Analysis Of Detection Performance And Fusion Algorithm For Distributed Surface Wave Othr

Distributed multi-ship based surface wave radar(DMS-SWR) is the new radar system which is developed from the shore-based surface wave over-the-horizon radar and the ship-based surface wave over-the-horizon radar. DMS-SWR exploits the ship formation with the multiple radar in order to compensate for technical limitations of the single ship-based or shore-based surface wave over-the-horizon radar. Therefore, it can significantly improve the overall performance of the system, such as the ability of detection, the accuracy of the detection and the ability to survive.According to the different distance between each ship in the ship formation, DMS-SWR can be divided into two kinds of working model, that is the combined distributed radar(CDR) and the mobile multi-based distributed radar(MMDR). The system in the CDR requires lesser distance between ships in the formation, generally less than 10 km to ensure the coherence of echo signals received by radars in each shipboard. Nevertheless in the system of MMDR, the distance between ships can be increased to 20-300 km, due to the high flexibility of the ships in the formations. Therefore, there is no longer coherence of the echo signals received by the radars and the echo can be processed separately through signal processing system built in each ship. The information of the multiple targets is sent to the fusion center for processing so as to improve the radar system’s detection performance.In the system of the CDR, the radar array with a larger aperture can be obtained by arranging several radars in ships together so as to improve the azimuth resolution of the radar system for the target in space. Because the distance between each ship is difficult to satisfy the half wave when it is beam forming, the large combined array produces a large number of grating lobe. That has seriously affected the detection zone of target bearing. When each ship moves mutually at a different speed, the composed large aperture array becomes time-varying array as the distance between ships changes constantly. Conditions for emerging the grating lobe will be broken. When the echo data of multiple snapshots is formed as a beam and accumulated, a beam of a narrow main lobe can be gotten and thus suppress the appearance of the grating lobe.In the system of MMDR, the working mode is single transmitter and multiple receivers. The information about the distance sum and speed sum between the radar transmitter ship, the radar receiver ship and the targets will be obtained by using own signal processing resources in each receiver ship, and be sent to the data fusion center or the transmitter ship. The fusion center will achieve the target positioning and the real speed by analyzing the spatial distribution of multiple ships and the obtained sum information about targets distance and speed.In the fusion center, target track can be obtained after the jointly processing the information about the distance and speed. Therefore, multiple radar receivers can get multiple track of the same target. Finally, the target track can be obtained more accurately through the tracking filter, association and fusion of the track in order to enhance the precision and performance of the system’s detection in MMDR.