Method and system for increasing the distance which can be unambiguously measured by a radar system

摘要

A radar system utilizes stretched radar pulses generated by multiplying the received radar pulse sequence by an auxiliary pulse sequence having a slightly lower pulse repetition frequency than the transmitted radar pulses. The pulse repetition period of the sequence of auxiliary pulses therefore exceeds the pulse repetition period of the transmitted radar pulses by a predetermined time difference. To eliminate echoes from undesired targets located more than a predetermined maximum distance from the radar the sequence of auxiliary pulses is synchronized to the sequence of transmitted radar pulses periodically with a synchronizing time including a predetermined number of transmitted radar pulses. The predetermined number is so chosen that the product of the number minus one, multiplied by the predetermined time difference, is equal to the time required for a radar pulse to travel back and forth from a target located at the predetermined maximum distance.