Experimental evaluation of passive radar approach for homeland security applications

By using the transmitters of opportunity, passive radar systems allow target detection and tracking without transmitting any RF energy. This approach ensures covert operation of the radar thus decreasing the risks of enemy detection and electronic countermeasures. In a nutshell, the passive radar utilizes the existing broadcast signals from multiple FM radio and TV transmitters, detects backscattered signals from targets, and employs advanced DSP algorithms to provide real time target position/speed estimation and tracking. In the first part of this work, the problem of estimating the true target position from three bi-static ranges is formulated and its solution is implemented using non-linear optimization tools. In the second part, the feasibility of using the passive radar approach for accurate target position detection is experimentally evaluated at 2.4 GHz. It is shown that the target range can be estimated with 50 feet resolution when a 6 MHz wide broadcast signal is used.