Question about estimating azimuth angle and elevation angle in 'demo/visualizer'

[kathy-lee]

Hi, first of all thank you for this open source package, it's very helpful! I just have one question when I try to write a function to generate point cloud from IWR1443BOOST raw ADC data, only 2 of the transmitting antennas on the azimuth (horizontal) axis are used and receiving antennas are 4. I think the demo/visualizer/main.py gives a good enough example to generate point cloud, but I can't understand the following steps inside beamforming_naive_mixed_xyz() which is invoked after aoa_bartlett() and peak_search_full_variance() :

        higher_rung = inputSignal[8:12]
        lower_rung = inputSignal[2:6]
        for j in range(num_out):
            ele_out = aoa_estimation_bf_one_point(4, higher_rung, steering_vec[max_theta[j]])
            azi_out = aoa_estimation_bf_one_point(4, lower_rung, steering_vec[max_theta[j]])
            num = azi_out * np.conj(ele_out)
            wz = np.arctan2(num.imag, num.real) / np.pi

            temp_angle = -est_range + max_theta[j] * est_resolution  # Converts to degrees, centered at boresight (0 degrees)
            # Make sure the temp angle generated is within bounds
            if np.abs(temp_angle) <= est_range and estimated_variance[j] < doa_var_thr:
                e_angle = np.arcsin(wz)
                a_angle = -1 * (np.pi / 180) * temp_angle  # Degrees to radians
                output_e_angles.append((180 / np.pi) * e_angle)  # Convert radians to degrees
                output_a_angles.append((180 / np.pi) * np.arcsin(np.sin(a_angle) * np.cos(e_angle)))  
                output_ranges.append(input_ranges[i])

Can someone tell me the process of these steps and what are higher_rung and lower_rung used for? In my case to get azimuth angle, shall I ignore those steps and directly take the result from peak_search_full_variance() after aoa_bartlett() as azimuth angle estimation? Many thanks in advance!