Another additional hurdle , developing tiny gps receiver chips that could be embedded yet still be sensitive enough to receive signals from thousands of miles out in space 而另一个不可忽视的因素则是全球定位系统信息接收芯片，它不但要能植入人体内，并且还应有足够的灵敏度，以接收来自几千英里外的太空定位卫星群发来的信息。
As well known , such performances as accuracy of satellite - based positioning system are heavily dependent on the number and geometric distribution of satellites being tracked , and gdop is a right measure of the geometry of the constellation 卫星定位系统的定位精度,很大程度上取决于定位卫星的数目和几何布局,而gdop正是衡量定位卫星布局优劣的一个量度。
Another additional hurdle , developing tiny gps receiver chips that could be embedded yet still be sensitive enough to receive signals from thousands of miles out in space . in addition to technical hurdles , many suspect that all sorts of legal and privacy issues would have to be cleared as well 而另一个不可忽视的因素则是全球定位系统信息接收芯片，它不但要能植入人体内，并且还应有足够的灵敏度，以接收来自几千英里外的太空定位卫星群发来的信息。
This thesis presents the acquisition method of synchronization codes and time mark codes under - 20db gaussian channel . then the total step length between initial state and current state can be calculated . basing on the step length , we can deduce the current state of pseudo - random codes , and implement the acquisition of the special pseudo - random codes 本文设计出时间标记码在信噪比达- 20dd时的捕获方案，在此基础上提出了由伪码历经的状态数，计算子码当前状态的方法，从而获得了在30秒内完成导航定位卫星信号直接捕获的方法与实现方案。
