The Tractive GPS tracker uses GPS (Global Positioning System) to accurately determine its location. The tracker receives signals from GPS satellites with a built-in GPS antenna and infers the distance to the satellites from the signal's travel time. The tracker can calculate its position when the distances to at least 4 satellites are established. The more GPS satellites it can detect, the greater the accuracy.
According to the U.S. SPS Performance Standard, GPS signals provide an accuracy of 7.8 m (25 ft) at a 95% confidence level when calculating the distance between satellite and receiver.
GPS signals can be influenced by various environmental factors. The following picture shows different sources of interference that can compromise GPS accuracy or even block the signal entirely.
I = Interference from particles in the ionosphere, 70 - 400 km above sea level. Due to the high concentration of ions and free elections in this area, GPS signals can be significantly altered.
II = Interference from water vapor in the troposphere. Especially on cloudy or rainy days, GPS accuracy can be reduced.
III = Interference due to reflections on buildings or hilly terrain. High-rise buildings or hills and mountains in the vicinity can block or alter GPS signals. Large water or glass surfaces can cause reflections that might throw off the tracker.
The interplay of these various types of interference can result in a discrepancy between the location shown in the GPS app and the real location of the tracker.
GPS inaccuracies occur mostly indoors, because GPS signals are blocked by walls and ceilings. When the GPS tracker doesn't receive GPS signal, it tries to determine its location based on the availability of cell towers. In this case the tracker can only give a rough estimate of its position (50m accuracy maximum).
Route recording and differences to smartphones and navigation systems
Moderns smartphones use a combination of GPS, cell networks, Bluetooth as well as large databases of WLAN networks to determine location. To get these databases Google and Apple collect a huge amount of user data. Tractive GPS doesn't collect any such user data and only makes use of GPS- and cell network signals to locate your pet.
Automotive navigation systems are optimized for street navigation. Imprecise positions away from roads are corrected automatically to match up with the street map. This leads to more accurate route recordings. Since pets frequently travel away from roads, a similar route optimization isn't possible for pet trackers.
Smartphones and navigation systems show the GPS positions directly on the built-in display. Pet trackers need to transmit the GPS data to the smartphone of the pet owner, before it can be displayed. Because this requires a lot of energy, it can only be done in certain time intervals. Individual position updates are then connected by straight lines in the location history, which can result in routes that don't quite match up with the actual path taken. To get more accurate GPS recordings, you can activate LIVE-Tracking anytime.