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https://github.com/gnss-sdr/gnss-sdr
synced 2024-12-15 04:30:33 +00:00
Revert wrong change
This commit is contained in:
Carles Fernandez
parent
a2de137864
commit
ec1b600077
@ -30,6 +30,7 @@
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*/
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#include "edc.h"
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#include "bits.h"
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#include "cnav_msg.h"
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@ -47,26 +48,26 @@
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* Block Viterbi decoding parameters.
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*/
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/** Viterbi decoder reversed polynomial A */
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#define GPS_L2C_V27_POLY_A (0x4F) /* 0b01001111 - reversed 0171*/
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#define GPS_L2C_V27_POLY_A (0x4F) /* 0b01001111 - reversed 0171*/
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/** Viterbi decoder reversed polynomial B */
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#define GPS_L2C_V27_POLY_B (0x6D) /* 0b01101101 - reversed 0133 */
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#define GPS_L2C_V27_POLY_B (0x6D) /* 0b01101101 - reversed 0133 */
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/*
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* GPS L2C message constants.
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*/
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/** GPS L2C preamble */
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const u32 GPS_CNAV_PREAMBLE1 = 0x989A73u;
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#define GPS_CNAV_PREAMBLE1 (0b10001011u)
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/** Inverted GPS L2C preamble */
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const u32 GPS_CNAV_PREAMBLE2 = 0x010F054u;
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#define GPS_CNAV_PREAMBLE2 (0b01110100u)
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/** GPS L2C preamble length in bits */
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#define GPS_CNAV_PREAMBLE_LENGTH (8)
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#define GPS_CNAV_PREAMBLE_LENGTH (8)
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/** GPS L2C CNAV message length in bits */
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#define GPS_CNAV_MSG_LENGTH (300)
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#define GPS_CNAV_MSG_LENGTH (300)
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/** GPS LC2 CNAV CRC length in bits */
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#define GPS_CNAV_MSG_CRC_LENGTH (24)
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#define GPS_CNAV_MSG_CRC_LENGTH (24)
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/** GPS L2C CNAV message payload length in bits */
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#define GPS_CNAV_MSG_DATA_LENGTH (GPS_CNAV_MSG_LENGTH - GPS_CNAV_MSG_CRC_LENGTH)
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#define GPS_CNAV_MSG_DATA_LENGTH (GPS_CNAV_MSG_LENGTH - GPS_CNAV_MSG_CRC_LENGTH)
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/** GPS L2C CNAV message lock detector threshold */
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#define GPS_CNAV_LOCK_MAX_CRC_FAILS (10)
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@ -84,7 +85,7 @@ const u32 GPS_CNAV_PREAMBLE2 = 0x010F054u;
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static u32 _cnav_compute_crc(cnav_v27_part_t *part)
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{
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u32 crc = crc24q_bits(0, part->decoded, GPS_CNAV_MSG_DATA_LENGTH,
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part->invert);
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part->invert);
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return crc;
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}
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@ -103,7 +104,7 @@ static u32 _cnav_compute_crc(cnav_v27_part_t *part)
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static u32 _cnav_extract_crc(const cnav_v27_part_t *part)
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{
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u32 crc = getbitu(part->decoded, GPS_CNAV_MSG_DATA_LENGTH,
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GPS_CNAV_MSG_CRC_LENGTH);
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GPS_CNAV_MSG_CRC_LENGTH);
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if (part->invert)
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{
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crc ^= 0xFFFFFF;
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@ -151,7 +152,7 @@ static void _cnav_rescan_preamble(cnav_v27_part_t *part)
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if (!part->preamble_seen && part->n_decoded >= GPS_CNAV_PREAMBLE_LENGTH)
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{
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bitshl(part->decoded, sizeof(part->decoded),
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part->n_decoded - GPS_CNAV_PREAMBLE_LENGTH + 1);
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part->n_decoded - GPS_CNAV_PREAMBLE_LENGTH + 1);
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part->n_decoded = GPS_CNAV_PREAMBLE_LENGTH - 1;
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}
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}
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@ -199,12 +200,11 @@ static void _cnav_add_symbol(cnav_v27_part_t *part, u8 ch)
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* - N - Number of bits to put into decoded buffer
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* - M - Number of bits in the tail to ignore.
