Changed Grid Square calculations.

Changed Grid Square  calculations from double to float that has adequate precision.

examples/FT8Receive/FT8Receive.ino

@@ -63,6 +63,10 @@
 #define ft8_min_freq FT8_FREQ_SPACING * LOW_FREQ_INDEX
 #define ft8_msg_samples 92
 
+// A couple of prototypes to help the compile order
+void init_DSP(void);
+void extract_power(int);
+
 // Alternate interface format.
 // #define W5BAA
 

examples/FT8Receive/decode_ft8R.ino

@@ -44,7 +44,7 @@ const int kMax_decoded_messages = 20;
 const int kMax_message_length = 20;
 const int kMin_score = 40;    // Minimum sync score threshold for candidates
 int validate_locator(char locator[]);
-int strindex(char s[],char t[]);
+int strindex(char s[], char t[]);
 
 typedef struct
     {
@@ -220,8 +220,8 @@ int ft8_decode(void) {
             strcpy(Target_Locator, new_decoded[num_decoded].field3);
             if (validate_locator(Target_Locator)  == 1)
                {
-               distance = Target_Distance(Target_Locator);
+               distance = Target_Distancef(Target_Locator);
-               new_decoded[num_decoded].distance = (int)distance;
+               new_decoded[num_decoded].distance = (int)(0.5f + distance);
                }
             else
                {

examples/FT8Receive/locatorR.ino

@@ -1,24 +1,16 @@
 /*
- * locator.ino
+ *  Was locator.ino
- *
  *  Created on: Nov 4, 2019
  *      Author: user
  */
+//   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'
 
-//#include "locator.h"
+const float32_t EARTH_RAD = 6371.0f;  //radius in km
-//#include <math.h>
+float32_t Latitude, Longitude;
-//#include "arm_math.h"
+float32_t Station_Latitude, Station_Longitude;
-
+float32_t Target_Latitude, Target_Longitude;
-// TODO -  Looks like single precision would be adequate - RSL
-
-const double EARTH_RAD = 6371;  //radius in km
-//void process_locator(char locator[]);
-//double distance(double lat1, double lon1, double lat2, double lon2);
-//double deg2rad(double deg);
-float Latitude, Longitude;
-float Station_Latitude, Station_Longitude;
-float Target_Latitude, Target_Longitude;
-//float Target_Distance(char target[]);
 
 void set_Station_Coordinates(char station[]){
 	process_locator(station);
@@ -26,21 +18,21 @@ void set_Station_Coordinates(char station[]){
 	Station_Longitude = Longitude;
 }
 
-float Target_Distance(char target[]) {
+float32_t Target_Distancef(char target[]) {
-	float targetDistance;
+	float32_t targetDistance;
 	process_locator(target);
 	Target_Latitude = Latitude;
 	Target_Longitude = Longitude;
-	targetDistance = (float) distance((double)Station_Latitude,(double)Station_Longitude,
+	targetDistance = distancef((float32_t)Station_Latitude, (float32_t)Station_Longitude,
-	                                  (double)Target_Latitude,(double)Target_Longitude);
+	                           (float32_t)Target_Latitude, (float32_t)Target_Longitude);
 	return targetDistance;
 }
 
 void process_locator(char locator[]) {
 	uint8_t A1, A2, N1, N2;
 	uint8_t A1_value, A2_value, N1_value, N2_value;
-	float Latitude_1, Latitude_2, Latitude_3;
+	float32_t Latitude_1, Latitude_2, Latitude_3;
-	float Longitude_1, Longitude_2, Longitude_3;
+	float32_t Longitude_1, Longitude_2, Longitude_3;
 	A1 = locator[0];
 	A2 = locator[1];
 	N1 = locator[2];
@@ -49,27 +41,29 @@ void process_locator(char locator[]) {
 	A2_value = A2-65;
 	N1_value = N1- 48;
 	N2_value = N2 - 48;
-	Latitude_1 = (float) A2_value * 10;
+	Latitude_1 = (float32_t) A2_value * 10.0f;
-	Latitude_2 = (float) N2_value;
+	Latitude_2 = (float32_t) N2_value;
-	Latitude_3 = (11.0/24.0 + 1.0/48.0) - 90.0;
+	Latitude_3 = (11.0f/24.0f + 1.0f/48.0f) - 90.0f;
 	Latitude = Latitude_1 + Latitude_2 + Latitude_3;
-	Longitude_1 = (float)A1_value * 20.0;
+	Longitude_1 = (float32_t)A1_value * 20.0f;
-	Longitude_2 = (float)N1_value * 2.0;
+	Longitude_2 = (float32_t)N1_value * 2.0f;
-	Longitude_3 = 11.0/12.0 +  1.0/24.0;
+	Longitude_3 = 11.0f/12.0f +  1.0f/24.0f;
-	Longitude =  Longitude_1  +  Longitude_2 + Longitude_3 - 180.0;
+	// global Longitude
+	Longitude =  Longitude_1  +  Longitude_2 + Longitude_3 - 180.0f;
 }
 
