Research On The Layout Technologies Of Ground-Based Navigation System With Base-Station

The new ground navigation system is a new type of radio positioning system which is proposed to overcome the shortcoming of the satellite navigation system composed of base station and user receiving equipment.The positioning accuracy of the navigation system is not only related to the time synchronization accuracy of the base station,the quality of transmitted signal and the processing performance of receiver,but also to the geometric accuracy factor influenced by the layout of the base station.This paper finished the base station navigation system design and optimization of base station layout based on the new ground-based navigation system.The main research is as follows:1 According to the evaluation of the positioning accuracy of ground-based navigation system,this paper proposed the weighted geometric dilution of precision(WGDOP)based on the study of positioning method of ground-based navigation system.For the code phase measurement,the main source of measurement error is the random error caused by the receiver thermal noise and WGDOP can accurately reflect the positioning accuracy of system compared with the traditional GDOP.For the carrier phase measurements,the main source of measurement error is no longer the random error caused by the receiver thermal noise and GDOP can reflect the positioning accuracy of system.2 This paper study the main constraints that affect layout of the base station and finished the analysis and simulation are completed from two aspects of the range and geometry of single station,concluded as follow:(1)The scope of the single station is mainly related to the signal power of the base station,the main lobe width of the antenna,the height of the base station and the sensitivity of the receiver.(2)The user's single point VDOP is inversely proportional to the maximum difference of the base station and the user's height angle sine.(3)When laying out 4 base stations,the symmetrical axis passing the vertex can not exist in the projection of the quadrilateral formed by the base station connection in horizontal plane to make the GDOP non-singular.3 This paper build a specific regional mode for user and proposed method of four-station layout called "two high and two low" and method of five-station layout called "one high and four low" based on regional user base station layout issues.Aiming at the occlusion of obstacles,adaptive genetic algorithm is used to solve the problem of base station layout,so that the positioning accuracy of users in the service area satisfies HDOP?2 and VDOP?6.4 In order to verify the proposed base station layout method,this paper carried out four-station and five-station positioning experiments.The experimental results show that the geometric accuracy satisfies HDOP?2 and VDOP?6,which proves the validity of the two layout methods.