Study On Instantaneous Position Reconstruction Methods Of Multi-beam Transducer In GPS Signal Blind Area

With the completion of the large buildings,such as the cross-sea bridge and the harbor,the safety of the buildings are highly concerned by the managers,and Around multi-beam underwater terrain surveys data is also an important indicator for assessing the safety of the building.Due to the blockage,blind zones of Global Positioning System(GPS)signals will be formed,which will directly result in lower accuracy of positioning data,and seriously affect the accuracy of multi-beam underwater terrain survey.Therefore,the instantaneous position of the multi-beam transducer in the GPS blind zone must be accurately reconstructed.This paper studied a kind of multi-beam transducer instantaneous position datum(planar and elevation)precision reconstruction technology in GPS signal blind zone,which ensuring the accuracy of underwater terrain surveys and providing a reliable theoretical and scientific basis for safety monitoring of large buildings at sea.On the basis of analysis of the current research,the following research that on the accurately reconstruction of the instantaneous position datum in the GPS signal blind zone is conducted on this paper.(1)A GPS/IMU combination multi-beam transducer instantaneous position n reconstruction system in the GPS blind zone is designed on this paper.(2)Study on reconstruction of instantaneous plane for multi-beam transducer.A multi-sensor time synchronization method is used to solve the problem that the sensors are not synchronized in time.In view of the low navigation accuracy of the GPS combination in GPS signal blind,the multi-modal Kalman filtering model is used to reconstruct multi-beam transducer instantaneous plane,which in combination with the weight judgment mechanism and the IMU error accumulation elimination model.(3)Study on reconstruction of instantaneous elevation for multi-beam transducer.Aiming at the short-time GPS signal anomaly,the method of extracting the long-period signal based on the digital filter is studied,and in combination with the Heave signal to modify the GPS elevation signal,so reconstruct multi-beam transducers instantaneous elevation datum in short-time GPS signal blind zone.In view of the abnormality of long-time GPS signals,dual-vessel measurement platform is used to reconstruct multi-beam transducers instantaneous elevation.(4)The multi-beam transducer instantaneous position datum reconstruction experiment was conducted in the Qingcaosha experimental area.The experimental results show that the accuracy of the position datum is good through proposed method by this paper,which proves the feasibility of it.