The NLOS Error Mitigation Joint Algorithm in Hybrid Positioning System Combining DTMB and GPS

Abstract

The increasing demands of position information have made the wireless location technology catch more and more attention nowadays. GPS (Global Positioning System) which has been widely used cannot localize successfully indoors and among buildings, its defects are increasingly prominent. Given the acceptable terrestrial digital television signals anytime and anywhere, as well as the advantages of high transmission power, low operating frequency and strict synchronization with absolute time, it is possible to achieve accurate positioning by Digital Television Terrestrial Multimedia Broadcasting (DTMB) and GPS. Electromagnetic waves have to propagate by deflection, refraction and scattering because of the obstructions in the surroundings of transmitting, we call it as Non-Line of Sight (NLOS) propagation, which results in NLOS errors [1]. In this paper we take some further study on the method of NLOS error mitigation based on the hybrid positioning system combining DTMB and GPS in view of a large number of obstacles in the urban environment. This algorithm, referred to as Range Dynamic Compensation and Linear Line of Position Joint Algorithm, can predict the next position of the object, which can be used to compensate the actual measured value for the purpose of reducing the NLOS errors. The Linear Line of Position Algorithm which utilizes the linear statistical location techniques straightforward rather than linearizing the system roughly is then applied to simplify the position coordinates calculations as well as mitigate the residual NLOS errors. The simulation testing result indicates that this joint algorithm significantly improved the location precision in areas with serious NLOS contamination.