Due to the difficulty in deducing the corresponding relationship between results and parameter settings of multiple phases sectionalized modulation (MPSM) jamming, a problem occurs when obtaining the optimal local suppression jamming effect, which limits the practical application of MPSM jamming. The traditional method struggles to meet the requirements by setting fixed parameters or random parameters. Therefore, an optimization algorithm for MPSM jamming based on particle swarm optimization (PSO) is proposed in this study to produce the optimal local suppression jamming effect and determine its corresponding parameter settings. First, we analyzed the relationship between the degree of mismatch and local suppression jamming effect. Then, we set appropriate fitness function and fitness value. Finally, we used PSO to calculate parameter settings of a section situation and phase situation, which minimizes the fitness function and fitness value. The optimization algorithm avoids the tremendous computation of traversing all parameter settings, is stable, the results are repeatable, and the algorithm provides the optimal local suppression jamming effect under different conditions. The simulation experiments demonstrate the feasibility and effectiveness of the optimization algorithm.

When imaging maneuvering targets using Inverse Synthetic Aperture Laser Radar (ISAL), echo pulses disperse in range and the Doppler frequency varies with the slow time. The conventional Range-Doppler (RD) imaging algorithm is inapplicable of producing acceptable image. To solve these problems, an ISAL imaging algorithm for maneuvering targets is proposed. Firstly, the echo model of ISAL is established for a maneuvering target. Research reveals that, for a uniformly accelerated target, the ISAL signal after optical heterodyne processing can be approximated as a multi-component linear frequency modulation (MLFM) signal with a uniform chirp rate; when the Doppler frequency variation in azimuth can be estimated as a first-order polynomial, sub-echoes in each range cell are MLFM signals with different chirp rates related to the scatterers' azimuth coordinates. Subsequently, fractional Fourier transform (FrFT) is in use for eliminating the range dispersion's problem. A method combining FrFT and CLEAN technique (FrFT-CLEAN) are proposed after motion compensation for azimuth imaging. Simulation results demonstrate the validity of the proposed algorithm.

Multiple phases sectionalized modulation (MPSM) jamming is a kind of blanket jamming method against linear frequency modulation (LFM) radar, which can produce range-controllable noise-like jamming effect by dividing the signal into multiple subsections in the time domain and modulating different phases on each subsection. However, the partial relationship between the jamming effect and jamming parameters is complicated, which decrease the controllability of MPSM jamming effect. By transforming the problem of the controllability of MPSM jamming effect into the problem of the optimization of MPSM jamming effect, an optimization algorithm based on genetic algorithm (GA) is proposed to solve the problem in this paper. In the optimization based on GA, first, the objective function is constructed according to the jamming evaluation, the parameters are coded, the population is initialized, and the fitness value of the initial population is calculated. Then, the selection operation, crossover operation and mutation operation are performed, the next population is generated and its fitness value is calculated. Finally, judge if reach the termination, continue or output the optimization result and its corresponding parameters. The optimization method proposed in this paper can not only effectively increase the controllability of MPSM jamming effect, but also optimize the jamming effect. The simulation results show that the optimization method is feasible and has strong stability. INDEX TERMS Linear frequency modulation (LFM) radar, multiple phases sectionalized modulation (MPSM) jamming, range-controllable blanket jamming, genetic algorithm (GA), jamming effect optimization.

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Abstract.The cross-eye jamming technique is a common method for monopulse tracking radar, which can cause a displacement towards the wrong direction and result in an angle deception. This paper proposes a modification of the traditional cross-eye jamming system, and the phase diversity processing of the received signal is introduced, and its precise expression of the offset is derived. The phase difference between the two branches of the signal processing is controllable, which is in the vicinity of 180 ° phase shift, reducing the coordination requirements of the two branches. Simulation with different parameters is conducted so as to prove the conclusion, and the flexible control of the jamming effort is realized by this new cross-eye jamming technique.