The variability of the aperture of the airborne opportunistic array radar enables its radio frequency radiation power control range be arbitrarily directed in space.This paper first presents the multi-aperture characteristics of an aircraft opportunistic array radar, and shows that the continuous changes of its multiple aperture values can be approximated by trigonometric functions.Then, in order to relax the strong constraints on the prediction error covariance during target tracking and improve target tracking performance, the ratio of Blackman window to Hamming window is designed as the relaxation factor of the prediction error covariance.Finally, the dwelling time optimization model of airborne opportunistic radar is analyzed and established based on the requirements of RF stealth.The simulation results show that the use of interactive multi-model and dwelling time optimization design based on the posterior Cramer-Rao bound constraints not only has better RF stealth performance, but also can save the resources and improve the target tracking performance of the airborne opportunistic radar.