Acoustic Positioning With Doppler Compensation and Deconvolution
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Solution Overview
Problem
Indoor real-time location systems face challenges in accurately determining the position of mobile communication devices due to Doppler shifts and multi-path interference, which affect the accuracy of location estimation.
Innovation Solution
The system compensates for Doppler effects in the received acoustic signals by performing Doppler effect compensation in the frequency domain, using a processing unit to determine Doppler shift frequencies and apply deconvolution decoding processes, including a library of Doppler matching templates and non-linear optimization routines to model signal transmission paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If Doppler effect compensation is performed in the frequency domain using deconvolution decoding, then location estimation precision is improved, but device complexity and processing requirements increase
Solution Approach 1:
The system performs preliminary Doppler effect compensation on acoustic signals before location estimation. By pre-processing the signals to correct Doppler shifts caused by device motion, the system improves measurement precision without requiring complex real-time calculations during location determination
Solution Approach 2:
The patent introduces an intermediary processing unit that performs deconvolution decoding between signal reception and location calculation. This intermediary component handles the complex frequency domain processing, separating the computational burden from the core location estimation function
2Measurement precision
If deconvolution decoding is applied to compensate for multi-path interference, then location accuracy is improved, but processing time and computational resources increase
Solution Approach 1:
The system performs deconvolution decoding as a preliminary processing step before location estimation. By pre-processing the acoustic signals to remove multi-path interference effects, the system achieves accurate location determination without requiring time-consuming iterative calculations during the actual location calculation
Solution Approach 2:
The patent extracts and removes the harmful multi-path interference components from the acoustic signals through deconvolution decoding. By separating the direct path signal from reflected paths, the system achieves accurate timing measurements without processing the entire complex signal mixture
3Measurement precision
If Doppler shift frequency determination is performed for all signal transmission paths, then location estimation accuracy is improved, but computational complexity increases
Solution Approach 1:
The system applies Doppler shift frequency determination selectively to significant signal transmission paths rather than uniformly to all paths. By identifying and processing only the dominant paths that contribute most to location accuracy, the system maintains precision while reducing computational complexity
Solution Approach 2:
The patent changes the processing approach by determining Doppler shift frequencies in the frequency domain rather than time domain. This parameter change in the mathematical domain enables more efficient calculation of Doppler effects across multiple transmission paths
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides accurate location estimation with a standard deviation of 2.5 to 25 centimeters, enhancing the precision of indoor location determination for moving devices by compensating for Doppler shifts and multi-path interference.
Implementation Method 1
The indoor real-time location system in accordance with the instant disclosure is configured to compensate Doppler effects in the received acoustic signal prior to performing a deconvolution decoding process
Implementation Method 2
Mobile communication devices receive acoustic signals from one or more transmitter stations
Implementation Method 3
The response function is a result of a direct signal transmission path and reflected signal transmission paths between the transmitter station and the mobile communication device
Data Source
AI summary
The present disclosure relates to an acoustic position determination system that includes a mobile communication device and at least one base transmitter unit. The mobile communication device is configured to transmit and receive acoustic signals. Due to relative movements between the mobile communication device and the base transmitter unit, frequencies of the received signals shift due to Doppler effect. The mobile communication device is configured to compensate Doppler frequency shifts in the received acoustic signals prior to performing a deconvolution decoding process. The mobile communication device is further configured to compensate Doppler frequency shifts and perform deconvolution decoding process on acoustic signals received from multiple signal transmission paths.