Method and apparatus for satellite positioning system time resolution

Abstract

A method and apparatus that reduces the number of possible time alignment possibilities to simplify the satellite positioning system time-ambiguity resolution problem is disclosed. The method may include receiving a first signal (160) from a satellite (150) of a first satellite positioning system and receiving a second signal (140) from a satellite (130) of a second satellite positioning system. The first signal can have a first modulation sequence length and the second signal can have a second modulation sequence length different from the first modulation sequence length. The method may also include determining a time offset between the first signal from the satellite of the first satellite positioning system and the second signal from the satellite of the second satellite positioning system based on an estimated propagation delay of the first signal and the second signal. The method may additionally include establishing a position of a satellite positioning receiver (120) based on the time offset.

Description

technical field [0001] The present disclosure relates to satellite positioning systems. More particularly, the present disclosure relates to satellite positioning system time resolution. Background technique [0002] Currently, in the Global Positioning System (GPS), the GPS receiver position can be obtained based on two pieces of information. The first piece of information is the relative propagation delay time of the signals from the different satellites, also called pseudo range. Propagation delays from at least four satellites may be required for three-dimensional spatial positioning. The second piece of information is the position of each satellite when it transmitted its signal. Once this information is available, the system of position equations can be solved. The position equation has four variables: three for the receiver's position (xu, yu, zu) and a fourth for the time offset (Tu) between the receiver's clock and the GSP system clock. Each satellite position ...

AI Technical Summary

Problems solved by technology

A time misalignment of 1ms common to all satellites used would result in a satellite position error of about 4m, which would result in an error of the same order in the receiver position calculation

The second reason is more serious

However, there remains the problem of aligning a given PN sequence starting within a subframe in a 4 second window, which offers 4,000 possibilities

Methods are known that can be used to attempt to resolve this ambiguity, such as that proposed by Mike King in U.S. Patent No. 6,346,911, but may require a significant amount of processing given the large number of temporal alignment possibilities

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