Geofencing Example

Geofencing Example

Let's consider the Gulf Princess, making its way from Djibouti to Galle in Sri Lanka. During the voyage, tracker behaviour will need to be updated to reflect the changing conditions of the voyage.

Embarkation from DjiboutiEmbarkation from Djibouti

Embarkation from Djibouti

First, in the Behaviours window, we'll:

  • Pick the geofence relating to the Gulf Princess' embarkation from Djibouti (in white).
  • First responders need to be alerted in case the Gulf Princess strays outside of the geofence.

Next, in the Messages window, we'll:

  • Pick the geofence relating to the Gulf Princess' embarkation from Djibouti (in white).
  • When inside the geofence, a single configuration message will be sent for Position Tracking only every 6 hours.
  • Set the validity period of this alert.

Define Behaviour

Behaviour Example - Djibouti-EmbarkationBehaviour Example - Djibouti-Embarkation

Behaviour Example - Djibouti-Embarkation

Send Configuration Messages

To set the position tracking to six hours while the Gulf Princess is inside the Djibouti-Embarkation geofence, we'll need to send a previously defined configuration profile. See Display Settings and Config Profiles for more information on how to create configuration files.

We expect the Gulf Princess to embark on the 17th of May, 2018 at 00:00 UTC and reach its last waypoint within the geofence on the 20th of May, 2018 at 00:00 UTC - that's three days at the most.

Messaging Example - Embarkation Geo FenceMessaging Example - Embarkation Geo Fence

Messaging Example - Embarkation Geo Fence

Next, we can define messages and behaviour for the yellow geofenced area called "1 Hr Transit". In this area, Position Tracking is set to every hour due to heavy traffic and piracy concerns.

Hourly TransmissionHourly Transmission

Hourly Transmission

To alert first responders if the Gulf Princess strays away from the yellow 1 Hour Transmit geofence, we'll:

  • Pick the "1 Hour Transmit" geofence
  • Set direction to "Outside" (an alert will be issued when the tracker is outside the geofenced area.)
  • Choose to alert first responders
Behaviour Example - Hourly TransmissionBehaviour Example - Hourly Transmission

Behaviour Example - Hourly Transmission

Next, we'll send the command for 1 hour position tracking while in the 1 Hour Transmit Geofence. We expect the Gulf Princess to embark on the 20th of May, 2018 at 00:00 UTC and reach its last waypoint within the geofence on the 21st of May, 2018 at 12:00 UTC - that's a day and a half at most.

In the Messages window we'll:

Messaging Example - Hourly Transmission Geo FenceMessaging Example - Hourly Transmission Geo Fence

Messaging Example - Hourly Transmission Geo Fence

What happens if the Gulf Princess hasn't reached the 1 Hour Transmit area within the time defined?

Message Alerts and Transmissions are based on a state change: This means that no message will be sent until the Gulf Princess is already in the defined geofence and a state change is registered.

The same exact methodology can be applied for the remainder of the voyage where:

  • Green indicates a two hour transmission time in a historically uneventful area of the voyage
  • Red indicates an 30 minute transmission time set that's set due to traffic concerns at the port of Djibouti.
Gulf Princess TripGulf Princess Trip

Gulf Princess Trip

Geo Fences and Battery Power

When a tracker is on mains power (ex. the RockFLEET, RockAIR), the GPS/Iridium antennas are always on. This means a short latency period between the first SBD transmission, a new ping alert indicating a configuration change/message, and the second SBD transmission.

For example, when the Gulf Princess crosses the white 'Embarkation' Geo Fence and enters the yellow '1 Hr Transmission', a previously scheduled SBD transmission takes place.

Consider that this new SBD transmission took place on this red marker - the current position transmitted and any waiting messages are received - but no new instructions are returned as this new position hasn't been processed.

The current position is now compared with the Geofence coordinates - a location change has been detected, and a ring alert is sent indication new messages/instructions are waiting. They'll be downloaded immediately.

When on battery power though, a tracker shuts down between SBD transmissions to conserve battery power. This results in a longer latency period between crossing a geofence and receiving new directions/messages from HQ.

Geofence bordersGeofence borders

Geofence borders

Thus, when creating Geofences for trackers using battery power (ex. RockSTAR) its important to design a geofence that will take into consideration the distance travelled during the latency period between SBD transmissions.