Research On The Method Of Combined Positioning Based On DTMB-GNSS

Among the complex urban environment, the number of satellites and its geometry graph structure observed by Global Navigation Satellite System (GNSS) receiver is not clearly, moreover, GNSS is easy to be effected by some factors such as sun magnetic storm, manmade interference, so it can not satisfy the accurate positioning depending on GNSS system in the complex urban environment.This paper is a sub subject of the research on digital TV ground broadcasting positioning technology based on DTMB standard which is the talent culturing plan of western light as CAS, it mainly takes the digital TV base station as one kind of fake satellite enhanced system, which use the digital TV signal and GNSS unite measure distance and positioning method to solve the problem like accurate positioning in the urban environment. This research will fill the blank of our digital TV navigation enhanced technology. It is very meaningful to enlarge the function and performance of our GNSS system navigation positioning. The concrete work as following:At first, it analyzes the DTMB system structure and signal frame structure, and takes an example as PN420 mode to research the relationship of signal frame head original phase; building the model of DTMB-GNSS combined positioning and analyzing the function. Second, it analyzes the principle of measuring the fake distance of DTMB, it proposals an acquisition and tracking method based on DTMB digital TV signal, and it also verifies the theory with Matlab. Taking examples from GNSS,it researchs position algorithm of combined positioning,and uses linear iterative method to solve position equation,it also verifies the theory and convergence with Matlab.At last, it builds the combined positioning system measurement platform by choosing China area positioning system (CAPS). It implants the site measurement in Xi'an city, and it draws and analyzes the positioning target practice graph with the real test data.The experiment result indicates that it can realize the fake distance measurement with DTMB; at the same time, it can carry out the accurate positioning by adopting DTMB-GNSS combined system in the complex urban environment.