First modernized GPS satellite Launched

A reader writes "The first GPS 2R-M satellite has launched from Cape Canaveral, Florida on top of a Boeing Delta 2 rocket. The government is now competing with Europe's Galileo system, and has added two additional military channels and one civilian channel, which will increase the accuracy and performance of GPS - as well as increase its resistance to jamming."

Comments

You Will Be Assimilated!

[AKAImBatman]

You know, I was about to ask the rocket scientists hanging around here (hi guys!) about how small new generation comsats were going to be. After all, there has been a tremendous increase in miniturization and technology since the original GPS sats were launched. (e.g. better microprocessors, denser batteries, more efficient solar panels, better propulsion, etc.) If we could get these sats small enough, it might be possible to deploy a GPS system for Mars in one or two launches.

Then I saw the borg cube that assimilated the Willy Wonka Chocolate Factory (Mirror) Excuse me while I pick my jaw up off the floor.

On another note, the picture makes it look like the design hasn't changed much from the original NAVSTAR configuration. I assume that these satellites are merely sharing the same chassis, and have very different internals?

Re:You Will Be Assimilated!

[madaxe42]

You find a way of fitting a Caesium fountain clock in a smaller case.

Re:You Will Be Assimilated!

[pr0nbot]

If we could get these sats small enough, it might be possible to deploy a GPS system for Mars in one or two launches.

OT... something I've been wondering about, with regard to long-range communication with satellites: we know how to do networks now, why aren't we peppering space with small node probes that travel away from Earth (i.e. aren't orbital satellites) but keep in touch with eachother and so can route the data from real science probes back to us from further and further out?

I suppose the number of nodes required would grow at the same order as the volume of a sphere (assuming we want to spray them in all directions) but we actually probably only want to send them out in specific directions.

Re:You Will Be Assimilated!

[GileadGreene]

On another note, the picture makes it look like the design hasn't changed much from the original NAVSTAR configuration. I assume that these satellites are merely sharing the same chassis, and have very different internals?

No, they're substantially different designs. Different manufacturers even (Rockwell vs Lockheed). But if you have a spacecraft performing the same mission, odds are it's going to have a similar configuration. The thing that makes them look most similar is the navigation signal antenna array (the "Willy Wonka Chocolate Factory"). Even those are slightly different between the two models. But since they're fundamentally performing the same function, thye look very similar ("form follows function").

Re:You Will Be Assimilated!

[speculatrix]

there has been a tremendous increase in miniturization and technology since the original GPS sats

your statement is naive in that it supposes that mil-spec and rad-hardened technology has advanced at the same rate. Once, it was the military who led the way and consumer devices followed; now, it's the other way round, and in fact the military/space people have big problems with obsolescence, especially with the recent EU rules on Reductions Of Hazardous Substances (often known as "lead free", but actually covers other things as well). In some instances, military kit is being forced to use automotive-spec components as replacements, because that's all that's available and at least the devices have a wider temperature range.

so, yes, mil- and space-spec hardware is advancing, but the testing cycle is far longer - think months rather than weeks. when you're spending $M's in launch fees, you've got to get it right!

Compatibility

[slimey_limey]

Will this improved accuracy come at the cost of compatibility? I already have a GPS reciever, and I don't want to have to buy a new one to make my data more accurate. (Magellan hasn't released new firmware for the SporTrak Basic since 2002, and I'm not holding my breath.)

Re:Compatibility

[AKAImBatman]

The new civilian channel is in addition to the existing channel, so your existing equipment should work. As more of these sats go online, you can expect to see gear that provides access to the second civilian channel. (Source)

What I have to wonder, though, is what will they do with the two new military channels? It seems that all the field soldiers tend to use civilian gear because the military gear is too heavy, unfriendly, ugly, and is in short supply. I suppose it would make the missiles hit their targets better, but it would be nice to know that our entire military can use the equipment.

