Dreaming of a Better World or Why We Must Push for Standardization of Electronic Monitoring

Imagine….  Electronic Monitoring is no longer based on the electronic bracelets, but rather, on a cutting-edge no-tag, self-installing solution that seamlessly interfaces with a user-friendly and flexible application that can be managed on the move. The EM programs manage all the stages of offender’s rehabilitation from in-facility tracking to location-based tracking outdoors. The EM solutions become so advanced, in fact, that now you not only can monitor offender’s whereabouts, but also health, levels of stress and mood, amounts of daily physical activity, calories consumed and burnt and much more. It is very clear how cost-and-socially-effective EM programs are, and they become part of a golden standard for rehabilitating prisoners, adopted by almost all the governments of the world.  As a result, the EM vendors are now a part of a much larger market, and so they see their revenues grow. The EM becomes a domain of progress and innovation, enabling safer communities and better world, while becoming a part of the eco-system of Smart Cities and Internet of Things.

There are reasons for the separation of this idyllic example. One of the most important is:

Lack of Standardization.

Why is standardization so important?

Industry-wide standards play a vital role in our globalizing world. Standards make an important contribution to national and international competitiveness.

Standardization does not just facilitate the transfer of knowledge but also the opening up of markets.

Standards support the innovation capability of enterprises for products, services and management by creating objective and internationally recognized parameters, targets and yardsticks for business activity.

They create leeway for innovation. Experience clearly shows that new technical standards often give a foothold to new technologies.

Standards are also a great help for the legislator and the administration. They provide assistance in the technical and practical implementation of legal requirements.

With civil servants participating in the drawing up of standards in their respective areas of expertise, standards can improve the description and implementation of legal requirements (http://www.directionsmag.com/entry/the-impact-of-international-standardization/123376).

Experience clearly shows that new technical standards often give a foothold to new technologies. Various industries ( e.g. semiconductors, environment,  energy, healthcare, transportation and many others) have successfully worked on and adopted international standardization which turned out highly beneficial for all the market players.  What were the benefits? –  Interoperability of products and services, innovation, improved design and quality of products, easier access to international markets and markets growth, better communication between manufacturers and suppliers and other benefits.

Why does Electronic Monitoring need standardization?

Today, a typical EM solution is the one where a single vendor provides all of the system components, creating a great deal of vendor dependency. Vendor dependency leads to mediocrity, stagnation and high solutions cost; the customers (government agencies and, ultimately, taxpayers) pay the high price. It also creates a distorted picture of EM program’s efficiency making EM’s progress harder to measure and analyze, as customers’ only source of information is vendor-based and with virtually zero objective information available.

The idyllic example at the beginning of the post might be a bit far-fetched but it comes to illustrate how standardization and interoperability can greatly benefit both the government agencies and the vendors.

If we can start turning the standardization wheel now, in the near future we should be able to achieve:

  1. Interoperability between solution components of different vendors – mixed vendor solutions, for optimal technological and budgeted solutions.
  2. Ease of integration with zero-touch provisioning.
  3. Improved hardware quality, durability (e.g.- battery life, location services) safety and performance.
  4. Better data analytics and information gathering.
  5. Adoption of “Best of Breed” approach, enabling technological and service excellence and implementation of new, out-of-industry technologies.
  6. Unlocking of the new markets and new revenue streams generation for the EM vendors.

 Archibald MacLeish said, “There’s only one thing more painful than learning from experience, and that is not learning from experience.”

 If nothing is done today, I believe, that our entire industry might pay a heavy price tomorrow.


What are your thoughts? Please share your comments and thoughts on the idea of standardization and interoperability. I would love to know how you perceive this concept, via https://www.em-is.com/index.php/contact/ or mail to emis@em-is.com 

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This Post was written by Mr. Nuno Caiado – Head of Portuguese EM dept.

Portugal started using Electronic Monitoring for Domestic Violence (DV) several years ago. Since 2012, it initially started with RF reverse tagging and later, GPS technology, which meant territorial and mobile exclusion zones, along with involving the victim in the Electronic Monitoring operations. Today, we manage around 475 cases on a daily basis nationwide. The program is managed by the EM Department, which is a part of the Probation branch of Portuguese Correctional Services.

The Domestic Violence program began with a very strong political drive, which caused the transition from RF to GPS too quickly. This was a very serious mistake that the Probation service could not avoid. We would like to pilot first, then gradually evaluate and extend.

Nonetheless, we consider GPS to be the right tool for the purpose of controlling DV offenders. GPS is more appropriate than RF because it provides more accurate information both for the offender and the victim, unlike with RF. With RF, you would just be alerted if the offender approached the victim at home and if the bracelet wasn’t removed. If it was removed, no alert will be generated (also when the battery is low).

