Global Positioning System (GPS) technology has become such a part of daily life, for civilian as well as military users, that next-generation GPS satellites are being built to be more accurate and harder to jam than ever before. In fact, Lockheed Martin is clearing the way for the use of third-generation GPS satellites. On August 20, the company shipped the first of the U.S. Air Force’s GPS III space vehicles (GPS III SV01) to Cape Canaveral, Fla. for its expected launch in December of this year. This third-generation GPS satellite will provide the most powerful version of the positioning system technology ever placed into orbit.Known more technically as GPS Block IIIA, the 10 satellites are the first segment of what will eventually replace the current constellation of 24 GPS satellites. Microwaves & RF Magazine reports a bit on the technical advances coming in Block IIIA.
The satellite features a new design, with three times greater accuracy than earlier versions of GPS satellites and eight times improved anti-jamming capabilities compared to earlier, second-generation GPS II satellites (which form the current constellation of GPS satellites).Wikipedia has more technical details on the new satellites than the technical trade magazine does, at least in the article linked to above. Wiki says that the last of the 10 Block IIIA satellites is currently scheduled for launch in the second quarter of 2023, five years from now. Finally, they say the new L1C signal (and presumably the others) won't be fully operational until all 24 GPS Block III satellites are operational, currently projected for the late 2020s. The companies that produce the single chip GPS receivers (such as...) embedded in phones and so much more have a little while to start producing receivers capable of these newer modes.
The GPS III satellite will also be the first space vehicle to broadcast the new L1C civilian signals. The L1C signals, which are shared by other international global navigation satellite systems such as Galileo, is expected to improve connectivity for commercial and civilian users.
(The first of the block III satellites, GPS III SV01, and a C-17. Is it being loaded or unloaded? Arriving CCAFS or departing Colorado? You decide. Lock Mart photo).
Good stuff. Now I wonder who's going to get those launch contracts.
ReplyDeleteI got nerdy because I knew the GPS system had to account for relativistic effects, but I didn't know the details. It turns out the altitude above the Earth has more of an effect than the velocity. Earth's gravitational field slows time, but at higher altitudes space-time is curved less, so it speeds up relative to us. That is more than the slowing caused by the velocity.
Real-World Relativity: The GPS Navigation System
This is going to sound strange, but I thought I saw who had the launch contract in the reading I was doing to prepare the article. I went back and didn't see it. I don't even see why I thought it was there.
DeleteI did a piece on the GPS and Relativity a few years ago. It's a cool aspect of the design.
"I Remember...." when I was working for a little start-up that did GPS stuff. There were times when we had to come in at odd hours so there were enough satellites in view to get a 3D fix.
ReplyDeleteAnd I got to watch a Block II spacecraft get lofted by an Atlas-Centaur from Vandenberg AFB. My first wife's super-cool Uncle Tony worked for Rockwell at VAFB and got us VIP access to watch the launch.
Will civilian users expect to upgrade their hardware in the near future due to connectivity issues brought about by this next gen system?
ReplyDeleteI'm not sure, but probably not. Probably when you upgrade your software, it will add decoding for L1C and the other new modes. The details of the chips they use depend on exactly what device, and I don't know much about what's commonly used.
DeleteI don't think the new features are going to be turned on except for tests at least until all 10 are in orbit. Later 2023 or 2024, as a guess.
Exciting stuff. GPS has changed the world in many ways. Made it smaller, made "nav" part of everyone's life, etc.
ReplyDelete