Acquisition_<signal>.dual_freq_assisted_doppler_narrowing (default
true, preserving current behavior) lets a specific signal's
acquisition be forced back to a full, unaided Doppler search even
while GNSS-SDR.assist_dual_frequency_acq is enabled for the other
signals. Knowingly reintroduces part of what f7948f4af retired under
#1097, under a clearer name -- see PR description for the regression
and spoofing-resilience evidence motivating it.
A complete, ready-to-edit example config for EVK1029_Signal_Source with
RF_channels=2, demonstrating the file_offset seeking option added in
this PR alongside the rest of the signal chain, acquisition/tracking
Doppler-narrowing assist, runtime visibility-aware acquisition search,
AGNSS aiding, and the remote monitor/telecommand interfaces -- all keys
verified against this branch's source to confirm they're implemented.
- Rename doppler_uncertanty -> doppler_uncertainty throughout (interface,
adapter, block, comments, log message).
- Fix the out-of-bounds write and mis-detection in narrowed-mode
activation: track it with an explicit d_doppler_search_narrowed flag,
set directly in set_doppler_uncertainty() and guarded on
d_num_doppler_bins > 1, instead of inferring it from
"d_num_doppler_bins_active < d_num_doppler_bins". That inferred check
broke two ways: for a 1-bin full grid (a valid, already-accepted
config), it still forced 2 active bins, writing past the grid/wipeoff
allocations sized to d_num_doppler_bins; for a 2-bin full grid, an
actually-narrowed request computes the same active count as the full
grid (2 < 2 is false), so it silently searched the full grid's own
bin layout instead of the assisted {center, center + doppler_max}
pair. Reproduced the out-of-bounds write directly (temporarily
reverting to the inferred check crashes with "corrupted double-linked
list" under the new NarrowingEnabledOneBinGrid test) and the
mis-detection (NarrowingEnabledTwoBinGrid).
- Keep the noise-reference bin out of candidate selection: both
max_to_input_power_statistic() and first_vs_second_peak_statistic()
now take a separate candidate_count, used only for the peak-search
loop bound; the CFAR path's own num_doppler_bins (used for the
"opposite bin" reference lookup) is unchanged. In narrowed mode,
candidate_count is 1 -- the noise-reference bin can no longer win and
be reported as the acquisition result, regardless of its own power
(verified against a live signal deliberately placed in the reference
bin instead of the known/candidate bin: reverting this fix, both the
CFAR and peak-ratio statistic mistakenly report the reference bin's
Doppler as if it were the assisted center).
- Recalibrate the acceptance threshold for narrowed acquisition: adds
d_threshold_narrowed, computed like d_threshold but with
num_doppler_bins = 1 (the true candidate count in narrowed mode)
instead of the full grid's bin count, since compute_threshold() folds
the candidate count into the false-alarm probability and reusing the
full-grid threshold in narrowed mode was effectively far stricter
than the requested PFA. get_threshold() returns it whenever
d_doppler_search_narrowed is true.
- Fix narrowed dump layout/metadata: ensure_dump_grid_allocated() now
sizes acq_grid to d_num_doppler_bins_active (not the full grid width),
matching what copy_magnitude_grid_to_dump_grid() actually writes each
cycle -- this also makes narrow<->full transitions between dumps
self-correcting. dump_results() writes accurate, mode-appropriate
doppler_max/doppler_step (the same {0, doppler_max} encoding
compute_statistics() uses internally when narrowed), plus new
doppler_center and doppler_narrowed fields so offline post-processing
can tell which encoding is in effect. Verified end to end against a
live dump (NarrowedDumpMetadata).
- Strengthen Acq_Conf::enable_doppler_narrowing's doc comment (default,
which implementations it applies to, its dependency on the caller
passing doppler_uncertainty == 0) and add a commented usage example
next to GNSS-SDR.assist_dual_frequency_acq in a dual-frequency
Galileo E1B+E5a example config.
- Add tests/.../pcps_acquisition_doppler_narrowing_test.cc: 8 focused
tests (narrowing enabled/disabled, 1-bin and 2-bin full-grid
configurations, CFAR and peak-ratio statistics, a full-narrow-full
transition, two-step acquisition with step-1 narrowing, and narrowed
dump metadata), built on the same real-capture/known-ground-truth
pattern as gps_l1_ca_pcps_acquisition_test.cc. Confirmed each targeted
regression test actually fails without its corresponding fix before
finalizing them.
Signed-off-by: joebre <joel.brenner@saphyrion.ch>
joebre