Compressed-Domain Star Tracking for Low-Memory Attitude Estimation

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Solution Overview

Problem

Current star-tracking systems require large amounts of memory and processing power to accurately determine the attitude of an object based on starfield images, which can be costly and power-intensive, especially in radiation-hardened environments.

Innovation Solution

The implementation of compressive sampling techniques to capture and process starfield image data in a compressed domain, reducing memory and processing requirements while maintaining accuracy, by identifying star positions and estimating attitude using fewer measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional star-tracking systems acquire and store large numbers of starfield images in memory, then measurement precision of attitude is improved, but memory requirements and processing power increase prohibitively

Engineering Contradiction:
Improveattitude estimation accuracyVSAvoidmemory usage
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent extracts only the essential information from starfield images by applying compressive sampling techniques that capture the most significant features while discarding redundant data. This allows attitude estimation to be performed on compressed representations rather than full-resolution images, dramatically reducing memory requirements while maintaining measurement precision.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system changes the parameter representation of starfield data by transforming images into a compressed domain using specific sampling matrices and reconstruction algorithms. This parameter transformation enables the same attitude information to be extracted from fewer, more efficiently encoded measurements.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If traditional systems process and average multiple starfield images to improve quality, then measurement precision is improved, but processing power and energy consumption increase

Engineering Contradiction:
Improvenoise reduction qualityVSAvoidprocessing energy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent applies compressive sampling as a preliminary action before full image processing. By pre-processing the starfield data through compression and noise filtering in the compressed domain, the system eliminates the need for computationally intensive averaging of multiple full-resolution images, significantly reducing energy consumption while maintaining noise reduction quality.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If radiation-hardened memory and circuits are used to protect against computational errors, then reliability is improved, but cost and processing limitations increase

Engineering Contradiction:
Improveradiation resistanceVSAvoidsystem cost and processing limitations
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies partial processing by performing attitude estimation directly on compressed data without fully reconstructing the original images. This partial action approach reduces the computational burden on rad-hard systems, allowing them to operate within their limited processing capabilities while maintaining reliability through error-correcting codes and robust algorithms designed for compressed sensing.

Inventive Principle:
Principle #16Partial or excessive action

4Measurement precision

If full-resolution starfield images are stored and processed, then measurement precision is improved, but input/output bandwidth and memory requirements increase

Engineering Contradiction:
Improvestar position accuracyVSAvoiddata storage volume
Core Design Contradiction:
Measurement precisionVSQuantity of substance

Solution Approach 1:

The patent creates a compressed copy of the starfield data that preserves the essential information needed for attitude estimation. This compressed representation serves as a surrogate for the full-resolution images, enabling accurate star position determination with dramatically reduced data storage volume and I/O bandwidth requirements.

Inventive Principle:
Principle #26Copying

Data Source

PatentUS8472737B2Attitude estimation in compressed domain
Publication Date: 2013.06.25 THE CHARLES STARK DRAPER LABORATORY INC
  • US8472737B2 patent drawing
  • US8472737B2 patent drawing
  • US8472737B2 patent drawing

AI summary

In general, in one embodiment, a starfield image as seen by an object is analyzed. Compressive samples are taken of the starfield image and, in the compressed domain, processed to remove noise. Stars in the starfield image are identified and used to determine an attitude of the object.