Computation of range velocity and direction of arrival in FMCW radar

Abstract

Frequency Modulated Continuous Wave (FMCW) radar is widely used in applications to find the range, velocity and angle of the target objects from the radar. The transmitted signal is in the form of chirp where the frequency increases linearly with time. After hitting the target object, the signal is received by the receiver antenna which contains the information about the range, velocity and angle of target object. The information is extracted using different signal processing algorithms like Fast Fourier Transform algorithm (FFT) and Multiple Signal Classification (MUSIC) algorithm. When Fast Fourier Transform (FFT) algorithm is used to estimate the Direction of Arrival (DOA), the angular resolution is less, as it is dependent on the number of points in FFT and number of receivers used. As Additive White Gaussian Noise (AWGN) gets added to the received signal, and in cases of low Signal to Noise Ratio (SNR), the angle estimation using FFT algorithm becomes difficult as many peaks were obtained in spectrum due to addition of noise. MUSIC algorithm uses Eigen value decomposition method and denoising occurs by suppressing the peaks due to noise. The angular resolution is also increased and this algorithm works good in noisy environment. The simulation was carried out in MATLAB and the results were also verified using the same.