A GPS tracking unit is a device that uses the Global Positioning System to determine the precise location of a vehicle, person, or other asset to which it is attached and to record the position of the asset at regular intervals. The recorded location data can be stored within the tracking unit, or it may be transmitted to a central location data base, or internet-connected computer, using a cellular (GPRS), radio, or satellite modem embedded in the unit. This allows the asset’s location to be displayed against a map backdrop either in real-time or when analysing the track later, using customized software. Such systems are not new; amateur radio operators have been operating their free GPS-based nationwide realtime Automatic Packet Reporting System (APRS) since 1982.

Types of GPS trackers.

Usually, a GPS tracker will fall into one of these three categories:

Data loggers

A GPS logger simply logs the position of the device at regular intervals in its internal memory. Modern GPS loggers have either a memory card slot, or internal flash memory and a USB port. Some act as a USB flash drive. This allows downloading of the data for further analyzing in a computer.

These kind of devices are most suited for use by sport enthusiasts: They carry it while practicing an outdoors sport, e.g. jogging or backpacking. When they return home, they download the data to a computer, to calculate the length and duration of the trip, or to over impose their paths over a map with the aid of GIS software. GPS devices are also integral tools in geocaching.

In the sport of gliding, competitors are sent to fly over closed circuit tasks of hundreds of kilometers. GPS loggers are used to prove that the competitors completed the task and stayed away from controlled airspace. The data stored over many hours in the loggers is downloaded after the flight is completed and is analysed by computing the start and finish times so determining the fastest competitors.

Most digital cameras save the time a photo was taken. Provided the camera clock was reasonably accurate, this time can be correlated with GPS log data, to provide an accurate location. This can be added to the picture, and is called geotagging.

In some Private Investigation cases, these data loggers are used to keep track of the vehicle or the fleet vehicle. The reason for using this device is so that a PI will not have to follow the target so closely and always has a backup source of data.

Data pushers

This is the kind of devices used by the security industry, which pushes (i.e. “sends”) the position of the device, at regular intervals, to a determined server, that can instantly analyze the data.

These devices started to become popular and cheaper at the same time as mobile phones. The falling prices of the SMS services, and smaller sizes of phone allowed to integrate the technologies at a fair price. A GPS receiver and a mobile phone sit side-by-side in the same box, powered by the same battery. At regular intervals, the phone sends a text message via SMS, containing the data from the GPS receiver.

Some companies provide data “push” technology, enabling sophisticated GPS tracking in business environments, specifically organizations that employ a mobile workforce, such as a commercial fleet.

Typical GPS tracking systems used in commercial fleets are comprised of two core parts; location hardware (or tracking device) and tracking software, this combination is often referred to as a vehicle tracking system. The tracking device is most often hardwire installed in the vehicle; connected to the ignition switch, battery and antennae. The typical tracking hardware for a fleet management solution uses GPS to pinpoint its location and then updates are transmitted at a regular timed interval or after an event trigger, e.g. ignition on / off. These location updates are commonly transmitted, coverage permitting, in Europe and increasingly in North America using GPRS. The location data are made available for viewing more often than not with many of the solutions sold today, via a website, accessed over the internet, where fleet activity can be viewed live or historically using digital maps and reports.

GPS tracking systems used in commercial fleets are often configured to transmit location and telemetry input data at a set update rate or when an event ( door open/close, auxiliary equipment on/off) triggers the unit to transmit data. Live GPS Tracking used in commercial fleets, generally refers to systems which update regularly at 1 minute, 2 minute or 5 minute intervals, whilst the ignition status is on. Some tracking systems combine timed updates with heading change triggered updates.

The applications of these kind of trackers include:

• Fleet control. For example, a delivery or taxi company may put such a tracker in every of its vehicles, thus allowing the staff to know if a vehicle is on time or late, or is doing its assigned route. The same applies for armored trucks transporting valuable goods, as it allows to pinpoint the exact site of a possible robbery.
• Stolen vehicle searching. Owners of expensive cars can put a tracker in it, and “activate” them in case of theft. “Activate” means that a command is issued to the tracker, via SMS or otherwise, and it will start acting as a fleet control device, allowing the user to know where the vehicle is.
• Animal control. When put on a wildlife animal (e.g. in a collar), it allows scientists to study its activities and migration patterns. Vaginal implant transmitters are used to mark the location where pregnant females give birth. Animal tracking collars may also be put on domestic animals, to locate them in case they get lost.
• Race control. In some sports, such as gliding, participants are required to have a tracker with them. This allows, among other applications, for race officials to know if the participants are cheating, taking unexpected shortcuts or how far apart they are. This use has been featured in the movie “Rat Race”, where some millionaires see the position of the racers in a wall map.
• Espionage/surveillance. When put on a person, or on his personal vehicle, it allows the person monitoring the tracking to know his/her habits. This application is used by private investigators.
• These devices are also used by some parents to track their children. The supporters claim that if cleverly used, this actually allows children more independence.
• Internet Fun. Some Web 2.0 pioneers have created their own personal web pages that show their position constantly, and in real-time, on a map within their website. These usually use data push from a GPS enabled cell phone.

