Temporal Nuller for GPS Narrow Band Interference Rejection

Solution Overview

Problem

Conventional GPS receivers face significant complexity and processing power requirements when attempting to remove narrow band interference/jamming power, which degrades navigation performance, especially in dynamic engagement scenarios.

Innovation Solution

A device and method that form a narrow band null in the GPS signal by splitting the input signal into multiple paths, introducing a fixed delay, and adjusting the phase shift to reject interfering frequencies, allowing the receiver to operate accurately even in the presence of jamming signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Fourier transformations or complex techniques are used to remove narrow band interference in the digital domain, then interference removal effectiveness is improved, but device complexity and processing power requirements increase significantly

Engineering Contradiction:

Improveinterference removal effectivenessVSAvoidprocessing complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential function needed for interference removal - creating a temporal null at the specific jamming frequency - rather than applying comprehensive digital signal processing. By using a simple delay line to create a notched filter effect, the system removes interference without the complexity of Fourier transformations, achieving the desired reliability with minimal processing overhead

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces expensive, complex digital processing resources with a simple, low-cost temporal nulling mechanism. The delay line-based approach uses minimal computational resources and can be implemented with basic circuitry, effectively trading a sophisticated but resource-intensive solution for a simple, lightweight alternative that achieves sufficient interference removal

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If conventional digital domain processing is used to remove narrow band interference, then interference rejection is improved, but processing power consumption increases

Engineering Contradiction:

Improveinterference rejectionVSAvoidprocessing power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent extracts only the essential function needed for interference removal - creating a temporal null at the specific jamming frequency - rather than applying comprehensive digital signal processing. By using a simple delay line to create a notched filter effect, the system removes interference without the complexity of Fourier transformations, achieving the desired reliability with minimal processing overhead

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces expensive, complex digital processing resources with a simple, low-cost temporal nulling mechanism. The delay line-based approach uses minimal computational resources and can be implemented with basic circuitry, effectively trading a sophisticated but resource-intensive solution for a simple, lightweight alternative that achieves sufficient interference removal

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 efficiently removes narrow band interference, enhancing GPS tracking accuracy and reducing processing complexity, enabling the GPS receiver to function effectively in jamming environments with improved signal integrity.

Implementation Method 1

at least one time delay device located within the first signal path, said at least one time delay device operative to introduce a time delay between a signal at an output of the at least one time delay device relative to a signal at an input of the at least one time delay device

Methodology Applied

Scientific EffectTime delay:

Implementation Method 2

an adjustable phase shifter in the first signal path. The phase shifter enables a frequency at which the null appears to be adjusted

Methodology Applied

Scientific EffectPhase shift:

Implementation Method 3

The output of the first signal path is combined with the output of the second signal path to form a narrow band null

Methodology Applied

Scientific EffectInterference cancellation: Interference

Data Source

PatentUS8159390B2Temporal CW nuller

Publication Date: 2012.04.17 RAYTHEON CO

AI summary

A temporal nuller for removing or minimizing narrow band interference/jamming power from a global positioning system (GPS) receiver's input includes a first signal path having a first input and a first output, at least one time delay device and an adjustable phase shift device located within the first signal path, and a second signal path having a second input and a second output. The first signal input is connected to the second signal input, and the first signal output is connected to the second signal output. Further, the at least one time delay device is operative to introduce a time delay between a signal at an output of the at least one time delay device relative to a signal at an input of the at least one time delay device.