[echoangle]

Not really, the Gyros described in the post are also essential. If you don’t know the attitude of the vehicle, you can’t point the engines in the direction your control algorithm says you should to hit the target.

Edit: I think I misunderstood the comment. Yes, you can use the absolute methods for rough guidance and then use relative positioning for the final approach. The article has a line about why the author doesn’t think that’s likely though.