Sure but this is good enough to be useful in many situations, whereas a GPS collar is impractical enough that it's unlikely to be regularly used. I just wanna throw a chip on the 3 dogs collars and forget about it except to swap batteries once a year. I don't want to be bothered charging active GPS collars every few days and putting a heavy device for the dogs to carry.

I'm sure it's possible to get the best of both worlds, it's just that no one have made it yet. An active GPS tracker does not have to be larger than a keyfob to your car nor does it need to be online all the time. A combination where the GPS is only activated once the tag has not seen a known device for 1 hour. That should give you a battery life measured in years with meter precision when it matters.

Great idea.