Under The High Repetition Frequency Tracking Algorithm Research Before Testing

In the face of threats of low-altitude/super-low-altitude penetration and stealth objects in recent years, there is an urgent need to improve the performance of airborne early warning radars with high pulse repetition frequency waveform to detect weak targets in a severe clutter environment. Track-Before-Detect (TBD) technology, accumulating the target energy along the trajectory to increase the signal-to-noise ratio (SNR), is an effective approach for radar to detect and track weak targets in a severe clutter environment. Therefore, TBD becomes one of the researching hotspot all over the world.The dissertation focuses on the problem of weak target detection and tracking in a high pulse repetition frequency radar and studies the TBD technique based on dynamic programming algorithm (DPA) and a target track initiating algorithm based on the improved modified Hough transform method. It mainly comprises:1. On the basis of the features of the target discrete state in a high PRF radar system, conditions of acceptability of using DPA in a high PRF radar system for target detection and tracking is analyzed, and the effect of the existence of the range ambiguity on the range transition step and azimuth transition step is discussed.2. For solving the problem of detecting and tracking a target moving with an approximate constant velocity in the range direction when its trajectory may be discontinuous in a high PRF radar system, a full-plane-DPA and a plot-DPA is proposed. With a modification of the target range transition step, the energy of target is accumulated along its trajectory effectively to detect and track this target.3. For solving the problem of how to detect and track a target that may be approximatively uniformly accelerated in the range direction in a high PRF radar system, the relationship between two adjacent range transition steps is discussed, and then an improved plot-DPA is proposed. The transition step is changed adaptively by predicting the target state in this algorithm, and then the target is detected and tracked effectively. 4. For solving the problem of how to make use of the priori knowledge of the target and the environment in DPA to improve the performance of target detection and tracking in a high PRF radar system, an envelope-likelihood-DPA and a complex-likelihood-DPA are proposed. With the use of the target amplitude information, the performance of target detection and tracking is improved.5. For solving the problem of target track initiating when its trajectory may be discontinuous in a high PRF radar system, a track initiation algorithm based on an improved modified Hough transform method is proposed. Corresponding criterions are added in this algorithm to complete track initiating for this target.The effectiveness of the methods is validated by simulations. The results show that a weak target in a dense clutter environment can be detected and tracked effectively by the proposed TBD in a high PRF radar system.