Coordinating Complementary Waveforms for Sidelobe Suppression

TL;DR

This paper introduces a method to design radar pulse trains and filters using Golay waveforms and binary sequences P and Q to suppress range sidelobes within a Doppler interval, improving radar resolution.

Contribution

The paper presents a novel joint design approach for transmit and receive sequences using Golay waveforms to control and nullify range sidelobes in radar systems.

Findings

Range sidelobes can be effectively suppressed within a Doppler interval.

A spectrum controlled by sequences P and Q determines sidelobe levels.

Tradeoff between sidelobe suppression order and signal-to-noise ratio is established.

Abstract

We present a general method for constructing radar transmit pulse trains and receive filters for which the radar point-spread function in delay and Doppler, given by the cross-ambiguity function of the transmit pulse train and the pulse train used in the receive filter, is essentially free of range sidelobes inside a Doppler interval around the zero-Doppler axis. The transmit pulse train is constructed by coordinating the transmission of a pair of Golay complementary waveforms across time according to zeros and ones in a binary sequence P. The pulse train used to filter the received signal is constructed in a similar way, in terms of sequencing the Golay waveforms, but each waveform in the pulse train is weighted by an element from another sequence Q. We show that a spectrum jointly determined by P and Q sequences controls the size of the range sidelobes of the cross-ambiguity function and by properly choosing P and Q we can clear out the range sidelobes inside a Doppler interval around the zero- Doppler axis. The joint design of P and Q enables a tradeoff between the order of the spectral null for range sidelobe suppression and the signal-to-noise ratio at the receiver output. We establish this trade-off and derive a necessary and sufficient condition for the construction of P and Q sequences that produce a null of a desired order.