This paper explores the low probability of intercept (LPI)-based optimal radar power allocation for target time delay estimation in joint radar and communications system. The basis of LPI-based optimal radar power allocation is to minimize the total power consumption of radar system under the constraints of a specified target time delay estimation accuracy and a quality of service (QoS) of communications base station. The expression for Cram閞-Rao lower bound (CRLB) is analytically derived and applied to gauge target time delay estimation accuracy. The resulting optimization problem is non-convex, which can be solved by the approach of linear programming. Several numerical results are provided to verify the superiority of the proposed radar power allocation in terms of the LPI performance of radar system. It is also shown that the LPI performance of radar benefits from cooperation with the communication system by reducing the total radiated energy of radar.

Radar power allocation; joint radar and communications system; Cram閞-Rao lower bound (CRLB); low probability of intercept (LPI)