FPGA Implementation Of Geomagnetic Navigation Based On ICCP Algorithm

In order to ensure the long-time and high accuracy navigation of the underwater vehicle,it is necessary for its INS(Inertial Navigation System)to correct and eliminate errors which increase with the accumulation of time.The developments of geophysical techniques promote the aided navigation research based on the geophysical character.As one of the geophysics character,the geomagnetic field is a field without source,and contains a wealth of information,such as the geomagnetic total intensity magnetic inclination,declination and so on.Meanwhile,the geomagnetic field has all terrain,all-weather,all-time fine features.Overall,the earth's magnetic field is a good natural coordinate for underwater geomagnetic aided navigation.The geomagnetic field data which were measured in Songhua Lake in our works were used to establish geomagnetic database.Then the aided navigation of ICCP(Iterative Closest Contour Point)marching algorithm was designed and implemented on FPGA and was verified the feasibility through MATLAB simulation.In this thesis,the establishment of geomagnetic database was introduced;the optical magnetic resonance theory and the Zeeman Effect theory were analyses.Then,the platform geomagnetic measurement hardware and software systems were introduced.Then the experiment of geomagnetic survey was described in detail and the measured data was processed in Surfer software.Finally,the digital geomagnetic library was established using processing data.The principles of ICCP algorithm were also described and the simulation of this algorithm was verified in MATLAB program.Meanwhile,the process and key technology of this algorithm were presented in detail.The closest contour point is the key point to this algorithm.Due to this issue,I proposed a method to find the closest point using the window contours and point to the segment nearest contour.In this method,the closest contour point was quickly and accurately found.Therefore,efficiency of the algorithm can be improved by this method.As the geomagnetic aided navigation algorithm,ICCP algorithm was implemented in FPGA hardware,and run in system on chip(Sopc)and peripherals powered platform.After geomagnetic marching,the corrected results of ICCP algorithm were outputted to the host computer.The flow of ICCP algorithm in FPGA hardware was follows: precision geomagnetic gallery access,high-precision geomagnetic field data transmission and the core calculation of ICCP algorithm.Compared with the MATLAB simulation results,the results of ICCP aided navigation was met the navigation requirements.And the correctness and feasibility of ICCP algorithm,which was running in FPGA hardware system,was verified.The results show that this work can provide a reference for INS navigation based on geomagnetic ICCP algorithm.