Electronic monitoring is court-ordered supervision that uses a wearable device, most often a GPS ankle bracelet, to track your location or detect alcohol use while you live in the community instead of sitting in jail or prison. Courts order it at nearly every stage of the justice system — pretrial release, probation, supervised release — and the technology has spread into immigration enforcement and domestic violence protection. The daily obligations, the fees, and the consequences of slipping up vary more than most people expect, and the details are where people get into trouble.
What the Device Actually Tracks
The specific technology assigned to you depends on what the court is trying to control. Four main types are in use.
GPS Tracking
A GPS tracker is a non-removable, waterproof, shock-resistant device fastened to the ankle (or, for documented medical reasons, the wrist) and worn 24 hours a day. It uses satellite signals, cell towers, and Wi-Fi to calculate your location continuously.1United States Courts. How Location Monitoring Works Your supervising officer programs inclusion zones (where you must stay) and exclusion zones (where you cannot go). Crossing either boundary triggers an immediate alert, and federal policy requires officers to respond to those alerts around the clock.2United States Courts. Location Monitoring Reference Guide
Radio Frequency Monitoring
Radio frequency (RF) monitoring is simpler and cheaper. You wear an ankle transmitter that sends a constant radio signal to a receiver plugged in at your home. The receiver logs when you enter and leave its range and relays that information to a central monitoring computer. RF can confirm whether you are home, but it cannot tell anyone where you are once you leave.3U.S. Courts. Chapter 3 – Location Monitoring (Probation and Supervised Release Conditions) That makes it a natural fit for curfew enforcement or home detention.
Alcohol Monitoring (SCRAM)
The Secure Continuous Remote Alcohol Monitor, or SCRAM, is an ankle bracelet that tests for alcohol through the skin. Every 30 minutes it samples perspiration and measures transdermal alcohol concentration, with a confirmation threshold of 0.02. The system can distinguish between alcohol you drank and alcohol from environmental sources like hand sanitizer or cleaning products.4Abbott Toxicology. SCRAM Continuous Alcohol Monitoring Courts commonly order SCRAM in DUI and DWI cases and for anyone whose release conditions prohibit drinking.
Voice Recognition and Biometric Check-Ins
Not every form of monitoring involves an ankle device. Voice recognition systems place or receive random phone calls (usually to a landline) to confirm you are at your approved location. Some districts have moved to smartphone-based check-ins that use facial recognition, fingerprints, or passwords, along with the phone’s GPS.3U.S. Courts. Chapter 3 – Location Monitoring (Probation and Supervised Release Conditions) These approaches are typically used for lower-risk participants.
When Courts Order Monitoring
Pretrial Release
Courts frequently order electronic monitoring as a condition of bail or pretrial release when a defendant poses a moderate flight risk but does not need to be held in jail awaiting trial. Under federal law, a court can require a defendant to remain at home during nonworking hours and have compliance monitored electronically, but only as an alternative to incarceration.5Office of the Law Revision Counsel. 18 US Code 3563 – Conditions of Probation
Probation and Supervised Release
After sentencing, monitoring can be imposed as a condition of probation or supervised release. Federal courts use three tiers. Curfew requires you to be home during set hours. Home detention allows you to leave for work, education, religious services, medical treatment, and pre-approved activities. Home incarceration is 24-hour lockdown, with exceptions only for medical emergencies and court appearances specifically approved by the judge.3U.S. Courts. Chapter 3 – Location Monitoring (Probation and Supervised Release Conditions) Officers are expected to reassess regularly whether the current technology and restriction level still fit, and to request court approval for modifications when they do not.
Immigration Enforcement
U.S. Immigration and Customs Enforcement runs Alternatives to Detention programs that place noncitizens on electronic monitoring while their immigration cases are pending. The program pairs case management with monitoring or other reporting requirements to improve court appearance rates without holding people in immigration facilities.6U.S. Department of Homeland Security. DHS/ICE/PIA-062 Alternatives to Detention (ATD) Program
Protective Orders in Domestic Violence Cases
GPS monitoring plays a growing role in enforcing protective orders. When a court orders a defendant to stay away from a victim, GPS exclusion zones can be drawn around the victim’s home, workplace, and children’s school. If the defendant crosses those boundaries, the monitoring center can contact the victim in real time.
What Daily Life Looks Like
The ankle bracelet is waterproof and designed to survive showers, baths, and ordinary daily activity. It is fitted tightly enough that it will not slip off but loosely enough to change socks. You cannot remove it.
The bigger practical disruption is charging. GPS devices need to be plugged in for roughly two hours every day, which means you are tethered to an outlet for a stretch (usually while sleeping). If the battery dies, the system flags it the same way it flags tampering, and your officer gets an alert.1United States Courts. How Location Monitoring Works
Your daily schedule is submitted to your supervising officer in advance. If something changes — a doctor’s appointment, a shift at work, a family emergency — you need prior approval. Showing up somewhere that was not on the approved schedule, even for a legitimate reason, can trigger an alert. This is where most people run into trouble: not because they are doing something wrong, but because they forgot to call their officer before deviating from the plan.