Most cases run as a pre-trial when court feels the urgency of controlling the aggressive impulses of offenders, while avoiding prison. For after-trial cases, offenders must be submitted to other programs focusing on aggressive behavior, such as Behaviorist programs. While in these programs, offenders learn to recognize the problem and then to control themselves.  This approach combined with EM seems to be a better solution in preventing recidivism. EM is an excellent tool to gather more knowledge on whether the exclusion zones are actually met by the offender.

However, we stress EM should not be used in all DV cases. We believe most cases do not require such aggressive and intrusive action that EM provides and a small number of other cases demands an even stronger response that only can be given by incarceration. The EM tool can be a great tool in cases with medium-risk offenders.

After studying 850 DV cases, we have a compliance rate between 97 and 98%, which is considered to be good. This figure seems to be high but why is that? We have identified three causes: 1.) Operations are conducted in a very rigorous way, where we try to pay attention to all events trying to connect them with the knowledge we have gathered of the persons involved) 2.) EM can be really corrective and pedagogical 3.) There is a net widening effect, which means there are too many low- risk offenders in the system.

Perhaps, it can be useful to highlight some key aspects based on our experience.

Pilot – always pilot first! The price of the absence of a pilot will always be paid at greater cost because knowledge about the technology and the settlement of the procedures was not acquired in an experimental and controlled environment. Consequently, this hands-on learning is done in the worst of circumstances.

Proximity – this is the most critical point to manage when you have a considerable amount of cases. In a majority of them, offenders and victims live in the same city borough or in the same small village. This is usually a severe problem in the management of operations. When people live closer to each other, there is a pattern of movements. People tend to use same local resources (transportation, supermarket, parks, services and stores) and to have overlap routines, which generate frequent alarms. You can have it due to intentional or unintentional approaches from both the offender and the victim. So, you can say you have a lot of information about two persons, but their indicators of behaviors needed to be read very carefully. This creates exhaustive work to follow the case. Not surprisingly, you can find a significant burnout among the staff. This issue would benefit from a technological solution to mitigate the problem.

Offenders under this kind of EM are frequently “wilder” than the traditional home curfew or house arrest offenders. Not being under the pressure to remain inside for 24 hours a day makes a difference because they feel the weight of the course of justice in a less severe manner, despite the limitations to which they are subjected to. Your offender’s behavior is more rugged and less disciplined because of this. On the other hand, DV victims are frequently dubious regarding their offenders, which reflects the behaviors in the system.

Telecoms – we use 2G, but it is a limited tool because you cannot use data and voice communications at the same time, unlike 3G, which we are changing to soon. Moreover, 3G is expected to provide faster communication as well.

Final comment – The EM industry should listen to the needs and concerns of their consumers. They should be inspired by the issues they face and strive to meet their needs in a way that will create solutions for justice.


If you have any questions or concerns, please contact me at nunocaiado@sapo.pt.

Keeping Privacy While Tracking

What does “privacy” mean in EM Location Tracking context

One of the most troubling aspects (mostly in Europe) while tracking an offender by a “GPS” device is the privacy. My interpretation of it, in this sense, is that the authorities respect the offender’s right to keep his location information to himself, unless this offender performs any breach. In most of the cases, the usage of GPS tracking is to enforce exclusion and inclusion zones (special zones) regime. So if this is the case, why do we need to collect location information while not in the special zones?

What are we trying to achieve with GPS tracking

From the supervision agency perspective, the “GPS” tracking intends to supervise the offender out of his residential place. Trying to understand what it means “to supervise” brings me to the following options:

  1. Knowing the location of the supervised subject continuously (very high risk, privacy is not an issue, etc.)
  2. Enforcement of special zones

The location tracking solutions, currently, are serving both options without distinction between the required option. Even if the agency is not interested with the location points of the subject while not in a special zone, the devices are reporting their lat/long points (the location information) which are saved in the memory and data-base of the EM system.  I wonder why it is needed for the second point, why do we need to store all location points even if not in the neighbourhood of the special zones? I guess the reason is that from the technology perspective it covers all options. On the other hand, when the agency wants to keep the offender’s privacy, these registered points are prohibited.

 How to combine privacy and GPS tracking objectives

The answer is quite simple: let the device report its location only while offender is in violation, such as crossing exclusion zone, or missing the inclusion zone.

There are two main approaches the EM vendors are taking with regards to the “GPS” device capabilities:

  1. Using a relatively simple device without significant calculations capabilities. The backend EM system is taking care of all calculations. In this approach, most of the devices are not aware of the special zones. They report all the location points and the EM backend system calculates whether there is a zone violation. In such architecture, it is obvious that locations points should be uploaded into the system. This is the first breach of privacy.
  2. The other approach brings almost complete independency of the location tracking device. These devices are aware of the special zones, they can calculate whether there is a zone violation or not and they can keep many location points in the internal device memory. In addition, these devices report the location point.

Using the second approach devices and disabling the upload of the location points can serve the enforcement of the special zones while maintaining the offender privacy. In order to support high reliability of such an approach, it is highly recommended to have “secondary evidence”, by another location mean, such as LBS.

