From aa8d5426f5d75449fdd7daec3c5a44d993a11b3f Mon Sep 17 00:00:00 2001 From: Carles Fernandez Date: Thu, 11 Jun 2026 15:22:50 +0200 Subject: [PATCH] Fix two-step acquisition for Glonass signals --- .../acquisition/gnuradio_blocks/pcps_acquisition.cc | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition.cc b/src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition.cc index bb24d6c5b..5e48e3e14 100644 --- a/src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition.cc +++ b/src/algorithms/acquisition/gnuradio_blocks/pcps_acquisition.cc @@ -296,7 +296,9 @@ void pcps_acquisition::update_grid_doppler_wipeoffs_step2() for (uint32_t doppler_index = 0; doppler_index < d_num_doppler_bins_step2; doppler_index++) { const float doppler = (static_cast(doppler_index) - static_cast(floor(d_num_doppler_bins_step2 / 2.0))) * d_acq_parameters.doppler_step2; - update_local_carrier(d_grid_doppler_wipeoffs_step_two[doppler_index], d_doppler_center_step_two + doppler); + // d_doppler_center_step_two holds the unbiased Doppler reported by the coarse + // stage, so the FDMA frequency offset must be added back to the wipeoff + update_local_carrier(d_grid_doppler_wipeoffs_step_two[doppler_index], static_cast(d_doppler_bias) + d_doppler_center_step_two + doppler); } }