Added WIP

matlab/detect.m

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+close all;
+clear all;
+
+center_frequency = 173500000;
+sampling_frequency = 2000000;
+target_frequency = 173763000;
+filter_frequency = 500;
+upsample_ratio = 1;
+downsample_ratio = 200;
+num_taps = 100;
+
+
+% get data
+data = raw2complex('/home/ntlhui/workspace/tmp/testData/RAW_DATA_000001_000001');
+tic
+signal_length = length(data) / sampling_frequency;
+shifted_signal = shift(data, target_frequency - (center_frequency + ...
+	filter_frequency), sampling_frequency);
+resampled_signal = resample(shifted_signal', upsample_ratio, downsample_ratio);
+match_output = match(resampled_signal, filter_frequency, num_taps, ...
+	sampling_frequency);
+resampled_t = 0:1 / (sampling_frequency / downsample_ratio) : 1 / (sampling_frequency / downsample_ratio) * (length(match_output) - 1);
+mean_output = mean(match_output);
+var_output = var(match_output);
+bound = mean_output + 3 * sqrt(var_output);
+toc
+plot(resampled_t, match_output);
+hold on;
+plot([0 max(resampled_t)], [bound bound]);
+plot([0 max(resampled_t)], [mean_output mean_output]);

matlab/integrating_filter.m

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+clear all;
+close all;
+
+run_num = 55;
+files = 41;
+data_dir = sprintf("/media/ntlhui/43C8-B1EA/2017.08.22/RUN_%06d", run_num);
+% data_dir = "/home/ntlhui/workspace/tmp/testData/";
+f_s = 2000000;
+
+ignore = mkdir(sprintf("RUN_%06d", run_num));
+
+int_len = 6400;
+
+final_freq = f_s / int_len;
+start_idx = 0;
+
+threshold = 100;
+for i = 1:files
+	data = raw2complex(sprintf("%s/RAW_DATA_%06d_%06d", data_dir, run_num, i));
+	mag_data = abs(data).^2;
+	% integrated_data = mag_data;
+	integrated_data = zeros(floor(length(data) / int_len), 1);
+	for j = 1:length(integrated_data)
+		integrated_data(j) = sum(mag_data((j - 1) * int_len + 1 : j * int_len - 1));
+	end
+	log_data = 20 * log10(integrated_data);
+
+	if threshold == 100
+		threshold = log_data(1);
+	end
+
+	time = start_idx / final_freq : 1 / final_freq : (start_idx + length(log_data) - 1) / final_freq;
+
+	plot(time, log_data);
+	saveas(gcf, sprintf("RUN_%06d/RAW_DATA_%06d_%06d.fig", run_num, run_num, i));
+	start_idx = start_idx + length(log_data);
+end
+
+close;

matlab/match.m

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+function [signal] = match(input_signal, filter_frequency, num_taps, sampling_freq)
+	filter_length = num_taps / sampling_freq;
+	t = 0:1/sampling_freq:filter_length - 1/sampling_freq;
+	filter_taps = cos(2 * pi * filter_frequency * t) + i * sin(2 * pi * filter_frequency * t);
+	filter_taps = filter_taps(:);
+	input_signal = input_signal(:);
+	conv_output = conv(input_signal, filter_taps);
+	amp = abs(conv_output);
+	signal = 10 * log10(amp);

matlab/shift.m

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+function [signal] = shift(input_signal, shift_amt, sampling_freq)
+	signal_length = length(input_signal) / sampling_freq;
+	t = 0:1/sampling_freq:signal_length - 1/sampling_freq;
+	mixing_signal = cos(-2 * pi * shift_amt * t) + i * sin(-2 * pi * shift_amt * t);
+	mixing_signal = mixing_signal(:);
+	input_signal = input_signal(:);
+	signal = input_signal .* mixing_signal;
+end

matlab/threshold_prototype.m

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+close all;
+clear all;
+
+threshold_history = csvread('/home/ntlhui/workspace/radio_collar_tracker_drone/tests/sdr_record/classifier_threshold.log');
+data_in = csvread('/home/ntlhui/workspace/radio_collar_tracker_drone/tests/sdr_record/classifier_in.log');
+% gps_data = csvread('/media/ntlhui/43C8-B1EA/2017.08.22/RUN_000055/GPS_000055');
+signal_start_time_s = 1502770034.363384;
+% gps_start_time_s = gps_data(1:1);
+% local time, lat, lon, global time, alt, relative alt, vx, vy, vz, hdg
+% lat = gps_data(:,2);
+% lon = gps_data(:,3);
+% gps_data_times = gps_data(:,1) - signal_start_time_s;
+f_s = 2000000/6400;
+time = 0:1/f_s:(length(data_in) - 1) / f_s;
+
+static_offset = 1.5;
+
+% recreation
+% avg_len = floor(0.25*f_s)
+% ping_len = ceil(0.02*f_s);
+% peak_history = [ones(ping_len,1) * data_in(1); data_in];
+% peak = zeros(length(data_in), 1);
+% for k = 1:length(peak)
+% 	peak(k) = max(peak_history(k:k+ping_len));
+% end
+% peak = [ones(avg_len,1) * peak(1); peak];
+% peak_threshold = zeros(length(data_in), 1);
+% for k = 1:length(peak_threshold)
+% 	peak_threshold = median(peak(k:k+avg_len)) + 0.5;
+% end
+
+% peak_history = [ones(avg_len,1) * data_in(1); data_in];
+% threshold = zeros(length(data_in),1);
+% for k = 1:length(threshold)
+% 	threshold(k) = mean(peak_history(k:k+avg_len)) + 1;
+% end
+
+
+figure;
+subplot(2,1,1);
+plot(time, data_in);
+hold on;
+grid on;
+plot(time, threshold_history+1.5);
+% plot(time, threshold);
+% plot(time, peak_threshold);
+lims = xlim;
+% subplot(2,1,2);
+% plot(gps_data_times, lat);
+% hold on;
+% grid on;
+% yyaxis right;
+% plot(gps_data_times, lon);
+% xlim(lims);