How to improve GNSS acquisition and accuracy

Description:

The minimum number of satellites for a reliable position is 5 and HDOP (deviation) should be 1.5 or lower.

To improve your GNSS acquisition, retention and accuracy, please try the following.

Steps:

On the physical tracker: 

- Make sure the antenna (label side of the tracker in case of an internal antenna) is: 

• Facing up perpendicular to the sky. 
• It is not tilted more than 45 degrees in any axis, with the top surface perpendicular to the sky. 
• Installed as close to the windshield as possible. 
• Without any metallic objects or wiring in between. 

- You could acquire an external GNSS antenna to improve GNSS fix acquisition. Check compatibility here:   

https://doc.ruptela.com/articles/#!accessories-publication/external-gnss-antenna/q/external/qp/1 

- If problems persist, try doing a deep reset:

• disconnect from power supply
• disconnect from internal battery (you can do this physically or via Advanced Configurator "Battery off" button).
• reconnect internal battery
• reconnect power supply

On the configuration: 

- Make sure all three GNSS systems are enabled: GPS, GLONASS and GALILEO. This will increase satellite availability and thus fix and accuracy. 

Filtering unreliable coordinates:

Without GPS fix:

If record header looks like the one below (all GNSS derived values are maxed out / error), it means the record was generated and sent without first acquiring a GNSS fix.

Coordinates will be:

While this does not usually happen, because the device will not send a record unless a valid GNSS fix has been previously acquired after first power on / reset, if Send data without GPS fix is checked, the device will nonetheless send the record with the faulty header.

To avoid receiving such records, simply uncheck the box:

With gps fix:

- Enable Navigation filtering

• Stationary (discards coordinates that do not meet accuracy criteria when vehicle is not moving).
• Active (discards coordinates that do not meet accuracy criteria when vehicle is moving).

(example below is the default, more information HERE)