Vehicle Tracking with WiFi: a Cheaper GPS?
WiFi hotspots may soon be used to track vehicles, for much less than the cost of a GPS system. WiFi – wireless fidelity or 802.11 networking – connects computers over a few hundred feet using high frequency radio signals. People use WiFi hotspots to surf the ‘Net on laptops and PDAs at businesses, airports, hotels, schools and coffee houses.WiFi signals can be also used to locate objects much the same way satellites triangulate position for GPS. Ground-based WiFi location systems, however, track assets in smaller, defined areas using RFID (Radio Frequency Identification) tags. These systems:--track trucks, trailers and cargo for Wal-mart in ports and shipping yards.--manage auto parts along the assembly line.--read “smart” license plates to alert parking enforcement for overdue vehicles in some cities in Britain. --manage and track the flow of tourist cars entering and leaving Venice, Italy.--locate children with RFID bracelets in Legoland in Denmark.--locate doctors and patients waiting for surgery.--assess shopping patterns using RFID tags embedded in shopping carts to target customers with advertising.WiFi location capability is being expanded to entire cities. Microsoft has been literally driving the streets across the U.S. “listening” for 802.11 signals. Using the unique identifier of the wireless router, it notes in the database the location of each WiFi hotspot. In June, Skyhook Wireless announced the commercial availability of its WiFi Positioning System (WPS) based on the same premise. Currently, the Boston company has mapped 25 major U.S. cities, including New York, Boston, Chicago, Los Angeles and San Francisco, and plans to increase that coverage to 100 cities by the end of the year.WiFi works better than GPS in urban environments. Tall buildings can block the view of satellites, says Ted Morgan, president of Skyhook Wireless. “We’ve done tests in which GPS has been off by thousands of meters,” he says. A WiFi location system can get to within 20 to 40 meters of an object, and it works indoors, where GPS does not. However, WiFi fails to triangulate position in large open areas with fewer hotspots, making WiFi tracking outside of urban centers and over long distances very inaccurate or impossible at this point. A WiFi location system could reduce the costs of vehicle location services. Skyhook’s WPS system is software-based and runs on any WiFi-enabled laptop, PDA or smartphone without the need for a GPS chip. RFID tags are cheaper than standard GPS system hardware. An active RFID tag used for vehicle tracking costs between $10 and $80. Hardware for a GPS system runs from $300 to over $1,000. Monthly fees for real-time tracking could be cheaper too. GPS providers charge between $20 and $60 per month per vehicle for using a wireless network to transmit location. A WiFi system needs the same network, but can transmit information in batch dumps, meaning shorter connection times and lower fees. Don’t go to your local Wal-Mart looking for WiFi system with all the functionality of a GPS AVL solution just yet. End-product providers such as Aeroscout and Tango Networks are concentrating on asset tracking and logistics solutions at present. Morgan says his WPS program is initially better suited as a complement to GPS, to take over in urban canyons where GPS fails. WiFi-only location systems are not too far off. Morgan says Skyhook is bidding on projects involving emergency response in New York to track police and rescue vehicles.