WP7607 GNSS poor reception

I have an odd behavior of the GNSS
I am testing the device indoor with a GNSS repeater installed on the ceiling
in the same position at the same conditions I get reasonable amount of satellites with SNR of 26 to 30 and then o satellites at all or 2,3 with SNR of 09 to 11
Using my Smartphone I can see about 15 satellites with SNR from 25 to 34

    • What could be the reason for the unstable readings?
    • Is there any SW command to improve the reception (i.e. enable internal LNA, configuring the internal LNA)



So the WP76 does not have an on board LNA so you have to use either a passive antenna or an active one and then supply it with a bias voltage as the WP76 will not do this although the port is tolerate to having one applied. this is almost certainly going to explain the difference in SNR and the number of SV’s you are seeing. It always comes down to the antenna being used as this is the single most influential component in any given GNSS system.

You also might want to check the constellations the unit is searching for using at!gnssconfig, you say you are seeing 15 SV’s on the smart phone, you are highly unlikely to be seeing 15 SV’s from the same constellation so this will also be aiding the phone in getting a fix (as well as probably using an active/very well tuned antenna).



Thanks Matt,

We have a problem getting fix even when using a GNSS generaor

After power on, a trail is injected to a Sierra module (conducted, via coax) using a GNSS generator (GSG-6 Orolia)
Fix is acquired within (X) minutes at -135dBm
When A new trail is injected from the GNSS generator no fix acquired
Factory Reset or GNSS disable/enable commands are not helping
Sometimes after long waits (10 minutes) fix is acquired
Workaround to force the new fix: rising the signal level to -110/120dBm

This workaround is not possible in real life, is there an explanation to this issue and how to solve it?