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GNSS receiver modes

August 06 2020

There are many GNSS receiver models and they use standard protocols to communicate with the device that receives the coordinates. Use one of these modes to take full advantage of the capabilities of your receiver. 

Internal receiver

Every modern android device has an internal GNSS receiver that can establish the current position of the device. These receivers use the GPS and GLONASS satellites and their accuracy is between 3 and 5 meters. When installed on your device, OnPOZ Collect will automatically discover and use the internal receiver. 

Mock location (external receiver acting as internal receiver)

This is a popular mode that takes over the internal receiver and makes the high-accuracy coordinates from an external receiver available for every application installed on the device. It is often used by RTK capable receivers. See an example of how to use this mode in the article Trimble Catalyst and OnPOZ Collect.

External receiver

External receivers are a more powerful version of the internal receiver of your smartphone or tablet. Depending on their specifications, they can provide very accurate coordinates – in many cases up to 1 or 2 centimeters. They are usually connected to the device via Bluetooth connection and are compatible with OnPOZ Collect. You can go to Settings > GNSS Device and choose your receiver from the list. The next step would be to choose the model of the device from the list or use one of the following modes:

Hemisphere compatible receiver

Hemisphere compatible devices provide an extensive number of GNSS logs that can be used to calculate an accurate position in post-processing mode. Accuracy of 1 to 3 centimeters can be achieved when the data is processed with OnPOZ Cloud Post-Processor.

NMEA compatible

If no other mode is supported by your receiver, you can choose NMEA. This standard protocol can be used with all GNSS receivers. The data collected in this mode cannot be post processed, however the accuracy is typically better than the accuracy of the internal receiver of a smartphone or tablet. When properly configured, the receiver outputs the following basic logs:

GGA (Time, Coordinates)
RMC (Time, Coordinates, in addition to GGA)
GSA (DOPS factors and satellites in use)
GST (accuracy/sigmas)
GSV (sky plot)