 // distance (km) on earth's surface from point 1 to point 2
-double distance(double lat1, double lon1, double lat2, double lon2) {
+float32_t distancef(float32_t lat1, float32_t lon1, float32_t lat2, float32_t lon2) {
-    double lat1r = deg2rad(lat1);
+    float32_t lat1r = deg2radf(lat1);
-    double lon1r = deg2rad(lon1);
+    float32_t lon1r = deg2radf(lon1);
-    double lat2r = deg2rad(lat2);
+    float32_t lat2r = deg2radf(lat2);
-    double lon2r = deg2rad(lon2);
+    float32_t lon2r = deg2radf(lon2);
-    return acos(sin(lat1r) * sin(lat2r)+cos(lat1r) * cos(lat2r) * cos(lon2r-lon1r)) * EARTH_RAD;
+    return acos(sinf(lat1r) * sinf(lat2r) +
+        cosf(lat1r) * cosf(lat2r) * cosf(lon2r-lon1r)) * EARTH_RAD;
 }
 
-// convert degrees to radians
+// convert degrees to radians (i.e., * PI/180)
-double deg2rad(double deg)
+float32_t deg2radf(float32_t deg)
 {
-    return deg * (PI / 180.0);
+    return deg * 0.017453292f;
 }

examples/FT8Receive/maidenheadR.ino

@@ -1,36 +1,31 @@
-//#include "maidenhead.h"
+//   maidenheadR.ino  Bob Larkin 12 Nov 2022
-//#include <math.h>
+// Built from the K. Goba double precision files.
-//#include <stdio.h>
+// Data types float precision, funtion unchanged, names have added 'f'
-//#include <string.h>
-
-//#ifdef __cplusplus
-//extern "C" {
-//#endif
-
-// TODO This looks like a float change??  RSL
 
 char letterizeR(int x) {
     return (char) x + 65;
 }
 
-char* get_mh(double lat, double lon, int size) {
+// Input lat, lon in degrees; Input grid locator size 4, 6, 8, or 10
+// Output grid square string pointer.
+char* get_mhf(float32_t lat, float32_t lon, int size) {
     static char locator[11];
-    double LON_F[]={20,2.0,0.083333,0.008333,0.0003472083333333333};
+    float32_t LON_F[]={20.0f, 2.0f, 0.0833333f, 0.008333f, 0.00034720833f};
-    double LAT_F[]={10,1.0,0.0416665,0.004166,0.0001735833333333333};
+    float32_t LAT_F[]={10.0f, 1.0f, 0.0416665f, 0.004166f, 0.00017358333f};
     int i;
-    lon += 180;
+    lon += 180.0f;
-    lat += 90;
+    lat += 90.0f;
 
     if (size <= 0 || size > 10) size = 6;
     size/=2; size*=2;
 
     for (i = 0; i < size/2; i++){
         if (i % 2 == 1) {
-            locator[i*2] = (char) (lon/LON_F[i] + '0');
+            locator[i*2]   = (char)(lon/LON_F[i] + '0');
-            locator[i*2+1] = (char) (lat/LAT_F[i] + '0');
+            locator[i*2+1] = (char)(lat/LAT_F[i] + '0');
         } else {
-            locator[i*2] = letterizeR((int) (lon/LON_F[i]));
+            locator[i*2]   = letterizeR((int)(lon/LON_F[i]));
-            locator[i*2+1] = letterizeR((int) (lat/LAT_F[i]));
+            locator[i*2+1] = letterizeR((int)(lat/LAT_F[i]));
         }
         lon = fmod(lon, LON_F[i]);
         lat = fmod(lat, LAT_F[i]);
@@ -47,32 +42,30 @@ char* complete_mh(char* locator) {
     return locator2;
 }
 
