Adding the monopulse tracking example for the ADRV9009ZU11EG RF-SOM.

trx_examples/streaming/adrv9009/ADRV9009ZU11EG_Monopulse_Tracking_Example.m

@@ -0,0 +1,211 @@
+clear all; close all;
+
+%% Configuration parameters
+uri = 'ip:analog';
+lo_freq = 5400000000 - 300000;
+tx_sine_baseband_freq = 300000;
+lambda_over_d_spacing = 1.93;
+sample_rate = 122880000;
+number_periods_sine_baseband = 12;
+num_samps = round((number_periods_sine_baseband * sample_rate) / tx_sine_baseband_freq);
+used_rx_channels = 4;
+rx_channels_used = [1, 2, 3, 4];
+rx_gain = 30;
+phase_step = 3;
+tracking_length = 200;
+
+%% Rx set up
+rx = adi.ADRV9009ZU11EG.Rx;
+rx.uri = uri;
+rx.CenterFrequency = lo_freq;
+rx.CenterFrequencyChipB = lo_freq;
+rx.EnabledChannels = rx_channels_used; 
+rx.SamplesPerFrame = num_samps;
+rx.GainControlMode = 'manual';
+rx.GainControlModeChipB = 'manual';
+rx.GainChannel0 = rx_gain;
+rx.GainChannel1 = rx_gain;
+rx.GainChannel0ChipB = rx_gain;
+rx.GainChannel1ChipB = rx_gain;
+rx.EnableCustomProfile = true;
+rx.CustomProfileFileName = ...
+    'Tx_BW200_IR245p76_Rx_BW200_OR245p76_ORx_BW200_OR245p76_ADRV9009.txt';
+
+%% Boresight Calibration
+disp('==================================================');
+disp('BORESIGHT CALIBRATION');
+disp('Place the transmitting antenna at BORESIGHT (0 degrees)');
+input('Press Enter when ready...');
+
+% Phase Calibration
+disp('Performing phase calibration...');
+repeat_ph_calculations = 10;
+num_channels = used_rx_channels - 1; % Exclude reference channel 0
+phase_diffs = zeros(num_channels, repeat_ph_calculations);
+
+for iteration = 1:repeat_ph_calculations
+    rx_samples = rx();
+
+    % Measure phase difference between ch0 and other channels
+    for ch = 2:used_rx_channels
+        errorV = angle(rx_samples(:,1) .* conj(rx_samples(:,ch))) * 180 / pi;
+        phase_diffs(ch-1, iteration) = mean(errorV);
+    end
+    fprintf('Iteration %d complete\n', iteration);
+end
+
+% Calculate average phase differences
+pcal = mean(phase_diffs, 2)'; % Average across iterations
+disp(['Phase calibration coefficients (pcal): ', num2str(pcal)]);
+
+%% Gain Calibration
+disp('Performing gain calibration...');
+rx_samples = rx();
+
+% Measure amplitudes from each channel
+amplitudes = max(abs(rx_samples));
+
+% Calculate gain coefficients relative to max amplitude channel
+[max_amplitude, max_idx] = max(amplitudes);
+gcal = max_amplitude ./ amplitudes;
+gcal(max_idx) = 1.0;
+
+disp(['Amplitude values: ', num2str(amplitudes)]);
+disp(['Gain calibration coefficients (gcal): ', num2str(gcal)]);
+
+disp('==================================================');
+
+%% Setup Beamforming Constants
+phase_cal = [0, pcal(1), pcal(2), pcal(3)];
+elem_spacing = (3e8/(lo_freq + tx_sine_baseband_freq))/(lambda_over_d_spacing);
+disp(['Element spacing of: ', num2str(elem_spacing), ' meters']);
+disp(['Number of elements: ', num2str(used_rx_channels)]);
+signal_freq = lo_freq;
+
+%% Initial Scan
+phases_to_sweep = -360/lambda_over_d_spacing : 2 : 360/lambda_over_d_spacing;
+num_sweep = length(phases_to_sweep);
+powers = zeros(1, num_sweep);
+angle_of_arrivals = zeros(1, num_sweep);
+phase_angles = zeros(1, num_sweep);
+
+disp('Receiving initial samples for sweep...');
+receive_samples = rx();
+
+% Apply gain calibration ONCE before sweep
+receive_samples = receive_samples .* gcal;
+
+% Apply boresight phase calibration (phase=0) to align channels
+channel_phases = mod(phase_cal(2:end), 360.0);
