How do Geofences use GPS?
20 Jun 2016 Jason 0
GPS data is not just useful on its own – when combined with other technology you can extend its usefulness in a lot of clever ways. Geofencing is one technology that can be used with GPS to create smart, automated solutions to some common problems.
Commercial fleets regularly use geofences to monitor the day-to-day operations of their mobile workforce, whether it’s keeping assets secure or verifying timesheets.
What is a geofence?
It can be any size or shape, even a straight line between two points.
Geofences are created using mapping software, which allow the user to draw the geofence over the desired area. It is made up of a collection of coordinates (latitude and longitude) or in the case of a circular geofence one point that forms the center.
Geofences can be used to keep things in (know if a vehicle or piece of equipment is removed from your yard) or to keep things out (a restricted area that vehicles need to avoid, such as a mining company keeping workers out of an area where explosives are being used).
How do geofences use GPS?
The connection between a geofence and GPS is all about location. A geofence has a fixed location and something using GPS (a vehicle, piece of equipment, or person) is generally moving (or can be moved).
For a GPS tracked object to work with a geofence there are some things that need to happen. The list below is an approximate order of how a geofence may be setup.
- A geofence is created using mapping/fleet management software, such as Telogis Fleet.
- The GPS tracked object needs to be able to report its position (latitude/longitude) to your software.
- The tracked object needs to be associated with your mapping software. In Telogis Fleet this happens automatically when new vehicles or assets are added (also called provisioned).
- A rule needs to be setup that triggers an alert when the tracked object enters (or leaves) the geofenced area.
With these steps completed you can start to use geofences and GPS together to improve business processes or report on the movement of tracked objects in relation to the geofenced area.
Do GPS tracked objects trigger a geofence alert instantly?
If you were to break through a literal security fence, it would likely trigger an instant alarm. Geofences, however, don’t always respond as instantaneously. This is due to the reporting rate of the GPS tracked object, which in most cases will be around 20 seconds.
This means an object could breach a geofence and the alert may only trigger 20 seconds later (or longer if it is a slower reporting rate).
Why would someone choose a slower reporting rate? Sometimes it is done if the GPS hardware is battery powered or there are limits to the amount of data that can be transmitted on the selected cellular data plan.
Does the object need to cross the geofence perimeter to trigger an alert?
In most cases, a geofence alert will be triggered when a tracked object moves across a geofence perimeter (the outline of the geofence) but this is not compulsory. An alert will be triggered whenever a tracked object reports from within a geofenced area.
This means you won’t be able to get around a geofence simply by tunneling underground to get inside!
Let us know in the comments if you have any other questions about geofences.
Categories: Fleet Management