Comparison of a modified periodogram and standard periodogram for current estimation by an HF surface radar

The periodogram and its variant, the Welch method, are two popular techniques used in spectral analysis. However, there has not been a thorough comparison of the estimation performances of these methods in current mapping by high frequency surface wave radar systems. Spectral leakage, frequency resolution, and variance are discussed in terms of the two applied techniques. The detection of a single-tone sinusoid signal is simulated as a simplified scenario for the Bragg frequency detection using the two methods. The comparison is then extended to more realistic simulations of Bragg echoes using typical radar operating parameters and a variety of signal to noise ratios (SNR). Both simple and complex physical variations in the current speed are simulated. Results from these simulations and field data indicate that the Welch method is capable of providing improvements in retrieved radial velocities.