[hamradio-commits] [gnss-sdr] 205/236: Bug fix in L2CM CNAV message decoder. The decoder is still experimental.

[Carles Fernandez]

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carles_fernandez-guest pushed a commit to branch next
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commit 60b6b98c52f64d8cdeafddacaae778abd2d0be71
Author: Javier Arribas <javiarribas at gmail.com>
Date:   Fri Apr 22 16:49:12 2016 +0200

    Bug fix in L2CM CNAV message decoder. The decoder is still experimental.
---
 ...sdr_multichannel_GPS_L2_M_Flexiband_bin_file_III_1b.conf |  5 ++++-
 .../gnuradio_blocks/gps_l2_m_telemetry_decoder_cc.cc        | 13 ++++++-------
 2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/conf/gnss-sdr_multichannel_GPS_L2_M_Flexiband_bin_file_III_1b.conf b/conf/gnss-sdr_multichannel_GPS_L2_M_Flexiband_bin_file_III_1b.conf
index 1857878..b8a3e9d 100644
--- a/conf/gnss-sdr_multichannel_GPS_L2_M_Flexiband_bin_file_III_1b.conf
+++ b/conf/gnss-sdr_multichannel_GPS_L2_M_Flexiband_bin_file_III_1b.conf
@@ -268,7 +268,9 @@ Resampler2.implementation=Pass_Through
 ;######### CHANNELS GLOBAL CONFIG ############
 ;#count: Number of available GPS satellite channels.
 Channels_1C.count=1
-Channels_2S.count=7
+Channels_2S.count=8
+
+;#GPS.prns=7,8
 
 ;#in_acquisition: Number of channels simultaneously acquiring for the whole receiver
 Channels.in_acquisition=1
@@ -289,6 +291,7 @@ Channel4.RF_channel_ID=1
 Channel5.RF_channel_ID=1
 Channel6.RF_channel_ID=1
 Channel7.RF_channel_ID=1
+Channel8.RF_channel_ID=1
 
 
 ;######### ACQUISITION GENERIC CONFIG ######
diff --git a/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l2_m_telemetry_decoder_cc.cc b/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l2_m_telemetry_decoder_cc.cc
index 0bdece0..81494f9 100644
--- a/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l2_m_telemetry_decoder_cc.cc
+++ b/src/algorithms/telemetry_decoder/gnuradio_blocks/gps_l2_m_telemetry_decoder_cc.cc
@@ -116,9 +116,6 @@ int gps_l2_m_telemetry_decoder_cc::general_work (int noutput_items __attribute__
     const Gnss_Synchro *in = (const Gnss_Synchro *)  input_items[0]; // input
     Gnss_Synchro *out = (Gnss_Synchro *) output_items[0];            // output
 
-    // store the time stamp of the first sample in the processed sample block
-    //double sample_stamp = in[0].Tracking_timestamp_secs;
-
     bool flag_new_cnav_frame = false;
     int last_frame_preamble_start = 0;
     // copy correlation samples into samples vector
@@ -131,7 +128,7 @@ int gps_l2_m_telemetry_decoder_cc::general_work (int noutput_items __attribute__
         {
             if (in[0].Flag_valid_symbol_output == false) // check if the tracking is locked
                 {
-                    //LOG(INFO)<< "Discarting channel "<<d_channel<<" tracking not ready!"<<std::endl;
+                    LOG(INFO)<< "Discarting channel "<<d_channel<<" tracking not ready!"<<std::endl;
                     d_flag_valid_word = false;
                 }
             else
@@ -152,14 +149,14 @@ int gps_l2_m_telemetry_decoder_cc::general_work (int noutput_items __attribute__
                             // they can be already aligned or shifted by one position
                             std::vector<int> bits;
 
-                            //bool symbol_alignment = d_symbol_aligner_and_decoder.get_bits(d_sample_buf, bits);
+                            d_symbol_aligner_and_decoder.get_bits(d_sample_buf, bits);
 
                             //std::stringstream ss;
                             //for (std::vector<int>::const_iterator bit_it = bits.begin(); bit_it < bits.end(); ++bit_it)
                             //    {
                             //        ss << *bit_it;
                             //    }
-                            // LOG(INFO) << "get_bits=" << ss.str() << std::endl;
+                            //LOG(INFO) << "get_bits=" << ss.str() << std::endl;
 
                             // search for preambles
                             // and extract the corresponding message candidates
@@ -187,12 +184,14 @@ int gps_l2_m_telemetry_decoder_cc::general_work (int noutput_items __attribute__
                                     d_flag_invert_input_symbols = d_flag_invert_buffer_symbols;
                                     std::vector<int> tmp_msg;
                                     std::string msg;
+                                    //todo: now the symbol buffer size is two CNAV frames because the preamble is not detected.
+                                    //      Use the first valid frame to realign the bufer symbols with the preamble start and not miss a frame
                                     LOG(INFO) << valid_msgs.size() << " GOOD L2C CNAV FRAME DETECTED! CH " <<this->d_channel;
                                     for (unsigned int i = 0;i < valid_msgs.size(); i++)
                                         {
                                             tmp_msg = valid_msgs.at(i).second;
                                             d_CNAV_Message.decode_page(tmp_msg);
-                                            //std::cout << "Valid CNAV frame with relative preamble start at " << valid_msgs.at(i).first << std::endl;
+                                            std::cout << "Valid CNAV frame with relative preamble start at " << valid_msgs.at(i).first << std::endl;
                                             flag_new_cnav_frame = true;
                                             d_flag_valid_word = true;
                                             last_frame_preamble_start = valid_msgs.at(i).first;

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