导航里什么是冷启动 、热启动、暖启动

Question

如题所述

Answer 1

热启动--GPS**器保存有其最后计算的可视卫星的位置、almanac(历书)和UTC时间，在重启以后，GPS**器以保存的上述内容为基础获取和计算当前卫星的最新位置。
Hot Start - The GPS receiver remembers its last calculated position and which satellites were in view, the almanac used, and the UTC Time. It then performs a reset and attempts to acquire satellites and calculate a new position based upon the previous information. This is the quickest re-acquisition of a GPS lock.

暖启动--GPS**器保存有最后计算的卫星的位置、历书和UTC时间，但保存的内容不是当前可视卫星的数据。GPS**器重启以后尝试去获得当前卫星和信号并计算其新位置。**器基于其最后的位置和历书得以大概知道当前天空中的可视卫星。

Warm Start - The GPS receiver remembers its last calculated position, almanac used, and knows the UTC Time, but not which satellites were in view. It then performs a reset and attempts to obtain the satellite signals and calculate a new position. The receiver has a general idea of which satellites to look for because it knows its last position and the almanac helps identify which satellites are visible in the sky. This takes longer than a Hot Start but not as long as a Cold Start.
冷启动：GPS**器清空了所有历史信息并重启，然后它尝试定位并锁定卫星，由于没有先前信息，这将花去很长的时间。GPS**器采用类似于轮询的方法，从所有的卫星中锁定信号，这将比事前知道该搜索哪些卫星要慢不少。这一类重新获取锁定要花最长的时间。

Cold Start - The GPS receiver dumps all information and resets. It then attempts to locate satellites and then calculate a GPS lock. This takes the longest because there is no known information. The GPS receiver has to attempt to lock a satellite signal from all of the satellites, basically like polling, which takes a lot longer than knowing which satellites to look for. This re-acquisition of a GPS lock takes the longest.
附注：比较和小结
热启动就是启动时可视的卫星信息和之前保存的信息是基本一致的。
暖启动和热启动的区别在于经管也保存了之前的卫星信息，可视搜星的时候可视卫星（当前卫星）并不是以前记忆的信息的卫星，但是保存的历史信息仍然有利于快速定位当前卫星。
冷启动，最好理解，就是在没有历史信息的情况下一个一个轮询的方式搜星定位，所需时间最长。

Answer 2

冷启动：以下几种情况开机均属冷启动。初次使用时；电池耗尽导致星历信息丢失时；关机状态下将接收机移动1000公里以上距离。

温启动：距离上次定位的时间超过两个小时的启动。

热启动：距离上次定位的时间小于两个小时的启动。