Research On The Detection And Repair Methods Of Beidou's High-precision Positioning Mid-cycle

As can compete with the American GPS,one of the world's four major satellite navigation system-the Compass satellite navigation system(Bei Dou Navigation Satellite System,BDS),it is China's own R&D and the navigation is currently the only one with a short message communication function positioning system,in many areas of military,marine,aviation,surveying,transportation,etc.has been widely used.With the continuous advancement of Compass navigation industry,navigation and positioning accuracy and reliability has been more and more attention.Using pseudorange positioning can not meet the requirements of high-precision.Therefore,it is needed to use observations of high precision carrier phase observations to realize position.However,there are questions of cycle slips in carrier phase positioning mode.In this paper,researching on Bei dou carrier phase positioning in the cycle slip detection and repair methods have provided a theoretical reference for high-precision positioning of Compass data preprocessing.On the basis of a single frequency cycle slip detection and repair methods and tri-frequency linear combination of theory,the methods of single-frequency cycle slip detection extended to Compass tri-frequency cycle slip detection and repair,and focus on the small cycle slip detection and repair,the carrier phase in the traditional time-domain cycle slips detection extends to the frequency domain and using the method of signal processing in the frequency domain It was proved that can effectively analyze small cycle slips.The main work in this paper is as follows:(1)For the occurrence of small cycle slips in single frequency carrier phase observations,probed with SVD and Hilbert component envelope transform method can achieve a small cycle slips identification and location.(2)The tri-frequency carrier phase measurements with a combination of features has been studied and tri-frequency combination having a longer wavelength,weaker ionospheric influence,smaller observation noise and other fine features than the single-frequency,significantly improved the quality of data,is helpful to improve the accuracy of cycle slip detection.The tri-frequency pseudorange phase and ionosphere residual method is applied to the tri-frequency carrier phase cycle slip detection,and construct three linearly independent tri-frequency estimations of combined cycle slip,there is no insensitive cycle slip and can be realized any combination of cycle slip detection,and this method ensures the ambiguity combination's whole circumference features.After the cycle slip have been detected,the detected cycle slip values just to be rounded instead of this epoch observations that including cycle slip to complete the cycle slip repair.The method is simple and easily be finished.(3)In order to explore different sampling rates on tri-band estimations of combined cycle slip,select Is,5s,10s,30s and so on BDS observation data from different sampling rate,and applied the triple frequency geometry-free phase and ionosphere residual method to construct a combination of cycle slip test estimation,according to the tri-band combinations cycle slip estimation's characteristics under different sampling rates,optimum sampling rate compass carrier phase observations can be obtained.(4)In order to improve the sensitivity of compass tri-band estimations of combined cycle slips,the use of super wide lane and second epoch difference method for constructing a test of combination cycle slip,the method is suitable for cycle slip detection under the conditions about dramatic changes of ionospheric;in addition,combined with the singularity detection principle,the observations of the cycle slip deemed as a singular point by wavelet transform that can "zoomed" the signal principle,the test of combination cycle slip containing mutation information of cycle slips can be deal with by wavelet decomposition,according to the location of modulus maxima point of the decomposed wavelet coefficients,therefore,positioning the frequency of cycle slip occurrence in triple frequency observation data.