Projective Particle Filter for Multi-Sensor 3D Tracking

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Solution Overview

Problem

Conventional methods face challenges in tracking dim targets in a cluttered background using space-based sensors, as they struggle to estimate the 3D state of moving targets due to atmospheric degradation and require fusion of data from multiple imaging sensors to overcome line-of-sight limitations.

Innovation Solution

A projective particle filter (PPF) method is employed for multi-sensor fusion, which samples a higher-dimensional state space, projects particle data onto an observation space, and combines measurement data to infer higher-dimensional information, enabling 3D target tracking without relying on target detection methods like thresholding, and directly fusing measurements from multiple sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional target detection methods (e.g., thresholding) are used, then the processing is simple, but the tracking accuracy of dim targets in cluttered environments deteriorates

Engineering Contradiction:
Improvetracking accuracyVSAvoidprocessing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent transitions from 2D image plane processing to 3D state space processing. By lifting particles from the 2D observation space to a 3D state space (including range dimension), the system achieves more accurate target state estimation while maintaining computational feasibility through the dimensionality change.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces an intermediate 3D state space as a mediator between the 2D sensor measurements and the final target state estimation. This intermediate space allows for more sophisticated processing that improves tracking accuracy without directly complicating the final output generation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If data from multiple imaging sensors are fused, then the tracking duration and reliability improve, but the device complexity increases

Engineering Contradiction:
Improvetracking reliabilityVSAvoidsensor fusion complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges measurements from multiple imaging sensors by projecting their respective particle representations onto a common 3D state space. This combining approach integrates information from multiple sensors to improve tracking reliability while avoiding the complexity of traditional multi-sensor fusion algorithms.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The 3D state space serves as a universal framework that can accommodate measurements from multiple different imaging sensors simultaneously. This multi-functional approach allows diverse sensor data to be integrated through a single unified processing mechanism, reducing overall system complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Duration of action of moving object

If atmospheric degradation is present, then the measurement quality deteriorates, but the tracking must continue during post-boost phase

Engineering Contradiction:
Improvetracking durationVSAvoidmeasurement quality
Core Design Contradiction:
Duration of action of moving objectVSMeasurement precision

Solution Approach 1:

The patent performs preliminary action by propagating particles through the 3D state space before actual measurement comparison. This predictive approach allows the system to maintain tracking during the post-boost phase by having particle representations ready that can be quickly compared against degraded measurements, extending tracking duration despite atmospheric degradation.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS10535144B1Projective particle filter for multi-sensor fusion
Publication Date: 2020.01.14 LOCKHEED MARTIN CORP
  • US10535144B1 patent drawing
  • US10535144B1 patent drawing
  • US10535144B1 patent drawing

AI summary

A method for multi-sensor fusion using a projective particle filter includes measuring, using a plurality of sensors, data related to one or more objects. A higher dimensional state space may be sampled using particle data. Particle data may be projected onto an observation space to extract measurement data. The measurement data are combined to infer higher-dimensional information. The higher dimensional state space includes presumed information related to one or more states associated with the one or more objects. The higher-dimensional information includes estimated information related to one or more states associated with the one or more objects.