Solution for Complex Amplitude in LCD Removal Algorithm

Large clutter discretes (LCDs) are spectrally bright localized clutter that can cause false alarms or missed target detections in space-time adaptive processing (STAP) data. For passive bistatic STAP, the LCD removal (LCDR) algorithm estimates the spatial/Doppler frequency and complex amplitude of the LCD and then removes it from the data. However, previous techniques to estimate the LCD’s amplitude were complicated and slow. This paper proposes a method that directly solves for the amplitude that minimizes the power output at the LCD’s spatial/Doppler frequency.

I. Introduction

This paper will improve complex amplitude estimation in the large clutter discrete (LCD) removal (LCDR) algorithm developed by Lievsay and Goodman in [1] by analytically solving for the LCD’s complex amplitude. An LCD is spectrally bright localized clutter that can be present in a scene and show up in passive space-time adaptive processing (STAP) data. When using STAP for ground moving target indication (GMTI), clutter is assumed to be any stationary object or scatterer not of tactical interest. Homogeneous clutter can be suppressed with matched filtering and estimating the clutter covariance matrix with the training data [2]. An LCD present in the scene is considered heterogeneous clutter, which is more difficult to estimate without prior knowledge of the scene. The LCDR algorithm removes the LCD from the STAP data, so then the clutter can be treated as homogeneous.