|
|
When looking at the various solutions that are available to remotely pinpoint and track a vehicle’s location, GPS is undoubtedly the most often talked about technology. A search of the Internet will uncover numerous companies that offer GPS vehicle tracking products and a few companies dedicated to RF tracking technologies. Depending on the intent of the system, one technology will certainly stand out as superior to the other. Following is a brief comparison of the two solutions.
GPS
 A GPS receiver receives radio signals from 24 satellites orbiting the Earth. If the receiver can receive a signal from at least 3 satellites simultaneously, it can calculate its own location, usually accurate to within a few feet. At this point, this location information must somehow be transmitted to a base station to be displayed on a computerized map. This can be accomplished in a number
of ways each with its own set of unique advantages and disadvantages. Most common, at least in the US, is to send the data over an analog cellular phone data channel, such as Aeris.net, which incredibly covers about 90% of the United States’ landmass. Another option is to send the data over a dialup cellular connection, or data can be sent as a Short Message Service (SMS) message. Yet another option would be to send the data over a satellite communication link, or lastly, over a local analog or digital radio system.
RF Tracking
 In an RF vehicle tracking system such as VectorTrac or LoJack, a radio transceiver, usually called a Vehicle Locator Unit or VLU, is installed in the vehicle and remains inactive until the vehicle needs to be located. When this occurs, the VLU is activated, usually by means of a remote radio activation signal that is transmitted from local radio towers. Once activated, the VLU will transmit a radio signal which can then be received by receivers located throughout the coverage area, either installed on towers, roof tops, in police cars, or as with VectorTrac, a combination of all three. In the VectorTrac system, tower and rooftop receivers will analyze the VLU’s radio signal,
calculating the angle of arrival and signal strength. These sites will then forward that information to a base station computer that will display the vehicle’s approximate location on a computerized map. Depending on the technology employed, the accuracy can be anywhere from several miles to a few hundred feet. Police or security cars equipped with Mobile Tracking Receivers are then directed to the area.
When the tracking vehicles are within 2-3 miles of the stolen vehicle, they will begin to receive the signal and
can then home in on its location. The tracking receivers will
then pinpoint the exact location of the vehicle, even if it is hidden in a garage or cargo container.
So which one is better?
The answer to that depends entirely on what kind of vehicle tracking you want to do.
For fleet management purposes, GPS is the way to go. GPS is accurate, can track numerous vehicles simultaneously, the information gets to your computer within a minute showing you exactly where the vehicle is located, which direction it is traveling, how fast it is going, and so on. All of this is exactly what you would want in a fleet management system. However, the GPS device is rather expensive, time consuming to
install, and the GPS antenna must be installed so that it can see the sky. Again, for fleet management purposes, these drawbacks can be justified by the cost benefits of having the system.
If, however, you want to recover stolen vehicles, RF tracking is the technology of choice. The reasons for this are many. Generally, only a very limited number of vehicles will be tracked at one time so tracking capacity is not an issue. Because the device remains in standby mode until the vehicle is stolen, both VectorTrac and LoJack can support virtually an unlimited number of vehicles. The RF tracking device is relatively inexpensive and easy to install, thus allowing widespread implementation and greater market penetration than would ever be possible with a more expensive GPS based system. In addition, the VLU can be hidden in any number of locations throughout the vehicle and there is no visible antenna. RF tracking systems also rely on their own infrastructure so revenue need not be shared with cell phone companies. Technically, RF tracking of stolen vehicles is very reliable as the radio signals are powerful and can penetrate obstructions such as buildings, garages and cargo containers, allowing vehicles to be recovered from places where a GPS system would be useless.
|
|
|
|
