[thot_experiment]

Most of this article feels like it's discussing irrelevant methods, you only need GPS to get it close (well for what they're doing they don't need GPS at all, though I'm sure it's used), we have much much more accurate ways of measuring the positions of things from a fixed reference point, 0.5cm deviation on your positional measurement is trivially achievable with optical systems. Why is the author spending paragraphs discussing IMU accuracy when we're trying to line up a rocket with a tower. You care about the rocket's relative position to the tower, you can put your measurement equipment on the tower, you don't need to worry about how accurate your accelerometers are.

I assume they are doing something much more clever/hardened, but you can trivially achieve much greater spatial accuracy with a Vive Tracking Puck for like $100.

[MadnessASAP]

Certainly lab equipment can measure distances well below 1 um fairly easily, I could manage 1 um in my garage. The issue is that the conditions at time of catch are VERY dynamic and not at all lab-like.

Your positioning system needs to acquire a fix at least 100m out in variable atmospheric conditions on a rocket undergoing heavy acceleration and dumping all kinds of heat, smoke and vibrations into itself, the atmosphere, and everything around it.

In addition having a fix on your tracking device is only half the game, not you have to figure out where the rest of the rocket is in relation to your tracking device. Which again, vibrations, temperature and manufacturing all have an effect.

So while yet, a vive tracking puck isn't entirely unlike the workable solution it is also entirely unsuitable as a solution and should not be used as a baseline to measure off of.

[thot_experiment]

So? Yeah it's a challenging environment, we know that. My point is that the default way to solve this problem is to track your object from your reference point.

[cubefox]

Bill Gerstenmaier was talking about the flight test 4 landing accuracy, which landed on the open sea in the Gulf of Mexico, not on the tower like the recent test flight 5. The only thing nearby was a buoy. I'm pretty certain it didn't have advanced laser systems.

[asadotzler]

The buoys were not trivial devices. See https://x.com/CosmicalChief/status/1626333723514834944

[cubefox]

Still, lasers on a buoy?

[Sammi]

This is the part about landing a space rocket that you wonder is not technically possible?

Looking at the image I can see a dark device on top of a mast that could be anything electronic.

[cubefox]

The buoy is shaking in the water, so it likely can't aim at ship.

[jameshart]

There’s a big cross in the middle of the landing pad that you’re trying to aim for - you don’t need advanced laser systems to get an accurate fix on where the landing pad is from the rocket - or where the rocket is form the landing pad for that matter.