also, in this case (as with all 'debris'), one of the vehicles is dead, so you can't do active ranging on it, just passive radar. Much less accurate. Active

also, in this case (as with all 'debris'), one of the vehicles is dead, so you can't do active ranging on it, just passive radar. Much less accurate. Active rangefinding is good to ~ meter accuracy at geosynch, passive radar is nowhere near that close. The two factors for how good your orbit fit are how good your range data is, and how frequently you get samples. To get accurate orbits, you need to look often, and there are lots of objects up there - way more than there are antennas on the ground keeping track of them.