Pulse compression radar is a technique used to improve the performance of radar systems by achieving high resolution and target detection capabilities while maintaining a relatively long pulse duration. Traditional radar systems typically use short pulses to achieve high-range resolution, but short pulses have limited energy and therefore lower detection capabilities for distant targets.
Pulse compression overcomes this limitation by encoding longer pulses with specific waveforms that allow them to achieve high range resolution equivalent to short pulses, while retaining the energy needed to effectively detect targets distant.
The principle of pulse compression involves modulating a long-duration radar pulse with an encoded waveform before transmission. This waveform coding spreads the pulse energy over a longer duration, effectively reducing its peak power without compromising the effective energy content of the pulse.
Upon receiving the reflected signal, the radar system correlates the received signal with the original transmitted waveform. This correlation process amplifies the received signal and compresses the pulse in the time domain, thereby achieving high range resolution equivalent to that of a short pulse while retaining the benefits of longer pulses, such as increased energy and improved detection capabilities.
In synthetic aperture radar (SAR), pulse compression plays a crucial role in producing high-resolution radar images of the Earth’s surface.
SAR systems use pulse compression to process radar echoes reflected from the ground. A SAR transmits long coherent pulses of radar energy and records the phase and amplitude of echoes received over a large synthetic aperture. By applying pulse compression techniques, SAR systems can achieve high azimuth resolution (along the direction of flight) and range resolution (perpendicular to the flight path).
This allows SAR to generate detailed, high-resolution images of terrain features, vegetation and man-made structures, making it invaluable for applications such as remote sensing, environmental monitoring and reconnaissance