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  GPS Satellite PRN 32; February 2008

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Author Topic:   GPS Satellite PRN 32; February 2008
jimh posted 10-02-2008 06:06 AM ET (US)   Profile for jimh   Send Email to jimh  
In February of 2008 the Global Positioning System (GPS) increased the number of satellites in use and brought into service a satellite transmitting with PRN code 32. The use of PRN code 32 was remarkable, and there was concern that some GPR receivers (GPSr) might not be properly tracking the new signal.

The PRN 32 code was used prior to February 2008, and beginning in June of 2007 the GPS broadcast almanac included it. Cf:
http://cgls.uscg.mil/pipermail/cgsic/2007-June/000064.html

It might be interesting to check your individual GPSr to verify that it can track the PRN 32 code satellite. Some GPSr units apparently can only track PRN codes up to 31.

RMS posted 10-02-2008 12:47 PM ET (US)     Profile for RMS  Send Email to RMS     
Older Northstar units are effected by the new satellite. My 951XD needed a software upgrade to function when the new satellite was "visible" to the unit. Bob
bluewaterpirate posted 10-02-2008 01:26 PM ET (US)     Profile for bluewaterpirate  Send Email to bluewaterpirate     
These two screen shots were taken of my Garmin 376c that resides on the dash of my truck. The unit uses the detachable antenna that game with the unit. It has the latest software update v 4.30 dtd 6.26.08

Picture 1 heading 020 mag at 60 mph

http://cdn-2-service.phanfare.com/images/4892322_2159339_48688527_Web_3/ Image-4892322-48688527-2-Web_0_22cdd4263470d8921370e7947c07b807_1

Picture 2 heading 290 mag at 45 mph

http://cdn-2-service.phanfare.com/images/4892322_2159339_48688526_Web_3/ Image-4892322-48688526-2-Web_0_c46dad31f103f7b2d4d9ef83639ba1c5_1

When I venture offshore I remove the unit from the truck and put in my ditch bag that I carry on my Ventura.


Tom

jimh posted 10-02-2008 01:27 PM ET (US)     Profile for jimh  Send Email to jimh     
To get a real-time indication of where the GPS satellites are and what their ground track looks like, you can use the fantastic JAVA application at

http://science.nasa.gov/Realtime/jtrack/3d/JTrack3d.html

It looks like PRN 32 passes over California.

jimh posted 10-02-2008 01:31 PM ET (US)     Profile for jimh  Send Email to jimh     
Tom--Have you a screen photograph of tracking PRN 32?
bluewaterpirate posted 10-02-2008 01:37 PM ET (US)     Profile for bluewaterpirate  Send Email to bluewaterpirate     
I'll look thru my video/picture library. My wife and I are spending next week at the beach so I'll be sure to get some screen shots of my skyviews offshore. I can't really remember if I've ever seen PRN 32.

Tom

bluewaterpirate posted 10-02-2008 02:15 PM ET (US)     Profile for bluewaterpirate  Send Email to bluewaterpirate     
Jim ....

In this video you can see that my Garmin 545 sees PRN 33 but can't lock onto it (watch the PRN 33 bar you can see it move up then down).

http://albums.phanfare.com/bluewaterpirate/ 2160001_2325228#imageID=31019702

bluewaterpirate posted 10-02-2008 05:37 PM ET (US)     Profile for bluewaterpirate  Send Email to bluewaterpirate     
Jim .....

Here's what you been looking for.

PRN 32, 48, & 51 displayed

http://cdn-2-service.phanfare.com/images/4892322_2159339_48705944_Web_3/ Image-4892322-48705944-2-Web_0_42a3862c1da4415d0184509f7a152f20_1

http://cdn-2-service.phanfare.com/images/4892322_2159339_48705945_Web_3/ Image-4892322-48705945-2-Web_0_bbbb54e9f00f862f304f1e4e6311089b_1

Tom

jimh posted 10-02-2008 06:02 PM ET (US)     Profile for jimh  Send Email to jimh     
Tom--That photograph is perfect. It shows your receiver is tracking the new WAAS satellites and the new medium-earth-orbit satellite in the GPS constellation. GARMIN has it all working FINE-BUSINESS.
bluewaterpirate posted 10-04-2008 11:34 AM ET (US)     Profile for bluewaterpirate  Send Email to bluewaterpirate     
Jim ......

Here is another picture taken 110 miles south of my Greenville NC location. This picture was taken from the end of my dock on the ICW in Ocean Isle Beach NC.

You can see the difference in azimuth to PRN 32 in the early morning -vs- the late afternoon. You can also see the 376c sees PRN 48 but can't lock onto the bird.

http://cdn-2-service.phanfare.com/images/4892322_2159339_48824284_Web_3/ Image-4892322-48824284-2-Web_0_73239a81dce21eed8035e982e50abab6_1


Tom

K Albus posted 10-13-2008 05:40 PM ET (US)     Profile for K Albus  Send Email to K Albus     
Closer to home for you, Jim: My Furuno GP 1850 WF was tracking PRN 32 on a recent boating adventure on Union Lake, in Michigan: http://i512.photobucket.com/albums/t329/kalbus/GPS/GPSSmall.jpg
Chuck Tribolet posted 10-14-2008 08:10 AM ET (US)     Profile for Chuck Tribolet  Send Email to Chuck Tribolet     
My ancient Garmin GPSmap 162 locks 32, 48, and 51.


Chuck

swist posted 10-15-2008 05:37 PM ET (US)     Profile for swist  Send Email to swist     
So if I have a Garmin 492 (newer model than Chuck's 162, but not the latest), do I need to worry about anything?
My accuracy is as good as it ever was (phenomenal).
jimh posted 10-15-2008 10:21 PM ET (US)     Profile for jimh  Send Email to jimh     
The discussion is in regard to the ability of GPS receivers to track a newer satellite which uses PRN 32. This PRN had not been used in a long time. Historically there was some prior use of PRN 32, but not in the recent past. The scope here is to discover if your GPS receiver tracks PRN 32.

To discover if your receiver tracks PRN 32, you just need to check the status display for your GPS when the satellite is in range. Here is a link to a good source of information that will display the real-time position of any GPS satellite:

http://www.n2yo.com/satellites/?c=20

Visit the above page, find PRN 32 and see if it is overhead of your position, then check your GPS status to see if it is tracked. Or, just check you GPS a few times and see if PRN shows up.

Based on the replies so far, it appears that PRN 32 is not a problem for most receivers.

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