Height Coordinate Bias Correction in Satellite Laser Positioning

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Solution Overview

Problem

Satellite/laser positioning systems face reduced accuracy in height coordinate determination due to unavailability of laser signals, particularly in construction applications where obstructions disrupt the line of sight between the rotating laser transmitter and receiver.

Innovation Solution

A height coordinate bias value is maintained during laser signal availability and applied to satellite signal-derived coordinates when the laser signal is unavailable, using a filter processor to generate corrected height coordinates and minimize fluctuations in position determination.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If laser signal is used for height coordinate determination, then measurement precision is improved, but reliability deteriorates due to signal obstructions

Engineering Contradiction:
Improveheight coordinate accuracyVSAvoidsignal availability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The system pre-calculates and stores bias values during periods when laser signals are available. These pre-calculated bias values represent the difference between laser-derived and satellite-derived height coordinates. When laser signals become unavailable, the system applies these pre-stored bias values to correct satellite-derived height coordinates, maintaining accuracy without requiring real-time laser signals.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The bias value acts as an intermediary that bridges the gap between laser signal availability and unavailability. By calculating the bias during laser signal availability and applying it during unavailability, the system mediates between the two signal sources, allowing satellite signals to provide continuous coverage while laser signals provide accuracy calibration when available.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If satellite signals are used during laser signal unavailability, then reliability is improved, but measurement precision deteriorates

Engineering Contradiction:
Improvecontinuous positioning capabilityVSAvoidheight coordinate accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The system changes the parameter being measured from raw height coordinates to bias values (differences between laser and satellite height coordinates). By working with bias values rather than absolute height coordinates, the system can apply corrections to satellite-derived heights, improving precision while maintaining the reliability of continuous satellite signal usage.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP1918732B1Method and apparatus for accurately determining height coordinates in a satellite/laser positioning system
Publication Date: 2011.11.02 TOPCON POSITIONING SYSTEMS INC
  • EP1918732B1 patent drawingFigure 1~2
  • EP1918732B1 patent drawingFigure 3~4
  • EP1918732B1 patent drawingFigure 5A~5B

AI summary

Disclosed is a method and apparatus for processing signals in a satellite/laser positioning system capable of generating location coordinates from received satellite signals and a received laser signal. A height coordinate bias value is maintained by a filter processor during periods when the laser signal is available. The height coordinate bias value represents an estimated difference between a satellite signal derived height coordinate and a laser signal derived height coordinate. During periods when the laser signal is available, the laser signal derived height coordinate is output. During periods when the laser signal is not available, a corrected height coordinate value is generated by applying the height coordinate bias value to the satellite signal derived height coordinate.