Study On Disturbance Factors Analysis And Matching Of Geomagnetic Positioning In Small Area

Geomagnetic positioning has become one of the hotspots of scholars' research in recent years because of the advantages of passivity,no radiation,and so on.At present,it is mostly used in equipment and weapons positioning and other military defense fields.The civilian application of geomagnetic navigation technology has just started and there is little research on the theoretical about the geomagnetic positioning in indoor and underground engineering fields.In order to study the spatial distribution characteristics,time-domain variation rule,disturbance variation characteristics and geomagnetic matching algorithm in a small area.Corridors,roads and tunnels of simulated mines are selected as research areas for experimental study.FVM-400 fluxgate magnetometer was used to measure geomagnetic data.The geomagnetic data of the total and three-axis components were analyzed after denoising and statistics.The geomagnetic features such as mean,variance,roughness and peak state are extracted to evaluate the adaptability of the area,compared the accuracy of NCOR,MAD and MSD algorithms,and an optimized matching algorithm MSD(P)is proposed.It can be found that the stability geomagnetic is relatively unchanged,and it is mainly reflected in the changes of anomaly field and environment field by monitoring in a small area.The time-domain monitoring can be found that the trend of the change of the total magnetic and the triaxial component is no difference,the fluctuation changes obviously within 24 hours,usually reaching minimum value at midday,and the repeated monitoring at different points in different solar days shows that the timedomain disturbance is not large,it is not more than 200 nT.The electronic equipment will disturb the geomagnetic in a certain extent.The maximum distance of disturbance caused by mobile phone operation is about 50 cm,and the disturbance value is below 100 nT.In the geomagnetic matching test,MSD,MAD and NCOR matching algorithms can achieve high accuracy without noise.After adding different noises of 20~100nT,the matching experiment shows that the positioning accuracy of matching results decreases with the increase of noise.The performance of MSD is well,the matching speed is fastest and the matching probability is higher.In order to eliminate the influence of random noise on the matching results of geomagnetic data,the matching input of MSD algorithm is optimized.The matching input is improved from geomagnetic sequence to adjacent magnetic difference sequence,and the MSD(P)matching model is established.Compared with MSD and MSD(P)after adding different noises,the matching speed of MSD(P)and MSD(P)is the same,but the robustness of MSD(P)is better,and the matching probability can reach 89% at 100 nT noise.The experimental results show that: the composition of geomagnetic is complex and the disturbance is larger,the positioning accuracy of current algorithms and measuring equipment is lower.In the later stage,the optimization of geomagnetic matching algorithm and the anti-jamming geomagnetic data acquisition should be carried out.Figure29;Table22;Reference 68...