PESTECH2001.COM SUPPLEMENT: Fleet Finder

GPS, or Global Positioning System, used to be considered so high-tech and proprietary that only the military could use it. In recent years, however, this state of the art technology very much has come into the mainstream. Today, companies and individuals, located anywhere around the world, can benefit from the many applications GPS lends itself to. Besides serving as a navigational device for those on land, at sea or in the air, GPS is also finding uses in such areas as tracking vehicles and machinery, vehicle recovery, biological research and mapping.

The ability to track vehicles, in real time and throughout a virtually unlimited area, is quite appealing to industries such as pest control, which use large fleets of vehicles to conduct their everyday business.

Using GPS, managers can pinpoint the locations of all their vehicles at a moment’s notice. They can also retrieve detailed information from each vehicle, including the length of time spent traveling, stopped and at job sites. Prior to GPS, obtaining this type of information was impossible.

Tony Reynolds, product manager for VDO Fleet Systems, Winchester, Va., discussed GPS and its applications at the Pestech2001.com conference. VDO is a supplier of GPS-based applications. Reynolds has close to 20 years experience with GPS technology. In addition to his work with VDO, Reynolds also works with the U.S. Department of Transportation on vehicle and driver safety issues and is participating in a study of commercial vehicle safety issues as a member of the Transportation Research Board.

In conjunction with Reynolds’ presentation, Lorna Henderson, regional sales director with @Road, a mobile resource management company, discussed the FleetASAP vehicle tracking system.

HOW IT WORKS. Reynolds explained that, by definition, GPS is a satellite-based radio navigational, positioning and time transfer system operated by the U.S. Department of Defense. "The system provides highly accurate position and velocity information and precise time on a continuous global basis to properly equipped users," he said.

The concept of GPS arose in 1957, when the Soviet government launched Sputnik, the first satellite. Witnessing this achievement, the U.S. government realized the growing importance of developing its own satellite program. The first U.S. satellites to be launched were Transit, in 1964, followed by Timation 1 in 1967. These early satellites could provide location information but were limited in their capabilities.

The first navigational satellite was launched in 1974 and served as the predecessor to today’s system. Today’s satellites are referred to as NAVSTAR satellites, or NAVigation Satellite for Timing and Ranging. The first NAVSTAR satellites were launched in 1978 and 1985.

The current GPS system got its first big boost in 1983 by President Ronald Reagan who mandated that the GPS signal be made available for free commercial use. Public awareness was heightened further during the Gulf War, when the U.S. military and its allies used more than 9,000 GPS receivers.

Today’s system consists of a "constellation" of 24 satellites located in six orbital planes around the earth at an altitude of 20,200 kilometers. Of the 24 satellites, 21 are in active use and three serve as "spares," Reynolds said. Each satellite broadcasts a "course-acquisition code," which contains specific information on that satellite and that satellite’s location in relation to the other satellites. It also contains highly precise time information that is used to pinpoint locations. The GPS signals are managed through a series of control stations worldwide.

FINDING OUT MORE. To obtain location information for a specific point on earth, all that’s needed is a special receiver unit or a "black box." The receiver uses the laws of geometry to pinpoint a location after collecting the location and time information from three or more satellites for a specific position. The satellites can also provide velocity information after a specific location has been pinpointed. Although the receiver takes care of all the mathematics behind these complex operations, Reynolds explained, the receiver must know the satellites’ exact locations in space to provide an accurate location.

There are occasions, Reynolds pointed out, when GPS doesn’t work. "The signal won’t go through earth or metal," he explained. Therefore, when drivers go through tunnels, through heavily wooded areas or near high buildings, for example, the GPS signal may be inaccessible or inaccurate. In these situations, some navigation applications use two additional technologies, Reynolds said: "dead reckoning" and "map matching" to estimate the driver’s location.

With dead reckoning, the program analyzes the driver’s past location, speed and direction to predict his current location. And map matching estimates the driver’s course using a series of "intelligent maps," Reynolds explained.

