How many meters do the GPS satellites wander around?
Barney asked:
The satellites wander around and are stabilized with short “burns” of rocket fuel. How many meters do they wander before the ground station orders them to move? I would also strongly suspect (correct me if I am wrong) that the absolute position can be corrected in software to some extent. but with accuracies on the ground of 5 meters or so, I would think the satellites would have to be pretty stable. Yet on the other hand it’s hard to imagine those things being nailed to the sky.
The satellites wander around and are stabilized with short “burns” of rocket fuel. How many meters do they wander before the ground station orders them to move? I would also strongly suspect (correct me if I am wrong) that the absolute position can be corrected in software to some extent. but with accuracies on the ground of 5 meters or so, I would think the satellites would have to be pretty stable. Yet on the other hand it’s hard to imagine those things being nailed to the sky.
That, is government information that they generally do not give out. It really doesn’t matter since their information is corrected by ground control. For our needs, they are “nailed” to the sky. With government code, their accuracy can be given in small factions of an inch. The “dithering” that the signals use, however, is to keep the locations of what the government kept as inaccurate to be just that, inaccurate. Sorry, but your need to know isn’t high enough for more than that.
Actually, they ARE nailed to the sky. The sky ends about 22,000 miles up, so the satellites all have very pointy ends that stick them to the sky’s surface when the rocket lifts them up. It is a fact verified by the fact that the stars all stay in the same place every night while the earth rotates! Also, it proves the moon is really only about a mile wide and circles the earth much closer than the mythical 250,000 miles they teach you in school. The astronauts only had to go up in the sky about 20 miles to land on it, so it wasn’t a very big deal, after all.