Hyperbolic CORDIC Inclinometer Circuit Accuracy

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Solution Overview

Problem

Existing CORDIC-based inclinometer calculations face errors in arcsine calculations due to double iteration and level shifting requirements, which increase circuit size and calculation time, and are prone to errors in determining resultant vector lengths.

Innovation Solution

A digital circuitry and method utilizing hyperbolic CORDIC calculations with pre-rotations to expand convergence conditions, allowing for accurate arcsine calculations without double iteration or level shifting, and incorporating an Arithmetic Logic Unit for sensitivity, offset, and rotation corrections to improve accuracy in inclinometer calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional CORDIC-based arcsine calculations are used, then calculation can be performed, but errors occur due to double iteration and level shifting requirements

Engineering Contradiction:
Improvecalculation accuracyVSAvoidcalculation reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent changes the calculation parameter from traditional circular CORDIC arcsine to hyperbolic CORDIC arcsine calculation. This parameter change eliminates the need for double iteration and level shifting operations, thereby removing the source of calculation errors while maintaining computational functionality.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If double iteration and level shifting are implemented, then arcsine calculation coverage is improved, but circuit size and calculation time increase

Engineering Contradiction:
Improvecalculation coverageVSAvoidcircuit size
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts and removes the unnecessary double iteration and level shifting operations from the CORDIC calculation process. By eliminating these redundant steps, the circuit complexity is reduced while the hyperbolic CORDIC method inherently provides adequate calculation coverage for inclinometer applications.

Inventive Principle:
Principle #2Taking out (Extraction)

3Adaptability or versatility

If double iteration and level shifting are used, then calculation range is expanded, but calculation time increases

Engineering Contradiction:
Improvecalculation rangeVSAvoidcalculation time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The patent changes the computational parameter from circular to hyperbolic CORDIC arcsine calculation. This parameter change reduces the number of iterative steps required while expanding the effective calculation range through pre-rotation techniques, thereby decreasing calculation time without sacrificing adaptability.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If sensitivity and offset corrections are added, then measurement accuracy is improved, but device complexity increases

Engineering Contradiction:
Improveinclinometer accuracyVSAvoidcircuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary correction actions for sensitivity and offset errors before the main CORDIC calculation process. By performing these corrections in advance using the Arithmetic Logic Unit, the main calculation path remains simple while achieving high measurement accuracy through pre-conditioning the input data.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3314204B1Digital circuitry and method for calculating inclinometer angles
Publication Date: 2020.08.05 MURATA MFG CO LTD
  • EP3314204B1 patent drawingFigure 1~2
  • EP3314204B1 patent drawingFigure 3~4
  • EP3314204B1 patent drawingFigure 5~6

AI summary

A method is disclosed for performing calculations for an inclinometer device, as is a digital circuitry for performing such calculations. The circuitry comprises an interface for receiving detection signals from a sensor device and a CORDIC unit for performing calculation of inclinometer output values characterizing a resultant vector. The CORDIC calculation unit is configured to perform a calculation for resolving the angle between a resultant vector and a programmable reference value using hyperbolic CORDIC calculation. Pre-rotation may be performed for a vector before hyperbolic CORDIC arctangent calculation phases.