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*/
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unsigned char tmp_bits[(GPS_L2C_V27_DECODE_BITS + GPS_L2C_V27_DELAY_BITS +
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CHAR_BIT - 1) /
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CHAR_BIT];
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unsigned char tmp_bits[ (GPS_L2C_V27_DECODE_BITS + GPS_L2C_V27_DELAY_BITS +
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CHAR_BIT - 1) / CHAR_BIT];
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v27_chainback_likely(&part->dec, tmp_bits,
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GPS_L2C_V27_DECODE_BITS + GPS_L2C_V27_DELAY_BITS);
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GPS_L2C_V27_DECODE_BITS + GPS_L2C_V27_DELAY_BITS);
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/* Read decoded bits and add them to the decoded buffer */
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bitcopy(part->decoded, part->n_decoded, tmp_bits, 0, GPS_L2C_V27_DECODE_BITS);
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@ -238,9 +238,10 @@ static void _cnav_add_symbol(cnav_v27_part_t *part, u8 ch)
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}
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if (part->preamble_seen && GPS_CNAV_MSG_LENGTH <= part->n_decoded)
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{
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/* We have collected 300 bits starting from message preamble. Now try
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* to compute CRC-24Q */
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u32 crc = _cnav_compute_crc(part);
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u32 crc = _cnav_compute_crc(part);
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u32 crc2 = _cnav_extract_crc(part);
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if (part->message_lock)
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@ -259,8 +260,8 @@ static void _cnav_add_symbol(cnav_v27_part_t *part, u8 ch)
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if (part->n_crc_fail > GPS_CNAV_LOCK_MAX_CRC_FAILS)
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{
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/* CRC has failed too many times - drop the lock. */
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part->n_crc_fail = 0;
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part->message_lock = false;
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part->n_crc_fail = 0;
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part->message_lock = false;
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part->preamble_seen = false;
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/* Try to find a new preamble, reuse data from buffer. */
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retry = true;
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@ -271,8 +272,8 @@ static void _cnav_add_symbol(cnav_v27_part_t *part, u8 ch)
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{
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/* CRC match - message can be decoded */
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part->message_lock = true;
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part->crc_ok = true;
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part->n_crc_fail = 0;
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part->crc_ok = true;
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part->n_crc_fail = 0;
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}
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else
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{
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@ -345,13 +346,13 @@ static bool _cnav_msg_decode(cnav_v27_part_t *part, cnav_msg_t *msg, u32 *delay)
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_cnav_msg_invert(part);
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}
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msg->prn = getbitu(part->decoded, 8, 6);
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msg->prn = getbitu(part->decoded, 8, 6);
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msg->msg_id = getbitu(part->decoded, 14, 6);
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msg->tow = getbitu(part->decoded, 20, 17);
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msg->alert = getbitu(part->decoded, 37, 1) ? true : false;
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msg->tow = getbitu(part->decoded, 20, 17);
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msg->alert = getbitu(part->decoded, 37, 1) ? true : false;
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/* copy RAW message for GNSS-SDR */
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memcpy(msg->raw_msg, part->decoded, GPS_L2C_V27_DECODE_BITS + GPS_L2C_V27_DELAY_BITS);
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memcpy(msg->raw_msg,part->decoded,GPS_L2C_V27_DECODE_BITS + GPS_L2C_V27_DELAY_BITS);
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*delay = (part->n_decoded - GPS_CNAV_MSG_LENGTH + GPS_L2C_V27_DELAY_BITS) * 2 + part->n_symbols;
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@ -387,15 +388,15 @@ void cnav_msg_decoder_init(cnav_msg_decoder_t *dec)
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{
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memset(dec, 0, sizeof(*dec));
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v27_init(&dec->part1.dec,
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dec->part1.decisions,
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GPS_L2_V27_HISTORY_LENGTH_BITS,
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cnav_msg_decoder_get_poly(),
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0);
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dec->part1.decisions,
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GPS_L2_V27_HISTORY_LENGTH_BITS,
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cnav_msg_decoder_get_poly(),
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0);
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v27_init(&dec->part2.dec,
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dec->part2.decisions,
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GPS_L2_V27_HISTORY_LENGTH_BITS,
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cnav_msg_decoder_get_poly(),
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0);
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dec->part2.decisions,
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GPS_L2_V27_HISTORY_LENGTH_BITS,
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cnav_msg_decoder_get_poly(),
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0);
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dec->part1.init = true;
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dec->part2.init = true;
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_cnav_add_symbol(&dec->part2, 0x80);
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@ -425,9 +426,9 @@ void cnav_msg_decoder_init(cnav_msg_decoder_t *dec)
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* \retval false More data is required.
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*/
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bool cnav_msg_decoder_add_symbol(cnav_msg_decoder_t *dec,
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u8 symbol,
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cnav_msg_t *msg,
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u32 *pdelay)
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u8 symbol,
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cnav_msg_t *msg,
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u32 *pdelay)
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{
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_cnav_add_symbol(&dec->part1, symbol);
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_cnav_add_symbol(&dec->part2, symbol);
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@ -469,7 +470,7 @@ const v27_poly_t *cnav_msg_decoder_get_poly(void)
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if (!initialized)
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{
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/* Coefficients for polynomial object */
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const signed char coeffs[2] = {GPS_L2C_V27_POLY_A, GPS_L2C_V27_POLY_B};
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const signed char coeffs[2] = { GPS_L2C_V27_POLY_A, GPS_L2C_V27_POLY_B };
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/* Racing condition handling: the data can be potential initialized more
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* than once in case multiple threads request concurrent access. However,
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