RWR (radar-warning receiver)/ESM (electronic warfare support measure) system usually uses traditional instantaneous frequency measure (IFM) technology to detect the frequency of signals in real time,but it can only estimate one frequency when it receives overlapping signals,and easily create frequency measurement errors.But in complex electromagnetic environment of the modern battle,pulses overlapping probability increase.So analyzing the influence of overlapping signals to IFM system is particularly important.Through the basic principle of IFM,analyzed each node response of IFM microwave phase discriminator in the case of double overlapping signals,built mathematical model of output U_I,U_Q and put forward a new algorithm—U_I,U_Q calculation algorithm that can estimate the frequency of double overlapping signals.Simulation results show that the algorithm can estimate the frequency of overlapping signals and keep advantages of original IFM.

To evaluate the jamming effect of ship inboard and outboard radar active jamming equipment against anti-ship missile,the effectiveness and quantitative evaluation criteria of the shipboard active jamming equipment to terminal guidance radar are proposed.The general requirements for the application of the evaluation criteria is clarified, the test method and application method of the evaluation criteria are stipulated. Evaluation criteria includes quotas and evaluation of quotas.The application of the evaluation criteria includes the measurement method of the quotas,the data processing and the result evaluating.

Aiming at the shortcomings of the traditional radar signal detection algorithm, such as inaccuracy, large computation and slow speed, a signal detection algorithm of GST Hough transform based on time frequency clustering criterion is proposed. The algorithm integrates the improved S transform and Hough transform based on the aggregation criterion of the standard deviation of the sliding window, and completes the signal detection combined with the threshold based on the Neyman Pearson criterion. The simulation results show that the algorithm has good detection results below 14 dB. Compared with other algorithms, it is concluded that the algorithm has good detection ability under low SNR condition, does not rely on prior information, and has strong applicability.

To improve the tracking accuracy of the hypersonic gliding target in the near space, a novel maneuvering model is established based on the change rule of flight path angle. In order to estimate the position and velocity of the target in the radar measurement coordinate system, the angle of the target's trajectory profile is analyzed. Because of the similar change rule between the change rate of flight path angle and that of the inclination angle, it is proposed to use the inclination angle instead of the flight path angle for establishing the maneuvering model. The change rate of inclination angle is described as a zero mean sinusoidal autocorrelation stochastic process and a Markov model is established. The angular relationship is mapped to the positional dimension for establishing a spatial model. To make the system state model linear, the model is divided into the front-end angle sub-filter and the back-end position sub-filter, and the angle sub-filter drives the position sub-filter for tracking. The parameters of the model are set through simulation. The experimental results show that the model has better tracking accuracy.

Aiming at the problem that the traditional algorithm cannot initiate the slow and small target (SST) track effectively, a track initiation method for SST based on image processing Hough transform is proposed. The parameters of the minimum circumscribed rectangle, consisting of F₃, F₂ and F₁, are introduced as the weighting factors of Hough transform, and these parameters are extracted in accumulation region by image marking technique. SST is successfully obtained by controlling the weighting factor of Hough transform, which improves the detection performance of the radar to the SST. Simulation results verify the effectiveness of the proposed algorithm.

Based on the traditional mass evaluation model, an iterative evaluation model to study the fuel mass and the take-off mass of tactical scramjet missile is devised, and an improved evaluation model is put forward by taking terminal guidance into account. By comparing these two kinds of evaluation models for fixed and moving targets, the source of evaluation error is achieved. The influence of range, target speed, distance of terminal guidance and cruise height on evaluation error is discussed. The simulation results show that the traditional mass evaluation model which ignores the terminal guidance is suitable for short range fixed targets and low speed targets, while the mass-evaluation model considering terminal guidance or modified model ignoring the terminal guidance are suitable for long range, high cruise height, long-distance terminal guidance and high speed targets.