Method for calibrating GPS standard time in TD-SCDMA radio communication system
A TD-SCDMA, standard time technology, applied in the field of calibrating GPS standard time, can solve the problem of affecting the receiving sensitivity of A-GPS receiver, the first positioning time, time difference, affecting the accuracy of GPS standard time, etc.
Active Publication Date: 2012-09-05
SPREADTRUM COMM (SHANGHAI) CO LTD
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Problems solved by technology
However, since there is a certain distance between the user terminal and the base station, the signal transmitted by the base station needs a certain transmission delay to reach the user terminal, so the difference between the frame header of the wireless frame obtained by the user terminal side and the actual frame header transmitted by the base station There is a time difference
In this way, there will be a certain error between the GPS standard time on the base station side and the actual GPS standard time on the terminal side, which will affect the accuracy of the GPS standard time obtained by the user terminal, and further affect the reception of the A-GPS receiver in the terminal device. Sensitivity and Time to First Fix
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[0047] Such as Figure 6 As shown, the TD-SCDMA wireless communication system includes a plurality of base stations 10, mobile terminals 30, and wireless network controllers 20, etc., wherein each base station 10 includes a GPS receiver (not shown) to receive GPS satellite signals to realize various Synchronization between base stations. In addition, the mobile terminal has an A-GPS receiver, so it can use relevant information from wireless networks and satellites for GPS positioning.
[0048] As known to those skilled in the art, during the positioning process, there must be such figure 1 As shown in the signal transmission, first, the base station transmits the signal, after the transmission delay T RA , the mobile terminal receives the signal, considering the actual transmission delay (that is, the time difference between the transmission and reception of the terminal), the terminal passes T Rx-Tx After the signal is transmitted, after that, after the transmission delay ...
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The invention discloses a method for calibrating GPS standard time in a TD-SCDMA wireless communication system, which comprises the following steps: firstly, obtaining base station GPS standard time by a mobile terminal which needs positioning, then, obtaining signal round trip time from a base station by a wireless network controller, obtaining receiving and sending time differences from the mobile terminal, calculating signal transmission delay according the time differences, then, sending the signal transmission delay to a corresponding mobile terminal by the wireless network controller, and calculating terminal GPS standard time according to the GPS standard time and the signal transmission delay of the base station by the mobile terminal. More accurate GPS standard time can be obtained on the mobile terminal through transferring measured base station signal transmission delay and calibrating base station side GPS standard time which is obtained by the mobile terminal, thereby thereceiving sensibility of an A-GPS receiver in a terminal device can be effectively improved, and the first positioning time can be reduced.
Description
technical field [0001] The invention relates to the field of TD-SCDMA wireless communication, in particular to a method for calibrating GPS standard time in the TD-SCDMA wireless communication system. Background technique [0002] GPS is a satellite-based positioning system that was originally designed and controlled by the U.S. military and is free for anyone to use. This system is composed of 24 satellites operating in 6 intermediate circular orbits, and the time for one satellite to circle the orbit is close to 12 hours. Each satellite is constantly sending information about the current time, the positions of all satellites, and some related data like almanac and ephemeris. A GPS receiver uses this information to calculate the distance between itself and the satellites. To determine position, a GPS receiver must receive signals from at least three satellites. [0003] Time to First Fix (TTFF) characterizes the time required for the first positioning of the GPS receiver...
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IPC IPC(8): H04B7/26G01S5/02
Inventor 吴涛
Owner SPREADTRUM COMM (SHANGHAI) CO LTD