Delta Carries GPS Satellite Into Orbit

[+Criminal]

Florida Today

October 18, 2007

 

Delta Carries GPS Satellite Into Orbit

 

Signals should start in 2 weeks

 

By Patrick Peterson, Florida Today

 

CAPE CANAVERAL - After a flawless launch and a 68-minute ride to orbit Wednesday, the newest Global Positioning System satellite is aloft and will soon be transmitting signals.

 

In two weeks, it will be able to send improved navigation signals to military and civilian GPS units, which are estimated to number 1 billion worldwide.

 

"You can get (the accuracy) down to a centimeter," said David Podlesney, GPS program director for Lockheed Martin, which built the satellite. "The applications are increasing exponentially."

 

Advanced bulldozers now have GPS units on each side of the blade to direct grading. Many cars now have GPS maps, and hunters and boaters use the system for navigation. The military relies on GPS for mid-air refueling and to direct missiles and weapons.

 

Launched at 8:23 a.m., the spacecraft is the fourth in a series of eight modernized satellites, which have increased signal power.

 

Two new military signals provide for improved accuracy, enhanced encryption and anti-jamming capabilities. A second civilian signal will provide users with an open access signal on a different frequency.

 

"The GPS constellation has worldwide significance and all of the satellites are launched from right here at the world's premier gateway to space," said Col. Stephen Butler, 45th Space Wing vice commander.

 

After launching from Complex 17A on a Delta 2 rocket with nine strap-on solid rocket boosters, the satellite, built for the Air Force, entered an orbit 11,000 miles above the earth. It will circle the Earth every 12 hours and will join a constellation of 30 other GPS satellites.

 

The GPS IIR-17 was the 77th consecutive Delta 2 rocket to deliver its payload. At least 25 Delta 2 rockets will fly during the next few years.

[+EScout]

Thanks for the news. Good to hear the progress.

[Rhialto]

What does it mean?

 

improved navigation signals to military and civilian GPS units

and

You can get (the accuracy) down to a centimeter

 

Which civilian GPSr are they talking about? Those we will buy in 3 years? Our current GPSr won't go below 3 meters, right?

[+GPSlug]

What does it mean?

 

improved navigation signals to military and civilian GPS units

and

You can get (the accuracy) down to a centimeter

 

Which civilian GPSr are they talking about? Those we will buy in 3 years? Our current GPSr won't go below 3 meters, right?

"Civilian" meaning commercial, rather than consumer.

[Rhialto]

What does it mean?

 

improved navigation signals to military and civilian GPS units

and

You can get (the accuracy) down to a centimeter

 

Which civilian GPSr are they talking about? Those we will buy in 3 years? Our current GPSr won't go below 3 meters, right?

"Civilian" meaning commercial, rather than consumer.

Ok, slightly different meaning in french.

[+Egnix]

"Civilian" meaning commercial, rather than consumer.

 

That's not true. "Consumers", like you and I use the civilian signal.

[+mousekakat]

Well, for the past 6 to 8 weeks, maybe more, it's been taking my TomTom a couple of minutes to find a signal, where in the past it's linked up almost immediately. Maybe this will help speed things up some!

[+Egnix]

What does it mean?

 

improved navigation signals to military and civilian GPS units

and

You can get (the accuracy) down to a centimeter

 

Which civilian GPSr are they talking about? Those we will buy in 3 years? Our current GPSr won't go below 3 meters, right?

 

This was the fourth modernized Block IIR (aka IIRM) satellite to launch. The IIRMs have a second civilian signal which will allow civilian users (like you and I) to have better accuracy. This, of course, requires a receiver to use both ("old" and "new") civilian signals to remove the navigation error caused Earth's ionosphere that you get when using just one signal.

 

So, yes, you will have to buy a new receiver to take advantage of this. You will also have to wait for more satellites to be launched so you will actually have the new satellites overhead. The remaining four IIRMs are slated to be launched over the next 11 months. Then we'll get the new Block IIF satellites...

 

I know the IIF birds have an increased signal power on L1 (the existing civilain channel), and I'm thinking I read that the IIRM birds do too. So, until we get new receivers, we should at least be able to benefit a little from better signal strength.

[+Egnix]

Well, for the past 6 to 8 weeks, maybe more, it's been taking my TomTom a couple of minutes to find a signal, where in the past it's linked up almost immediately. Maybe this will help speed things up some!

 

Wow, that is very intersting to hear. That seems to coincide with the deployment of the new "operational control segment" software (the software the maintains the constellation). We've had some hiccups (as one would expect with a new system), but things seem to be settling down.

I hadn't noticed any difference in my receivers, but I usually don't pay close attention. I'd be intrested to hear if your TomTom starts to act more 'normal'.

