Research Projects

Pulse coherent tracking radar determines the range to a target using the pulse timing techniques and uses the Doppler effect of the returned signal to determine the target object's velocity. In Range-Doppler processing, the target is assumed to stay in the same range bin during the coherent processing interval (CPI) and a Fourier transform along the slow-time dimension is used to focus the target signature. Range migration occurs when the target passes into multiple bins over the CPI. As a result, the Doppler signature of a target smears in both range and Doppler domains. Combined with the wide bandwidth, the long CPI, and the high radial velocity between the target and the radar, this combination of factors causes significant linear range migration over the CPI. With range migration accumulated from profile to profile, range profile alignment is destroyed which results in the degradation of the coherent integration gain. Therefore, migration compensation must be considered. Keystone Transformation proposed to correct the range walk(the linear component of the range migration) and it is combined with the Doppler phase compensation to image the moving target. Keystone transform in Pulsed Doppler radar to remove the range migration effect and improve the performance of detection.