Offender Management Product Testing

BACKGROUND Home Office CAST (Centre for Applied Science and Technology) has been tasked with assessing a product, known in the industry as an electronic tag. These tags are used by government for the purpose of offender management.

Upon authorisation from a UK court of law a tag is assigned and fitted to an offender. Fitment is typically around the ankle and legitimate removal thereof is only possible through the authorised use of special equipment.

Once fitted the tag is activated to perform one or both of two functions: 1. Alert the authorities to a bridge of agreed terms, for example leaving or entering set boundaries, or tampering with the tag’s normal operation 2.

Continuous reporting of the geographical location of the wearer The main components inside the tag are the mobile transceiver module and the GNSS (Global Navigation Satellite System) module. The mobile transceiver module allows for a number of mobile communication technologies, but currently most of the UK products employ only 2g GSM (900/1800) and 3g UMTS.

The GNSS receiver module also allows for a number of different satellite-based location systems, but currently uses mostly GPS (Global Positioning System). Both the Alerts and the Geographic Location Data are transmitted to a secure web server via the mobile phone network.

The web server has a graphical user interface, allowing human operators to monitor assigned tags. Tags can also be individually interrogated to provide immediate status updates or to perform configuration changes.

This can either be done remotely via the mobile phone network, or locally via an onboard infrared or short range RF (Radio Frequency) transceiver facility REQUIREMENT One particular tag model has undergone hardware and software updates. In order to verify this improvement CAST needs to test and compare the results of both the original and the updated tag.

As testing needs to be consistent and repeatable, it’s essential that it be done in a controlled environment that involves a shielded and absorber-lined chamber. Furthermore, to determine the degree of operational consistency between tags, up to three of both the old and of the new tags will be made available for testing, amounting to a possible maximum of six tags being tested. Given the changes claimed by the supplier, testing must focus on three aspects: • Performance of the 2g/3g transceiver together with its antenna • Performance of the GPS receiver together with its antenna • Duration of operation on a single charge under worst case conditions Although it will be left to individual bidders to decide upon the most appropriate way of testing these aspects, testing is likely to require the use of a 2g/3g base station simulator, a GPS simulator, and the ability of the test chamber to allow signal from the live GPS and 2g/3g networks to be made available within the chamber.