[Geo_ge]

I'm running a Raspberry Pi based GNSS receiver from a 26 Ah SLA battery and an 80W panel. Just passed 2 weeks of uptime in a cloudy period of southern hemisphere autumn.

A monte carlo simulation using historical conditions said it had a ~95% chance of no downtime over 3 winter months. A slightly larger battery would bring that up to 99%.

The Pi (3b+), GNSS reciever (u-blox ZED F9P), and Waveshare 7600G 4G modem average about 3.5W idle. The GNSS reciever is about 0.1 - 0.2 W of that. Wifi would be more energy efficient, I imagine.

[simgt]

Is it an RTK base station? If so I'd love to know more about why you set one up.

[Qqqwxs]

It's functionally equivalent to an RTK base station (the configuration script I'm using is even called "RTKbase"[0]), but it's being used for researching GPS-based soil moisture retrieval[1]. Basically the GPS signal bounces off the ground and causes an interference pattern that changes based on the wetness of the soil.

There is actually a permanent survey grade GNSS reciever about 200 m away from the u-blox receiver. But the geography around it (too hilly) means it doesn't work for soil moisture retrieval.

[0] https://github.com/Stefal/rtkbase/ [1] https://gnssrefl.readthedocs.io/en/latest/pages/understand.h...

[simgt]

Thanks for the details! I had no idea that estimating soil moisture from the signal was a thing

[myself248]

Are you contributing to Galmon.eu? Sounds like you might be in a useful location.