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Misc NMEA and Harris 'NMEA' GPS Fixes/Tweaks;

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lwvmobile
2023-12-17 22:58:59 -05:00
parent 34b0040b04
commit daa200d655
2 changed files with 26 additions and 15 deletions
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2
src/dmr_block.c
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@@ -438,7 +438,7 @@ void nmea_iec_61162_1 (dsd_opts * opts, dsd_state * state, uint8_t * input, uint
longitude = ( (float)nmea_edeg + ((float)nmea_emin*m_unit) + ((float)nmea_eminf*mm_unit) );
if (!nmea_ns) latitude *= -1.0f; //0 is South, 1 is North
if (nmea_ew) longitude *= -1.0f; //0 is West, 1 is East
if (!nmea_ew) longitude *= -1.0f; //0 is West, 1 is East
fprintf (stderr, " GPS: %f%s, %f%s;", latitude, deg_glyph, longitude, deg_glyph);

39
src/p25p2_vpdu.c
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@@ -40,13 +40,15 @@ void nmea_harris (dsd_opts * opts, dsd_state * state, uint8_t * input, uint32_t
{
//GPS working, Time Working (old method), COG and Speed are logical on due west sample
//TODO: Fiddle/Test various ns and ew bits for proper signs incase its located elsewhere
//TODO: Fiddle/Test various ns and ew bits for proper signs in case its located elsewhere
//UPDATE: Found two contiguous bits that always work on all my accumulated samples
//the bits also place it with the 'lone' flagged bit observed prior
uint8_t nmea_ns = input[72]; //north/south (lat sign) //72
uint8_t nmea_ew = input[88]; //east/west (lon sign) //88
uint8_t nmea_ns = input[88]; //north/south (lat sign) //72 previously used bit
uint8_t nmea_ew = input[89]; //east/west (lon sign) //88 previously used bit
uint8_t nmea_q = input[147]; //Quality Indicator (last fix or current fix)
// uint8_t nmea_speed = (uint8_t)ConvertBitIntoBytes(&input[129], 7); //129,7
uint8_t nmea_speed = (uint8_t)ConvertBitIntoBytes(&input[129], 6); //this works without speed manip /2 on due west sample and also doesn't overlap with cog
uint8_t nmea_speed = (uint8_t)ConvertBitIntoBytes(&input[129], 6); //this is one bit shorter than called for, but I believe it works
//Latitude Bits
uint8_t nmea_ndeg = (uint8_t)ConvertBitIntoBytes(&input[65], 7); //Latitude Degrees
@@ -79,22 +81,23 @@ void nmea_harris (dsd_opts * opts, dsd_state * state, uint8_t * input, uint32_t
float m_unit = 1.0f / 60.0f;
float mm_unit = 1.0f / 600000.0f;
//debug speed adjustments
// nmea_speed /= 2;
//speed conversion
float fmps, fmph, fkph = 0.0f; //conversion of knots to mps, kph, and mph values
fmps = (float)nmea_speed * 0.514444; UNUSED(fmps);
fmph = (float)nmea_speed * 1.15078f; UNUSED(fmph);
fkph = (float)nmea_speed * 1.852f;
fkph = (float)nmea_speed * 1.852f; UNUSED(fkph);
//calculate decimal representation of latidude and longitude (need some samples to test)
latitude = ( (float)nmea_ndeg + ((float)nmea_nmin*m_unit) + ((float)nmea_nminf*mm_unit) );
longitude = ( (float)nmea_edeg + ((float)nmea_emin*m_unit) + ((float)nmea_eminf*mm_unit) );
//This is opposite (seemingly) compared to the version specified by DMR UDT NMEA, could still be different bits involved (to be tested)
if (nmea_ns) latitude *= -1.0f; //1 is South, 0 is North
if (nmea_ew) longitude *= -1.0f; //1 is West, 0 is East
// if (nmea_ns) latitude *= -1.0f; //1 is South, 0 is North
// if (nmea_ew) longitude *= -1.0f; //1 is West, 0 is East
//DMR UDT NMEA original version (working now with new bit selection 88 and 89 like how DMR UDT NMEA format specifies)
if (!nmea_ns) latitude *= -1.0f; //0 is South, 1 is North
if (!nmea_ew) longitude *= -1.0f; //0 is West, 1 is East
fprintf (stderr, "\n");
@@ -103,18 +106,18 @@ void nmea_harris (dsd_opts * opts, dsd_state * state, uint8_t * input, uint32_t
//Speed in Knots (assuming in knots, and not in mps, or kph)
if (nmea_speed > 126)
fprintf (stderr, " SPD > 126 knots or %f MPH;", fmph);
fprintf (stderr, " SPD > 126 knots or %f MPH;", fmph); //using MPH here, its Harris, they're in the U.S.
else
fprintf (stderr, " SPD: %d knots; %f mph;", nmea_speed, fmph);
fprintf (stderr, " SPD: %d knots; %f MPH;", nmea_speed, fmph);
//Course Over Ground (COG)
fprintf (stderr, " COG: %03d%s;", nmea_cog, deg_glyph); //%360
//debug speed
fprintf (stderr, " RSPD: %02X;", nmea_speed);
// fprintf (stderr, " RSPD: %02X;", nmea_speed);
//debug cog
fprintf (stderr, " RCOG: %03X;", nmea_cog >> 0);
// fprintf (stderr, " RCOG: %03X;", nmea_cog >> 0);
//UTC Time
fprintf (stderr, " T: %02d:%02d:%02d UTC;", thour, tmin, tsec);
@@ -148,6 +151,14 @@ void nmea_harris (dsd_opts * opts, dsd_state * state, uint8_t * input, uint32_t
}
//NOTE: There seems to be a few more octets left undecoded in this PDU
//not including the CRC obviously, unsure of their meaning, could relate
//to other GPS functions like precision, etc, unknown.
//NOTE2: All these values are just best effort based on observation and
//making map points match using logic and distance over time for speed and course
//without any documentation, any of these values may still be wrong
}
//fallback version (if desired/required)