GPS Receiver Time Acquisition Algorithm for Low-Power Watches

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Solution Overview

Problem

Conventional GPS receivers designed for position determination are power-intensive and not optimized for low-power timekeeping applications, such as wristwatches, where they consume excessive energy and are not suitable due to their focus on navigation rather than time reporting.

Innovation Solution

A GPS chip optimized for timekeeping applications, which reduces power consumption by minimizing necessary components and processing elements, using a local oscillator to predict GPS message arrival and provide periodic time updates to calibrate internal oscillators, allowing for accurate timekeeping with reduced semiconductor area and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a conventional GPS receiver designed for position determination is used, then positioning accuracy is improved, but power consumption increases excessively

Engineering Contradiction:

Improvepositioning accuracyVSAvoidpower consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent extracts and removes unnecessary components and processing elements from the conventional GPS receiver that are not required for timekeeping applications. Specifically, it eliminates position calculation modules, navigation algorithms, and other functionality beyond time acquisition, thereby reducing power consumption while maintaining accurate time reporting

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The GPS receiver is segmented into essential timekeeping functions versus optional positioning functions. The patent implements only the critical time acquisition and synchronization components, separating these from the full positioning suite, which enables low-power operation for dedicated timekeeping applications

Inventive Principle:

Principle #1Segmentation

2Adaptability or versatility

If a GPS receiver optimized for navigation is used, then positioning capability is improved, but device complexity increases

Engineering Contradiction:

Improvenavigation capabilityVSAvoiddevice complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes navigation-related components and processing logic from the GPS receiver, retaining only the essential time acquisition and synchronization functionality. This reduces device complexity while maintaining adaptability for timekeeping applications

Inventive Principle:

Principle #2Taking out (Extraction)

3Adaptability or versatility

If a full-featured GPS chip is integrated into a timepiece, then positioning functionality is improved, but semiconductor area increases

Engineering Contradiction:

Improvepositioning functionalityVSAvoidsemiconductor area

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

The patent extracts and removes positioning-related hardware components from the GPS chip integration, retaining only the essential time acquisition and synchronization circuitry. This reduces the semiconductor area occupied while maintaining positioning functionality for timekeeping purposes

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS7920441B2Optimized time acquisition algorithm for low-power GPS-based watch applications

Publication Date: 2011.04.05 QUALCOMM INC

AI summary

A GPS enabled timepiece. A Global Positioning System (GPS) enabled timepiece in accordance with the present invention comprises a timepiece, the timepiece comprising a local oscillator, and a GPS receiver, coupled to the timepiece, the GPS receiver using the local oscillator to predict a time arrival of a GPS message from a GPS satellite, wherein the GPS receiver is powered on based on the predicted time.