A - GPS positioning

　　AGPS is a method to assist GPS positioning. AGPS and GPS are the same, only with the help of the network. GPS module must be used for positioning. Without GPS module, this positioning is useless. A-GPS positioning is used to speed up the positioning speed, because of the cold start of GPS, star search speed is very slow (need to head more than 20 satellites one by one search), about 2 minutes to search. Made AGPS positioning can take advantage of the * * * * general positioning of your position, and then send the position through the network to the server, the server according to the location will be at this point through your head satellite parameter (which few, frequency, the information such as location, elevation) feedback to your positioning equipment, equipment of GPS satellite can be targeted to search, At this point your search speed greatly increased, a few seconds can be located.

　　Principle: The receiver receives the GPS satellite broadcast, through the analysis of visible GPS satellite position, distance and other information and the corresponding algorithm to get their own position information.

　　Advantages: Compared with GPS, 1, star search positioning fast, whether it is cold start, hot start, second fixed 2, effectively reduce the power consumption of the device 3, alleviate the weak GPS signal can not locate or reduce the accuracy of the problem 4, the computing ability of the mobile device requirements are lower.

　　Disadvantages :1, must be connected to the Internet, if your device can not access the Internet, or shut down and there is no wifi around, you can not use AGPS to achieve the fixed effect. 2, must have AGPS location server support 3, like GPS, still cannot perfectly solve the indoor (indoor cannot receive GPS signal) positioning problem.

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