Pulse compression is a signal processing technique used in radar and sonar systems to achieve high-range resolution while maintaining high signal strength. This involves modulating the radar pulse in such a way that the pulse occupies a longer duration of time than a conventional pulse of the same peak power. This extended pulse duration allows for better discrimination between closely spaced targets, improving the radar’s ability to detect small objects or distinguish between different reflective surfaces. Pulse compression techniques typically use complex waveforms, such as linear frequency modulation (LFM) or encoded waveforms, to achieve these benefits.
The benefits of pulse compression include improved range resolution and target detection capabilities. By compressing the radar pulse in time using techniques such as LFM or encoded waveforms, radar systems can achieve much finer resolution for measuring distance to targets. This increased resolution enables detection of smaller objects and better differentiation between closely spaced targets, which is particularly advantageous in environments with clutter or when tracking multiple targets simultaneously. Pulse compression also improves the radar’s ability to detect weak signals, improving overall sensitivity and operational performance in harsh conditions.
Pulse compression using the linear frequency modulation (LFM) technique is a specific method where the radar pulse is modulated with a linearly increasing or decreasing frequency over its duration. This modulation creates a CHIRP waveform, where the frequency changes linearly with time. When this CHIRP pulse is transmitted and then received after reflecting off a target, the received signal is mixed with a replica of the transmitted chirp pulse. The mixing process, known as correlation, compresses the chirping pulse in time, effectively shrinking its duration. This compressed pulse has the same energy as the original longer pulse but with significantly improved range resolution. LFM pulse compression is widely used in radar systems for its simplicity, efficiency, and ability to achieve high resolution while maintaining high signal power and sensitivity.