Spread Spectrum Signal Waveform Segmentation

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Solution Overview

Problem

Current signal modulation techniques in satellite navigation systems face challenges in achieving high spectral control while maintaining good synchronization capabilities, leading to interference issues and reduced tracking performance due to filtering of secondary lobes.

Innovation Solution

A spread-spectrum signal is generated by combining a first and a second binary waveform at distinct rates, with adjustable amplitudes, allowing for improved spectral isolation and enhanced tracking performance through a real linear combination modulated with a binary sequence, which can include navigation data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If filtering or reducing the secondary lobes of a signal is applied to improve spectral isolation, then spectral control is improved, but synchronisation capabilities and positioning accuracy are degraded

Engineering Contradiction:

Improvespectral interferenceVSAvoidpositioning accuracy

Core Design Contradiction:

Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent segments the spreading waveform into multiple binary waveforms at different rates (first binary waveform at first rate, second binary waveform at second rate). This segmentation allows independent control of spectral components while maintaining synchronization capabilities through the structured combination of segmented waveforms.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a composite spreading waveform by linearly combining multiple binary waveforms with different rates and amplitudes. This composite structure enables simultaneous achievement of spectral isolation (through controlled harmonic content) and synchronization (through maintained waveform structure recognition).

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If using higher number of waveform levels to approach sinusoidal waveform, then spectral power density at carrier frequency is reduced improving spectral isolation, but harmonics are filtered and tracking performances are degraded

Engineering Contradiction:

Improvespectral power density at carrierVSAvoidtracking performance

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent employs dynamic waveform rates, using at least two binary waveforms at distinct rates (first rate and second rate). This dynamic approach allows the signal to adaptively control spectral distribution across different frequency components, reducing carrier frequency power density while preserving tracking performance through the structured rate variations.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies different characteristics to different parts of the waveform by using binary waveforms at different rates. The first binary waveform provides certain spectral characteristics while the second binary waveform at a different rate provides complementary characteristics, achieving local optimization of spectral properties without global degradation of tracking performance.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS8189646B2Spread spectrum signal

Publication Date: 2012.05.29 CENT NAT DETUD SPATIALES (CNES)

AI summary

A spread-spectrum signal comprises a spreading waveform modulating a carrier wave and containing a real linear combination of a first waveform at a first waveform rate and a second waveform at a second waveform rate, the first waveform rate being distinct from the second waveform rate and both waveform rates being distinct and non-zero. The linear combination of the first and the second waveform is modulated with at least one binary sequence comprising a signal identification code.