What eliminates second-time-around targets in the Primary Surveillance Radar (PSR)?

The correct choice focuses on the technique of staggering the coherent processing interval (CPI) along with the implementation of an M of N function. This method is designed to address the challenge posed by second-time-around targets, which occur when a radar signal reflects off a target and returns to the radar site after a significant delay.

By staggering the CPI, the system can differentiate between the first return of a radar pulse and subsequent returns that may originate from the same object. This differentiation is crucial because second-time-around targets can create confusion in tracking and identifying the actual location and movement of the target.

The M of N function enhances this capability by ensuring that only those returns which meet specific criteria are considered for tracking. This approach effectively filters out signals that could lead to erroneous target identifications, thereby improving the overall reliability and accuracy of the radar system.

Adopting this strategy allows the radar to better manage the complexities of tracking objects at varied distances and avoids the misinterpretation of delayed returns as new targets. This systematic management of echoes is essential for maintaining clear and precise radar readings, especially in environments with multiple moving objects.