GPS Receiver Hibernation Control Using Temperature-Tracked Timing

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Solution Overview

Problem

GPS navigation devices consume excessive power due to limited techniques for maintaining accurate reference frequency and time during hibernation, leading to shorter battery life, as current solutions like TCXO and RTC oscillators face challenges with power consumption and accuracy.

Innovation Solution

Incorporating a temperature recorder circuit and power manager that operate during hibernation to maintain GPS receiver time and reference frequency accuracy, using a time reference device to generate clock signals and a temperature recorder circuit to sense temperature and send wake-up signals to electrical components, such as the GPS signal processing system and frequency reference device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If TCXO is used as frequency reference during hibernation, then reference frequency accuracy is improved, but power consumption increases

Engineering Contradiction:

Improvereference frequency accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The system uses periodic temperature sampling during hibernation to track temperature changes, then periodically wakes up the TCXO only when temperature changes exceed a threshold, rather than keeping it continuously running. This periodic action maintains frequency accuracy while significantly reducing power consumption during stable temperature periods.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The temperature recorder circuit continuously monitors temperature during hibernation in advance, predicting when temperature changes might affect frequency accuracy. This preliminary action allows the system to wake up the TCXO proactively before frequency drift occurs, rather than reacting after accuracy degradation.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If GPS receiver operates continuously to maintain time accuracy, then GPS acquisition performance is improved, but battery life decreases

Engineering Contradiction:

ImproveGPS acquisition performanceVSAvoidbattery life

Core Design Contradiction:

Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The temperature recorder circuit continuously monitors temperature during hibernation in advance, tracking environmental conditions that affect time and frequency accuracy. This preliminary monitoring allows the system to maintain awareness of accuracy-degrading conditions without continuous GPS operation, enabling selective wake-up only when necessary.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses temperature feedback to determine when to wake up the GPS receiver. By continuously monitoring temperature and comparing it against stored baseline data, the system receives feedback about environmental conditions, triggering wake-up events only when temperature changes indicate potential accuracy degradation, thus optimizing the balance between performance and power consumption.

Inventive Principle:

Principle #23Feedback

3Use of energy by moving object

If RTC crystal oscillator is used for time reference during hibernation, then power consumption is reduced, but time accuracy deteriorates due to frequency excursions

Engineering Contradiction:

Improvepower consumptionVSAvoidtime accuracy

Core Design Contradiction:

Use of energy by moving objectVSMeasurement precision

Solution Approach 1:

The temperature recorder circuit acts as an intermediary between the RTC oscillator and the TCXO frequency reference. It monitors temperature conditions and mediates when to switch from the low-power RTC to the accurate TCXO, using temperature as the intermediate parameter to predict when frequency excursions will occur without continuous operation of the expensive TCXO.

Inventive Principle:

Principle #24Intermediary (Mediator)

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 approach reduces power consumption while maintaining accuracy, extending battery life by allowing GPS navigation devices to conserve energy and improve GPS acquisition performance.

Implementation Method 1

The temperature recorder senses the temperature of the time reference device

Methodology Applied

Scientific EffectTemperature sensing:

Data Source

PatentUS8185083B2Systems and methods for managing power consumption

Publication Date: 2012.05.22 QUALCOMM TECH INT

AI summary

GPS navigation devices or GPS receivers can consume less power by using a temperature recorder circuit and/or a power manager in maintaining the accuracies of the GPS receiver time and reference frequency to improve battery life. A representative receiver includes a time reference device and the temperature recorder circuit that operate while the receiver hibernates. The time reference device generates clock signals and the temperature recorder circuit receives and operates using the clock signals from the time reference device. The temperature recorder senses the temperature of the time reference device. The temperature recorder circuit is designed to send a wake-up signal to at least one electrical component of the receiver to wake up the electrical component of the receiver. The electrical component of the receiver includes at least one of the following: a GPS signal processing system and a frequency reference device.