Music-Enhanced CFAR for High Frequency Over-the-Horizon Radar

To increase the number of location options for an HF surface-wave radar (HFSWR) there is significant interest in reducing the physical size of the receive array. Reducing the aperture results in a degradation of both sensitivity and azimuth information. Azimuth accuracy may be retained by the use of high-resolution methods (such as MUSIC) that have a significantly smaller beamwidth than standard beamforming. It is expected that the application of these high-resolution methods will help retain azimuth information with reduced aperture size. This paper evaluates the effects of reducing the physical aperture of the linear receive array used in HFSWR and using post-detection azimuth re-estimation by high-resolution methods to maintain azimuth resolution, accuracy, and hence tracking performance. This paper is limited to evaluating the effect of increased azimuth beamwidth and does not address the issue of reduced radar sensitivity. Data for the evaluation was obtained from an HFSWR system located at Cape Race, Newfoundland, Canada. The accuracy of the detection centroid for a full 16-element array is compared to the accuracy for a half-aperture 8-element array. It is shown that similar accuracy can be achieved from the shortened array employing the MUSIC-Enhanced CFAR compared to the full size array using the conventional CFAR processing.