以自主方式提高GPS动态定位精度的新技术研究

With the support of NSF, our group can keep going forward in the front of GPS research area. We not only have done the research of the subject, but also carried out some other related research, and have achieved many results. So we said that the NSF subject is just like a hatcher to hatch some new research results.This subject applying is based on the improvement of GPS positioning precision with C/S code receiver. Just at the beginning of this subject, that is, at May 1, 2000, the US government decided to cancel the SA (Selective Availability) of GPS, to make the C/A code receiver precision be 20 m (2drms) from original 100m. Because the object of the research is to improve the positioning precision of C/A code receiver from 100m to 30m, now the precision has been 20m after SA off, how to do for this subject ? is that necessary to improve C/A code positioning precision at the condition of SA off ? There is a comment on the necessity for DGPS after SA off, which is from the specialists of US ION, which said that the applications of GPS is dependent on the precision, if the precision of 20m is not high enough to satisfy some applications, the DGPS is necessary. So the augment systems of GPS are under deployment. That is to say the research of improving GSP positioning precision is necessary.At the condition of new GPS signals, the research and experiment is continued, and the algorithm is modified and optimized. At fixed points the algorithm of modified ARMA model is tested, the precision is improved up to 5m. In the kinematic tests, the kinematic modified ARMA model is derived, the route approaching method is used, and some good results are achieved..Because the research results have not applied the China Patent, the related papers can not be published. The Patent will be applied in several months.At the support of the NSF, our group have carried out a new research test, position differential test. Position differential technology is a technology problem not solved from 80's in US DGPS researches. The problem is that the users and the reference station should use the same constellation to give the position data, which is different in practical usage. We derived a transform algorithm to transform the pseudorang corrections into position corrections to correct the user's position. The test based on this algorithm has achieved the precision improvement up to 3m, just is the precision of DGPS. This method is suitable to the user position monitoring system, such as vehicle tracking system. In user position monitoring system, the user's positions are corrected at monitoring center, so the user equipment cost is reduced greatly. In the tests, the differential reference station is not only set in monitoring center, but also can be anywhere in the DGPS operation area. If the reference station is not at the monitoring center, there should be the pseudorange corrections receiver at monitoring center, we call it SOFT REFERENCE STATION. The related paper will be published in US ION GPS 2003. The research result has applied a China Invention Patent.The two research results of the subject have applied and will apply the Patent, next is to spread their applications. China government has encouraged the applications of satellite navigation technology, so our research results will have wide application areas..Because the research of improving GPS precision autonomously only improves the precision 2 times after SA off, to use a hardware processor with GPS receiver is not feasible. This algorithm can only be useful in GPS Chip set processor. The position differential technology has filled up a blank of GPS application areas in the world. In user position monitoring system, his method will deduce the system cost 80% with the same precision as DGPS

GPS的应用取决于其精度。世界上以自主方式提高GPS定位精度研究的尚未解决的难点是在线实时数据处理和动态数据处理。本人的前期研究已得到了用变参变阶时变模型解决定点数据在线处理问题，使定位精度由100米提高到25米。本研究将用变参变阶时变模型对速度和加俣冉性谙叽恚岣叨ㄎ痪龋唤惴ㄓ糜布迪忠栽谑澜缤乒悴⒋褡宀敌纬伞