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Bug fix in GPS L1 CA telemetry decoder, increased subframe realiability

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This commit is contained in:
Javier Arribas 2019-05-15 17:35:10 +02:00
parent e1d01d3b97
commit 93bea1591b
1 changed files with 6 additions and 5 deletions
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11
src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l1_ca_telemetry_decoder_gs.cc
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@ -160,10 +160,10 @@ bool gps_l1_ca_telemetry_decoder_gs::gps_word_parityCheck(uint32_t gpsword)
parity = parity & 0x3F; parity = parity & 0x3F;
if (parity == (gpsword & 0x3F)) if (parity == (gpsword & 0x3F))
{ {
return (true); return true;
} }
return (false); return false;
} }
@ -215,7 +215,7 @@ bool gps_l1_ca_telemetry_decoder_gs::decode_subframe()
int32_t word_index = 0; int32_t word_index = 0;
uint32_t GPS_frame_4bytes = 0; uint32_t GPS_frame_4bytes = 0;
float symbol_accumulator = 0; float symbol_accumulator = 0;
bool subframe_synchro_confirmation = false; bool subframe_synchro_confirmation = true;
for (float subframe_symbol : d_symbol_history) for (float subframe_symbol : d_symbol_history)
{ {
// ******* SYMBOL TO BIT ******* // ******* SYMBOL TO BIT *******
@ -261,9 +261,10 @@ bool gps_l1_ca_telemetry_decoder_gs::decode_subframe()
{ {
GPS_frame_4bytes ^= 0x3FFFFFC0; // invert the data bits (using XOR) GPS_frame_4bytes ^= 0x3FFFFFC0; // invert the data bits (using XOR)
} }
if (gps_l1_ca_telemetry_decoder_gs::gps_word_parityCheck(GPS_frame_4bytes)) //check parity. If ANY word inside the subframe fails the parity, set subframe_synchro_confirmation = false
if (not gps_l1_ca_telemetry_decoder_gs::gps_word_parityCheck(GPS_frame_4bytes))
{ {
subframe_synchro_confirmation = true; subframe_synchro_confirmation = false;
} }
// add word to subframe // add word to subframe
// insert the word in the correct position of the subframe // insert the word in the correct position of the subframe