New improved GPS satellites going up

The first was launched recently and 15 more are anticipated by the end of 2006.

http://www.newscientist.com/article.ns?id=dn8051

Stronger signals and more accurate clock are a few of the improvements. (Accurate to within 8 nanoseconds per day).
Also going from analog to digital. Uh, is a nanosecond quicker than the blink of an eye? <img src="/images/graemlins/smirk.gif" alt="" />

Any idea how long it's going to be before new civilian units are available to take advantage of the new features? Other than the stronger signal, we can use that now of course.

Thanks for the link! That's good news.

Interesting to note the article mentioned Europe is developing their own satellite navigation network. All of a sudden the U.S. GPS system isn't the only game in town.

I remember reading about a controversy between US GPS signals and the new Galileo frequencies. Has that been resolved?

As I recall, the controversy was over the fact that Galileo (meant solely for civillian/commercial use) operated on a frequency that overlapped the military GPS channels. In a military engagement, the US armed forces would want to deny the enemy any use of global positioning by jamming the civillian GPS channel. Unfortunately, trying to jam Galileo's signal would also mean jamming its own military channels as well. Someone please correct me if I'm wrong about this.

Anyway, I'm still waiting for the ability to find a lost contact lens on the floor with global positioning. "It's 25.4329832 cm to your left...no, your OTHER left..." <img src="/images/graemlins/wink.gif" alt="" /> (Dumb Matrix reference)

"U.S. Secretary of State Colin Powell and Loyola de Palacio, the European Commission's Vice-President with particular responsibility for transportation and energy matters, will sign an agreement on GPS/Galileo cooperation June 26 at the U.S.-European Union summit in Ireland. ...."

The rest of the article is at http://www.gpsworld.com/gpsworld/article/articleDetail.jsp?id=101129

Actually, Russia has had their own system for several years. Known as GLONASS. Ours is NAVSTAR.
Read on:

http://www.leeselect.com/magellan/general_info.htm

The way I read it is that they are now civilian friendly as well as militarily. Go to Google and type in "BOEING GPS SATELLITES" and you will get a whole "PLETHORA" of information. Check that word, plethora. Sounds like something Chris would use to confuse the rest of us illiterates. <img src="/images/graemlins/grin.gif" alt="" />

I believe I read somewhere in all that stuff I Googled that one of the things these new sats do is correct or improve the jamming problem.

Plethora is a good word. It is my verbal quiver next to head scrathers like cornicoppia and surrounded.

*new recruit* They've got us surrounded!
*old sargent* "Yeah, they can't get away from us now!"

Thank God they've finally improved the clock accuracy from 11 nanoseconds down to 8. I was getting plenty tired of showing up at appointments 3 nanoseconds late! <img src="/images/graemlins/wink.gif" alt="" />

I know you're kidding, but check this out:

1 nanosecond is 1/1000000000 of a second, or 1.0 x 10^-9.

2 nanoseconds per day, cumulative error, 2.0E-9 * 365, is 7.3E-7.

Still doesn't sound like much? Light moves at 186,282 miles per second. In 7.37 x 10^-7 seconds, light moves 0.136 miles. Or 718 feet. Going from 11 to 8 nanoseconds improves positional accuracy a noticable amount.

Now I have never tried to substantiate this, but I've read that the typical eye blink is in the neighborhood of 40 milliseconds. Well . . . you asked. Let's see . . . one thousand one. . . Nope. One thou . . . Nope. One t . . . Nope. On . . . Nope. It's dang fast, that's for sure.

Only if your travelling near the speed of light <img src="/images/graemlins/smirk.gif" alt="" />

If you are stationary or moving relatively slowly (less than say 700 mph), the propogational delay shouldn't be much of a factor. My GPS doesn't update fast enough to be accurate if I am moving much more than 100 mph anyways, certainly at the highest resolution, where by the time it updates I am already several hundred feet beyond the marker and off the screen already.

Hmm, that sounds about right. Fractionally, I think the range for most eye blinks was between 1/20 and 1 60 of a second (50 milliseconds to 15 milliseconds).

Groo...
The time as recorded by the sattelites is periodically updated from the ground. So those errors never have a chance to accumulate. The ground stations have enough room for a really good atomic clock.

True. It's a contrived example. But people easily forget just how fast light travels. 1 nanosecond is just about 1 foot.

I figured the on board clocks received updates from the ground... I'm guessing the ephemeris is updated from the ground too. But the onboard clock accuracy improvement is still important. I wonder if the improved accuracy allows for either fewer updates, or better accuracy if ground based updates are... interrupted... for some reason. <img src="/images/graemlins/frown.gif" alt="" />