In some old school systems you can do this by overflying a point with a known lat/lon (VOR/airfield etc.), setting said lat/lon, and updating the INS when over the point. Essentially telling the INS, "here's our location, now do math.."
It's not something that you're gonna fly an RNAV from, but it'd be a lot better than having your pos be over BFE when you're on final at ATL.