Research And Design Of Pseudolite In-door Positioning Navigation System

Global navigation satellite system (GNSS) is a space based wireless positioning system. Anywhere on the earth, whenever the user received signals of GNSS satellites perfectly, the user always can locate him. For these positioning systems using wireless signal, the attenuation of signal is an unavoidable obstruction. So, when the signal arrived at the ground, the navigation signals from satellites are easy to be obstructed by the buildings, tree, wall and so on. In some situations, such as urban canyons, positioning in valleys and in deep open-cut mines, because the navigation signals usually are not able to be received, it will bound the application of satellite navigation technique more or less. Now, this problem can be solved by a new navigation technology that is pseudolite positioning technique.Pseudolites have many advantages, such as strongly anti-jammiing, flexible configurations and low cost. It is established that the pseudolites can increase the number of satellites and improve the geometric strength of positioning solutions. And the usage of pseudolites can enhance the accuracy, integrity and availability of GNSS. It also can extend the application field in which is not possible with satellite-only GNSS, such as city valleys and indoors. The emphasis in this work has been placed on:First, in this research, the principle and structure of pseudolite signals were analyzed. The navigation message for pseudolite was been designed and improved, because we want to get the measurements from an ordinary business hardware receiver. All of these were basic design of the pseudolite hardware and circuit.Then, based indoor positioning requirements, a program of low-cost pseudolite design was proposed, and through the spectrum analyzer and the receiver, the designed pseudolite signals can be captured and tracked stable. These were as a basis of indoor positioning hardware. An algorithm used in the system was analyzed and derived as the position method, which can deal with the receiver output measurement information and obtain the results .Meantime the design of pseudolite distributing and the constitute of the in-door network is considered to improve the accuracy. Finally, in the laboratory, an experiment was conducted for static and dynamic positioning to test the signal transmission and system design.