Posts Tagged ‘gps technologies’

TeleNav Launches GPS Vehicle Tracker with AT&T

Saturday, January 10th, 2009



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TeleNav announced that AT&T has added TeleNav Vehicle Tracker to its portfolio of enterprise mobility services.

TeleNav Vehicle Tracker is a GPS-enabled device that is hard-wired or embedded onto a vehicle for monitoring and managing fleet operations. Once installed, TeleNav Vehicle Tracker powers up and is active without requiring any additional driver interaction or resources.

TeleNav says its Vehicle Tracker is accompanied by TeleNav’s password-protected and Web-based management console. Managers can log onto the site and view the location of each vehicle in the fleet.

TeleNav Vehicle Tracker is available immediately on AT&T’s wireless network. The TeleNav Vehicle Tracker device is $399, with a monthly service charge of about $34 per device (additional taxes and fees apply) with a qualified AT&T data plan and TeleNav Vehicle Tracker service plan rates. Customers also pay a one-time setup fee of $19.99 per unit and an $18 data plan activation fee. Volume pricing may be available.

Source: Wireless Week

Researchers Demonstrate How to Spoof GPS Devices

Tuesday, September 30th, 2008

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With millions of GPS-based navigation devices on the road today, it is time someone considered the question: What if there’s an attack on the GPS network itself?

Researchers at Virginia Tech and Cornell University spent more than a year building equipment that can transmit fake GPS signals capable of fooling receivers.

“GPS is woven into our technology infrastructure, just like the power grid or the water system,” said Paul Kintner, electrical and computer engineering professor and director of the Cornell GPS Laboratory in a statement. “If it were attacked, there would be a serious impact.”

GPS is a U.S. government-built navigation system of more than 30 satellites circling earth twice a day in specific orbits. The satellites transmit signals to receivers on land, sea and in air. Based on the signals received from the satellites, devices are able to triangulate their exact positions on the globe. But if those satellite signals were wrong — or were spoofed — a GPS device might come up with the wrong location based on the signals it was receiving.

The researchers started by programming a briefcase-size GPS receiver used in the research of the uppermost part of the Earth’s atmosphere, known as ionospheric research, to send out fake signals. The phony receiver was placed in the proximity of a navigation device, where it anticipated the signal being transmitted from the GPS satellite. Almost instantly, the reprogrammed receiver sent out a false signal that the GPS-based navigation device took for the real thing.

The experiments to show the vulnerability of GPS receivers to spoofing could help devise methods to guard against such attacks, says Brent Ledvina, an assistant professor of electrical and computer engineering at Virginia Tech, and will be detailed in a research paper to be released Thursday.

“It’s almost like someone nearby is spoofing your favorite radio station by transmitting at the same frequency but higher power fooling your receiver into believing it is getting the right station,” says Ledvina.

The idea of GPS receiver spoofing has already been considered by federal authorities. In a December 2003 report, the Department of Homeland Security detailed seven countermeasures including monitoring the absolute and relative GPS signal strength, monitoring the satellite identification codes and the number of signals received and checking the time intervals between the received signals to guard against spoofs.

Still those fall short and would not have successfully fended off the signals produced by a reprogrammed receiver, said the researchers.

Instead they have suggested a few countermeasures that involve both hardware and software changes. “We have two patent applications which include a software algorithm to help make changes to how receivers react to signals,” says Ledvina.

The other patent is around the spoofer tool used, he says. “The idea is to help government and other companies use it to potentially make better receivers,” says Ledvina.

Photo: NASA

Links: HomeLandSecurity, wired

RFID-enabled crop tracking

Saturday, July 12th, 2008

RFID producer Intelleflex Corp. has announced a joint solution with Minds Inc., a information systems provider for the road construction and agriculture industries, to create a system that would automate tracking of crop harvesting.

The solution combines GPS, RFID and wireless communications technologies to provide real-time visibility into the time-sensitive operations of field harvesting. Using this solution, growers and harvesters can track the exact location, timing and efficiency of harvesters, as well as the arrival, loading and departure time of crop transport vehicles.

“In the crunch of harvest time, people are focused on the task at hand (i.e. the harvesting of crops), and not the tracking, recording and communications of operational data. As a result, there is often a lack of the information required to ensure the most efficient operation,” said Pierre Vidaillac, president of Minds Inc.

In the new system, GPS units and RFID readers are mounted on harvesters to track their whereabouts in the field as well as the arrival, loading and departure times of transport vehicles. The information is then transmitted wirelessly for immediate access over the web and mobile phones.

Intelleflex and Minds Inc. have previously collaborated on a similar system which tracking hot mix asphalt for the road construction industry.

Source: RFID News

Sources of Errors in GPS

Wednesday, July 2nd, 2008

Selective Availability

The most relevant factor for the inaccuracy of the GPS system is no longer an issue. On May 2, 2000 5:05 am (MEZ) the so-called selective availability (SA) was turned off. Selective availability is an artificial falsification of the time in the L1 signal transmitted by the satellite. For civil GPS receivers that leads to a less accurate position determination (fluctuation of about 50 m during a few minutes). Additionally the ephemeris data are transmitted with lower accuracy, meaning that the transmitted satellite positions do not comply with the actual positions. In this way an inaccuracy of the position of 50 – 150 m can be achieved for several hours. While in times of selective availability the position determination with civil receivers had an accuracy of approximately 10 m, nowadays 20 m or even less is usual. Especially the determination of heights has improved considerably from the deactivation of SA (having been more or less useless before).

The reasons for SA were safety concerns. For example terrorists should not be provided with the possibility of locating important buildings with homemade remote control weapons. Paradoxically, during the first gulf war in 1990, SA had to be deactivated partially, as not enough military receivers were available for the American troops. 10000 civil receivers were acquired (Magellan and Trimble instruments), making a very precise orientation possible in a desert with no landmarks.

Meanwhile SA is permanently deactivated due to the broad distribution and world wide use of the GPS system.

The following two graphs show the improvement of position determination after deactivation of SA. The edge length of the diagrams is 200 m, the data were collected on May 1, 2000 and May 3, 2000 over a period of 24 h each. While with SA 95 % of all points are located within a radius of 45 m, without SA 95 % of all points are within a radius of 6.3 m.

Plot of the position determination with and without SA
(Diagram from http://www.igeb.gov/sa/diagram.shtml (page no longer available)
With friendly permission of Dr. Milbert (NOAA))
Plot of the position determination with SAPlot of the position determination without SA

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