Your Obligations While Being Monitored
The specific conditions depend on your court order, but most programs share a core set of requirements:
- Keep the device charged. A dead battery triggers the same alert as tampering. GPS units generally need about two hours of charging a day.
- Follow your curfew. Be at your designated location during the hours set by the court.
- Stay within approved zones. GPS-monitored individuals have programmed inclusion and exclusion zones; common exclusion zones include schools, parks, and a victim’s residence.2United States Courts. Location Monitoring Reference Guide
- Abstain from alcohol or drugs if ordered. SCRAM and drug-testing conditions detect violations automatically.
- Check in with your officer on the schedule you are given — monthly, weekly, or daily, by phone, in person, or by app.
- Get prior approval for any schedule change.
- Do not tamper with the device. It detects attempts to cut, loosen, block, or shield it, and tampering alerts require an immediate officer response.2United States Courts. Location Monitoring Reference Guide
What Happens If You Violate the Conditions
Not all violations are treated the same. A minor slip — coming home 45 minutes after curfew, letting the battery die once — is often handled administratively. Your officer may give a verbal warning, tighten your conditions, increase the frequency of check-ins, or bump you to a higher supervision level. Those consequences sting, but they do not necessarily put you back in front of a judge.
Serious violations are a different story. Cutting off the bracelet, absconding, picking up a new arrest, or repeatedly ignoring curfew will typically be reported to the court. The judge can then modify your conditions, extend your monitoring period, or revoke your release. Under federal law, a court revoking supervised release can send you to prison for up to five years if the underlying offense was a Class A felony, three years for a Class B felony, two years for a Class C or D felony, and one year for lesser offenses.7Office of the Law Revision Counsel. 18 US Code 3583 – Inclusion of a Term of Supervised Release After Imprisonment Certain violations trigger mandatory revocation: possessing a controlled substance, possessing a firearm, or refusing drug testing all require the court to revoke supervised release, with limited exceptions.
Courts rarely revoke someone’s release on a computer-generated alert alone. The alert prompts an investigation, and the officer gathers additional evidence before formal proceedings. But the alert is not harmless. It creates a paper trail, and a pattern of minor violations can eventually look like a serious compliance problem.
Who Pays
In many jurisdictions, you pay for your own monitoring. Programs commonly charge a daily fee that ranges from a few dollars to $40, depending on the technology and the jurisdiction. GPS generally costs more than RF. One-time setup or installation fees can add another $25 to $300. Even at $10 a day, a six-month monitoring period runs $1,800 out of pocket.
Some jurisdictions offer sliding-scale fees based on income, and courts can sometimes waive or reduce fees for people who qualify as indigent. If you cannot afford the fees, raise it with your attorney before the monitoring order is entered. Courts are more receptive to fee discussions during sentencing than after you have fallen behind on payments.
Privacy and Constitutional Limits
The U.S. Supreme Court addressed the privacy question directly in 2015, ruling in Grady v. North Carolina that attaching a monitoring device to a person’s body without consent to track their movements is a search under the Fourth Amendment.8Justia Law. Grady v North Carolina, 575 US 306 (2015) That does not make monitoring unconstitutional; it means the government needs a reasonable basis for ordering it. A court order tied to a criminal case or release condition almost always satisfies that standard.
The practical concern is what happens to the data. GPS monitoring produces a minute-by-minute record of everywhere you go for months or years. Who can access that data, and how long it is retained, varies by jurisdiction and vendor. Some agencies delete data on a set retention schedule; others preserve it indefinitely if it has evidentiary value. The monitoring vendor typically has access to the raw location data as well, usually without identifying information attached.
Federal policy requires location monitoring to be “dynamic,” meaning officers should regularly reevaluate whether the current technology and restriction level are still appropriate and request court modifications when circumstances change.3U.S. Courts. Chapter 3 – Location Monitoring (Probation and Supervised Release Conditions) If your compliance record is strong, your officer can recommend stepping down to a less restrictive technology or ending monitoring early.
How Monitoring Starts and Ends
Monitoring begins with a court order or directive from a supervising authority specifying the technology, the duration, and the conditions. The device is typically installed at a probation office, though some installations happen at a residence or at the jail on the day of release. Your officer programs the schedule, zones, and curfew into the system, and the device goes live.
It ends when you complete the court-ordered term, when the court grants early termination, or when your officer recommends and the court approves a modification removing the monitoring condition. Under federal supervised release, a court can terminate supervision early after you have completed at least one year, if your conduct and the interests of justice support it.7Office of the Law Revision Counsel. 18 US Code 3583 – Inclusion of a Term of Supervised Release After Imprisonment You return to the office, the device comes off, and the monitoring obligation is over.