Velocity measurement using angular- and frequency-correlation techniques

Detecting and estimating the velocity of slowly moving targets from a moving platform is difficult due to the Doppler broadening of the ground clutter. The latest MTI (moving target indicator) technique employs STAP (space time adaptive processing) to reduce the clutter´s signal and thus is able to detect the target´s speed. This technique has proven to be very effective for detecting high-speed targets and also for some slower moving targets such as helicopters. If, however, the target´s speed is small, such as ground targets, the target´s signal is reduced along with the clutter, again rendering the detection of the target´s speed difficult. The techniques described in this paper utilize the signals from a multiple sensor system and are based on the correlation of the scattered waves of the target. The Doppler shift of the correlation function is then used to obtain the target´s velocity. Unlike conventional MTI radar, our technique makes use of the Doppler shifted phase of the correlation of the scattered waves. Controlled experiments were conducted with an X-band radar and good agreement was obtained with numerical simulations