The Global Positioning System (GPS) uses satellites orbiting in space to help users on the ground to precisely determine their location almost anywhere in the world. GPS was originally launched in the 1970’s and primarily intended for use as a military navigation system. In the decades since it was first introduced, both the accuracy and availability of GPS has greatly improved, and the system is now used widely by civilians.
Today, the use of GPS has become a part of our everyday life. GPS systems are included in smart phones, automobile navigation systems, and many other consumer devices.
The Use of GPS for Security Purposes
Security professionals were quick to recognize the potential for GPS to be used in security applications, particularly for the tracking of stolen objects. Soon after GPS was made available for civilian use, several manufacturers introduced “GPS trackers” that were intended to allow the tracking of vehicles and other objects. While these early products were somewhat effective, they were relatively large, making them difficult to conceal. They also suffered from a short battery life unless the units were connected to a permanent source of power.
There are three main categories of GPS products used for security purposes: GPS Asset Trackers, GPS Vehicle Trackers, and GPS Personal Trackers.
GPS Asset Trackers
GPS Asset Trackers are used to track high-value items such as cash, jewelry, narcotics, electronics, and other merchandise. The primary purpose of GPS Asset Trackers is to allow the recovery of stolen merchandise and the apprehension of the criminals who stole it. The use of GPS Asset Trackers may also have a deterrent effect if criminals are aware that the premises that they intend to rob or burglarize are using tracking devices.
GPS Asset Trackers are typically concealed within the items that they are intended to track. When the criminal takes the item, he or she also unintentionally takes the tracking device. When the device is moved, it becomes activated, causing an alarm message to be transmitted to a monitoring center, and allowing the position of the device to be tracked using GPS.
GPS Asset Trackers are available in a variety of different sizes and shapes, allowing them to be concealed within a variety of different types of merchandise. Options include devices that can be hidden in pill bottles, packages of cigarettes, jewelry, cell phones, and bundles of currency.
GPS Asset Trackers use a combination of cellular telephone and GPS technology. The cellular technology is used to transmit the alarm signal to the off-site monitoring center, while the GPS technology is used to determine the precise location of the tracking device.
GPS Vehicle Trackers
GPS Vehicle Trackers are used to track the location of vehicles, such as delivery trucks and tractor trailer rigs, but can also be used to track trailers, heavy-equipment, and storage containers. GPS Vehicle Trackers are similar to the GPS Asset Trackers described above, but are built more rugged to handle the extreme conditions that can be found in a vehicle. Most GPS Vehicle Trackers can also be powered from the vehicle’s electrical system, making them less reliant on batteries.
There are three types of GPS Trackers commonly used: Passive trackers, active trackers, and on-demand trackers.
Passive trackers are installed on the vehicle and are used to gather data on where the vehicle has been used and when. To gather data from the tracker, the user must generally remove the tracker from the vehicle and plug-it in to a computer. The data can then be downloaded and reviewed using an application program provided by the tracker manufacturer. Passive trackers are available for less than $200 in the US and typically require no monthly monitoring fee.
Active trackers provide continuous, real-time tracking of vehicles. This allows the user to know where every vehicle equipped with a tracking device is located at any given time. Active trackers can also be set to sound an alert when a vehicle deviates from an assigned route, stays at a location longer than expected, or is speeding or otherwise being driven in an unsafe manner.
On-demand trackers are installed on a vehicle but remain dormant until activated remotely by the user. To activate the tracker, the user logs on the manufacturer’s website, enters name and password, and then clicks an icon to enable tracking. The vehicle’s location is then shown on a map, along with its speed and heading if the vehicle is in motion. Once tracking is activated, the vehicle may be tracked for up to 24 hours before tracking must be reactivated again.
GPS Personal Trackers
GPS Personal Trackers are used to track people. GPS Personal Trackers are small portable devices that can be carried in a pocket or on a belt, or worn around the wrist or neck. GPS Personal Trackers use a combination of cellular telephone and GPS technology. The cellular technology is used to transmit the alarm signal and to allow two-way communications to an off-site monitoring center. The GPS technology is used to determine the precise location of the tracking device.
To activate the tracker, the user presses a panic button located on the device. This sends an immediate signal to the monitoring center, and establishes a voice communications path between the user and the operator at the monitoring center. The operator then speaks with the user to determine the nature of the problem. If required, the operator can then dispatch the appropriate emergency personnel to the user’s location. If for some reason the user cannot speak, the operator would typically dispatch help to the users location based on GPS coordinates.
Limitations of GPS Technology
While GPS tracking devices can be useful tools, they do have their limitations. The most obvious is GPS’s requirement to have a clear view of satellites orbiting above the earth in order to determine location. GPS signals can be blocked when the tracking device is in a building, covered by dense trees, or in an urban environment where tall buildings can obstruct the path between the device and the sky. GPS signals can also be blocked by metal containers and walls and ceilings that are constructed using metallic materials. Most tracking devices will transmit their last known position when the GPS signal is lost, and then resume transmitting real-time information again once the signal is restored.