GPS Ionospheric Delay Estimation With Single-Channel Power Saving

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Solution Overview

Problem

GPS receivers in power-constrained applications face challenges in managing power consumption due to the need to continuously operate multiple processing chains to compensate for ionospheric delay, which reduces battery life.

Innovation Solution

Implementing a power management system that selectively powers off one of the processing chains (L1 or L2) during ionospheric delay estimation, using the remaining channel's upper and lower sidebands to calculate ionospheric delay, and periodically reactivating the other chain to refine estimates when delay drift exceeds a threshold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If both L1 and L2 processing chains are continuously operated to accurately compensate for ionospheric delay, then measurement precision is improved, but power consumption increases

Engineering Contradiction:

Improveionospheric delay measurement precisionVSAvoidGPS receiver power consumption

Core Design Contradiction:

Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic action by alternating between dual-channel operation mode (both L1 and L2 processing chains active) and single-channel operation mode (one processing chain powered down). The system periodically switches between these modes based on ionospheric activity levels, using the upper and lower sidebands of the active channel to estimate ionospheric delay during single-channel operation, thereby reducing power consumption while maintaining acceptable measurement precision

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent applies partial action by using only the upper and lower sidebands of the active GPS signal channel for ionospheric delay estimation during single-channel operation, rather than requiring full dual-channel processing. This partial utilization of signal components enables the system to achieve functional ionospheric compensation with reduced power consumption

Inventive Principle:

Principle #16Partial or excessive action

2Duration of action of moving object

If one processing chain is powered off to reduce power consumption, then battery life is extended, but ionospheric delay estimation accuracy deteriorates

Engineering Contradiction:

Improvebattery lifeVSAvoidionospheric delay estimation accuracy

Core Design Contradiction:

Duration of action of moving objectVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediary approach by using the upper and lower sidebands of the active channel as substitute measurements for full dual-channel ionospheric delay estimation. These sideband measurements serve as intermediate data that enable reasonable ionospheric delay estimation without requiring both L1 and L2 processing chains to be simultaneously active, thus extending battery life while maintaining acceptable accuracy

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system dynamically changes operational parameters by switching between dual-channel and single-channel modes based on ionospheric activity conditions. When ionospheric activity is low, the system transitions to single-channel mode with sideband-based estimation, accepting reduced precision for extended battery life. When activity increases, the system returns to dual-channel mode to maintain accuracy

Inventive Principle:

Principle #35Parameter changes

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 and extends battery life by accurately estimating ionospheric delay while minimizing continuous operation of both processing chains.

Implementation Method 1

measuring the rate of change of phase differences between two frequency separated GPS signals (e.g., the L1 GPS signal and the L2 GPS signal)

Methodology Applied

Scientific EffectPhase difference measurement:

Implementation Method 2

GPS signals which are transmitted from satellites are subject to ionospheric induced delay effects

Methodology Applied

Scientific EffectIonospheric delay:

Implementation Method 3

the ionospheric delay is estimated based on the rate of change of phase differences between the upper and lower sidebands of the signal in the channel that is powered on

Methodology Applied

Scientific EffectSideband phase difference measurement:

Data Source

PatentUS12566277B2Ionospheric delay measurement for reduced GPS power consumption

Publication Date: 2026.03.03 BAE SYSTEMS INFORMATION ANDELECTRONIC SYSTEMS INTEGRATION INC

AI summary

Techniques are provided for power management of a global positioning system (GPS) receiver. A methodology implementing the techniques according to an embodiment includes calculating a pedestal ionospheric delay based on a phase difference between a first GPS signal at a first center frequency and a second GPS signal at a second center frequency. The method also includes powering off a processing chain configured to provide the second GPS signal. The method further includes calculating, at periodic intervals, a secondary ionospheric delay based on a phase difference between an upper sideband and a lower sideband of the first GPS signal and accumulating differences between consecutively calculated secondary ionospheric delays. The method further includes, in response to the accumulated differences exceeding a threshold value, powering on the processing chain configured to provide the second GPS signal and recalculating the pedestal ionospheric delay.