Clutter-based array calibration for enhanced geolocation accuracy

Accurate target geolocation is critical to ground moving target indication (GMTI) performance. Large geolocation errors can make interpreting GMTI detection results difficult, particularly in dense target environments. Geolocation errors can result from a combination of antenna channel errors and platform inertial navigation system (INS) biases. In this paper we develop clutter-based array calibration techniques that remove unknown, channel-to-channel, phase and amplitude errors. These clutter-based techniques utilize distributed clutter for calibration and require no a priori knowledge of the scene or calibration targets. We also apply these techniques to estimate the platform orientation, which significantly improves cross-range geolocation accuracy as compared to platform INS orientation estimates. We present results on measured X-band data.