Another advantage of such an approach may be increased battery life. If there is no need to upload routinely the location points, the device can decide on the enable/disable location mechanism. If the offender is far away from a special zone and movements are low, the location mechanism can be disabled and will extend the battery life.

We will be happy to get your thoughts and feedbacks in order to better understand if this approach can mitigate the conflict of privacy and offender tracking. You can send your feeback here, or by email to emis@em-is.com.

GPS Location Tracking for Electronic Monitoring – Part 1


This article is the first part out of a two, describing technical and operational aspects of using Location Tracking (GPS) solution for electronic monitoring of offenders. The second part will provide insights about the common location tracking approaches, one and two piece solutions. The working definition for Electronic Monitoring is a system that monitors people of interest to the law or under probation or supervision.

Because most of the experts, users and decision-makers in this industry are not technologically-focused, we aim to give the technical and operational background that will increase your knowledge of the area without technical explanations and jargon.

Location Tracking (GPS)

Location tracking enables community supervision agencies to track subjects anywhere, not just when they’re close to a predefined point (the RF receiver). This enables them to know where subjects are at any point in time.

Unlike RF technology, location tracking for subject supervision began about     a decade ago, in the US. A few years ago, the only EM systems in Europe were based on RF technology. However, use of location tracking technology in Europe has grown in the past four years, although it remains low in comparison to North and Latin America. Most new EM product development focuses on location tracking rather than RF technology.

The basis of location tracking is a device worn on the subject’s ankle. This device contains a GPS receiver module, a cellular communication module (usually GSM in Europe), control, indication and memory elements. The GPS receiver manages the device’s satellite signal reception and location calculation. This location is reported to back-end servers by the communication module.

Location tracking technology should meet two criteria. Firstly, it should accurately identify the device location at all times and anywhere, including underground, underwater, indoors, outdoors, etc. Secondly, privacy considerations must be kept to the fore. As location tracking devices are usually used to enforce subjects staying inside an inclusion zone or outside an exclusion zone, law enforcement agencies should not need to know where subjects are most of the time, only when they are crossing a prohibited boundary. For this reason, data collected by location tracking devices must be carefully handled.

Problems arise because to calculate location, a GPS needs to acquire information from four satellites. This means that the probability of receiving the required signals while the subject is at home is low. For this reason, there is usually no functional GPS when a subject is at home. Even outside the house, in urban and underground areas for example, reception can be dodgy, so there is a significant amount of time when GPS is non-functional.

To mitigate this problem, most equipment vendors include additional RF transmitter/receivers to locate the offender while they are in a predefined location e.g. school, work, home. This additional module, which is part of the GPS ankle bracelet, communicates with a home unit (HU), or beacon, put in set locations. When the RF and HU units can communicate, there is no need for GPS as the location is assumed known.

The problem becomes more complex in other locations. LBS (Location-Based Services) are often used instead of GPS. LBS derive location from the proximity of tracking devices and cell towers. However, as this location is usually based on a single tower, information can be inaccurate, ambiguous or misleading.

A complementary approach is assisted GPS (A-GPS). One method is assistance with time to first fix (TTFF), i.e. getting GPS location faster when the satellite signal reception is renewed. Another uses LBS as described earlier. However, the accuracy of LBS can be improved by using a minimum of three towers. Location is computed using triangulation of information about cell tower IDs and the signal strength the tracking device receives from each tower.

Other location tracking options include using other satellite systems like Glonass, which may improve reception depending on the  location over the globe; dead reckoning based on inertial measurements; WiFi-based tracking; computation of the propagation of RF waves.

A device that could track location anywhere would probably use a smart algorithm to combine and integrate some or all of those technologies.

Battery Life in Location Tracking Devices

 Battery life is a particularly important factor in location tracking devices. This includes the time it lasts after charging, and how many charge cycles the battery can withstand before replacement. Operation time after charging depends on the following aspects:

  • Battery condition – The electrical capacity of the battery degrades after a certain number of charging cycles. A battery’s ability to withstand many charge cycles depends on its quality, but in EM equipment this period is usually between 12 and 18 months (taking one charging cycle per day). Battery performance is also affected by the environment (e.g. temperature, humidity), by usage profiles and more.
  • Operational working profile – The GPS (location) and GSM (communication) modules are heavy electrical power consumers. As requirements for GPS samples and communication to the backend increase, device operation time between charging cycles decreases. Hybrid or passive modes can come in useful here. EM vendors declare a battery life between 36 and 96 hours, but without information about the usage profile this information is not useful and cannot be comparable.
  • Initial electric capacity of battery – Obviously, a fully-charged battery will last longer between charge cycles.


Pros and Cons of Location Tracking Technology vs. RF technology


  1. Tracking (almost) everywhere, not just at home.
  2. Boundary (inclusion and exclusion zones) enforcement.
  3. Potential for expansion tools (e.g. crime correlation).


  1. Subject co-operation required, especially for charging.
  2. Poor indoor performance as a standalone solution.
  3. More staff needed than for home detention.