on android there is microG with the unified location modules. this is the part that can locate you by surrounding cell towers or wifi networks. you can use a third party database and save that to your device.
For the 'assisted' part: i think there are alternate download servers for the satellite data that is required for the A-... part. I don't know much about that, though. I believe they are incorporated into privacy oriented android versions like GrapheneOS or CalyxOS.