Jump to content

New GPS satellite launching Thursday morning


Egnix

Recommended Posts

Weather permitting, GPS 2F-3 (SVN65) will be launching tomorrow morning at 8:10am EDT. Spaceflight Now will have live updates, and I think they also broadcast the launch. The site also has pictures, diagrams etc.

It looks like the satellite will be given PRN 24 (the number you would see on your GPS receiver). Expect about 2 weeks after launch for the satellite to be ready for use.

Link to comment

Is this one of the new generation of satellites which will have improved accuracy? By improved, I think I read a 10X improvement or from 20-feet to 2-feet accuracy, assuming a suitable receiver.

 

If true, how many similar satellites before this is all ready to use?

 

Thanks

 

This is the third satellite of what is called "Block IIF", which is the latest generation of GPS satellite. There will be a total of 12 of these Block IIF satellites.

The Block IIF satellites have more powerful transmitters than previous generations, so should help accuracy a little bit. This is the main immediate benefit to the geocacher. They also have a new civilian signal (called 'L5'), although you'll need a receiver that can receive this new signal. Though, I'm not sure if the new satellites are transmitting the new signal yet.

 

The building of the next generation, Block III, is already underway. I'm not sure what new features it will provide.

Link to comment
They also have a new civilian signal (called 'L5'), although you'll need a receiver that can receive this new signal.

I suspect this is the answer I'm seeking. Bit of Chicken and Egg here. No sense turning on L5 until you have a full constellation of L5 satellites and then we'll need to purchase L5 receivers. At this pace, 5 more years?

 

No doubt the Block III satellites will also have the L5 signal.

 

Thanks for the details. :)

Link to comment
They also have a new civilian signal (called 'L5'), although you'll need a receiver that can receive this new signal.

I suspect this is the answer I'm seeking. Bit of Chicken and Egg here. No sense turning on L5 until you have a full constellation of L5 satellites and then we'll need to purchase L5 receivers. At this pace, 5 more years?

 

No doubt the Block III satellites will also have the L5 signal.

 

Thanks for the details. :)

 

Sorry, I kind of avoided your last question, since I don't know much about L5. O:) The GPS control system doesn't yet have the capability to monitor the L5 signal, so I would doubt they would turn the signal on when they can't monitor it yet. ;)

 

The launch pace is kind of unpredictable. The next launch after tomorrow's launch is scheduled for March. There's always talk of launching several in a year, but it always seems to end up being 1-2 a year.

Link to comment

Pretty amazing how predictable rocket launches have become, it's rare to have a failure.

 

It's expensive to have a failure. ;)

 

The only non-test launch failure I can recall unfortunately had a GPS satellite (IIR-1) on board. That was back in January of '97. There are videos of it on youtube.

Link to comment

A few of the early SpaceX Falcon 1 rockets had major failures some years ago, and I think a couple of paying-customer payloads were lost (nothing so large or important as a GPS satellite!). But those were early days for a new company, and they've done pretty well since. ULA's Delta 4 and Atlas 5 rockets are expensive, but have proven quite reliable, and American launchers have had a good record overall the past 10 years or so.

 

However, there's some indication that the upper stage engine on today's DIV-M suffered a partial failure, and had to burn extra long to compensate. The GPS satellite ended up in its correct orbit, but it's not clear if the upper stage can complete its normal "disposal" burn (which causes it to re-enter the atmosphere instead of remaining in orbit and causing a navigation/junk hazard).

Link to comment

Is this one of the new generation of satellites which will have improved accuracy? By improved, I think I read a 10X improvement or from 20-feet to 2-feet accuracy, assuming a suitable receiver.

 

If true, how many similar satellites before this is all ready to use?

 

Thanks

 

This is the third satellite of what is called "Block IIF", which is the latest generation of GPS satellite. There will be a total of 12 of these Block IIF satellites.

The Block IIF satellites have more powerful transmitters than previous generations, so should help accuracy a little bit. This is the main immediate benefit to the geocacher. They also have a new civilian signal (called 'L5'), although you'll need a receiver that can receive this new signal. Though, I'm not sure if the new satellites are transmitting the new signal yet.

 

The building of the next generation, Block III, is already underway. I'm not sure what new features it will provide.

 

According to this the margin of error should go down to 3 feet with an increase in power to receive in difficult locations (urban canyons and tree cover). Even with this I still think finding a small bison in a tree will be just as difficult.

Link to comment

Is this one of the new generation of satellites which will have improved accuracy? By improved, I think I read a 10X improvement or from 20-feet to 2-feet accuracy, assuming a suitable receiver.

 

If true, how many similar satellites before this is all ready to use?

 

Thanks

 

This is the third satellite of what is called "Block IIF", which is the latest generation of GPS satellite. There will be a total of 12 of these Block IIF satellites.

