Analysis of Direction-of-Arrival Estimation for a Floating High-Frequency Radar With Yaw Rotation

Mounting a high-frequency radar on a floating platform can increase flexibility compared to a shore-based high-frequency radar. However, the direction-of-arrival (DOA) estimation is significantly affected by yaw rotation. To analyze the DOA estimation results and optimize the adaptive beamforming methods for yaw compensation, two parameters are introduced: the beam shape keeping factor (BSKF) and the gain of noise power (GNP). The BSKF represents the integration of steering vector errors in the beam domain, while the GNP is the 2-norm ratio between the optimal and reference weight vectors. A smaller BSKF tends to have a reduced DOA estimation bias, and a lower GNP indicates a higher signal-to-noise ratio (SNR). Thus, BSKF and GNP are used to separately evaluate the bias and the stability of the DOA estimation. To avoid the SNR loss caused by adaptive beamforming, a comprehensive adaptive beamforming method is proposed, which balances BSKF and GNP. The effectiveness of these two parameters is confirmed through simulations and field experiments. Results show that an adaptive beamforming method for yaw compensation should minimize both BSKF and GNP.