := 1000*squawk_a + 100*squawk_b + 10*squawk_c + squawk_d
+			ti.Squawk = int(squawk)
 		}
 
-	}
+		ti.NACp = int((frame[25] >> 4) & 0x0F)
+		ti.PriorityStatus = (frame[23] >> 5) & 0x07
 
-	// OK.
+		// Following section is future-use for debugging and / or additional status info on UAT traffic. Message parsing needs testing.
-	//	fmt.Printf("%d, %d, %06X\n", msg_type, ti.Addr_type, ti.Icao_addr)
+		/*
+			//declaration for mode status flags -- parse for debug logging
+			var status_sil byte
+			//var status_transmit_mso byte
+			var status_sda byte
+			//var status_nacv byte
+			//var status_nicbaro byte
+			//var status_sil_supp byte
+			//var status_geom_vert_acc byte
+			//var status_sa_flag byte
+			var capability_uat_in bool
+			var capability_1090_in bool
+			//var capability_tcas bool
+			//var capability_cdti bool
+			//var opmode_tcas_active bool
+			//var opmode_ident_active bool
+			//var opmode_rec_atc_serv bool
+
+			// these are present in v1 and v2 messages
+			status_sil = frame[23] & 0x03
+			//status_transmit_mso = frame[24] >> 2
+			//status_nacv = (frame[25] >> 1) & 0x07
+			//status_nicbaro = frame[25] & 0x01
+
+			// other status and capability bits are different between v1 and v2
+			if uat_version == 2 {
+				status_sda = frame[24] & 0x03
+				capability_uat_in = (frame[26] >> 7) != 0
+				capability_1090_in = ((frame[26] >> 6) & 0x01) != 0
+				//capability_tcas = ((frame[26] >> 5) & 0x01) != 0
+				//opmode_tcas_active = ((frame[26] >> 4) & 0x01) != 0
+				//opmode_ident_active = ((frame[26] >> 3) & 0x01) != 0
+				//opmode_rec_atc_serv = ((frame[26] >> 2) & 0x01) != 0
+				//status_sil_supp = frame[26] & 0x01
+				//status_geom_vert_acc = (frame[27] >> 6) & 0x03
+				//status_sa_flag = (frame[27] >> 5) & 0x01
+
+			} else if uat_version == 1 {
+				//capability_cdti = (frame[26] >> 7) != 0
+				//capability_tcas = ((frame[26] >> 6) & 0x01) != 0
+				//opmode_tcas_active = ((frame[26] >> 5) & 0x01) != 0
+				//opmode_ident_active = ((frame[26] >> 4) & 0x01) != 0
+				//opmode_rec_atc_serv = ((frame[26] >> 3) & 0x01) != 0
+			}
+
+			log.Printf("Additional UAT mode status for %06X: Version = %d; SIL = %d; SDA = %d; 978 In = %v; 1090 In = %v\n",icao_addr,uat_version,status_sil,status_sda,capability_uat_in,capability_1090_in)
+		*/
+	}
 
 	ti.NIC = int(frame[11] & 0x0F)
 
-	if (msg_type == 1) || (msg_type == 3) { // Since NACp is passed with normal UATreports, no need to use our ES hack.
-		ti.NACp = int((frame[25] >> 4) & 0x0F)
-	}
-
 	var power float64
 	if signalLevel > 0 {
 		power = 20 * (math.Log10(float64(signalLevel) / 1000)) // reported amplitude is 0-1000. Normalize to max = 1 and do amplitude dB calculation (20 dB per decade)
@@ -625,7 +668,6 @@ func parseDownlinkReport(s string, signalLevel int) {
 		ti.Last_speed = stratuxClock.Time
 	}
 
-	//OK.
 	//	fmt.Printf("ns_vel %d, ew_vel %d, track %d, speed_valid %t, speed %d, vvel_geo %t, vvel %d\n", ns_vel, ew_vel, track, speed_valid, speed, vvel_geo, vvel)
 
 	/*
@@ -639,7 +681,6 @@ func parseDownlinkReport(s string, signalLevel int) {
 		}
 	*/
 
-	//OK.
 	//	fmt.Printf("tisb_site_id %d, utc_coupled %t\n", tisb_site_id, utc_coupled)
 
 	ti.Timestamp = time.Now()