Positioning Device Clock Synchronization via Telecommunications Network Strobe
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Solution Overview
Problem
Current mobile phone GPS systems face challenges in reducing the time to first fix (TTFF) due to inaccurate quartz oscillators and the difficulty of synchronizing clocks using a fourth satellite, especially in urban areas where signal strength and visibility are limited, leading to delays and disruptions during emergency situations.
Innovation Solution
A method and device that request a reference time value from a digital telecommunications network to synchronize the positioning receiver's clock, using a comparator to generate a timing strobe at a predefined counter value, allowing for parallel assistance data reception and reducing latency, thereby improving clock synchronization and resilience to cellular handovers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the GPS receiver is switched off for most of the time to save battery capacity, then power consumption is reduced, but the time to first fix (TTFF) increases
Solution Approach 1:
The patent applies preliminary action by pre-synchronizing the GPS receiver clock with telecommunications network timing before GPS signal acquisition. The receiver obtains timing reference from the cellular network's synchronized timing structure, preparing the clock in advance so that when GPS signals are acquired, the receiver is already time-aligned, reducing TTFF without requiring continuous operation
2Measurement precision
If a fourth satellite is used to synchronize the clocks, then clock synchronization accuracy is improved, but the complexity of implementation increases and reliability decreases in urban areas
Solution Approach 1:
The patent uses the telecommunications network as an intermediary to provide timing synchronization. Instead of relying on a fourth GPS satellite, the receiver uses the cellular network's synchronized timing infrastructure (which itself is synchronized to GPS time) as a mediator to transfer precise timing reference to the GPS receiver, bypassing the need for direct satellite visibility
Solution Approach 2:
The patent replaces the mechanical/GPS-based clock synchronization method (requiring satellite signals) with an electromagnetic-based telecommunications network timing system. The cellular network's timing structure, carried via radio signals, substitutes for the traditional GPS satellite signal-based synchronization, providing a more reliable path in urban environments
3Device complexity
If the GPS receiver clock is not synchronized accurately, then device complexity is reduced, but the productivity of location determination decreases
Solution Approach 1:
The patent applies self-service by having the GPS receiver automatically obtain timing synchronization from the telecommunications network without requiring complex external synchronization equipment or manual intervention. The receiver independently accesses the network's timing reference and self-synchronizes its clock, maintaining simplicity while enabling fast location determination
Data Source
AI summary
A positioning unit and telecommunications unit wherein a reference time value from is requested from a telecommunications network to start the positioning receiver. A strobe is scheduled to be transmitted from the telecommunications unit to the positioning receiver when the positioning receiver is armed. A current and predefined value of the counter is compared and the strobe is generated when the counter current value equals the predefined value. The strobe time of generation is recorded in relation to a structure of the signal transmitted by the digital telecommunications network in the current serving cell. The reference time value from the telecommunications network is received, wherein the reference time value is related to a structure of the signal transmitted by the network. The accurate time of generation of the strobe based on said reference time value is calculated transmitted to said positioning unit.