Strange Trips

The commonest reasons why trips will be inaccurate on the platform are:

1. Non-sequential data, 

2. Long periods between updates, and 

2. GPS Jumps.

The following are examples of Devices sending data out of sequence, and creating strange trips. 

In this example, the data points are in the incorrect order, and the vehicle looks like it went backwards then forwards, on a highway.

In the next example, there is a sideways movement of the asset, which creates a strange trip.

To investigate whether the Device has sent data out of sequence, non-sequential data, use the Telemetry available from the Device. 

Here is an example of data sent out of sequence to the server: the server received data at 02h45, and the device thought it had created it at 05:04:27:

If any out of sequence data is noticed, please contact your hardware supplier. They may require the Telemetry for the day/trip in question, therefore it is always advisable to download it when looking at strange trips.

Long Periods Between Updates

The update or logging interval of a Device will determine how much data is received and what a Trip will look like on the platform. In the example below, the data points are being reversed geo-coded correctly, however, because of the infrequency of the data points, the Asset appear to have cut corners along the winding road. 

The Telemetry for the device can be checked to determine the frequency of the updates.

Visual representation on the platform will be effected by the update interval, and this needs to be determined, based on cost, and any other factor, by the solution provider. 

GPS Jumps

GPS jumps occur as a result of a loss of GPS reception, and the Device not knowing where it is in space and time. This occurs in the following circumstances:

Urban canyon effect

Errors can be introduced when signals are reflected off buildings or geographical structure such as rock face, etc.

Attenuation of Signal

An example of this is when the vehicle drives into an underground parking garage, or tunnel or the device is fitted in such a way that the signal is shielded.

Other causes

A Device may reset every so often if the installation is causing a problem with the power connection, or the battery for the vehicle is faulty. Resetting may interfere with the Device's ability to keep a solid GPS lock.

In this example, the Device jumped to the equator and back - the second data point in the sequence. In this case the Device had a faulty power supply and reset itself during trips.

To determine is a trip looks strange due to a GPS jump, view and download the telemetry for the trip in question, and look for strange coordinates, out of keeping with the rest.