Search

Background. In radar systems, phase code-domain keying signals are widely used. Continuous signals of this kind have the advantage of low side lobes of the cross-correlation function and high noise immunity, but have limitations on the size of the area of view associated with the presence of ambiguity peaks. Aim. The paper considers the possibility of increasing the unambiguity of determining the time delay of the phase-code shift keyed signal in a correlation meter based on a combined FPGA-based coding rule. Methods. To achieve this goal, a numerical simulation of a correlation time delay meter with modulating signals formed by different coding rules was performed. Results. It is proposed in the correlation meter with continuous reception of the phase-code shift keyed signal to improve the accuracy of measuring the time delay and the unambiguity of determining the location of remote objects, as a modulating signal, use a signal formed by two pseudo-random sequences that are the same according to the coding rule, but different in duration. The results of numerical simulation of the post-detection digital processing system based on the proposed method are presented. Conclusion. The application of the proposed coding rule makes it possible to implement a correlation meter with a minimum amount of computing resources while increasing the unambiguity and expanding the range of measured time delays.

The six-polarization shift keying quadrature (6PolSK-QPSK) has been proved to be an alternative to four-dimensional (4D) modulation scheme. A variety of transmission compensation schemes have been developed for 24-Point 6PolSK-QPSK combining the advantages of polarization multiplexing quadrature phase shift keying (PM-QPSK) and polarization switched quadrature phase shift keying (PS-QPSK). In order to further improve the transmission rate of the signal system, 32-Point 6PolSK-QPSK signal modulation has been studied. We propose a novel encoding rule and compensation scheme for 32-Point 6PolSK-QPSK modulation by classifying symbols. The simulation tool based on VPItransmissionMaker10.1 is equipped with 32-Point 6PolSK-QPSK signal transmission system and the off-line digital signal processing (DSP) module is applied to MATLAB to prove the method proposed in this paper. The simulation results show that the error performance of 2.6 dB and 8.7 dB are improved for unrevised and revised data transmission, compared with the 32-Point 6PolSK-QPSK signal scheme obtained by rotating PM-QPSK.