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27 August 2007

The Department of Corrections is introducing Global Positioning System (GPS) technology for limited uses, after two year trials that included ‘live’ tests of the equipment involving offenders in the community.

Community Probation and Psychological Services’ General Manager Katrina Casey says GPS is to be used for up to 60 offenders a year to record their whereabouts while employed at large work sites, training institutions, or when they take journeys, for example to attend a funeral.

She says the trials showed the new technology could, in some circumstances, be used to supplement the existing electronic monitoring system, used currently for offenders subject to Electronic Monitoring. There was no prospect that the GPS technology could be used to replace existing technology, as it was too unreliable. In effect GPS would, in limited situations, replace manual monitoring or expand possible places that can be monitored.

Trials being undertaken in the United Kingdom show the public has an incorrect perception that GPS involves real time tracking of offenders, and that the monitoring company is able to actively watch the offender via satellite. Neither could or will happen in New Zealand in the short to medium term, Ms Casey says.

She says both countries have tested GPS as a retrospective monitoring tool only. Offenders need to carry a GPS locator unit when they leave their residence, and their location is transmitted to a unit stored at a central monitoring centre.

In retrospective tracking mode, the information is accessed and analysed over the next day or two. Any abnormalities in movements are relayed to the probation officer, for possible breach action to be taken against the offender.

Ms Casey says the New Zealand trials have been successful in showing that GPS equipment can help with monitoring offenders in large “inclusion” zones other than their homes - such as if they are working in a construction yard, or if they are undertaking education at a tertiary institution. This means the circumstances in which employment can be approved for offenders subject to Electronic monitoring can be expanded.

From October this year, the 20 units bought at a cost of $165,000 for the trials will be used for commitments such as work, education, or compassionate or reintegrative absences, for individual offenders on sentences of Home Detention, with offenders who have residential conditions on their Parole Orders, and also for some offenders on Extended Supervision Orders. Standard electronic monitoring equipment will still be used while the offenders are at their homes.

Meanwhile trials are to continue for Voice Verification Technology (VVT) with the aim of using it in part to monitor a new Community Detention (electronic curfew) sentence being introduced in October.

Ms Casey said the VVT trials have so far shown the equipment can confirm identity, but have not proven that it can confirm the telephone number used - and therefore the location of an offender.

She says the Department will continue to compare research and experience of such new technologies with other Corrections’ jurisdictions around the world, including the United Kingdom, to seek the most effective means of monitoring offenders on community-based sentences.

Please see background notes attached. For further information contact the Communications Services Desk:

Background notes:

The Department has completed two phases of trials of two new electronic monitoring technologies - global positioning system (GPS) technology and voice verification technology (VVT).

Phase I took place during 2005 and tested technology using staff and other (non-offender) volunteers. Phase II took place between May 2006 and March 2007 and tested the technology in a live operational context.

The trials were designed to test the:

  • Technologies themselves (reliability and accuracy)
  • Operation in New Zealand’s geography and infrastructure
  • Effectiveness in the Community Probation and Psychological Services’ environment - within the legislative framework, and types of offenders and situations where the technology could be used.

A total 42 offenders were monitored using GPS technology in addition to standard technology.

  • Standard technology involves an ankle bracelet that signals via radio frequency to a home monitoring unit placed in the home boundary. This unit relays information via cellular technology directly to a central monitoring unit (Chubb office).
  • GPS technology uses the same ankle bracelet to signal a GPS locator unit (cell phone size) that the offender carries whenever they leave their residence. The locator unit communicates with a GPS positioning satellite to record location, and the information is sent from the locator unit to the central monitoring unit via cellular technology.

An average of five or six offenders were monitored at any given time through the 10 months of Phase II trials. Those monitored included offenders convicted of dishonesty, drug-related, violence and sexual offending.

A total 14 offenders were monitored using VVT, with the primary purpose to test the ability of the technology to “voice match”.

GPS conclusions

GPS technology:

  • should only be used as a retrospective monitoring tool, as there are significant risks associated with its potential use as an active (real time) tool in New Zealand;
  • should only be used in conjunction with standard electronic monitoring technology, not as a stand-alone monitoring technology;
  • should only be used in situations where it is not possible to obtain sufficient monitoring of the offender using other monitoring methods;
  • can be used to retrospectively monitor the whereabouts of offenders on home detention, (and on occasion parole and extended supervision, as long as they are willing and able to co-operate with the requirement to use the equipment appropriately);
  • can be a useful tool to retrospectively monitor compliance with large exclusion and inclusion zones, and compliance with approved travel routes; and
  • has limited use as a tool to monitor compliance with small inclusion or exclusion zones (including individual buildings).

GPS - limitations

It had been hoped that the trials would demonstrate that GPS monitoring is a useful tool for managing the risk posed by child sex offenders (e.g. by monitoring special conditions to stay away from areas where children are likely to be present, such as schools). However, the trials have shown that there are a number of practical problems associated with this approach (particularly around the size of the boundaries that have to be set, and the limited accuracy of the monitoring information).

GPS - uses

The trials have indicated that there are a relatively small number of circumstances in which GPS technology is the only appropriate method of monitoring the offender’s whereabouts. However, where this is the case, the benefits for the individual offender can be significant (e.g. the ability to retain or obtain employment, and the ability to attend a long or distant pro-social activity, that would otherwise not be permitted).

VVT conclusions

The trials concluded that VVT can confirm the identity of an offender, and can be used to make random calls to a specified telephone number, during a specified period.

It has not conclusively demonstrated that VVT can confirm the telephone number used, and thereby the location of the offender. Overseas experience indicates this can be done, so New Zealand research and testing will continue with a view for its use in the proposed Community Detention sentence. This is effectively an electronic curfew sentence that judges might consider suitable for ‘boy racer’ and some property offenders.


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