Tracker V2 GPS accuracy

RE: Tracker V2 GPS accuracy

Håkon Alseth — Wed, 23 Nov 2022 09:39:24 GMT

Hi,

It does not filter on DOP, but allows the GNSS to run longer, which in most cases improves the accuracy of the fix.

The location API allows you to set the amount of consecutive fixes in the configuration struct that is passed to the library:

https://github.com/nrfconnect/sdk-nrf/blob/v2.1.2/samples/nrf9160/location/src/main.c#L102

In this case, it loads the default configuration, which is _ACCURACY_NORMAL:

https://github.com/nrfconnect/sdk-nrf/blob/v2.1.2/lib/location/location.c#L130

In _LOW and _NORMAL mode, the "num_consecutive_fixes" member has no effect, as per the API documentation:

https://github.com/nrfconnect/sdk-nrf/blob/v2.1.2/include/modem/location.h#L178-L184

Kind regards,

Håkon

RE: Tracker V2 GPS accuracy

Gerbert — Tue, 22 Nov 2022 12:33:49 GMT

Thanks. I have found some brief explanation:

	/** @brief Desired accuracy level.
	 *
	 * @details If accuracy is set to LOCATION_ACCURACY_LOW, GNSS relaxes the
	 * criteria for a qualifying fix and may produce fixes using only three satellites.
	 *
	 * If accuracy is set to LOCATION_ACCURACY_HIGH, instead of using the first fix, GNSS is
	 * allowed to run for a longer time. This typically improves the location accuracy.
	 */

Can you explain how "run for a longer time" is handled? Is it only time based (eg running +5s after first fix) or are there also other GNSS KPI's involved (eg HDOP, etc)?

RE: Tracker V2 GPS accuracy

Håkon Alseth — Tue, 22 Nov 2022 11:38:26 GMT

Hi,

ATv2 in current tagged versions (including v2.1.0) has a limited option to configure the GNSS, unfortunately.

However, in future tagged versions, it will start to use the location module:

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/libraries/modem/location.html

Which is enabled with this commit:

https://github.com/nrfconnect/sdk-nrf/commit/8b2c475ed7368aaac606af4c53885009331ae35a

With the location module, you can set the accuracy of your requested GNSS signal to low/normal/high:

https://github.com/nrfconnect/sdk-nrf/blob/v2.1.2/samples/nrf9160/location/src/main.c#L152

Kind regards,

Håkon