Research On Improvement Of Ambiguity Resolution With GIF Combination

The research object of this paper is the method of integer ambiguity resolution.First of all,the paper makes a research on the present progress on it,and introduces several common methods and improved methods put forward by scholars for specific application background.The research background of this paper is UAV Landing on Ship.Because of the short landing process and high reliability requirement,after the UAV enters the communication range,initialization must be fast and high accurately completed.To meet the requirement,this paper presents a method of ambiguity resolution with GIF(Geo-Iono-Free)combination,which can make full use of the long baseline observation information to complete the initialization quickly.GNSS observation model is the basis of calculating unknown parameters using satellite observations.In this paper,detailed introduction has made,including the non difference,single difference and double difference observation models.Then,error sources of the models and some corresponding method of correction are also interpreted.Because this paper is to use the observation combination resolute ambiguity,the observation combination theory is one of the research emphases in this paper.This paper gives the definition of combined observation and the general mathematical expression,and analyzes the influence of the combination coefficient on the characteristics of combined observation.Then selects several common combined observations,and makes the introduction of the application.After introducing the combined observation,the introduction on geometry-based model has be done,including single epoch geometry-based ambiguity resolution model,multi-epoch geometry-based ambiguity resolution model and ambiguity integer solution search algorithm.Content described above is the theoretical basis of this paper.Considering the application background,ambiguity resolution with GIF combination has been proposed.In this method,the GIF combination is used to solve the wide lane ambiguity,and the accuracy of the combination is improved by filtering continually.The wide lane ambiguity is used as the observation to accelerate the single frequency ambiguity resolution.This paper introduces the thinking and mathematical model of the method.In order to verify the method feasibility,some experiments have been done and a package of software has been written.Result shows that:(1)The speed of ambiguity resolution with GIF combination is faster than geometry-based model and the phenomenon is more obvious at the long baseline;(2)Compared to the geometry-based model,the success rate of the ambiguity resolution with the GIF combination is not reduced.(3)The speed of ambiguity resolution will be faster along with the filter time increase.In conclusion,compared to the geometry-based model,the resolution method with GIF combination has obvious advantage in initialization speed,and the new method has practical application value.