The Block IIF satellites have more powerful transmitters than previous generations, so should help accuracy a little bit. This is the main immediate benefit to the geocacher. They also have a new civilian signal (called 'L5'), although you'll need a receiver that can receive this new signal. Though, I'm not sure if the new satellites are transmitting the new signal yet.

 

The building of the next generation, Block III, is already underway. I'm not sure what new features it will provide.

 

According to this the margin of error should go down to 3 feet with an increase in power to receive in difficult locations (urban canyons and tree cover). Even with this I still think finding a small bison in a tree will be just as difficult.

With three feet accuracy at least you know *which* side to search.

Link to comment

Just curious....Saw this thread and I turned on my 60csx to see if this new sat will appear on it's sat screen. Left the GPS on for an hour while on a ride. 24 never showed up in the list of received sats.

 

I'm wondering why. Is this new sat viewable from the southeastern US? Also, it seems that in the past I recall a change in the WAAS sats required firmware updates so that the older units could "see" the changes in the constellation. Will this be true for this new sat? Thanks.

Link to comment

Late yesterday, I tried to find 24 from my Utah location, on a 60Cx. After a few minutes I checked the Sat Page and could see a bar for 24, but no icon. Then I let it continue to download a new Almanac for about 15 minutes. Then I did a reboot, and there was 24 up in the NE, replacing 9. Still had a 9 bar, but no icon. Then I did the same with the GPS 60, and after the reboot 9 was showing, but I could see a tad bit of 24 showing behind it.

This morning they were west of me, still 90% covering each other. When I updated the SporTrak, and then a reboot, it also showed 24 behind and just a wee bit above 9. Good that I did this before 11 AM MST, just before they fell off of the SW corner of the Sat Page

When I checked the above link, it showed the two almost covering each other, along with the tracking history.

I guess then 24 must be replacing 9.

Link to comment

I guess then 24 must be replacing 9.

 

I doesn't work that way.

The numbers you see on your GPSr are the PRNs (Psuedo-Random Noise) numbers. This is a fixed set of numbers for operational GPS satellites ranging from 1 to 32 (If you see a number greater than 32 on your GPSr, it is either a WAAS or EGNOS satellite). I'm not sure how the orbital 'planes' and 'slots' are laid out, but PRN 9 is currently in plane/slot A1 and PRN 24 is currently in plane/slot A5. IIRC, they recently increased the number of slots from 4 to 6, so it could be that slot 1 and slot 5 are close to each other.

 

So, the PRN numbers are always recycled and apply to the current operational constellation. The satellites do have a unique number...well, actually a few unique numbers...but the common one is the "SVN" (Space Vehicle Number). This new satellite is SVN65, and it replaced SVN27 IIRC. SVN39 uses PRN 9 that you see on your GPSr....

Link to comment

I guess then 24 must be replacing 9.

 

I doesn't work that way.

The numbers you see on your GPSr are the PRNs (Psuedo-Random Noise) numbers. This is a fixed set of numbers for operational GPS satellites ranging from 1 to 32 (If you see a number greater than 32 on your GPSr, it is either a WAAS or EGNOS satellite). I'm not sure how the orbital 'planes' and 'slots' are laid out, but PRN 9 is currently in plane/slot A1 and PRN 24 is currently in plane/slot A5. IIRC, they recently increased the number of slots from 4 to 6, so it could be that slot 1 and slot 5 are close to each other.

 

So, the PRN numbers are always recycled and apply to the current operational constellation. The satellites do have a unique number...well, actually a few unique numbers...but the common one is the "SVN" (Space Vehicle Number). This new satellite is SVN65, and it replaced SVN27 IIRC. SVN39 uses PRN 9 that you see on your GPSr....

 

Great info!

 

Do you have a link or link(s) with information for all currently active GPS satellites and locations, etc? I know google is my friend, but you have quickly summed up much information I have yet to find :)

Link to comment

I guess then 24 must be replacing 9.

 

I doesn't work that way.

The numbers you see on your GPSr are the PRNs (Psuedo-Random Noise) numbers. This is a fixed set of numbers for operational GPS satellites ranging from 1 to 32 (If you see a number greater than 32 on your GPSr, it is either a WAAS or EGNOS satellite). I'm not sure how the orbital 'planes' and 'slots' are laid out, but PRN 9 is currently in plane/slot A1 and PRN 24 is currently in plane/slot A5. IIRC, they recently increased the number of slots from 4 to 6, so it could be that slot 1 and slot 5 are close to each other.

 

So, the PRN numbers are always recycled and apply to the current operational constellation. The satellites do have a unique number...well, actually a few unique numbers...but the common one is the "SVN" (Space Vehicle Number). This new satellite is SVN65, and it replaced SVN27 IIRC. SVN39 uses PRN 9 that you see on your GPSr....

 

Or a GLONOSS satelite.

Edited by jholly
Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...