Temperature-Compensated Clock Circuit for Satellite Positioning

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Solution Overview

Problem

Existing mobile wireless communications devices face accuracy issues with satellite positioning when cellular network timing signals are unavailable, leading to prolonged Time To First Fix (TTFF) due to the reliance on inaccurate clock signals.

Innovation Solution

A wireless communications device with a temperature-compensated clock circuit and a clock correction circuit that stores historical correction values, allowing for accurate clock calibration using cellular network timing signals when available, and utilizing these values to correct the satellite positioning clock when signals are unavailable.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the device relies on the temperature-compensated clock circuit without cellular network timing signals, then the device can operate independently, but the clock accuracy deteriorates leading to prolonged TTFF

Engineering Contradiction:

Improveindependent operation capabilityVSAvoidclock accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The system performs preliminary calibration of the temperature-compensated clock circuit against cellular network timing signals when available. Historical correction values are stored in advance and applied later when cellular signals are unavailable, thus preparing the system beforehand to maintain accuracy during independent operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors the clock signal accuracy by comparing it with cellular network timing signals when available. Correction values are generated based on the detected deviations and fed back to adjust the temperature-compensated clock circuit, ensuring ongoing accuracy improvement and maintenance.

Inventive Principle:

Principle #23Feedback

2Measurement precision

If the device uses cellular network timing signals for clock calibration, then clock accuracy is improved, but the device becomes dependent on network availability

Engineering Contradiction:

Improveclock accuracyVSAvoidnetwork independence

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The temperature-compensated clock circuit acts as an intermediary between the cellular network timing signals and the satellite positioning clock circuit. It receives calibration from cellular signals and provides corrected timing to the GPS receiver, enabling network-independent operation with maintained accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If the device implements frequency aiding with cellular oscillator correction, then cellular and GPS reference clock signals are more accurate, but the device complexity increases

Engineering Contradiction:

Improvereference clock signal accuracyVSAvoidclock correction system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system merges the temperature compensation function and the clock correction function into a single integrated temperature-compensated clock circuit. This consolidation reduces the number of separate components and simplifies the overall system architecture while maintaining the dual benefits of temperature stability and network-based accuracy correction.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The temperature-compensated clock circuit serves multiple functions: it provides temperature compensation for the crystal oscillator, receives calibration from cellular network timing signals, stores historical correction values, and provides corrected timing signals to both the cellular transceiver and GPS receiver. This multi-functionality reduces the need for separate dedicated components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution enables faster and more accurate satellite positioning by maintaining clock accuracy even without cellular network timing signals, reducing TTFF and improving overall navigation performance.

Implementation Method 1

a temperature-compensated clock circuit for providing a corrected clock signal

Methodology Applied

Scientific EffectTemperature compensation: Thermal Expansion

Data Source

PatentUS8687645B2Wireless communications device providing temperature-compensated clock correction features and related methods

Publication Date: 2014.04.01 MALIKIE INNOVATIONS LTD

AI summary

A wireless communications device may include a portable housing and a temperature-compensated clock circuit carried by the portable housing. The device may further include a wireless receiver carried by the portable housing for receiving timing signals, when available, from a wireless network, and a satellite positioning clock circuit carried by the portable housing. A clock correction circuit may be carried by the portable housing for correcting the temperature-compensated clock circuit based upon timing signals from the wireless network when available, and storing historical correction values for corresponding temperatures. The clock correction circuit may also correct the temperature-compensated clock circuit based upon the stored historical correction values when timing signals are unavailable from the wireless network, and correct the satellite positioning clock based upon the temperature-compensated clock circuit.