Some GPS-based applications that apply to the pest control industry include products that offer turn-by-turn directions, dynamic re-routing and a driver management system. In the product from VDO, the driver management system monitors such things as the driver’s speed, idle time and engine usage. Meanwhile, dynamic re-routing provides the driver with alternate driving directions, should the original route become inaccessible. VDO also offers vehicle recovery systems.

Among the many other applications for GPS is search and rescue of lost hikers, downed aircraft or misguided vehicles. GPS can also be used to broadcast traffic problems and help route drivers around them.

Another growing GPS application is precision farming, which helps to provide crop yield and fertilizer application information. And GPS has many uses in research, such as collecting migratory patterns and habitation requirements. The use of GPS has also accelerated the process for converting aerial photography to digital maps.

Vehicle tracking and fleet management is another growing application for GPS. Lorna Henderson, regional sales director with @Road, discussed this technology at the Pestech2001.com conference, presenting information about the company’s FleetASAP system, an Internet-based vehicle tracking system.

The FleetASAP system uses GPS, along with wireless communication devices and the Internet to help companies manage their fleets. Under the service, an Internet Location Manager or "iLM," is installed into each vehicle. This iLm is connected with the Internet via wireless modem. Companies also have the option to purchase a special messaging screen that can be used to provide real-time two-way messaging between managers and drivers. Managers then track their vehicles by logging into the FleetASAP website, using a password.

The main benefit of using this system, Henderson said, is that managers can log in anytime and anywhere to collect specific information on their vehicles. All data collected is stored on the Internet, to be downloaded by each individual user.

CONCLUSION. Reynolds noted that while the GPS technology is powerful, if not presented properly to employees, it could be viewed as a coercive tool. Therefore, managers who decide to use GPS for fleet management must be sure to explain its many benefits.

Employees should be made aware of the safety benefits, training advantages and cost reductions provided by GPS. The cost savings could then be used to increase wages. "If you can’t make the user of the technology part of the solution," Reynolds said, "it’s not going to work." On the other side of the coin, "if used appropriately, GPS can build your business," he said.

As with other high-tech ventures, a number of potentially confusing terms have developed to describe GPS and its mechanics. Here is a short listing of some of the terms you may hear as you learn more about GPS and its applications:

Acquisition time: The time it takes for a GPS receiver to acquire satellite signals and determine the initial position. Three satellites are needed for a 2D-position fix (only horizontal coordinates; for locations on land) and four are needed for a 3D-position fix (horizontal coordinates plus elevation; for locations in the air).

Almanac: Set of parameters used by a GPS receiver to predict the approximate locations of a GPS satellite and the expected satellite clock offset (or constant difference in the time reading between two clocks). Each GPS satellite contains and transmits the almanac data for all GPS satellites.

Atomic clock: A clock whose frequency is maintained using electromagnetic waves that are emitted or absorbed in the transition of atomic particles between energy states. The frequency of an atomic transmission is very precise, resulting in very stable clocks. GPS satellites carry multiple atomic clocks.

Constellation: Refers to the collection of orbiting GPS satellites. The GPS constellation consists of 24 satellites in 12-hour circular orbits at an altitude of 20,200 kilometers. Four satellites are spaced in each of six orbital planes.

Course acquisition code (C/A code; also referred to as clear acquisition code): Consists of a sequence of 1023 bits (0 or 1) that repeats every millisecond. Each satellite broadcasts a unique 1023-bit sequence that allows a receiver to distinguish between various satellites and to quickly lock on to a satellite.

Elevation mask: An adjustable feature of GPS receivers that specifies that a satellite must be at least a specified number of degrees above the horizon before the signals from the satellite are to be used. Satellites at low elevation levels (five degrees or less) have lower signal strengths and are more prone to loss of lock thus causing noisy solutions.

NAVSTAR: Stands for NAVigation Satellite for Timing and Ranging. This is another term for GPS or is sometimes used in conjunction with GPS as in "NAVSTAR GPS."

Position fix: The GPS receiver’s computed position coordinates.

Pseudo-random code: The identifying signature signal transmitted by each GPS satellite and mirrored by the GPS receiver in order to separate and retrieve the signal from background noise.

Precise positioning system (PPS): The more accurate GPS capability that is restricted to authorized, typically military, users.