Indoor Location Estimation Using Probe Response Delay Compensation
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Solution Overview
Problem
Indoor navigation systems face challenges in achieving accurate location estimation due to the inability to receive signals from global-navigation-satellite-systems (GNSS) satellites, leading to inaccuracies in Time-of-Flight (ToF) measurements and subsequent distance calculations, which affect the precision of location determination.
Innovation Solution
The system communicates a probe request and response between a wireless communication device and a mobile device, incorporating a delay value to account for processing delays, allowing for accurate distance estimation and location calculation using trilateration methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If Time-of-Flight (ToF) measurement method is used for indoor navigation, then location estimation can be achieved without GNSS satellites, but the measurement accuracy deteriorates due to unaccounted processing delays
Solution Approach 1:
The system performs preliminary characterization of processing delays by measuring the time difference between signal transmission and reception at known locations. These delay characteristics are stored and applied as compensation values in subsequent ToF measurements, enabling accurate distance calculation without real-time delay analysis.
Solution Approach 2:
The system incorporates feedback mechanisms where the measured ToF values are compared against expected values based on known geometry. The difference indicates processing delay errors, which are then used to adjust and refine the delay compensation parameters for improved measurement accuracy in subsequent operations.
2Device complexity
If processing delays are not accounted for in ToF measurements, then the measurement process remains simple, but the location estimation accuracy deteriorates
Solution Approach 1:
Processing delay characteristics are characterized and stored in advance during system setup or calibration phase. This preliminary action eliminates the need for complex real-time delay analysis during actual measurements, maintaining operational simplicity while improving accuracy through pre-computed compensation values.
Solution Approach 2:
The system introduces delay compensation parameters as intermediary values that bridge the simple ToF measurement process and the accurate distance calculation. These parameters are easily obtained through preliminary measurements and serve as correction factors that can be applied without complicating the core measurement methodology.
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 enhances the accuracy of location estimation in indoor environments by accounting for processing delays, thereby improving the precision of distance calculations and location determination.
Implementation Method 1
The ToF may be defined as the overall time a signal propagates from a first station, e.g., a user ('client') mobile device, to a second station, e.g., an access point (AP), and back to the first station. A distance between the first and second stations may be calculated based on the ToF value.
Data Source
AI summary
Some demonstrative embodiments include devices, systems and/or methods of estimating a location of a mobile device. For example, an apparatus may include a controller to control a first wireless communication device to communicate a probe request with a second wireless communication device and to communicate a probe response with the second wireless communication device, wherein the probe response includes a delay value representing a delay period between a reception of the probe request and a transmission of a frame in response to the probe request.