[+fastforty]

Government & military organizations have access to MUCH higher detail then we do. They can target a projectile's impact down to the inch & they can read the novel you're reading on your sundeck with better clarity then you can (they could probably look down your bathroom drain vent & let you know that you have a nasty hair clog brewing in there, if they have a notion to). I don't think these new satellites are going to make our lives any easier, we're still going to be stuck with civilian accuracy.

[+Egnix]

GPS IIR-17 (aka SVN55, aka PRN15) was turned on for use yesterday. So GPS receivers should see satellite 15 back on the grid (when it's overhead, of course).

 

As for fastforty's reply... If you don't want to take advantage of the improved /civilian/ accuracy of the new satellites, that is completely up to you (and your receiver).

[Rhialto]

Ok then if I see a little 15 under a bar I know my GPSr receive the signal from this brand new sat?

[+Egnix]

Ok then if I see a little 15 under a bar I know my GPSr receive the signal from this brand new sat?

 

Right...unless, for some odd reason, your receiver doesn't use the satellite's PRN number.

 

As I look into this a little more, it's obvious the satellite is broadcasting the navigation data, though it might still be set as "unhealthy". So, a receiver would receive the data, but not use it because of it being set unhealthy.

[+GPSlug]

15 is fully alive, but if your GPSr hasn't picked up a newer almanac saying so, it might not look for 15 until it does.

[+Egnix]

15 is fully alive, but if your GPSr hasn't picked up a newer almanac saying so, it might not look for 15 until it does.

 

Yeah, I was looking at an old almanac which still marked it unhealthy.

[BelchFire]

15 is fully alive, but if your GPSr hasn't picked up a newer almanac saying so, it might not look for 15 until it does.

Is this an automatic thing, or something the user must do manually?

[+mousekakat]

Almanac?

 

Unhealthy?

 

Ummm.. I have a Tomtom ONE... what do I need to do to be sure I'm getting the signal from this sat?

[+GPSlug]

It's automatic. Don't worry about it.

[+Egnix]

Almanac?

 

Unhealthy?

 

Ummm.. I have a Tomtom ONE... what do I need to do to be sure I'm getting the signal from this sat?

 

The almanac is part of the data the satellite sends to your receiver. It has positional, health, etc. data. If the there is a problem, or in this case, it's a brand new satellite, the almanac will say where the satellite is, but set the "health" fields to unhealthy so your receiver doesn't use potentially bad navigation data.

 

As GPSlug said, it's automatic, but if you're really itching to see the new satellite, leave your receiver on (with it receiving a "locked" signal from some SVs) for 15 minutes. It will have an updated almanac in that time.

Edited November 2, 2007 by Egnix

[+DENelson83]

Just so you know, PRN 15 is now completely healthy and ready to use for navigation.

[+JT & PJ Cole]

Are there receivers on the civilian/consumer market available today that can take advantage of these new improved signals?

[+Egnix]

Here's a good article on the new L2C signal. Keep in mind the article was written when there was only one Block IIRM satellite in the sky. With the latest launch, we how have four IIRMs in the sky with 4 more planned by this time next year.

[+JT & PJ Cole]

Here's a good article on the new L2C signal. Keep in mind the article was written when there was only one Block IIRM satellite in the sky. With the latest launch, we how have four IIRMs in the sky with 4 more planned by this time next year.

 

infomative article.

These new satellites will make civilian GPS use quite a bit different different than today. Having sub meter accuracy might take some of the challenge out of caching. But I do not think it will be any more help to me finding my way through a town I have never visited before. However my battery might last a little longer.

 

I am guessing that due to the change in frequency, current models will not be of much use in a few years. I'll keep my 60cs as long as it still does the job.

[+Egnix]

I am guessing that due to the change in frequency, current models will not be of much use in a few years. I'll keep my 60cs as long as it still does the job.

 

It's not a change in frequency. It's an additional channel on a different frequency. The new satellites won't degrade performance of current GPS receivers.

[+EraSeek]

Let me put out there the way I understand this, then our resident experts can fill in the holes in my understanding.

 

First of all ( and of this I am certain) the new sats provide a more powerful signal which our current GPS's can utilize. This improves reception.

 

The L2c system provides a second frequency along side the original frequency. The benefit here being that the differing frequencies will pass through the atmosphere (ionosphere) at differing rates depending on the then present conditions. The GPS compares these two frequencies and the offset of their reception and that tells the GPS what kind of signal delay is present, and adjusts your position solution to compensate for that error. Much like what WAAS does only on the spot, but only on the atmospheric end of things. It does not provide adjustments for sat position and relativity as WAAS does. Thus both will still be in use.

 

I am not sure this will give centimeter accuracy, but perhaps meter-accuracy.

If it does give centimeter-accuracy I like to hear how it does that.

[Rhialto]

I am not sure this will give centimeter accuracy, but perhaps meter-accuracy.

But with our current GPSr, the minimum they can show is 3m, I believe they were programmed like this so there is no way it will display 2m, or am I wrong? I don't know if a new firmware will be able to change this or if new hardware will be required.