Attitude Sensor Bias Correction via Auxiliary Driftless System

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Solution Overview

Problem

Accelerometer-based attitude sensors experience bias drift over time, leading to errors in pitch and roll measurements, particularly at high latitudes where small errors in pitch and roll introduce large errors in magnetic heading calculations.

Innovation Solution

An attitude sensor system with automatic bias correction, comprising a primary attitude sensor and an auxiliary driftless system, estimates and corrects accelerometer bias using multiple-orientation gravimeters, fluid-based tilt sensors, or reduced-range accelerometers, and microcontroller processing to generate bias-corrected output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If accelerometer-based attitude sensors are used, then pitch and roll measurements can be obtained, but bias drift over time introduces errors in measurements

Engineering Contradiction:

Improvepitch and roll measurement accuracyVSAvoidmeasurement stability over time

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The system continuously monitors accelerometer output and feeds the bias estimate back to correct the measurements in real-time, maintaining accuracy over extended periods without manual recalibration

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The auxiliary sensor system automatically detects and corrects accelerometer bias without requiring external intervention or manual recalibration, enabling the system to self-correct measurement errors

Inventive Principle:

Principle #25Self-service

2Measurement precision

If conventional attitude sensors are used at high latitudes, then magnetic heading can be calculated, but small pitch and roll errors introduce large heading errors

Engineering Contradiction:

Improvemagnetic heading accuracyVSAvoiderror amplification at high latitudes

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The system proactively corrects pitch and roll measurements before they are used to calculate magnetic heading, preventing error amplification rather than correcting it after the fact

Inventive Principle:

Principle #9Preliminary anti-action

3Measurement precision

If accelerometer bias is calibrated under controlled conditions, then initial accuracy can be achieved, but bias drift occurs after calibration

Engineering Contradiction:

Improveinitial measurement accuracyVSAvoidcalibration validity period

Core Design Contradiction:

Measurement precisionVSDuration of action of moving object

Solution Approach 1:

The auxiliary sensor system operates continuously to monitor and correct accelerometer bias, extending the effective calibration period indefinitely through ongoing correction rather than periodic recalibration

Inventive Principle:

Principle #20Continuity of useful action

4Measurement precision

If an auxiliary sensor system is added for bias correction, then measurement accuracy improves, but device complexity increases

Engineering Contradiction:

Improveattitude measurement accuracyVSAvoidsensor system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The auxiliary sensor system serves multiple functions: it provides backup attitude information, detects accelerometer bias, and enables continuous correction, justifying its inclusion through multiple benefits rather than single-purpose correction

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11293778B1Attitude sensor system with automatic accelerometer bias correction

Publication Date: 2022.04.05 TIAX LLC

AI summary

An attitude sensor system with automatic bias correction having a primary attitude sensor wherein the primary attitude sensor comprises at least one accelerometer and an auxiliary sensor system configured to automatically estimate a bias of the accelerometer of the primary attitude sensor such that the resulting error is removed from an output of the attitude sensor system.