Absolute-Distance Multilateration for Self-Calibration
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Solution Overview
Problem
Existing multilateration systems face accuracy issues due to angle information resolution limits, leading to decreased measurement precision, and the estimation of system parameters in relative distance measurement methods is often inaccurate with no systematic method for determining initial values, resulting in convergence failures or local minimums during optimization.
Innovation Solution
A multilateration system using absolute distance measurement for self-calibration, which includes a tracking unit with multiple tracking devices and a control calculation part for dead path estimation and position calculation, employing nonlinear optimization to accurately determine the central positions of tracking devices and object coordinates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If distance information only is used for multilateration, then angle measurement resolution limits are avoided, but system parameters estimation accuracy decreases due to simultaneous estimation requirements
Solution Approach 1:
The patent segments the parameter estimation process into two distinct stages: first estimating dead path parameters using absolute distance measurements, then estimating tracking device position parameters using the pre-obtained dead path values. This segmentation reduces the number of parameters estimated simultaneously, improving both measurement precision and estimation reliability.
Solution Approach 2:
The patent performs preliminary estimation of dead path parameters before estimating the tracking device position parameters. By obtaining dead path values first through absolute distance measurements from at least four tracking devices to a reference object, the system establishes a foundation that improves the accuracy of subsequent position parameter estimation.
2Reliability
If simultaneous estimation of system parameters is performed, then complete calibration is achieved, but convergence failure or local minimum occurs due to lack of systematic initial value determination
Solution Approach 1:
The patent performs preliminary estimation of dead path parameters before estimating the tracking device position parameters. By obtaining dead path values first through absolute distance measurements from at least four tracking devices to a reference object, the system establishes a foundation that improves the accuracy of subsequent position parameter estimation.
Solution Approach 2:
The patent changes the estimation sequence and reduces the number of parameters estimated at each stage. First, dead path parameters are estimated using absolute distance measurements, then position parameters are estimated using the pre-obtained dead path values. This parameter change strategy prevents optimization convergence issues.
Data Source
AI summary
In a multilateration system based on an absolute distance measurement and a multilateration method using the multilateration system, the multilateration system is configured to obtain spatial coordinates of an object moving in a space. The system includes a tracking unit having a plurality of tracking devices, and a control calculation part having a dead path estimation part and a tracking device position calculation part. The tracking devices are positioned differently with each other and each of the tracking devices measures a distance to the object. The dead path estimation part is configured to pre-estimate a dead path which is a distance between a measurement reference surface of each tracking device and a central position of each tracking device. The tracking device position calculation part is configured to calculate the central position of each tracking device via nonlinear optimization.