Cell Tower Fallback

Many DM devices support 'cell tower fallback' for location.


On battery powered devices, this is used to provide a rough location if a GPS (or Wi-Fi) fix fails. This can be useful in extending the localisation abilities of a device.

Devices:

  • Falcon - All FW versions
  • Oyster2 - 2.17/3.17
  • Remora2 - 2.14/3.14
  • Yabby Cellular GPS - 2.19/3.19
  • Yabby Cellular Wi-Fi - All versions

Some hard wired devices can be configured to fall back to cell tower location if GPS Jamming is detected. For details see GPS Jamming and Interference Detection

Devices:

  • Dart2 - 2.13/3.13
  • G120 - 2.14

Platform Support

Currently, Telematics Guru only supports this feature on the Yabby Wi-Fi and Falcon - as a fallback location for when a Wi-Fi scan fails. A cell ID does not give a location, it has to be passed on to a location service (like Google's Geolocation API) which retrieves an approximate location (for a fee). 

3rd party platforms are able to implement this if required. If you require this feature on Telematics Guru for a specific device, speak to our support team.

TABLE OF CONTENTS


Set up (battery powered devices)

  1. Ensure your device firmware supports the feature
  2. Set the Cell Tower Fallback parameter to YES (found under the Advanced Tracking parameter tab)

Set up (hard-wired devices)

  1. Ensure your device firmware supports this feature
  2. Set the Cell Tower Fallback parameter to YES on the GPS Jamming IOs parameter tab. 

See GPS Jamming and Interference Detection for further details. 


How does it work?

Cell Tower Scan

If a GPS fix fails, or GPS is being jammed, then a cell tower scan is done. The serving tower is returned. The device will then report to the server:

  • Cell ID
  • Location Area Code
  • Mobile Country Code (MCC)
  • Mobile Network Code (MNC)

For integrators - this is Field 28 in the integration documents. Any cell scan results will be sent as an upload with log reason 49 - Cell Tower Connection.

Determining the location (Lat/Long)

These values in an of themselves don't constitute the Latitude and Longitude of the device for display on a map. The position must be calculated and this can be done through various location services like Google's Geolocation API. The data can be passed to this service via API call and the Lat/Long is returned. Services of this nature charge a fee per lookup or per month. 

For the Falcon and Yabby Wi-Fi, this is integrated into Telematics Guru with a charge per lookup as per the Digital Matter price list.
For the Remora2, Yabby Cellular GPS and Oyster 2, Telematics Guru will simply ignore any cell scan data - so this feature is currently for those using 3rd party platforms only. It may be integrated in future if there is demand. Contact us if you require this feature on Telematics Guru. 

Accuracy

The cell scan is typically accurate to within 1km. So it is useful for a rough idea of where your device is i.e - 'has it left the depot?', what suburb am I in?, not 'what street am I on?'

Other, more accurate cell location services exist - but are not available on these devices - as the uBlox cellular modem only returns the tower which it is connected to. Higher accuracy requires the device having knowledge of multiple towers in range. This may become available on future DM products. 


Applications

As mentioned, the accuracy of a Cell Scan is not great in comparison to a GPS fix. It can be useful as a 'last resort' fix. If you are expecting to be regularly indoors, a device like the Falcon (combo GPS + WiFi, optional cell fallback) or Yabby Wi-Fi (WiFi + cell fallback) may be a better choice. Additionally the cost of look-ups must be factored in to the equation - however However this feature on the Remora2, Yabby Cellular GPS and Oyster 2 is useful for:

Tracking assets in shipping containers

Often GPS fixes will fail when a device is placed inside a shipping container, but the device can still connect to the cellular network. When out in the field, the asset can be tracked via GPS, and the device's Bluetooth functionality taken advantage of. A typical problem is that once the device is loaded into the container and GPS fixes fail, we may be able to get uploads but we lose all visibility of device location. It will report the exact same GPS location (i.e. the last valid fix) until the container is unloaded (maybe not until it reaches another country!) Cell tower fallback is enough to give us a rough location, so we know it left the port/depot/warehouse - which is invaluable when managing the movement of shipments as an operational tool.

Theft/tampering prevention

The ability to fall back to a cell location while GPS is jammed means we can still track a devices rough location in the event of jamming. Thieves may attempt to jam GPS signals, if successful, the device will stop updating it's location as it cannot acuquire new GPS fixes. Cell Fallback will give a rough location and may enable the asset to be recovered. 

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