Study On The Marine Satellite Dynamic Positioning Accuracy Testing Technology

This dissemination discussed the test of marine dynamic positioning accuracy for satellitepositioning equipment, mainly studied processing principle of dynamic accuracy testing data,error sources and processing methods of the dynamic accuracy testing data,and dynamicaccuracy assessment methods. The main work of this dissemination are summarized as follows:Processing of dynamic accuracy testing data were studied. Time system and coordinatesystem used in the dynamic accuracy testing and the conversion between the various systemwere introduced; computer internal time system were synchronized by satellitetiming.Synchronization parameters solving method included first-order polynomial model, thetime synchronization method using before and after data, and the scalar-weighted least squarecombination approach. By these methods the time stamp of the total station measurement ofangle and ranging data were converted to GPS time system.The processing of total station angle and ranging data were studied. The known coordinateof the dynamic test site was passed to the dynamic platform by using the total stationmeasurement data; accuracy assessment method of GPS positioning data was discussed; thewhole processing procedure of dynamic accuracy testing data was given.Error source and response method of dynamic accuracy testing were discussed. From thedynamic test site error, the total station measurement error, and inertial measurement error,system error was analyzed, the error propagation formula was derived, and numerical analysis ofthe actual situation was done; analysis showed that for the dynamic test site error, it was mainlyin basement direction error,numerical calculations showed that in order to improve accuracy thereference point accuracy should be increased and the distance between the reference point andsighting point should be increased, and the latter was more effective and important.For the totalstation measurement error, the impact of instrument calibration error was very small, the errorwas mainly caused by external conditions, of which the most important was the refractive indexerror;for this error the main method was to choose a favorable time of observation; inertialmeasurement error mainly depended on the platform radius and the attitude parameters accuracyof the inertial measurement equipment; numerical calculations showed that for the selectedradius of the platform, and generally priced inertial measurement equipment,the error can bereduced to a negligible extent, so inertial measurement error can be ignored.Experimental analysis was done. Two experiments were designed; experiment one used onetotal station to track the dynamic testing platform, through the comprehensive data processing software, the results of the assessment was given; experiment two used two total station to trackdynamic testing platform, the both assessment results were analyzed comparatively. Finally,three experiments were compared.Dynamic accuracy assessment methods were mainly researched. In order to solve theproblem when assessed the dynamic positioning accuracy of GPS using high-precision totalstation, a new method of dynamic positioning accuracy assessment based on trajectory bias wasproposed,in which the trajectory was acted as assenment element. First，when the trajectory ofGPS and total station was parallel,the proposed method was proved,and when the trajectory wascurve,it was proved simply.And then the implementation steps of the method was proposed.Finally, the experiment result showed that assement result of the proposed method correspondedwith the traditional method,so was the error trendline.All showed that the proposed method waseffective.