For static nodes... I wonder if instead of GPS we could use Light Level Geolocation?

[mofosyne]

LLG - ligh level geolocator

Apparently can "estimate its own location on earth with accuracy of few dozens of kilometers" and is very energy efficient.

Might be an interesting way to provide position service without having to set the GPS coordinate.

There's a writeup in https://hackaday.io/project/28550-light-level-geolocator about the light logger hardware (Plus http://www.jaromir.sk/llg.html).

I suspect the algorithm requires accurate timestamp.

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Wikipedia: https://en.wikipedia.org/wiki/Light_level_geolocator

[mofosyne]

Hmmm... I also wonder if we could use solar panel voltage (for solar powered nodes) for geolocation as well.

[mofosyne]

Ah this is more on the theory:

https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2656.13036

And yes it needs an accurate clock... so a node that is minimally configured (or powered up without a clock) needs to somehow resync the time. As is explained below

https://www.migratetech.co.uk/geolocation_9.html

What is important is to have a time reference to an accurate clock. Invariably, for a number of reasons, longitude is more accurately determined than latitude for light level geolocation.

[rcarteraz]

If it's static and you don't need a GPS, then just set the position using fixed position.