GPS SNR testing

The command executes a GPS SNR test.

GPS L1 frequency is 1575.42 MHz and this test expects the CW in signal generator to be 1575.750 MHz, i.e. the offset is 330 kHz. The measurement duration is 1 ms.

The command parameter and its value are the following:

<test>
2 – GPS SNR

GPS SNR

<operation>
1 – ON
Note: Automatic stop, i.e. no "OFF" needed.

GPS SNR ON has one parameter:

<param0>
RX signal power at antenna in dBm
Valid range from −127 to −25 or 0 = default gain −105 dBm.

Response syntax when <operation> is ON:

%XRFTEST: <snr>,<antenna_power>

The response value is the following:

<snr>
The result of the SNR measurement in q4 dB. q4 means that dividing the result by 24 = 16 gives dB.
<antenna_power>
Measured power at antenna, in q8 dBm. q8 means that dividing the result by 28 = 256 gives dBm.

The following command example executes an GPS SNR test:

%XRFTEST=2,1,0
%XRFTEST: 514,-19968 
OK
Note: 514/16 = 32.125 dB and −19968/256 = −78 dBm.