Vertical Positioning Technologies and its Application of Pseudolites Augmentation

GPS has been broadly applied in every fields of our social life, since the environment around us has been becoming more and more complicated, satellite navigation positioning technology under severe geometry, weather and jamming conditions gains more and more attention. However, It is well known that the GPS satellite navigation system lacks vertical information, which results in poor vertical accuracy. On the other hand a pseudolite navigation system provides very good vertical information thus improving the vertical accuracy which is crucial for airplane precision landing. In satellite navigation and positioning applications, pseudolite undertakes two tasks. First, pseudolite can improve range measurement accuracy by elimination the common pseudorange error between the pseudolite site and user. Second, pseudolite can reduce vertical dilution of precision (VDOP) by an additional pseudorange measurement. This paper mainly discuss the principle of pseudolite reducing VDOP and improving vertical measurement accuracy significantly. Also, the estimation of VDOP maximum values is given. With the help of simulation, the simulation results indicate that the augmentation of pseudolite can improve dramatically positioning accuracy, satisfying requirement of civil aviation APV.