正在尴尬之际,又豁然发现我这个10公里误差处文字的颜色不同,好像是链接。点开一看果然链向: http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/gps.html。该网页豁然写着:【This sounds small, but the high-precision required of the GPS system requires nanosecond accuracy, and 38 microseconds is 38,000 nanoseconds. If these effects were not properly taken into account, a navigational fix based on the GPS constellation would be false after only 2 minutes, and errors in global positions would continue to accumulate at a rate of about 10 kilometers each day! 】 (这听起来小,但GPS的高精度要求纳秒级的准确度,而38微秒是3万8千纳秒。如果这些效应没有考虑,GPS定位两分钟后就不行了,误差将以每天10千米的速度累积!) (注一)
再追踪发现这个网页的作者是 Richard W. Pogge, 乃俄亥俄州立大学天文系教授,专业方向是活跃星系核以及气体星云的天体物理。