Place Lab: Device Positioning Using Radio Beacons in the Wild

Abstract

Location awareness is an important capability for mobile computing. Yet inexpensive, pervasive positioning-a requirement for wide-scale adoption of location-aware computing-has been elusive. We demonstrate a radio beacon-based approach to location, called Place Lab, that can overcome the lack of ubiquity and high-cost found in existing location sensing approaches. Using Place Lab, commodity laptops, PDAs and cell phones estimate their position by listening for the cell IDs of fixed radio beacons, such as wireless access points, and referencing the beacons' positions in a cached database. We present experimental results showing that 802.11 and GSM beacons are sufficiently pervasive in the greater Seattle area to achieve 20-40 meter median accuracy with nearly 100% coverage measured by availability in people's daily lives.

Moving on from Weiser’s Vision of Calm Computing: Engaging UbiComp Experiences

“…More studies are needed that examine what people do with their current tools and devices in their surrounding environments. In addition, more studies are needed of UbiComp technologies being used in situ or the wild -to help illuminate how people can construct, appropriate and use them [e.g., 16,22,23,29].…”

GSM indoor localization

“…These previous efforts to use GSM for localization differ from the work reported in this paper in that they used narrow fingerprints that include the signal strength for the current cell [12,15] or the 6-strongest cells [14]. In contrast, we used wide fingerprints that include up to 29 different GSM channels in addition to the 6-strongest GSM cells, which significantly improve localization accuracy.…”

“…The Place Lab system employed a map built using war-driving software and a simple radio model to estimate a cell phone's location with 100-150 m accuracy in a city environment [15]. The goal of Place Lab was to provide coarse-grained accuracy with minimal mapping effort.…”

Bootstrapping a Location Service Through Geocoded Postal Addresses

“…Wide area WiFi localization techniques as provided by Place Lab [1] or commercial providers [2], however, rely on a location service that provides geographic position of third-party WiFi access points identified by their MAC address.…”

“…From this dataset, the position of access points can then be estimated using a number of heuristics such as position of maximum signal strength, or centroid of all access point sightings. 1 This process is inaccurate [4] and it is laborious, since it requires physically driving a vehicle through the road network in the intended coverage area. It needs to be repeated periodically to update the dataset, since owners of access points upgrade their hardware (resulting in a change of MAC address), or move with the access point to a different geographic location.…”