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Phase Enhancement changes

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Phase enhancement is used to try and increase the signal amplitude when
Nyquist sample aliasing is suspected. In previous versions, this was
enabled by default. In this version, the default is off. There is now an
additional command line switch --phase-enhance to turn it on.

There are also additional debug statistics which count the number of
phase demodulation failures in for both uncorrected and phase corrected
passes.
This commit is contained in:
Malcolm Robb 2013-05-22 13:23:54 +01:00
parent b481c76909
commit e50c2a5a54
1 changed files with 78 additions and 19 deletions
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77
dump1090.c
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@ -56,7 +56,7 @@
// MinorVer changes when additional features are added, but not for bug fixes (range 00-99)
// DayDate & Year changes for all changes, including for bug fixes. It represent the release date of the update
//
#define MODES_DUMP1090_VERSION "1.06.2105.13"
#define MODES_DUMP1090_VERSION "1.06.2205.13"
#define MODES_USER_LATITUDE_DFLT (0.0)
#define MODES_USER_LONGITUDE_DFLT (0.0)
@ -227,6 +227,7 @@ struct {
/* Configuration */
char *filename; /* Input form file, --ifile option. */
int phase_enhance; /* Enable phase enhancement if true */
int fix_errors; /* Single bit error correction if true. */
int check_crc; /* Only display messages with good CRC. */
int raw; /* Raw output format. */
@ -264,7 +265,10 @@ struct {
/* Statistics */
unsigned int stat_valid_preamble;
unsigned int stat_demodulated;
unsigned int stat_demodulated0;
unsigned int stat_demodulated1;
unsigned int stat_demodulated2;
unsigned int stat_demodulated3;
unsigned int stat_goodcrc;
unsigned int stat_badcrc;
unsigned int stat_fixed;
@ -273,6 +277,15 @@ struct {
unsigned int stat_http_requests;
unsigned int stat_sbs_connections;
unsigned int stat_out_of_phase;
unsigned int stat_ph_demodulated0;
unsigned int stat_ph_demodulated1;
unsigned int stat_ph_demodulated2;
unsigned int stat_ph_demodulated3;
unsigned int stat_ph_goodcrc;
unsigned int stat_ph_badcrc;
unsigned int stat_ph_fixed;
unsigned int stat_ph_single_bit_fix;
unsigned int stat_ph_two_bits_fix;
unsigned int stat_DF_Len_Corrected;
unsigned int stat_DF_Type_Corrected;
unsigned int stat_ModeAC;
@ -2547,10 +2560,41 @@ void detectModeS(uint16_t *m, uint32_t mlen) {
// Update statistics
if (Modes.stats) {
if (mm.crcok || use_correction || mm.correctedbits) {
if (errors == 0) Modes.stat_demodulated++;
if (use_correction) {
switch (errors) {
case 0: {Modes.stat_ph_demodulated0++; break;}
case 1: {Modes.stat_ph_demodulated1++; break;}
case 2: {Modes.stat_ph_demodulated2++; break;}
default:{Modes.stat_ph_demodulated3++; break;}
}
} else {
switch (errors) {
case 0: {Modes.stat_demodulated0++; break;}
case 1: {Modes.stat_demodulated1++; break;}
case 2: {Modes.stat_demodulated2++; break;}
default:{Modes.stat_demodulated3++; break;}
}
}
if (mm.correctedbits == 0) {
if (use_correction) {
if (mm.crcok) {Modes.stat_ph_goodcrc++;}
else {Modes.stat_ph_badcrc++;}
} else {
if (mm.crcok) {Modes.stat_goodcrc++;}
else {Modes.stat_badcrc++;}
}
} else if (use_correction) {
Modes.stat_ph_badcrc++;
Modes.stat_ph_fixed++;
if (mm.correctedbits == 1) {
Modes.stat_ph_single_bit_fix++;
} else if (mm.correctedbits == 2) {
Modes.stat_ph_two_bits_fix++;
}
} else {
Modes.stat_badcrc++;
Modes.stat_fixed++;
@ -2591,8 +2635,8 @@ void detectModeS(uint16_t *m, uint32_t mlen) {
}
}
// Retry with phase correction if possible.
