Scaled accuracy based power allocation for multi-target tracking with colocated MIMO radars

A colocated MIMO radar system can offer enhanced multi-target tracking (MTT) performance due to its agile multibeam working mode, in which multiple transmit beams are synthesized simultaneously using probing signals from individual colocated transmitters. To ensure that the limited transmitting power resource of a colocated MIMO radar is exploited effectively, in this paper, a scaled accuracy based power allocation framework (SA-PAF) is proposed for MTT. For a given total power budget, an overall MTT performance objective is optimized by adjusting the transmit power of each beam based on the feedback information in the tracking recursion cycle. An overall cost function (OCF), which is a combination of individual target cost functions (ITCF), is designed as the overall performance objective of the optimization problem. The necessity of ITCF is due to the fact that the impact of the state estimation error on the objective function should be different for each target due to its unique importance (or threat level) and the corresponding tracking accuracy requirement among multiple targets. The proposed OCF can quantify the global MTT performance while properly taking into account different target priorities through ITCFs. To formulate the OCF based framework as an optimization problem, we use the exponential function that employs the posterior Cramér–Rao lower bound (PCRLB) as the tracking performance measure as the instantiation of ITCF. It is shown that the proposed scheme is non-convex in the presence of a clutter. Then, the Zoutendijk method of feasible directions (ZMFD) is used to find the suboptimal power allocation solutions. Simulation results verify the superiority of the proposed power allocation algorithm in terms of achieving the effective overall performance of MTT while taking into account the differences targets priorities.