From 1a2ba41e1bae91c690d69f751dd957fb08f44354 Mon Sep 17 00:00:00 2001
From: Bob Larkin <bob@janbob.com>
Date: Mon, 14 Nov 2022 10:49:16 -0800
Subject: [PATCH] Added azimuth calculation

---
 examples/FT8Receive/FT8Receive.ino  | 13 ++++++++++---
 examples/FT8Receive/decode_ft8R.ino |  7 +++++--
 examples/FT8Receive/locatorR.ino    | 22 ++++++++++++++++++++--
 3 files changed, 35 insertions(+), 7 deletions(-)

diff --git a/examples/FT8Receive/FT8Receive.ino b/examples/FT8Receive/FT8Receive.ino
index 7cfe373..11bc9c4 100644
--- a/examples/FT8Receive/FT8Receive.ino
+++ b/examples/FT8Receive/FT8Receive.ino
@@ -1,6 +1,7 @@
 // FT8Receive.ino  13 Oct 2022  Bob Larkin, W7PUA
 // Simple command-line reception of WSJT FT8 signals for
 // amateur radio.
+// Added azimuth calculation.  Bob 14 Nov 2022
 
 /*
  * Huge thanks to Charley Hill, W5BAA, for his Pocket FT8 work, much of which
@@ -120,7 +121,9 @@ int     master_decoded;
 #define FT8_RCV_IDLE 0
 #define FT8_RCV_DATA_COLLECT 1
 #define FT8_RCV_FIND_POWERS 2
-#define FT8_RCV_DECODE 3
+#define FT8_RCV_READY_DECODE 3
+#define FT8_RCV_DECODE 4
+
 int rcvFT8State = FT8_RCV_IDLE;
 int master_offset, offset_step;
 int Target_Flag = 0;
@@ -304,13 +307,16 @@ void loop(void)  {
       Serial.print("Extract Power, fft count = "); Serial.println( demod1.getFFTCount() );
 #endif
       extract_power(master_offset);    // Do FFT and log powers
-      rcvFT8State = FT8_RCV_DATA_COLLECT;
+	  if(demod1.getFFTCount() >= 184)
+		 rcvFT8State = FT8_RCV_READY_DECODE;
+	  else
+         rcvFT8State = FT8_RCV_DATA_COLLECT;
 #ifdef DEBUG1
       Serial.println("Power array updated");
 #endif
       }
 
-   if(rcvFT8State!=FT8_RCV_IDLE  && demod1.getFFTCount() >= 184)
+   if(rcvFT8State==FT8_RCV_READY_DECODE )
       {
       rcvFT8State = FT8_RCV_DECODE;
 #ifdef DEBUG1
@@ -318,6 +324,7 @@ void loop(void)  {
 #endif
       tu = micros();
       num_decoded_msg = ft8_decode();
+	  printFT8Received();
       rcvFT8State = FT8_RCV_IDLE;
       master_decoded = num_decoded_msg;
 #ifdef DEBUG1
diff --git a/examples/FT8Receive/decode_ft8R.ino b/examples/FT8Receive/decode_ft8R.ino
index b43b56c..a8d2aa1 100644
--- a/examples/FT8Receive/decode_ft8R.ino
+++ b/examples/FT8Receive/decode_ft8R.ino
@@ -57,6 +57,7 @@ typedef struct
     int  sync_score;
     int  snr;
     int  distance;
+	float32_t azimuth;           // Added Nov 2022
     } Decode;
 
 Decode new_decoded[20];
@@ -222,6 +223,7 @@ int ft8_decode(void) {
                {
                distance = Target_Distancef(Target_Locator);
                new_decoded[num_decoded].distance = (int)(0.5f + distance);
+			   new_decoded[num_decoded].azimuth = Target_Azimuthf(Target_Locator);
                }
             else
                {
@@ -233,7 +235,7 @@ int ft8_decode(void) {
 		}  // End, duplicate not found
       }  //End of big decode loop
 	  noiseMeasured = false;    // Global flag for Process_DSP_R
-      printFT8Received();
+      //printFT8Received();  // Move to main INO
    return num_decoded;
    }
 
@@ -254,7 +256,8 @@ void printFT8Received(void)  {
         Serial.print(" snr="); Serial.print(new_decoded[kk].snr);
 		if(new_decoded[kk].distance > 0)
 		   {
-		   Serial.print(" km="); Serial.println(new_decoded[kk].distance);
+		   Serial.print(" km="); Serial.print(new_decoded[kk].distance);
+		   Serial.print(" az="); Serial.println(new_decoded[kk].azimuth, 1);
 		   }
 	    else
 		   Serial.println("");
diff --git a/examples/FT8Receive/locatorR.ino b/examples/FT8Receive/locatorR.ino
index 1d0c03d..fbd048c 100644
--- a/examples/FT8Receive/locatorR.ino
+++ b/examples/FT8Receive/locatorR.ino
@@ -6,6 +6,7 @@
 //   locatorR.ino  Bob Larkin 12 Nov 2022
 // Built from the K. Goba double precision files.
 // Data types float precision, funtion unchanged, names have added 'f'
+// Added azimuth calculations  Bob  14 Nov 2022
 
 const float32_t EARTH_RAD = 6371.0f;  //radius in km
 float32_t Latitude, Longitude;
@@ -21,11 +22,28 @@ float32_t Target_Distancef(char target[]) {
 	process_locator(target);
 	Target_Latitude = Latitude;
 	Target_Longitude = Longitude;
-	targetDistance = distancef((float32_t)Station_Latitude, (float32_t)Station_Longitude,
-	                           (float32_t)Target_Latitude, (float32_t)Target_Longitude);
+	targetDistance = distancef(Station_Latitude, Station_Longitude,
+	                            Target_Latitude, Target_Longitude);
 	return targetDistance;
 }
 
+// Azimuth added 14 Nov 2022 - This duplicates some of the calculations in distance
+// but the number of targets this is run on is small, so won't restructure.
+float32_t Target_Azimuthf(char target[]) {
+	float32_t targetAz;
+	float d2r = 0.017453292f;
+	process_locator(target);
+	Target_Latitude = Latitude;
+	Target_Longitude = Longitude;
+    float32_t y = sinf(d2r*(Target_Longitude - Station_Longitude)) * cosf(Target_Latitude*d2r);
+    float32_t x = cosf(Station_Latitude*d2r) * sinf(Target_Latitude*d2r) - 
+      sinf(Station_Latitude*d2r) * cosf(Target_Latitude*d2r) * cosf(d2r*(Target_Longitude - Station_Longitude));
+    targetAz = 57.2957795f*atan2f(y, x);
+    if(targetAz<0.0f)
+       targetAz += 360.0f;		
+	return targetAz;
+}
+
 void process_locator(char locator[]) {
 	uint8_t A1, A2, N1, N2;
 	uint8_t A1_value, A2_value, N1_value, N2_value;