-double mh2lon(char* locator) {
+// Convert grid square string to longitude
-    double field, square, subsquare, extsquare, precsquare;
+float32_t mh2lonf(char* locator) {
+    float32_t field, square, subsquare, extsquare, precsquare;
     int len = strlen(locator);
     if (len > 10) return 0;
     if (len < 10) locator = complete_mh(locator);
-    field      = (locator[0] - 'A') * 20.0;
+    field      = (locator[0] - 'A') * 20.0f;
-    square     = (locator[2] - '0') * 2.0;
+    square     = (locator[2] - '0') * 2.0f;
-    subsquare  = (locator[4] - 'A') / 12.0;
+    subsquare  = (locator[4] - 'A') / 12.0f;
-    extsquare  = (locator[6] - '0') / 120.0;
+    extsquare  = (locator[6] - '0') / 120.0f;
-    precsquare = (locator[8] - 'A') / 2880.0;
+    precsquare = (locator[8] - 'A') / 2880.0f;
-    return field + square + subsquare + extsquare + precsquare - 180;
+    return field + square + subsquare + extsquare + precsquare - 180.0f;
 }
 
-double mh2lat(char* locator) {
+// Convert grid square string to latitude
-    double field, square, subsquare, extsquare, precsquare;
+float32_t mh2latf(char* locator) {
+    float field, square, subsquare, extsquare, precsquare;
     int len = strlen(locator);
     if (len > 10) return 0;
     if (len < 10) locator = complete_mh(locator);
-    field      = (locator[1] - 'A') * 10.0;
+    field      = (locator[1] - 'A') * 10.0f;
-    square     = (locator[3] - '0') * 1.0;
+    square     = (locator[3] - '0') * 1.0f;
-    subsquare  = (locator[5] - 'A') / 24.0;
+    subsquare  = (locator[5] - 'A') / 24.0f;
-    extsquare  = (locator[7] - '0') / 240.0;
+    extsquare  = (locator[7] - '0') / 240.0f;
-    precsquare = (locator[9] - 'A') / 5760.0;
+    precsquare = (locator[9] - 'A') / 5760.0f;
     return field + square + subsquare + extsquare + precsquare - 90;
 }
-
-//#ifdef __cplusplus
-//}
-//#endif

radioFT8Demodulator_F32.h

@@ -115,7 +115,7 @@ public:
    void initialize(void)  {
       // Initialize 2 FIR instances (ARM DSP Math Library)
       //arm_fir_init_f32 (arm_fir_instance_f32 *S, uint16_t numTaps,
-                   const float32_t *pCoeffs, float32_t *pState, uint32_t blockSize)
+      //          const float32_t *pCoeffs, float32_t *pState, uint32_t blockSize)
       arm_fir_init_f32(&fir_inst1, 55,  &firDecimate1[0], &dec1FIRWork[0], 128UL);
       arm_fir_init_f32(&fir_inst2, 167, &firDecimate2[0], &dec2FIRWork[0], 128UL);
    // CHECK SAMPLE RATE AND SET index  <<<<<<<<<<<<<
@@ -350,7 +350,7 @@ int32_t kkk;
  * Sampling frequency = 96000 Hz
  * 0 Hz - 3200 Hz  ripple = 0.065 dB
  * 9600 Hz - 48000 Hz att = -81.1 dB   */
-const float32_t firDecimate1[55] = {      // constexpr static
+float32_t firDecimate1[55] = {      // constexpr static
  0.000037640f,  0.000248621f,  0.000535682f,  0.001017563f,  0.001647298,
  0.002359693f,  0.003009942f,  0.003388980f,  0.003245855f,  0.002335195,
  0.000482309f, -0.002343975f, -0.005965316f, -0.009953093f, -0.013627779f,
@@ -367,7 +367,7 @@ const float32_t firDecimate1[55] = {      // constexpr static
  * Sampling frequency = 19200 Hz
  * 0 Hz - 2800 Hz ripple = 0.073 dB
  * 3200 Hz - 9600 Hz att = -80.0 dB  */
-const float32_t firDecimate2[167] = {
+float32_t firDecimate2[167] = {
  0.000200074f,  0.000438821f,  0.000648425f,  0.000636175f,  0.000315069f,
 -0.000193500f, -0.000591064f, -0.000600896f, -0.000202482f,  0.000301473f,
  0.000486276f,  0.000152104f, -0.000466930f, -0.000846593f, -0.000601871f,