mirror of
https://github.com/gnss-sdr/gnss-sdr
synced 2024-06-25 06:23:18 +00:00
122 lines
3.3 KiB
Matlab
122 lines
3.3 KiB
Matlab
% Reads GNSS-SDR Acquisition dump binary file using the provided
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% function and plot acquisition grid of acquisition statistic of PRN sat.
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% CAF input must be 0 or 1 depending if the user desires to read the file
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% that resolves doppler ambiguity or not.
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%
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% This function analyzes a experiment performed by Marc Sales in the framework
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% of the Google Summer of Code (GSoC) 2014, with the collaboration of Luis Esteve, Javier Arribas
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% and Carles Fernandez, related to the extension of GNSS-SDR to Galileo.
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%
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% Marc Sales marcsales92(at)gmail.com,
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% Luis Esteve, 2014. luis(at)epsilon-formacion.com
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% -------------------------------------------------------------------------
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%
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% GNSS-SDR is a Global Navigation Satellite System software-defined receiver.
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% This file is part of GNSS-SDR.
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%
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% Copyright (C) 2010-2019 (see AUTHORS file for a list of contributors)
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% SPDX-License-Identifier: GPL-3.0-or-later
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%
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% -------------------------------------------------------------------------
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%
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function plot_acq_grid_gsoc_e5(sat,CAF)
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path='/home/marc/git/gnss-sdr/data/';
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file=[path 'test_statistics_E5a_sat_' num2str(sat) '_doppler_0.dat'];
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sampling_freq_Hz=32E6
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%Doppler_max_Hz = 14875
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%Doppler_min_Hz = -15000
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%Doppler_step_Hz = 125
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Doppler_max_Hz = 10000
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Doppler_min_Hz = -10000
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Doppler_step_Hz = 250
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% read files
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%x=read_complex_binary (file);
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%x=load_complex_data(file); % complex
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%l_y=length(x);
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myFile = java.io.File(file);
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flen = length(myFile);
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l_y=flen/4;% float
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Doppler_axes=Doppler_min_Hz:Doppler_step_Hz:Doppler_max_Hz;
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l_x=length(Doppler_axes);
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acq_grid = zeros(l_x,l_y);
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index=0;
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for k=Doppler_min_Hz:Doppler_step_Hz:Doppler_max_Hz
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index=index+1;
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filename=[path 'test_statistics_E5a_sat_' num2str(sat) '_doppler_' num2str(k) '.dat'];
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fid=fopen(filename,'r');
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xx=fread(fid,'float');%floats from squared correlation
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%xx=load_complex_data (filename); %complex
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acq_grid(index,:)=abs(xx);
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end
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[fila,col]=find(acq_grid==max(max(acq_grid)));
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if (CAF > 0)
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filename=[path 'test_statistics_E5a_sat_' num2str(sat) '_CAF.dat'];
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fid=fopen(filename,'r');
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xx=fread(fid,'float');%floats from squared correlation
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acq_grid(:,col(1))=abs(xx);
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Doppler_error_Hz = Doppler_axes(xx==max(xx))
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maximum_correlation_peak = max(xx)
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else
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Doppler_error_Hz = Doppler_axes(fila)
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maximum_correlation_peak = max(max(acq_grid))
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end
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delay_error_sps = col -1
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noise_grid=acq_grid;
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delay_span=floor(3*sampling_freq_Hz/(1.023e7));
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Doppler_span=floor(500/Doppler_step_Hz);
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noise_grid(fila-Doppler_span:fila+Doppler_span,col-delay_span:col+delay_span)=0;
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n=numel(noise_grid)-(2*delay_span+1)*(2*Doppler_span+1);
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noise_floor= sum(sum(noise_grid))/n
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Gain_dbs = 10*log10(maximum_correlation_peak/noise_floor)
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%% Plot 3D FULL RESOLUTION
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[X,Y] = meshgrid(Doppler_axes,1:1:l_y);
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figure;
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surf(X,Y,acq_grid');
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xlabel('Doppler(Hz)');ylabel('Code Delay(samples)');title(['GLRT statistic of Galileo Parallel Code Phase Search Acquisition. PRN ' num2str(sat)]);
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end
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function x=load_complex_data(file)
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fid = fopen(file,'r');
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%fid = fopen('signal_source.dat','r');
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myFile = java.io.File(file);
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flen = length(myFile);
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num_samples=flen/8; % 8 bytes (2 single floats) per complex sample
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for k=1:num_samples
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a(1:2) = fread(fid, 2, 'float');
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x(k) = a(1) + a(2)*1i;
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k=k+1;
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end
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end
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