+The AIIM Team Posted March 18, 2003 Share Posted March 18, 2003 I know that one was launched earlier this year. Don't they show up as uniform numbers on GPSr's? Also, please link me to a website where I can learn about the GPS constellation. Thank you. The A.I.M. Team: Ali, Ivan and Lil Mikayla, Jacksonville, Florida Equipment: Garmin eMap 32MB memory, Palm VIIx, Old College Eastport backpack, VW Jetta Wagon and Isuzu Trooper (hers) Quote Link to comment
+Prime Suspect Posted March 18, 2003 Share Posted March 18, 2003 They've decided to abandon the numeric naming system. The next satellite will be known as "Larry". Quote Link to comment
rag-a-muffin Posted March 18, 2003 Share Posted March 18, 2003 SVN 56, PRN 16 Launched 29 JAN 03; usable 18 FEB 03; operating on Rb std Unusable 14 Mar 1956 UT to 15 Mar 0214 UT due to repositioning maintenance. Should show up on your unit as 16. With some rough estimation and guessing, it looks like you should be able to see Satellite #16 in Jacksonville, FL between 1:00 and 5:00 EST. Those times can be AM or PM, since GPS satellites are on a 12 hour orbit (technically-- 11 minutes, 58 seconds). Please let me know if this is accurate or not. I'd love to know whether or not I've worked this somewhat complicated math problem correctly or not. Let me know what you find out. Robb. [This message was edited by rag-a-muffin on March 18, 2003 at 05:55 PM.] Quote Link to comment
+Poindexter Posted March 18, 2003 Share Posted March 18, 2003 There are 32 available PRN's for the constellation excluding WAAS satellites. Satellites are brought in and out of service as needed and new satellites replace older ones so these PRN's are recycled. Quote Link to comment
+The AIIM Team Posted March 18, 2003 Author Share Posted March 18, 2003 Ragamuffin: Thanks for the straight answer. I won't be outside to check GPS sats between 1 and 5 until the weekend but I will POP this thread and post back. Others, thanks for the chuckle. I am pretty sure I saw 16 earlier in the month on my GPSr. I'll post back l8tr. The A.I.M. Team: Ali, Ivan and Lil Mikayla, Jacksonville, Florida Equipment: Garmin eMap 32MB memory, Palm VIIx, Old College Eastport backpack, VW Jetta Wagon and Isuzu Trooper (hers) Quote Link to comment
Kerry. Posted March 19, 2003 Share Posted March 19, 2003 quote:Originally posted by rag-a-muffin:.... With some rough estimation and guessing, it looks like you should be able to see Satellite #16 in Jacksonville, FL between 1:00 and 5:00 EST. Those times can be AM or PM, since GPS satellites are on a 12 hour orbit (technically-- 11 minutes, 58 seconds). Please let me know if this is accurate or not. I'd love to know whether or not I've worked this somewhat complicated math problem correctly or not .... Correct, not quite, PRN 16 would only be visible between just before midnight to approx 7am (as @ 19/3) absolute max (there will be no equiv pm time) and dependent on the surrounding terrain and mask angle of the receiver being used. To be only (specifically) visible between 1am and 5am would require obstructions and/or mask angle of around 30 degrees, which is certainly much (much) higher then receiver mask angles or there's big heaps of mountains specifically located at rising (~190 deg True) and setting (~40 degrees T) locations. Cheers, Kerry. I never get lost everybody keeps telling me where to go Quote Link to comment
dave and jaime Posted March 19, 2003 Share Posted March 19, 2003 according to lecia geosystems, i ought be able to get #16 from 2:30am until 9:30am. im at 47'35N 52'43W (st john's, newfoundland) is this about right? Quote Link to comment
rag-a-muffin Posted March 19, 2003 Share Posted March 19, 2003 Kerry: Why is there no equivalent PM time? Just curious...I'm somewhat new to it all, and love trying to figure out how all this technology comes together. FYI - I did use a mask angle of 30 degrees for my calculations, to be on the safe side, but I assume it's probably a lot less, especially in Jacksonville, FL. Quote Link to comment
Kerry. Posted March 20, 2003 Share Posted March 20, 2003 Rag-a-muffin, Apart from the orbit inclinations GPS satellites are in 12 hour orbits and the Earth rotates once in 24 hours (or rather 23 hours and 56 minutes approx) so when a satellite is back to the same spot 12 hours latter where one first saw it, your effectively on the other side of the world. The approx 4 minutes difference in Earth orbit is why from one day to the next the time difference will increase by about 4 minutes and effectively the positions will progressively shift from day to day. dave & jaime, that's about right. Cheers, Kerry. I never get lost everybody keeps telling me where to go [This message was edited by Kerry on March 20, 2003 at 01:39 PM.] Quote Link to comment
+Navdog Posted March 22, 2003 Share Posted March 22, 2003 Is there a website that will show the satellite constellation for a specific area at a future date/time? The adventures of Navdog, Justdog, and Otterpup Quote Link to comment
Kerry. Posted March 22, 2003 Share Posted March 22, 2003 quote:Originally posted by Navdog:Is there a website that will show the satellite constellation for a specific area at a future date/time? The best option is some of the mission planning software which is freely available for download but how far into the future will depend on system changes and the availability of the latest almanac. One of the better Mission Planning Software programs can be download HERE and don't forget to download the latest almanac. Cheers, Kerry. I never get lost everybody keeps telling me where to go Quote Link to comment
Kerry. Posted March 22, 2003 Share Posted March 22, 2003 Oh by the way the next GPS satellite launch (GPS IIR-9) is now re-scheduled for March 31, somewhere between 21:54 to 22:08 UTC. Cheers, Kerry. I never get lost everybody keeps telling me where to go Quote Link to comment
+EraSeek Posted March 22, 2003 Share Posted March 22, 2003 quote:Originally posted by Navdog:Is there a website that will show the satellite constellation for a specific area at a future date/time? http://www.moondog3.com http://www.moondog3.com Here try this: http://sirius.chinalake.navy.mil/satpred/ Quote Link to comment
+Navdog Posted March 23, 2003 Share Posted March 23, 2003 Thanks guys for the links about satellite predictions. I just recently placed a cache up near a headwall to a canyon and the walls on three sides make it difficult to get a sat lock below a 45° angle. Knowing the optimal time to get a good fix in a situaton like that will allow me in the future to plan accordingly to get a good reading for posting the cache coords, of course future finders may need a detailed hint, because they might not be so lucky, but at least I will know the initial coords are good. The adventures of Navdog, Justdog, and Otterpup Quote Link to comment
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