Passive Wi-Fi Geolocation Using Signal Strength and Trilateration
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Solution Overview
Problem
Existing geolocation systems for wireless devices are cumbersome, expensive, and inaccurate in non-open areas due to signal reflection and degradation, and rely on extensive external databases that require manual data population and are prone to inaccuracy.
Innovation Solution
A method using a user's local wireless device with built-in GPS and Wi-Fi receivers to passively detect and geolocate target wireless devices through signal strength measurement and trilateration algorithms, eliminating the need for specialized equipment and external databases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If highly-specialized equipment is used to obtain highly accurate geolocation results in open areas, then measurement precision is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent makes the user's existing wireless device serve multiple functions: it acts as both the detection device for receiving Wi-Fi signals and the processing device for executing geolocation algorithms, while also serving as the display device for showing results. This eliminates the need for separate specialized geolocation equipment.
Solution Approach 2:
The system uses the user's own wireless device resources (GPS receiver, Wi-Fi receiver, processor, display) to perform geolocation autonomously without requiring external specialized equipment or databases. The device serves itself by utilizing its built-in components for signal detection, processing, and result presentation.
2Measurement precision
If conventional geolocation systems use extensive external databases to look up latitude and longitude coordinates, then measurement precision may be improved, but loss of time increases due to manual data population requirements
Solution Approach 1:
The system eliminates the need for manual database population by using the user's wireless device to autonomously detect Wi-Fi access points, receive their coordinates, and perform geolocation calculations in real-time. The device serves itself by gathering necessary data on-demand rather than relying on pre-populated databases that require manual maintenance.
Solution Approach 2:
The system obtains Wi-Fi access point coordinate information in advance through wireless communication, storing it locally for immediate use in geolocation calculations. This preliminary acquisition of reference data eliminates the need for time-consuming manual database population and lookup operations.
3Quantity of substance
If conventional systems rely on wardriving to populate databases with access point locations, then quantity of substance (database size) increases, but reliability decreases due to inaccurate coarse location data
Solution Approach 1:
The patent extracts only the essential and accurate data elements needed for geolocation (Wi-Fi access point coordinates received through wireless communication) rather than relying on large volumes of coarse location data from wardriving. This selective extraction of precise data improves reliability while reducing unnecessary data volume.
Solution Approach 2:
Instead of maintaining large, static databases that require continuous manual updates and are prone to inaccuracies, the system uses lightweight, dynamically received coordinate information from Wi-Fi access points that can be obtained on-demand. This approach replaces bulky, maintenance-intensive databases with efficient, real-time data acquisition.
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
Enables simple, accurate, and autonomous geolocation of remote wireless devices in real-time without interrogating them directly, using off-the-shelf devices like smartphones, reducing costs and improving accuracy in various environments.
Implementation Method 1
uses a Global Positioning System (GPS) receiver, which is common on most wireless devices
Implementation Method 2
use the received signal strength from the target remote wireless device... Signal strength (Received Signal Strength Indication or RSSI) for the located remote wireless devices may be measured
Implementation Method 3
The processor(s) may then apply a filtering algorithm to narrow the resolved number of candidate sets of possible GPS coordinates to a single set of GPS coordinates that represents a best approximation of a geographic position of the particular target remote wireless device
Data Source
AI summary
A system and method for using a receiving wireless device to passively detect target wireless devices or access points, quantify signal strengths of the target wireless devices or access points, and accurately identify a position for, or geolocate, the target wireless devices or access points. A position of the receiving wireless device is determined and correlated with a signal strength received from a target wireless device taken from multiple positions of the receiving wireless device. A trilateration algorithm is applied to the correlated date to obtain coarse geographic positions for the target wireless device, then a filtering algorithm is applied to obtain an accurate position for the target wireless device, which is in turn displayed to a user of the receiving wireless device.