Basics
GPS tracker: what it is, how it works and what it is for
A GPS tracker reports a vehicle position over the mobile network. Here is what is inside one, how the position reaches your phone, and what the data is actually used for.
Updated · 6 min read · Runic
Short answer
A GPS tracker is a small device fitted to a vehicle or asset. It reads its position from GPS satellites, then sends that position over a mobile network to a server, where you see it on a live map. Most trackers report every 10 to 60 seconds while moving and far less often when parked.
Key takeaways
- A tracker needs two radios: GPS to read position, and a mobile SIM to send it.
- Plug-in OBD trackers take about two minutes; hardwired units are fitted by an installer.
- Accuracy in open air is typically 3–5 metres; dense cities and underground parking are worse.
What is inside a GPS tracker
Three parts do the work. A GNSS receiver listens to satellites and calculates a position. A cellular modem with a SIM sends that position to the platform. A small controller decides when to send, buffers positions when there is no signal, and reads vehicle signals such as ignition state.
Hardwired units add an internal backup battery so they keep reporting for a while if the vehicle battery is disconnected — which is exactly what happens during a theft.
How a position reaches your phone
The tracker fixes its position, wraps it with speed, heading and ignition state, and pushes it to the platform over the mobile network. The platform stores it, turns consecutive points into trips, and evaluates your rules — geofence crossings, movement while parked, harsh events.
- Moving: a position every 10–60 seconds
- Parked: a heartbeat every few minutes to hours
- No coverage: positions are buffered on the device and sent when signal returns
What people actually use it for
For a private owner it is mostly recovery and reassurance: where is the car, has it moved, alert me if it does. For a company it is operational: proof of service, working hours, route history for disputes, and knowing which vehicle is closest to the next job.
Insurers and rental firms use the same data for mileage and usage evidence, which is why a good tracker keeps trip history rather than only the last position.
How accurate is it
With a clear view of the sky, expect 3–5 metres. Urban canyons, metal-heavy vehicle bodies and underground parking degrade that, and an indoor tracker may show its last known outdoor point. This is normal behaviour, not a fault: a tracker reports the last position it could trust.
Frequently asked questions
- Does a GPS tracker need a SIM card?
- Yes. GPS gives the device its position, but a mobile SIM is what sends the position to the platform. With Runic the connectivity is part of the annual plan.
- Does a tracker drain the vehicle battery?
- A wired tracker draws a few milliamps in sleep, which is negligible for a vehicle used weekly. For vehicles parked for months, use a battery-powered asset tracker instead.
- Can a GPS tracker be jammed?
- A determined thief can use a jammer. That is why tamper and power-cut alerts matter: you get notified the moment the signal or power drops, not hours later.