Global Positioning System devices are commonly used to find your location in the world, plotting position using satellites, cell-tower triangulation or a combination of the two. When used for investigations or simply keeping tabs on your employee or child's whereabouts, employing GPS tracking can be incredibly useful. Understanding the different types of GPS tracking will help you make a determination as to which is the most effective for your needs. In terms of accuracy, there is very little difference between active and passive GPS tracking devices. The key difference lies in data retrieval.
Active GPS trackers show in real time the location of a vehicle or individual, which you could track on a laptop with the right software. Commonly known as data pushers, active trackers require a monthly fee and are typically about three times the initial cost of passive devices. Since data is logged remotely and constantly or at preset intervals, internal memory or storage is not normally a relevant concern. Active GPS devices can plot an individual or vehicle within 2 meters, or roughly 6 feet, from their actual spot.
Passive trackers require retrieving the device and plugging it into a PC to view the device's collected details. Also known as data loggers, these units require retrieval and connection to a PC to view and store collected data. Passive trackers are good for companies wishing to improve delivery times, evaluating delivery drivers based on their times and knowing the amount of time vehicles remain idle. Passive trackers are also commonly used by private investigators monitoring suspicions of spousal infidelity. Passive units have a finite amount of memory, which must be cleared periodically like a flash drive.
Size and Portability
GPS trackers installed in vehicles tend to be smaller, roughly the size of a deck of cards and even as small as a pack of matches in the case of the TecNet TTL-1000 GPS Tracker/Logger. Small size enables easier installation -- and easier concealment. Trackers in the form of wristwatches and handheld GPS units that perform tracking functions come in a variety of sizes common to both devices. In general, dedicated tracking units fit in the palm of your hand, easily tucked under the dash or behind the trunk liner in most vehicles.
Hikers and rescue personnel who use wrist or handheld active trackers will have to replace batteries on occasion. In vehicle units wired to the car battery, replacement isn't a consideration. Battery life for portable devices will vary based on other functions the units perform, such as whether the tracker is part of a full-on GPS wrist piece or smartphone, and whether the unit logs or pushes data. Because each unit's term in the field will vary prior to battery replacement, it is always best to consult the individual unit's manual for replacement intervals.
Active GPS monitoring normally requires a cellular network to send data back to the connected PC or facility. In many rural places, coverage is spotty or nonexistent. In these cases, the key appeal for active tracking is lost, as the data will stop transmitting until it is again within range of cell towers. There is debate on whether data gleaned from GPS trackers is legally admissible in court, or whether it potentially constitutes illegal search. Although the debate is ongoing, the recent case of United States v. Jones indicates as much. Although this probably won't be a concern when tracking the location of minor children or of employees using company vehicles, such rulings may have an impact in future criminal cases. For example, in United States v. Jones, the U.S. Supreme Court held that placing a tracking device on Jones' vehicle without his consent constituted illegal search and seizure, in violation of the Fourth Amendment. Jones was indicted because a GPS device tracked his vehicle to a drug house, but -- in part because his vehicle constituted personal property -- the search was deemed illegal.
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