Study On The Theory And Method Of Moving Platform Multi-antenna Precise Positioning With Constraint Conditions

Multi-antenna positioning has been widely used in deformation monitoring and Unmanned Aerial Vehicle(UAV)measurement.But the existing multi-antenna methods are mostly used for attitude determination,there are few methods which have been used for moving platform positioning.In multi-antenna positioning,several antennas are set on the moving platform and at least one base station is needed.Single-frequency receivers are usually set on the moving platform due to the equipment space and cost limitations.While the seting of base stations are more flexible which can either be continuously operating reference stations(CORS)or self-contained receivers.Because ambiguity constraints have been added in multi-antenna positioning,the success rate and reliability of ambiguity decomposition can be improved.This improvement can not only improve the reliability of attitude determination but also help to determine the precise position of the moving platform.The detection and repair of cycle slips of multi-positioning can also provide help for the ambiguity resolution on the fly(OTF).The core research contents of this dissertation are cycle slip detection theory and fast ambiguity resolution in multi-antenna positioning,including the following aspects:1.The cycle slip detection and repair algorithm of triple frequency carrier phase observatons are studied.A new triple frequency cycle slip detection and repair method was put forward based on total electron content rate(TECR).This method can be used for cycle slip detection and repair for undifferenced triple frequency observations received by base station.Through the establishing of three linearly independent triple frequency combinations(a new optimal GF combination,an optimal phase and code combination and an optimal GIF combination),cycle slip can be detected.Then the LAMBDA algorithm is used to fix the integer value of cycle slip.The predicrion residual of time differenced first order ionospheric delay can be used to judge wheather the cycle slip has been correctly repaired.The experiments results show that all of larger than or equal to one cycle slips can be detected and repaired correctly under low sampling rate or active ionospheric conditions.Especially the success rate of detection and repair of insensitive cycle slip(1,1,1)can reach100%.2.A new constrained Kalman filter model is proposed by using the attitude information of mobile platform such as pitch angle or roll angle to establish the inclination constraint conditions between receivers of mobile platform.At the same time,the constrained Kalman filter with fixed baseline length is analyzed.By processing the real observation of the mobile platform,the results show that the cycle slips even for 1 cycle can be detected and repaired accurately.The constrained Kalman filter model with trajectory constraint information is used to detecte and repair the cycle slip of the long baseline.Experimental results show that the cycle slip detection performance of this method is improved greatly compared with the traditional Kalman filter.However,when the speed of the moving platform is disturbed greatly,the cycle slip detection value is also disturbed greatly.3.In order to promote the successe rate of ambiguity resolution of single frequency ultra-short baseline on mobile platform,the inclination angle constraints of ultra-short baseline are used to improve the precision of float ambiguity.The experimental results show that the success rate of ambiguity resolution can reach 90% directly using LAMBDA algorithm.When the ambiguity fixed failure at the first time using baseline length as the condition,the ambiguities of 95% epochs can be fixed successfully within 10 times search in the ambiguity space and the correct ambiguity of all the epochs can be fixed within 40 times search.By contrast,when the standard LAMBDA method without any constraint has been used,there are several epochs in which the correct ambiguity can not be fixed even if the search scope is extended to 2000.4.For the precise positioning of the main antenna of the moving platform,the most important issue remains decomposing ambiguity of baseline composed by master antenna and base station correctly.Track slope constraint and ultra-short baseline ambiguity constraint are added to the multi-antenna positioning model.And LAMBDA algorithm is used to resolve ambiguity.Dual-antennas and triple-antennas mobile platform positioning models are studied in this dissertation.The research results show that,with the increasing of the number of receivers equipped on mobile platform,the success rate of ambiguity resolution increases significantly,and the success rate of ambiguity resolution will be further improved if the trajectory slope constraint is added.The success rate of static and dynamic single epoch ambiguity resolution of the three-antennas mobile platform positioning model can reach 100% and 96% respectively on condition that 7 GPS satellites are observed and slope constraints are added.