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A new coherent detection method based on generalized likelihood ratio test(GLRT) and constrained GLRT(CGLRT) is proposed, which can be used in coherent detection for frequency diversity separated sub-array radar. The Keystone transform is employed to compensate the Doppler frequency discrepancy introduced by frequency diversity. Theoretical analysis and simulation results show that frequency diversity separated sub-array radar obtains better detection performance and better angle ambiguity resolution performance compared with its counterpart using single frequency, and the Doppler frequency discrepancy can be compensated by the Keystone transform regardless of the unknown target radial velocity. [ABSTRACT FROM AUTHOR]

Aiming at the solution of sidelobe problems of phase-coded radar signals, a novel method of code agility is proposed here. Different codes selected randomly are transmitted from pulse to pulse, and the return waves are projected to the radar line of sight after matched filtering for eaeh echo and DFT processing for each range cell. A criterion for code selection is established as well. Theoretical analysis and experiments indicated that this technique suits for various biphase codes or polyphase codes, with perfect effect of sidelobe suppression. In addition, the capability of small targets detection is improved. Furthermore, good reduction performance can be retained even if target return waveforms are eclipsed to a great extent due to high duty cycle. [ABSTRACT FROM AUTHOR]

According to the coherent phase-coded pulse train (CPCPT) signals used in terminal radar seeker, a long-term coherent integration method is proposed. Without requiring any accurate velocity information, Keystone transformation is used for range migration compensation. Fourier transform is carried out for the coherent integration. In order to reduce the computation complexity, DFT-IFFT algorithm is used for the implementation of Keystone transformation. In support of the method, CPCPT maintains the coherent integration gain and the resolution in range and Doppler without the range-Doppler coupling. Some computer simulation results are presented which illustrate the effectivity of the method. [ABSTRACT FROM AUTHOR]

A new digital radio frequency memory (DRFM) system architecture based on digital channelized receiver is introduced. The theory of channelized receiver is stated and the realization structure based on polyphase filters is derived, and the diagram of radar countermeasure system based on this idea is proposed. The DRFM system based on digital channelized receiver take the advantage of broadband coverage of channelized receiver, and guarantees the frequency accuracy of the reproductive signals. The system can significantly reduce the requirement for calculation resources, the complex modulation process can easliy be achieved due to the decimated low speed data rate. [ABSTRACT FROM AUTHOR]