Signal jamming==profit

[jurt1235]

Step plan to GPS signal jamming profit:
1. Launch GPS satellites and sell lots of GPS devices
2. Launch jamming satellite (last week news)
3. Launch new GPS satellite system which is less prone to jamming
4. Sell new receivers => profit!

Re:Look everyone! Somone who didn't RTFA!

[AKAImBatman]

Yeah, I did read it. The part that stuck out to me was that the new sats were about 60 pounds heavier than the old ones. Now I understand that they couldn't have gotten all the new features in for only 60 pounds without modern technology. Still, I can't help but think that it could have been a lot smaller than that.

Then again, I'd like to see a day when we can create useful PongSats, for this stuff but I supposed that won't be happening anytime soon. (Especially not when you need a large tranceiver!)

Re:which #

[Toaste]

From the article: "GPS 2R-M1 will assume the Plane C, Slot 4 position, taking over for the GPS 2A-20 craft launched in May 1993."

From the designation of the old satellite, I presume that this position is number 20 on GPS receiving equipment. Just a guess.

By the way, does anybody know how they plan to move the old one out of the way? According to info found here the origional was a 3-axis stabilized NAVSTAR, but I doubt it will be able to move significantly with only its thrusters.

Another interesting point: the page lists the design life of this series at 7.5 years. Which means this satellite was replaced a mere 4 years, 10 months, and 13 days beyond its expected service life.

Specs?

[adminispheroid]

Anybody know what's on the new civilian channel? e.g. is it the same kinda stuff as the two existing channels, on a new carrier? Or is it a new code?

Re:Specs?

[Anonymous Coward]

The new civilian code is probably a longer signal that repeats less often. This gives better accuracy but takes longer to determine position when first switched on. Using the lower accuracy signal would allow for a rapid first estimate of postion while the GPS would become more accurate once the position using the new signal was calculated. The military GPS systems use the civilian signal to estimate their position more quickly.

Russians using GPS

[Thagg]

I was fairly astonished to see in the recent issue of Aviation Week that Russia is now building GPS-guided bombs. Presumably this is just using the civilian signal, which could be disabled or degraded in a conflict theater -- but still, it was an fairly amazing development. I suppose that it's conceivable that AvWeek got the facts wrong, and that it was a GLONASS-guided bomb, but they're usually pretty good about that sort of thing.

Thad Beier

Re:Jamming by whom?

[Dun Malg]

Can they not use multiple stations to make it appear the signal is coming from a place where it is not?

No, all that would do is present multiple individual targets. Modern direction finding equipment uses such advanced digital processing that it can separately identify two transmitters right next to each other based on subtle differences between them caused by things like inherent manufacturing variations in the transmitters' modulation circuitry.

How soon?

[Ced_Ex]

How soon do we realize the benefit of this new satellite? Should we be able to see results right away just from one satellite? Or will we have to wait for 2 more satellites and hope that our GPS connects to the 3 newest ones in order to get the better resolution?

Television as GPS

[tocs]

Why do you need newer and fancier GPS satellites when you can just use satellite television signals.

Re:I see jamming in action regularly

[Kjella]

How effective would that jamming really be.... since anyone smart enough to build a cruise missile that could use GPS for guidance would be equally intelligent enough to build a cruise missile to simply home in on the jamming single it's self. Or even with out that could simply free fly the last little distance around the jammer and still hit extremely close to the target.

1) He might not know it is there
2) The jamming dish (or array of jammers) is presumably far away from any critical installation. If the military managed to radio mark their own targets, I'd classify that as gross incompetence. (also, that'd be "the jamming signal itself")
3) "Simply"? Yes, you could make a system that would try to determine a "last known good position/direction", calculate direction and distance to target and fly it in blind, but it'd be a rather major modification. A much more likely scenarion is that someone gets their hands on a GPS-guided missile (american, russian, whatever), program it up with coordinates and launch it only to fail miserably.
4) Who's to say the system can't actually deflect missiles? Instead of going wild (that's just the default state), an incoming missile detected on radar can be "redirected" to a designated detonation area, simply by making it believe it is hitting the target.

Kjella