Call new error correction code. Instead of bit positions record no. of corrected bits.
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parent
6d5d7a4244
commit
feab602088
52
dump1090.c
52
dump1090.c
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@ -286,7 +286,7 @@ struct modesMessage {
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int msgtype; // Downlink format #
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int crcok; // True if CRC was valid
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uint32_t crc; // Message CRC
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int errorbit; // Bit corrected. -1 if no bit corrected
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int correctedbits; // No. of bits corrected
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uint32_t addr; // ICAO Address from bytes 1 2 and 3
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int phase_corrected; // True if phase correction was applied
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uint64_t timestampMsg; // Timestamp of the message
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@ -657,12 +657,7 @@ void dumpRawMessageJS(char *descr, unsigned char *msg,
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int start = offset - padding;
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int end = offset + (MODES_PREAMBLE_SAMPLES)+(MODES_LONG_MSG_SAMPLES) - 1;
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FILE *fp;
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int j, fix1 = -1, fix2 = -1;
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if (fixable != -1) {
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fix1 = fixable & 0xff;
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if (fixable > 255) fix2 = fixable >> 8;
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}
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int j;
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if ((fp = fopen("frames.js","a")) == NULL) {
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fprintf(stderr, "Error opening frames.js: %s\n", strerror(errno));
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@ -674,8 +669,8 @@ void dumpRawMessageJS(char *descr, unsigned char *msg,
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fprintf(fp,"%d", j < 0 ? 0 : m[j]);
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if (j != end) fprintf(fp,",");
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}
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fprintf(fp,"], \"fix1\": %d, \"fix2\": %d, \"bits\": %d, \"hex\": \"",
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fix1, fix2, modesMessageLenByType(msg[0]>>3));
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fprintf(fp,"], \"fixed\": %d, \"bits\": %d, \"hex\": \"",
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fixable, modesMessageLenByType(msg[0]>>3));
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for (j = 0; j < MODES_LONG_MSG_BYTES; j++)
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fprintf(fp,"\\x%02x",msg[j]);
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fprintf(fp,"\"});\n");
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@ -699,12 +694,10 @@ void dumpRawMessage(char *descr, unsigned char *msg,
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{
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int j;
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int msgtype = msg[0] >> 3;
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int fixable = -1;
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int fixable = 0;
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if (msgtype == 17) {
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fixable = fixSingleBitErrors(msg, MODES_LONG_MSG_BITS);
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if (fixable == -1)
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fixable = fixTwoBitsErrors(msg, MODES_LONG_MSG_BITS);
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fixable = fixBitErrors(msg, MODES_LONG_MSG_BITS);
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}
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if (Modes.debug & MODES_DEBUG_JS) {
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@ -1067,7 +1060,7 @@ void decodeModeAMessage(struct modesMessage *mm, int ModeA)
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// Not much else we can tell from a Mode A/C reply.
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// Just fudge up a few bits to keep other code happy
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mm->crcok = 1;
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mm->errorbit = -1;
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mm->correctedbits = 0;
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}
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/* ===================== Mode S detection and decoding ===================== */
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@ -1712,7 +1705,7 @@ void decodeModesMessage(struct modesMessage *mm, unsigned char *msg) {
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// Get the message type ASAP as other operations depend on this
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mm->msgtype = msg[0] >> 3; // Downlink Format
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mm->msgbits = modesMessageLenByType(mm->msgtype);
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mm->errorbit = -1; // No errors fixed
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mm->correctedbits = 0; // No errors fixed
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mm->phase_corrected = 0;
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mm->crc = modesChecksum(msg, mm->msgbits);
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@ -1728,10 +1721,10 @@ void decodeModesMessage(struct modesMessage *mm, unsigned char *msg) {
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// using the results. Perhaps check the ICAO against known aircraft, and check
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// IID against known good IID's. That's a TODO.
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//
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mm->errorbit = fixSingleBitErrors(msg, mm->msgbits);
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if ((mm->errorbit == -1) && (Modes.aggressive)) {
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mm->errorbit = fixTwoBitsErrors(msg, mm->msgbits);
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}
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mm->correctedbits = fixBitErrors(msg, mm->msgbits);
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//if ((mm->errorbit == -1) && (Modes.aggressive)) {
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// mm->errorbit = fixTwoBitsErrors(msg, mm->msgbits);
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//}
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}
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//
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// Note that most of the other computation happens *after* we fix the
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@ -1751,7 +1744,7 @@ void decodeModesMessage(struct modesMessage *mm, unsigned char *msg) {
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mm->crcok = (mm->crc == 0);
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mm->addr = (msg[1] << 16) | (msg[2] << 8) | (msg[3]);
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if (-1 != mm->errorbit) {
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if (0 != mm->correctedbits) {
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// DF 17 : if (error corrected) force crc = 0 but do not try to add this address
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// to the whitelist of recently seen ICAO addresses.
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mm->crc = 0;
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@ -1997,8 +1990,8 @@ void displayModesMessage(struct modesMessage *mm) {
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if (mm->msgtype < 32)
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printf("CRC: %06x (%s)\n", (int)mm->crc, mm->crcok ? "ok" : "wrong");
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if (mm->errorbit != -1)
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printf("Single bit error fixed, bit %d\n", mm->errorbit);
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if (mm->correctedbits != 0)
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printf("No. of bit errors fixed: %d\n", mm->correctedbits);
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if (mm->msgtype == 0) { // DF 0
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printf("DF 0: Short Air-Air Surveillance.\n");
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@ -2470,16 +2463,17 @@ void detectModeS(uint16_t *m, uint32_t mlen) {
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if (Modes.stats) {
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if (mm.crcok || use_correction) {
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if (errors == 0) Modes.stat_demodulated++;
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if (mm.errorbit == -1) {
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if (mm.correctedbits == 0) {
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if (mm.crcok) {Modes.stat_goodcrc++;}
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else {Modes.stat_badcrc++;}
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} else {
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Modes.stat_badcrc++;
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Modes.stat_fixed++;
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if (mm.errorbit < MODES_LONG_MSG_BITS)
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{Modes.stat_single_bit_fix++;}
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else
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{Modes.stat_two_bits_fix++;}
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if (mm.correctedbits == 1) {
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Modes.stat_single_bit_fix++;
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} else if (mm.correctedbits == 2) {
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Modes.stat_two_bits_fix++;
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}
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}
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}
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}
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@ -2490,10 +2484,10 @@ void detectModeS(uint16_t *m, uint32_t mlen) {
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dumpRawMessage("Demodulated with 0 errors", msg, m, j);
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else if (Modes.debug & MODES_DEBUG_BADCRC &&
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mm.msgtype == 17 &&
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(!mm.crcok || mm.errorbit != -1))
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(!mm.crcok || mm.correctedbits != 0))
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dumpRawMessage("Decoded with bad CRC", msg, m, j);
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else if (Modes.debug & MODES_DEBUG_GOODCRC && mm.crcok &&
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mm.errorbit == -1)
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mm.correctedbits == 0)
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dumpRawMessage("Decoded with good CRC", msg, m, j);
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}
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