You're Under House Arrest: How GPS Monitoring Devices Work
A practical, day-to-day guide explaining exactly how your ankle monitor tracks your location, enforces your schedule, and communicates with your supervising officer.
Hearing a judge order you to house arrest can be a relief—it means you are going home instead of to jail. However, the anxiety quickly sets in when you realize you will be wearing a tracking device 24/7. How does it know where you are? What happens if you step outside? Will it randomly go off?
At My GPS Monitor, we believe that understanding the technology is the best way to alleviate that anxiety and ensure you complete your program successfully. Here is exactly how your GPS ankle monitor works while you are on house arrest.
The Tracking Mechanics: Satellites and Cell Towers
The device strapped to your ankle (like the ReliAlert™XC4) is essentially a highly ruggedized smartphone without a screen. It uses two primary methods to determine your location:
1. GPS Satellites
The device constantly receives signals from global positioning satellites orbiting the earth. By calculating the time it takes for these signals to arrive, the device pinpoints your exact location on the globe, usually within a few feet. It does this every 2 seconds.
2. Cellular Triangulation
If you are deep inside a concrete building or a basement where satellite signals can't reach, the device automatically switches to the 4G LTE cellular network. It triangulates your position based on your distance from nearby cell towers, ensuring your location is never "lost."
Inclusion Zones and Schedules
Knowing your location is only half the battle; the system must know if you are allowed to be there. This is managed through mapping software.
During your intake process, an "Inclusion Zone" is drawn around your home. If your rules state you cannot leave your property, the moment the GPS dot crosses that digital boundary, an alert is sent.
If you have approved work or school hours, the system uses scheduling. For example, the software knows that between 8:00 AM and 5:00 PM, your inclusion zone shifts to your workplace. If you leave work early, or stop at a location not on your approved route, the system flags it as a violation.
Exclusion Zones
Conversely, "Exclusion Zones" are places you are legally forbidden to go, such as a victim's home or a certain neighborhood. Entering an exclusion zone triggers the highest level of alert, often dispatching law enforcement immediately.
Communication: The Device Can Talk
One of the most surprising features for new wearers is that the device can talk to you. As detailed in our post debunking monitor myths, the device features 3-way voice communication.
If you are nearing a boundary, or if your battery is critically low, the monitoring center can call the device. It will ring, auto-answer, and a live operator will speak to you through the ankle monitor, instructing you to correct your behavior before a formal violation is recorded.
Your Responsibilities
The technology is advanced, but it requires your cooperation. To avoid violations, you must:
- Charge Daily: You must sit tethered to the wall charger for at least 2 hours every day. A dead battery is a violation.
- Protect the Device: While waterproof for showering, you cannot submerge it in a bath or pool. You must not tamper with the strap.
- Stick to the Schedule: Deviations from your approved schedule, even minor ones, will trigger alerts.
Conclusion
House arrest relies on a complex web of satellites, cellular networks, and mapping software. By understanding how the device tracks you, enforces your zones, and communicates, you can navigate your time on monitoring smoothly and without incident.