Sequential Tracking and Offline Demodulation for GPS Signal Robustness

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Solution Overview

Problem

Conventional Satellite Positioning System (SPS) receivers face challenges in providing continuous tracking and demodulation under low signal levels and high signal dynamics, making it difficult to implement adaptive processing schemes in real-time.

Innovation Solution

The solution involves decoupling real-time signal acquisition from offline frequency tracking and demodulation, using a sequential tracking unit with automatic frequency control and offline software demodulation, allowing for variable integration times and robust signal detection, which helps in avoiding False Locks and optimizing performance across varying signal conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional hardware solutions are used for real-time signal processing, then processing speed is maintained, but adaptability to varying signal conditions deteriorates

Engineering Contradiction:

Improveadaptability to varying signal conditionsVSAvoidprocessing scheme complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The signal processing function is segmented into two distinct parts: real-time acquisition processing handled by conventional hardware, and offline frequency tracking and demodulation handled by software. This segmentation allows each part to be optimized independently, with hardware providing speed and software providing adaptability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent replaces complex adaptive hardware processing schemes with software-based offline processing. By substituting mechanical/hardware-based real-time processing with software-based offline processing, the system achieves greater adaptability to varying signal conditions while maintaining processing capability through the separation of real-time and offline functions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If real-time adaptive processing is implemented, then signal tracking accuracy is improved, but processing delay increases

Engineering Contradiction:

Improvesignal tracking accuracyVSAvoidprocessing delay

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The processing function is segmented such that real-time acquisition is handled separately from offline frequency tracking. This segmentation allows real-time tracking to maintain accuracy without the processing delays introduced by complex adaptive algorithms, as the offline processing can analyze accumulated data without compromising real-time performance.

Inventive Principle:

Principle #1Segmentation

3Reliability

If variable integration time tracking is used, then signal detection robustness is improved, but processing complexity increases

Engineering Contradiction:

Improvesignal detection robustnessVSAvoidtracking algorithm complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex real-time adaptive tracking algorithms with software-based offline processing. By substituting hardware-based real-time processing with software-based offline processing, the system achieves greater robustness in signal detection through variable integration time while managing complexity through the separation of processing functions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS8135097B2Sequential tracking and offline demodulation in receiver

Publication Date: 2012.03.13 QUALCOMM INC

AI summary

An apparatus and method for tracking a desired signal by sequentially tracking the desired signal with a variable integration time, performing automatic frequency control of the desired signal, and demodulating the desired signal using offline software. In one aspect, the automatic frequency control is performed using the offline software. In one aspect, the desired signal is from a GPS satellite.