if (!mm.crcok && !mm.correctedbits && !use_correction && j && detectOutOfPhase(pPreamble)) {
// Retry with phase correction if enabled, necessary and possible.
if (Modes.phase_enhance && !mm.crcok && !mm.correctedbits && !use_correction && j && detectOutOfPhase(pPreamble)) {
use_correction = 1; j--;
} else {
use_correction = 0;
@ -3986,6 +4030,7 @@ void showHelp(void) {
"--fix Enable single-bits error correction using CRC\n"
"--no-fix Disable single-bits error correction using CRC\n"
"--no-crc-check Disable messages with broken CRC (discouraged)\n"
"--phase-enhance Enable phase enhancement\n"
"--aggressive More CPU for more messages (two bits fixes, ...)\n"
"--mlat display raw messages in Beast ascii mode\n"
"--stats With --ifile print stats at exit. No other output\n"
@ -4064,6 +4109,8 @@ int main(int argc, char **argv) {
Modes.aggressive = 0;
} else if (!strcmp(argv[j],"--no-crc-check")) {
Modes.check_crc = 0;
} else if (!strcmp(argv[j],"--phase-enhance")) {
Modes.phase_enhance = 1;
} else if (!strcmp(argv[j],"--raw")) {
Modes.raw = 1;
} else if (!strcmp(argv[j],"--net")) {
@ -4208,17 +4255,29 @@ int main(int argc, char **argv) {
if (Modes.stats) {
printf("\n\n");
printf("%d ModeA/C detected\n", Modes.stat_ModeAC);
printf("%d valid preambles\n", Modes.stat_valid_preamble);
printf("%d valid Mode-S preambles\n", Modes.stat_valid_preamble);
printf("%d DF-?? fields corrected for length\n", Modes.stat_DF_Len_Corrected);
printf("%d DF-?? fields corrected for type\n", Modes.stat_DF_Type_Corrected);
printf("%d demodulated again after phase correction\n", Modes.stat_out_of_phase);
printf("%d demodulated with zero errors\n", Modes.stat_demodulated);
printf("%d demodulated with 0 errors\n", Modes.stat_demodulated0);
printf("%d demodulated with 1 error\n", Modes.stat_demodulated1);
printf("%d demodulated with 2 errors\n", Modes.stat_demodulated2);
printf("%d demodulated with > 2 errors\n", Modes.stat_demodulated3);
printf("%d with good crc\n", Modes.stat_goodcrc);
printf("%d with bad crc\n", Modes.stat_badcrc);
printf("%d errors corrected\n", Modes.stat_fixed);
printf("%d single bit errors\n", Modes.stat_single_bit_fix);
printf("%d two bits errors\n", Modes.stat_two_bits_fix);
printf("%d total usable messages\n", Modes.stat_goodcrc + Modes.stat_fixed);
printf("%d phase enhancement attempts\n", Modes.stat_out_of_phase);
printf("%d phase enhanced demodulated with 0 errors\n", Modes.stat_ph_demodulated0);
printf("%d phase enhanced demodulated with 1 error\n", Modes.stat_ph_demodulated1);
printf("%d phase enhanced demodulated with 2 errors\n", Modes.stat_ph_demodulated2);
printf("%d phase enhanced demodulated with > 2 errors\n", Modes.stat_ph_demodulated3);
printf("%d phase enhanced with good crc\n", Modes.stat_ph_goodcrc);
printf("%d phase enhanced with bad crc\n", Modes.stat_ph_badcrc);
printf("%d phase enhanced errors corrected\n", Modes.stat_ph_fixed);
printf("%d phase enhanced single bit errors\n", Modes.stat_ph_single_bit_fix);
printf("%d phase enhanced two bits errors\n", Modes.stat_ph_two_bits_fix);
printf("%d total usable messages\n", Modes.stat_goodcrc + Modes.stat_ph_goodcrc + Modes.stat_fixed + Modes.stat_ph_fixed);
}
if (Modes.filename == NULL) {