WLAN Fine Timing Assistance for GNSS Signal Acquisition
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Solution Overview
Problem
Global navigation satellite systems (GNSS) face challenges in acquiring satellite signals in areas with high signal attenuation, leading to prolonged acquisition times or failure, especially in mobile devices that lack precise timing assistance.
Innovation Solution
The provision of fine timing assistance via wireless local area networks (WLAN) synchronizes GNSS receivers by adjusting their clocks using fine time assistance information, reducing the number of code delays to be searched and accelerating satellite signal acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If satellite signal attenuation increases, then the receiver must integrate the received signal over a longer period of time, but this leads to excessively long acquisition time or failure to acquire signals
Solution Approach 1:
The patent applies preliminary action by obtaining coarse timing information from WLAN before GNSS signal acquisition. The mobile device receives timing data from a WLAN access point that has been synchronized to GNSS satellites, allowing the device to pre-adjust its local oscillator frequency and phase. This preliminary timing adjustment reduces the search space for code phase and Doppler frequency, enabling faster acquisition even in attenuated signal conditions without requiring excessively long integration periods
2Measurement precision
If the receiver integrates the received signal over a longer period of time to compensate for signal attenuation, then measurement precision improves, but productivity decreases
Solution Approach 1:
The patent uses WLAN timing information as an intermediary to bridge the gap between the mobile device and GNSS satellites. The WLAN access point acts as a mediator that has already performed timing synchronization with GNSS, and relays this timing information to the mobile device. This intermediary timing reference allows the device to achieve accurate location determination without requiring long signal integration periods, thus maintaining both precision and productivity
3Loss of time
If fine timing assistance is provided via WLAN, then signal acquisition time is reduced, but device complexity increases
Solution Approach 1:
The patent applies universality by utilizing the existing WLAN infrastructure and its timing capabilities for the dual purpose of wireless communication and GNSS timing assistance. The WLAN access point serves both as a communication node and as a timing reference source synchronized to GNSS. This multi-functionality allows the mobile device to leverage already-deployed infrastructure without adding significant complexity, achieving fast acquisition by using the WLAN system for both data and timing reference
Data Source
AI summary
Apparatus and method for providing fine timing assistance to global navigation satellite systems (GNSS) via wireless local area network (WLAN). In one embodiment, a method for synchronizing a global navigation satellite system (GNSS) receiver includes receiving, by a wireless device, via a wireless local area network (WLAN), fine time assistance information transmitted by an assisting device connected to the WLAN. A time value of a GNSS clock of the wireless device is adjusted based on the fine time assistance information. Based on the adjusted time value, GNSS codes of a GNSS positioning signal are acquired by the wireless device.