Querying all of cell_measure is kind of expensive. I wonder if we could add the `psc` field to the cell table. That way we have a pre-calculated cell lat/lon for each cell and can query the cell table for all matching radio/mcc/mnc/psc candidates. The estimated lat/lon is somewhere in the middle of the cell and not on the edges, so we'd probably need to extend the 1km radius to get matches.

But querying a 300k table with a nice index is preferable to querying a 40m table (or maintaining an index on that one).