Data pullers

Contrary to a data pusher, that sends the position of the device at regular intervals (push technology), these devices are always-on and can be queried as often as required (pull technology). This technology is not in widespread use, but an example of this kind of device is a computer connected to the Internet and running gpsd.

These can often be used in the case where the location of the tracker will only need to be known occasionally e.g. placed in property that may be stolen.

Data Pullers are coming into more common usage in the form of devices containing a GPS receiver and a cell phone which, when sent a special SMS message reply to the message with their location.

Potential abuse of GPS trackers

These devices can also raise concerns about personal privacy. Over time, the information collected could reveal a typical pattern of movements. They can also be used for surveillance.

USA

In the US, the use of GPS trackers by government authorities, such as police, is limited by the 4th Amendment of the United States Constitution, so, police, for example, usually require a search warrant in most circumstances. While police have placed GPS trackers in vehicles without warrant, this usage was questioned in court in early 2009.

Use by a private citizens is regulated in some states, such as California, where California Penal Code Section 637.7 states:

(a) No person or entity in this state shall use an electronic tracking device to determine the location or movement of a person.

(b) This section shall not apply when the registered owner, lesser, or lessee of a vehicle has consented to the use of the electronic tracking device with respect to that vehicle. (

c) This section shall not apply to the lawful use of an electronic tracking device by a law enforcement agency.

(d) As used in this section, “electronic tracking device” means any device attached to a vehicle or other movable thing that reveals its location or movement by transmission of electronic signals.

(e) A violation of this section is a misdemeanor.

( f ) A violation of this section by a person, business, firm, company, association, partnership, or corporation licensed under Division 3 (commencing with Section 5000) of the Business and Professions Code shall constitute grounds for revocation of the license issued to that person, business, firm, company, association, partnership, or corporation, pursuant to the provisions that provide for the revocation of the license as set forth in Division 3 (commencing with Section 5000) of the Business and Professions Code.

Note that 637.7 pertains to all electronic tracking devices, and does not differentiate between those that rely on GPS technology or not. As the laws catch up with the times, it is plausible that all 50 states will eventually enact laws similar to those of California.

Of course, other laws, like the common law invasion of privacy tort as well as state criminal wiretapping statutes (for example, the wiretapping statute of the Commonwealth of Massachusetts, which is extremely restrictive) potentially cover the use of GPS tracking devices by private citizens without consent of the individual being so tracked. Privacy can also be a problem when people use the devices to track the activities of a loved one. GPS tracking devices have also been put on religious statues in order to track the whereabouts of the statue if stolen.

Recently, debate ensued about a Georgia proposal to outlaw hidden GPS tracking, with an exception for law enforcement officers but not for private investigators. See Georgia HB 16 – Electronic tracking device; location of person without consent (2009).

Brazil

In Brazil a new law was approved in order to obligate GPS installation in every new car in Brazil as from August 2009 Contran 245, this law was assigned to the Denatran. The law segregated the LBS service provider from the equipment manufacture and the Telco provider. Hence LBS would be provided by the leading RF service providers in the country and will be an easy option to every Brazilian.

This law had a clear determination to use the GPS tracking and location capacity in order to provide the recovery of stolen car in case of a theft. For the insurance companies, for the final user this will be a great benefit, the recovery services would be provided by the local and national police through the recovery services providers. In Brazil due to high theft rate (5%) such a product is a need.

Countermeasures against GPS trackers

The consumer electronics market was quick to offer remedies (radar detectors) to radar guns; a similar market may exist for devices to counter satellite tracking devices. Radio jamming of the relevant GPS or cell phone frequencies would be an option, as would a device which could detect the RF emissions of the GPS receiver circuitry. However, jamming of GPS signals could create a safety hazard to vehicles or aircraft within line of sight of the jammer, and any deliberate radio interference is likely to be illegal in most Western countries.

Besides this, jamming the transmission frequency of an industrial grade GPS transmitter would only work temporarily because most of them use a “store and forward” procedure to store up points that were not received and transmit them again later. This capability is built-in so tracked vehicles don’t lose data when they are out of cellular range temporarily. Jamming the actual GPS frequency, however, would result in the GPS transmitter simply thinking it had lost sight of the satellites.