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How does Identicom help locate a lone worker?

Introduction

One of the primary goals of any lone worker protection system should be to get assistance to that worker as soon as possible should it be required. As such, gaining an understanding of the exact location of that worker is important, without this it is likely that delays will be incurred in getting help to the worker or indeed not at all.

From a technology perspective there are two common methods used in gaining a location in the context of lone worker applications. The first method sees the use of satellites (GPS) to gain a position and then report this typically using a mobile phone technology. The second is to gain a location from just the mobile phone network (LBS) and report using the same.

Currently, Connexion2 uses the latter of these two methods with its Identicom product as well as using the amber alert function to allow the user to record details of their whereabouts.

Global Positioning by Satellite (GPS)

Over the past five years GPS is a technology that has become widely recognised largely because of the use of GPS in vehicle tracking or in-vehicle navigation applications. With in vehicle tracking applications the location of the vehicle is taken from satellites and fed over a communications channel (usually GSM) to a central point which will then track the location on a map.

The benefits of GPS are as follows:

  1. High accuracy location, typically within 10m
  2. Significant market awareness leads to low barrier to entry

The disadvantages of GPS are as follows:

  1. A location fix can only be identified if at least 3 satellites can be seen by a device
  2. From cold start a ‘time to first fix’ (TTFF) can often take between 30-90seconds
  3. The device being located needs a dedicated GPS antenna, chipset and software
  4. Power consumption in the device is significantly more leading to reduced useage time
  5. There is a cost of additional hardware in the device

Out of the above disadvantages it is the first one that provides the major challenge particularly in the context of locating people. The one significant difference between locating a vehicle and a person is that vehicles by default spend the bulk of their time outdoors whilst the opposite is true for most people. GPS does not work effectively if the ‘line of sight’ between a device and the satellites is obscured. Not only does this render GPS ineffective indoors but also if any material gets in the way of this ‘line of sight’. It is fair to assume therefore that a worker in a vehicle or in a station or operating in a dense urban area with tall buildings may struggle to get a location fix from GPS.

Location Based Services (LBS)

The use of LBS on regular GSM based mobile phone networks is relatively new, it has only been in the last few years that the network operators in most countries have made LBS available for commercial purposes. As such it is a relatively unknown technology and has yet to gain broad market awareness. LBS works by feeding information back from the GSM network cell(s) that the device is currently logged onto back to a central point that then views this on a map. Currently the information fed back will include the exact location of the base station (cell) that the device is logged to and also information about the cell sector (i.e. direction within the cell) and the distance from the cell*.

The benefits of LBS are as follows:

  1. No additional hardware or software is required in the device
  2. A location fix can be achieved irrespective of indoor/outdoor coverage
  3. No delays in TTFF

The disadvantages of LBS are as follows:

  1. The accuracy of the location is not as good as GPS
  2. The density of cells available in the area helps define the accuracy of the location
  3. Currently a ‘location request’ incurs a cost from the GSM network operator

The simple fact that LBS will operate indoors as well as outdoors means that it is preferred in applications involving people, particularly those like many lone workers who face issues when they are inside a building. However, the lower level of accuracy means that it is often not possible to rely on LBS alone to identify the exact location of a person. Typically in urban or well populated areas the level of accuracy achieved will be 50-250m. In rural locations though, accuracy can often be several kilometres. It is therefore beneficial in many applications to ‘cross reference’ an LBS position with any other known data. Examples of this could include the known route of a bus (for location transport workers) or the known home addresses of patients (for social care workers or healthcare staff).

Amber Alert

Identicom has a unique ‘amber alert’ function. This dedicated single button on the unit provides the user with a simple ability to record details of their whereabouts. When activated the Identicom amber alert calls a predefined number (typically at an Alarm Receiving Centre, ARC) where the short call from the user is then recorded. This recording is not listened to at the time of recording and will only ever be used if an incident occurs and the user generates a red alert for assistance. At this point an operator in the ARC is able to replay the recording and cross reference the location details given with an LBS location taken on the Identicom.

The benefits of Amber Alert are as follows:

  1. Puts the worker in control, allows them to share the responsibility for their safety
  2. Simple one button operation and minimum time taken to record (typically 30seconds)
  3. Highly accurate location data
  4. No issues re indoors/outdoors
  5. Helps the employer and employee share responsibility for the employee's safety and forms part of a workers dynamic risk assessment

The disadvantages of Amber Alert are as follows:

  1. Not useful to all workers, particularly those where time is of the essence (e.g. paramedics)
  2. Not useful if constantly mobile (e.g. some traffic wardens)

What will happen in the future?

Both GPS and LBS technologies are the subject of significant investments in research and development being made by a number of interested parties. It is fair to assume therefore that in the future both of these methods will improve both in terms of accuracy, cost and in addressing the other technical and commercial barriers to entry. There are already significant trials in Japan of Assisted GPS (A-GPS) which is a hybrid of the two technologies which uses the cell base stations to cut down the typical TTFF. Initial trials though have disappointed in regard to addressing indoor coverage issues.

Similarly, trials of GSM cell base station triangulation techniques are ongoing in which Connexion2 is involved. The two primary areas being worked on are improving the accuracy of locations and reducing costs of operation.

Notes

*GSM Network dependant, check with Connexion2 for further details

It is suggested that the reader checks with Connexion2 for regular updates to this document given the changing nature of the technology involved.