The performance of target detection using long-time integration would be influenced by the migrations of range and doppler frequency.In order to analyze the influence in the external illuminating radar which makes use of TV radio signal

an associated ambiguity function expressed by the time delay

doppler shift

time delay varying rate and chirp rate is defined.Subsequently

the average associated ambiguity function and integration loss of the TV radio signal are both derived.The relationship of the integration loss with the velocity

acceleration and integration time is obtained.And some conclusions are also acquired.This research can provide some theoretical reference for analyzing the performance of target detection in the external illuminating radar.