LPD feature improvement in random PRF radar signals

The random PRF method has been suggested for the design of LPD (low probability of detection) radar signals. The LPD improvement in using this kind of signal is discussed quantitatively. First, a detection theoretic approach is used to find the optimum detectors of the unauthorised receiver (ESM receiver) and their performance for both constant PRF and random PRF signals. Then, the effect of the random PRF method on the authorised receiver (radar receiver) is investigated. Based on these analyses and definition of a proper measure, the constant PRF signals are compared with random PRF signals from the LPD point of view. By finding a simple formula for the improvement caused by the random PRF method, it is shown that random PRF signals are more secure than constant PRF signals. This formulation can help the radar designer to evaluate radar security and also to obtain the required security level by choosing suitable parameters.