论文部分内容阅读
1 GPS的军用与民用之间的矛盾美国国防部(DOD)看来已不能阻挠进一步开发商用GPS即差动GPS(DGPS),这对那些打GPS主意的公司是个好兆头,但也带来了严峻的保密问题。 DGPS的原理很简单:GPS接收机参考点具有已知精确的全球位置,GPS用户可以利用这些参考点对导致性能降低的因素进行校正,如对流层干扰和天电干扰。使用INMARSAT(国际海事卫星组织的通讯服务)传输数据可将GPS地面站的覆盖面扩大到2000km之远。标准定位服务(SPS)用户的接收机上没有能利用精度15m以下的精确定位服务(PPS)
1 Conflicts between Military and Civil GPS The DOD seems unlikely to stop further development of commercial GPS or differential GPS (DGPS), which bodes well for companies that are guessing GPS but also brings Severe confidentiality issues. The principle of DGPS is simple: The GPS receiver reference points have known, well-known global locations that GPS users can use to correct for performance degradation factors such as tropospheric interference and antenna interference. The use of INMARSAT (the International Maritime Satellite Organization’s communications service) to transmit data can extend the coverage of GPS ground stations up to 2000km. Standard Positioning Service (SPS) users do not have the ability to use Precise Positioning Service (PPS) at receivers of up to 15m accuracy