论GPS星座组成及若干抗AS方案

Discussion on Formation of GPS Constellation and Some Schemes to Anti -AS

本文首先讨论GPS星座组成及美国的用政策，阐述了AS措施及其对GPS测量的影响。然后，对抗AS的若干方案进行介绍，分别对平方法、互相关法、码相关干法及P－W技术（Ashtech法）进行叙述和评论，指出它们的优缺点，评述它们在GPS技术发展过程所起的作用。最后，对GPS星座建成后的形势作了小结，并对当前我国GPS事业的有关问题提出四点建议。

Above all, this paper to discuss the formation of GPS constellation and the AS policy in US, to expound the AS measures and Its effect on GPS surveying. Then, to introduce some schemes of AS - resistant. The method including square, cros s-correlation, code - correlation square and P - W technique (Ashtech method) are reviewed, pointed out theirs advantage and shortage, and reviewedtheirs role in the development of GPS technique. Lastly, the paper presents a briefsummary on the situation after that a GPS constellation is built, and makes four suggestions on relative problem for the cause of GPS, at present in our country.