GNSS Receiver Timing via Wired Network Synchronization
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Solution Overview
Problem
Consumer-grade GNSS receivers have limited coherent integration time due to unstable crystal oscillators, which restricts their sensitivity and ability to maintain lock with GNSS signals, especially in mobile environments and indoor conditions.
Innovation Solution
A method that uses a wired network with a stable time base synchronized to the GNSS clock to provide accurate timing information to GNSS receivers, enabling longer integration times and improved sensitivity through synchronization with connectivity devices like WiFi transceivers, which act as geolocation beacons, and transmit ephemeris data for rapid satellite signal acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If coherent integration time is extended to improve sensitivity, then sensitivity is improved, but time base stability deteriorates due to crystal oscillator drift
Solution Approach 1:
The system performs preliminary time synchronization by receiving timing information from wired network connectivity devices before GNSS signal acquisition. This preliminary action establishes an accurate time reference that compensates for crystal oscillator drift, enabling extended coherent integration times without losing time base stability. The receiver uses the wired network timing to pre-synchronize its time base, allowing it to maintain stability over longer integration periods.
2Adaptability or versatility
If extensive frequency and code offset search is performed to achieve satellite lock, then acquisition capability is improved, but time is lost
Solution Approach 1:
The wired network connectivity device acts as an intermediary that provides timing information and ephemeris data to the GNSS receiver. This intermediary role allows the receiver to obtain critical satellite information without performing an extensive search, significantly reducing acquisition time. The connectivity device mediates between the GNSS satellites and the receiver, delivering pre-processed timing and orbital data that eliminates the need for exhaustive frequency and code offset scanning.
3Ease of manufacture
If crystal oscillator cost is reduced to make consumer-grade receivers affordable, then device cost is improved, but time base stability deteriorates
Solution Approach 1:
The system uses self-service by leveraging existing wired network infrastructure and connectivity devices that are already present in consumer environments. Instead of requiring the GNSS receiver to independently maintain high-stability time base hardware, it utilizes the timing services provided by the wired network infrastructure. This self-service approach allows consumer-grade receivers with low-cost oscillators to achieve accurate timing through network-provided synchronization services.
Data Source
AI summary
A GNSS receiver communicates with any connectivity device, such as a WiFi device that is, in turn, in communication with a wired network having access to the DTI timing. Such connectivity devices may set their timing and frame synchronization to the DTI and thus serve as Geopositioning beacons, thereby enabling the GNSS receiver to accurately determine its position. The GNSS receiver may also use the DTI timing supplied by such a network to perform relatively long integration time so as to achieve substantially improved sensitivity that is necessary for indoor Geopositioning applications. Furthermore, the GNSS data, such as satellite orbital information, may also be propagated by such devices at high speed. By providing this data to the GNSS receivers via such connectivity devices in a rapid fashion, the GNSS receivers are enabled to receive the transmitted data associated with the satellite without waiting for the GNSS transmission from the satellites.