+channel_phases_rad = deg2rad(channel_phases);
+receive_samples(:, 2:end) = receive_samples(:, 2:end) .* exp(1j * channel_phases_rad);
+
+% Sweep over angle
+sweep_idx = 0;
+for phase = phases_to_sweep
+    sweep_idx = sweep_idx + 1;
+    rx_samps = receive_samples; % Copy the received samples
+
+    % Apply Phase Steering on top of boresight calibration
+    idx = 0:used_rx_channels-1;
+    steering_phases = mod(phase * idx, 360.0);
+    steering_phases_rad = deg2rad(steering_phases);
+    rx_samps = rx_samps .* exp(1j * steering_phases_rad);
+
+    % Steer Angle Calculation
+    val = (3e8 * deg2rad(phase)) / (2 * pi * signal_freq * elem_spacing);
+    val = max(min(val, 1), -1);
+    steer_angle = rad2deg(asin(val));
+    angle_of_arrivals(sweep_idx) = steer_angle;
+    phase_angles(sweep_idx) = phase;
+
+    % Sum beam
+    data_sum = sum(rx_samps, 2);
+    power_dB = 10*log10(sum(abs(data_sum).^2));
+    powers(sweep_idx) = power_dB;
+end
+
+powers = powers - max(powers);
+[~, max_idx] = max(powers);
+current_phase = phase_angles(max_idx);
+max_angle = angle_of_arrivals(max_idx);
+
+disp(['Initial estimated angle: ', num2str(max_angle)]);
+
+%% Plot
+figure(1);
+clf;
+hAx = axes;
+% Plot angle history against time index
+% X-axis: Angle (-30 to 30), Y-axis: Time/Sample (0 to 200)
+hLine = plot(hAx, NaN, NaN);
+title('Monopulse Tracking:  Angle vs Time');
+xlabel('Steering Angle (deg)');
+ylabel('Time Step');
+xlim([-30, 30]);
+ylim([0, tracking_length]);
+grid on;
+
+tracking_angles = ones(1, tracking_length) * 180;
+tracking_angles(1:end-1) = -180;
+
+% Initial plot update
+set(hLine, 'XData', tracking_angles, 'YData', 1:tracking_length);
+drawnow;
+
+%% Tracking Loop
+try
+    disp('Starting tracking loop. Press Ctrl+C to stop.');
+    while true
+        % Receive samples
+        data = rx();
+
+        % Apply Gain calibration
+        data = data .* gcal;
+
+        % Apply boresight phase calibration first
+        channel_phases = mod(phase_cal(2:end), 360.0);
+        channel_phases_rad = deg2rad(channel_phases);
+        data(:, 2:end) = data(:, 2:end) .* exp(1j * channel_phases_rad);
+
+        % Apply steering phase on top of boresight calibration
+        idx = 0:used_rx_channels-1;
+        steering_phases = mod(current_phase * idx, 360.0);
+        steering_phases_rad = deg2rad(steering_phases);
+        data = data .* exp(1j * steering_phases_rad);
+
+        % Sum and Delta Beams
+        % Sum: ch0+ch1+ch2+ch3
+        % Delta: (ch0+ch1)-(ch2+ch3)
+        sum_beam = data(:,1) + data(:,2) + data(:,3) + data(:,4);
+        delta_beam = (data(:,1) + data(:,2)) - (data(:,3) + data(:,4));
+
+        % Correlation
+        sum_delta_correlation = sum(sum_beam .* conj(delta_beam));
+
+        err_val = angle(sum_delta_correlation);
+
+        if sign(err_val) > 0
+            current_phase = current_phase - phase_step;
+        else
+            current_phase = current_phase + phase_step;
+        end
+
+        % Update estimated angle
+        val = (3e8 * deg2rad(current_phase)) / (2 * pi * signal_freq * elem_spacing);
+        val = max(min(val, 1), -1);
+        steer_angle = rad2deg(asin(val));
+
+        % Update History
+        tracking_angles = [tracking_angles(2:end), steer_angle];
+
+        set(hLine, 'XData', tracking_angles, 'YData', 1:tracking_length);
+        drawnow limitrate;
+    end
+catch ME
+    disp('Loop stopped or error occurred.');
+    disp(ME.message);
+end
+
+%% Cleanup
+release(rx);