GNSS Optimized Combinations And Application On Cycle-slip Detection

With the rapid development of satellite navigation system,multi-frequency GNSS solution will become a norm,it is generally believed that multi-frequency data to improve the reliability of the positioning solution is expected to speed up the convergence speed of ambiguity fixed,but multi-frequency GNSS solution The advantages of this is not entirely clear,this article for the tri-band data combination in the cycle jump detection and repair applications discussed,mainly including the following five aspects:1.Geometric model of combined observationsThe basic observation equation contains multiple error terms,and it is often difficult to balance the weights of the errors when selecting the combination coefficients.Different applications often require different combinations of features,and the commonly used algebra models often focus on a certain requirement The number of combinations in the field,it is difficult to reflect the link between all the combinations and contradictions,with the navigation satellite to provide the number of frequency points,algebra combination model of the limitations will be more obvious.In order to solve the problem of optimal selection of tri-band data,this paper constructs a three-dimensional geometric model of tri-band data combination,uses space coordinate system to represent all possible combinations,and transforms the algebraic model of observation quantity into geometric model.The combination of the characteristics of the combination of the use of coordinate points described,intuitive description of the different characteristics of the distribution of the coefficient of distribution area,will facilitate the analysis of these combinations of sets of contradictions and links between the preferred cycle for the detection and repair of the combination of the provision of the basis The2.Cycle slip detection model based on combined observationsBased on the analysis of the traditional cycle jump detection method,the limitation of the cycle jump detection method is clarified,and the evaluation index of the cycle jump detection algorithm is proposed to describe the influence of the cycle jump.The Limitations and Advantages of Detection Algorithm.In order to solve the problem of threshold,this paper takes the practical application demand as the guidance to determine the threshold,ensures the reliability of the algorithm,avoids the ambiguity of the whole cycle of the "pseudo cycle jump",and balance the contradiction between the threshold and the insensitive week The large threshold guarantees the reliability of the cycle jump detection,and improves the completeness of the algorithm on the basis of satisfying the reliability.Based on the combination of the amount of cycle jump detection algorithm with high precision,real-time characteristics,and for single-station data processing,the main reason is that there is insensitive week jump.In this paper,three-dimensional geometric model is used to describe the causes of the non-sensitive cycle slip,and its distribution range and regularity.The model is verified by the actual observation data,and the common combination observations In the range of a certain coordinate within the insensitive week jump,so in the threshold to determine the conditions,how to reduce or eliminate the insensitive cycle is the cycle of jump detection algorithm optimization of the main direction,in addition to the cycle of the repair is built on the cycle of jump detection On the basis of it can be regarded as the reverse solution process of the cycle jump detection,so the study of the non-sensitive week jump is also prepared for the cycle of the cycle to find the part of the solution.3.Optimization model of multiple carrier phase combinations on cycle slip detectionAt present,the use of multiple GF combination of joint detection cycle of the solution,and too much GF combination will cause greater pressure to calculate,and detect the effect of insensitive weeks is not clear.In this paper,based on the combined observation of the weekly jump detection model,this paper analyzes the geometrical principle of multiple GF combinations to detect the cycle slip.The principle of increasing the amount of GF combination can reduce the insensitive week The number of GF combinations is proved by two experiments,and the number of GF combinations is proved to be appropriate.The selection of the coefficients of the two GF combinations determines the effect of detecting the insensitive week slip.In this paper,the linear model of the coefficient and the number of non-sensitive weeks is constructed by analyzing the cross section of the common non-sensitive circumference distribution area.The optimal conditions of the GF combination are deduced by this model,and the conditions 2 GF combinations,the Beidou tri-band measured data validation,select the two GF combination of obvious advantages,consistent with the theoretical analysis.For non-sensitive weeks of multiple GF combinations,this type of insensitive week is not sensitive to most combinations.In this paper,we analyze the causes of this kind of "stubborn" insensitive week jumps,and propose the coefficient optimization model for the specific insensitive week slip.We choose the combination coefficient which is sensitive to it,and the combined coefficient can be valid Detects a specific insensitive cycle slip,and the coefficient optimization model is suitable for cycle slip caused by ionospheric scintillation.4.Use the pseudorange phase combination to optimize detection algorithmThe coefficient optimization model for specific insensitive weekframes can effectively solve the individual problems in the "stubborn" insensitive weekfinding,and can not fully detect such "stubborn" insensitive weekframes,nor can it complete the week slip repair.In this paper,we introduce the pseudorange phase combination as the combination of the third combination and the carrier phase combination to detect the cycle slip.In this paper,we analyze the geometrical principle of the pseudo-range phase combination to detect the cycle slip,and theoretically verify that the pseudo-And the combination of the pseudo-range combination and the carrier phase combination is used to detect the influence of the non-sensitive cycle slip in the limited range.The principle of combined detection of the pseudo-range phase combination and the carrier phase combination is studied in the geometric model.The optimization scheme is proposed and the pseudo-phase combination is selected to verify the optimization effect.The experiment shows that after the MW combination is not sensitive There is only one jump,so in the search cycle integer integer solution,if the threshold is set to 1 times the error,only a single integer node.5.Use combined observations to repair cycle slipIn view of the high reliability required to repair the cycle jump,this paper first obtains the estimated value of the cycle slip,and then obtains the integer solution of the cycle slip.Firstly,we use the probing amount of the cycle jump to find the estimated value of the cycle,that is,the spring jump based on the principle of the cycle jump detection.By means of three sets of simultaneous detection equations,The accuracy range of the evaluation is analyzed in the three-dimensional coordinate system,and the optimal combination quantity is verified to be the condition of the periodic jump.In the search area traversal search all possible integer nodes,and verify that the search of the integer node to meet the requirements of the repair cycle,repair weeks after the calendar residuals must be less than double the error,to ensure that after the repair cycle Of the observed value of the sequence does not exist gross error,and there are a number of conditions to meet the true value of the repair will not be guaranteed to ensure the reliability of the repair algorithm,and finally by the Big Dipper measured data to verify,join the week jump are correct repair,Multiple truths.The experimental results show that the method has high success rate and has good reliability.