+The Blind Acorn Posted January 10, 2005 Share Posted January 10, 2005 How many satellites generally show up on your Satellite screen on Garmin or Magellan??? I'm not talking about how many you get lock with, but how many will the unit search for... Quote Link to comment
+wolves shepherd Posted January 10, 2005 Share Posted January 10, 2005 There are (were?) 32 "block 1" Sats. Do to their orbits, only a certain number are visible from your location. I've had days where only about 8 were even "possible" from my location. I don't know how many "block 2" sats are up. (These are the ones with WAAS frequencies integrated.) All of this is from fuzzy memory. If you REALLY want to know check out Joe & Jacks GPS site. Just search for that and it will come up. It's like www.gpsinfo.com or something similar. Quote Link to comment
+macatac1961 Posted January 11, 2005 Share Posted January 11, 2005 On the Magellan Sportrak Pro there are 12 slots for signal bars along the bottom of the sat screen. The highest number under those bars is 30 but I'm not sure what those numbers signify. Quote Link to comment
+Poindexter Posted January 11, 2005 Share Posted January 11, 2005 (edited) There were only 11 block I satellites. The WAAS satellites are not part of the GPS constellation, but are seperate geostationary satellites above the equator. The GPS constellation of satellites are in about a 60 degree inclination orbit and therefore do not go directly over the poles. The closer you are to the equator, the more satellites you are likely to have in view at one time. At 39 degrees North latitude where I am, I have seen 11 once but usually see somewhere between 6-9. Edited January 11, 2005 by Poindexter Quote Link to comment
+Sputnik 57 Posted January 11, 2005 Share Posted January 11, 2005 Most GPSr will search for and show 12 sats. A few newer models are claiming 14. I rarely get 12, and don't think more than 6 or 7 adds much. The idea of 14 is apparently up to 12 Block 1 and 2 WAAS birds at a time. Sounds more like Madison Avenue than Silicon Valley to me. Quote Link to comment
+tirediron Posted January 11, 2005 Share Posted January 11, 2005 Typically 4 - 8 on either coast of Canada (Where I do most of my 'caching) Quote Link to comment
+Bionico Posted January 11, 2005 Share Posted January 11, 2005 According to the United States Naval Observatory website at http://tycho.usno.navy.mil/gps.html "The current GPS constellation consists of 30 Block II/IIA/IIR satellites. All the Block I's have been decommissioned. Another page in their website, at ftp://tycho.usno.navy.mil/pub/gps/gpsb2.txt , they describe the different types of GPS "birds" and if gives you a history of EACH GPS "bird" ever launched (or almost-launched, one didn't make it). You can even go to http://science.nasa.gov/Realtime/JTrack/3D/JTrack3D.html (over at NASA) and scroll to see the current positions of the GPS "birds". On the menu of the 3-D image go to "Satellite" and click on "Select" then, on the pull-down menu labeled "Types" choose "Navigation". When the menu resets itself, pull-down the menu under "Navigation" and find the satellites labeled (obviously) GPS BIIsomething. Quote Link to comment
+Sputnik 57 Posted January 11, 2005 Share Posted January 11, 2005 You can even go to http://science.nasa.gov/Realtime/JTrack/3D/JTrack3D.html (over at NASA) and scroll to see the current positions of the GPS "birds". On the menu of the 3-D image go to "Satellite" and click on "Select" then, on the pull-down menu labeled "Types" choose "Navigation". When the menu resets itself, pull-down the menu under "Navigation" and find the satellites labeled (obviously) GPS BIIsomething. OK, not quite as useful as the Trible page, but I've gotta say that is really cool! Quote Link to comment
+Jeeping Family Posted January 11, 2005 Share Posted January 11, 2005 Sputnik beat me to it. Very nice site. Quote Link to comment
+wolves shepherd Posted January 11, 2005 Share Posted January 11, 2005 I knew once I pulled rusty numbers out of my head someone would come back and correct me. thanks guys. Quote Link to comment
+Poindexter Posted January 11, 2005 Share Posted January 11, 2005 10 satellites this morning on my GPSMap76S at 39°N latitude. Quote Link to comment
ThePup Posted January 12, 2005 Share Posted January 12, 2005 I'm not talking about how many you get lock with, but how many will the unit search for... In reference to your "True that there are 24 available" question in the subject - Yes. A Full pattern is considered 24 active at any one time, in 6 (?) different orbits. There's also one 'spare' satellite in each orbit to take over should one of the 4 active ones fail at any time, or go down due to maintenince. It's impossible to see all 24 at any one time, and very rare to see the full 12 that most GPSrs are capable of locking to. As at Tue Jan 11 17:55:15 UTC 2005, There is only one of the 30 unusable, and there's scheduled maintenance on another set to occur from 18 Jan 1830 UT to 19 Jan 0630 UT. (Repositioning) Here's another bit snipped from a text file - "The U.S. Air Force Space Command (AFSC) formally declared the GPS satellite constellation as having met the requirement for full operational capability (FOC) as of April 27, 1995. Requirements include: 24 operational satellites (Block II/IIA/IIR) functioning in their assigned orbits and successful testing completed for operational military functionality." Bionico - Those tycho.usno.etc.etc pages are good info! Quote Link to comment
+The Blind Acorn Posted January 12, 2005 Author Share Posted January 12, 2005 WOW I've enjoyed your responses along with the webpages that Bionocle posted. Thanks alot. I'll leave this forum open if someone else wants to post. Quote Link to comment
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