Mobile Device Location via Timing Offset Calibration
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Solution Overview
Problem
Existing methods for location estimation of mobile devices in 3G UMTS systems, such as AGPS, are limited by the need for satellite signals, which are not always available indoors or in areas with signal blockages, resulting in 30-50% of mobile devices being unable to report accurate location information.
Innovation Solution
The method utilizes relative timing offset information from mobile devices, combined with AGPS data, to calibrate calculations and determine the location of mobile devices with GPS-like accuracy, independent of network intelligence, by measuring propagation delays and timing offsets between cell sites and mobile devices, and crowd-sourcing information from multiple devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If AGPS is used for location estimation, then location accuracy is improved, but the method fails when satellite signals are unavailable (30-50% of mobile locates cannot return AGPS location information)
Solution Approach 1:
The patent introduces network probes as intermediary devices deployed at base stations to measure timing offsets. These probes act as mediators between the mobile device and the network, collecting timing information that can be used to calculate location without requiring GPS satellites. The timing offset measurements from multiple base stations serve as intermediary data that enables location estimation in GPS-denied areas.
Solution Approach 2:
The patent replaces the mechanical/GPS-based location determination system with a network-based timing measurement system. Instead of relying on satellite signals and GPS receivers, the system uses timing offset measurements from network probes and mathematical calculations to determine location. This substitution allows location estimation to work in environments where GPS signals are blocked.
2Reliability
If network probes are used to measure timing offsets, then location estimation is enabled for indoor devices, but the method requires network functionality that may not always be available
Solution Approach 1:
The patent implements self-service by having mobile devices perform the timing offset measurements themselves using their own GPS receivers and network interfaces. The mobile devices autonomously measure the timing differences between base station pairs and report this information back to the network. This eliminates the need for complex network-side probe deployments and allows any mobile device to contribute to location estimation without requiring special network infrastructure.
Solution Approach 2:
The patent makes the timing offset measurement capability universal by enabling any mobile device with a GPS receiver and network interface to perform measurements. The same measurement mechanism works regardless of the specific base station pair or network configuration. This universal approach allows location estimation to function across different network operators and deployment scenarios without requiring operator-specific network probes.
3Measurement precision
If existing network-based location methods are used, then location can be determined, but the method cannot locate devices serviced by base stations not operated by the same network operator
Solution Approach 1:
The patent extracts the location estimation capability from the network operator's infrastructure and places it in the mobile device itself. By having the mobile device measure timing offsets and perform location calculations independently, the system eliminates dependency on the home network operator's infrastructure. This extraction allows devices to be located accurately regardless of which network operator provides the serving base stations, as long as timing measurement functionality is available on the device.
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 allows for accurate location determination of all 3G mobile devices, both with and without GPS, without relying on network data, enabling precise location tracking even in areas where satellite signals are unavailable, and can be deployed by entities other than network operators.
Implementation Method 1
measuring a timing difference between signals from two base stations; the timing difference includes a propagation delay component
Data Source
AI summary
The present disclosure provides devices, systems, and methods to utilize relative timing offset information reported by one or more mobile devices. When coupled with AGPS information reported by one or more mobile devices, the offset information is be used to calibrate calculations and subsequently to locate all 3G mobiles with GPS-like accuracy, whether or not a GPS receiver is available on said mobile device being located. A determination of a propagation delay between one or more cell sites and a mobile device is reported to a network and used to calibrate unknown information such as a timing offset, to improve the accuracy of a detected location. The relative timing offset can be applied to determine a location for all other mobile devices within the area served by the known base station. The present disclosure utilizes this method in conjunction with information crowd-sourced from a plurality of mobile devices.