The term "Man Down" is commonly used and applied to a specific type of device carried by remote workers. However, in my view, it should be considered a concept rather than an actual gadget, and as such the term has perhaps become an over-used adjective.

Nevertheless, there are many examples where a member of staff or sub-contractor works alone and could face a potentially hazardous situation, and in such a situation devices that can communicate the user's location back to a monitoring team at base, as well as send alarms can be extremely valuable. That said, no device, by itself, can ever be totally relied upon to protect someone unless there is attentive supervision and a prepared scenario-based action plan.

For example, no "Man Down" GPS device will be able to work if any one of its core components such as Battery, GPS or GPRS are unable to work properly. In dangerous situations this may be a relatively common situation, and the device may suffer in the same incident that causes the worker to become a "man down" in the first place. A so-called "Man-Down" device, on its own, is unlikely to be of any use to a security guard who falls down a hole on a building site for example.

A more balanced and pragmatic approach has intelligence based in the monitoring team and their systems to monitor the movement of tracked people and draw inferences based on the observed behaviour, and where necessary take pro-active steps to intervene. The procedure will also need to involve detailed assessment of the signal coverage in the specific area to be monitored. If the unit stops sending any information, or the location information that it does send shows an unexpected lack of movement, then the watching agent can initiate a "Man Down" procedure if only to eliminate any doubt as to the well being of the monitored individual. The response is then driven from the monitoring team with responsibility to oversee the care and safety of the field staff, and is likely to involve relaying alerts on to other tracked people.

"Man Down!" is really a warning for people to stop what they are doing and be prepared to seek out and help someone who may be in trouble, for example, if they have not moved for a few minutes and are within a known danger area.

Most commercial GPS tracking devices will provide the location reporting element of a "Man Down" system and support sending of single press panic alarms.

Some manufacturers provide units with built-in motion detectors, for example an accelerometer, that can detect an abrupt fall. This may be built into a GPS tracking and communication device - or is a second unit carried by the individual, that can communicate over Bluetooth with a communication device.

So in conclusion, the quality of a "Man Down" system will be highly dependent on the quality of the reporting and response procedures, and the solution must factor in the likelihood that any device issued to the lone worker may not be able to function at the instant a "Man Down" incident actually occurs.