+Hank30721 Posted May 3, 2010 Share Posted May 3, 2010 Things are not looking good for G-15. Good article from space.com: Out of Control Satellite Quote Link to comment
+PDOP's Posted May 3, 2010 Share Posted May 3, 2010 I need someone to explain this (in small words) Depending on their position at the time of failure, these satellites tend to migrate toward one of two libration points, at 105 degrees west and 75 degrees east. Figures compiled by XL Insurance of New York, an underwriter of space risks, say that more than 160 satellites are gathered at these two points, which Bednarek described as the orbital equivalent of valleys. Quote Link to comment
+Red90 Posted May 3, 2010 Share Posted May 3, 2010 http://en.wikipedia.org/wiki/Lagrangian_point Quote Link to comment
+ecanderson Posted May 4, 2010 Share Posted May 4, 2010 (edited) I need someone to explain this (in small words)It means that steering wheel fell off the satellite, and that since it won't stay in its own lane it tends to create problems for other drivers, and eventually, geosync satellites whose steering wheels fall off all wind up in basically the same parking lot. Edited May 4, 2010 by ecanderson Quote Link to comment
+EraSeek Posted May 4, 2010 Share Posted May 4, 2010 http://en.wikipedia.org/wiki/Lagrangian_point I have a cache dealing with this: http://www.geocaching.com/seek/cache_detai...cd-78aa4062ced6 Quote Link to comment
+dfx Posted May 4, 2010 Share Posted May 4, 2010 http://en.wikipedia.org/wiki/Lagrangian_point doesn't that only relate to points between two stellar objects (such as sun/earth or earth/moon), and not to points relative to only one stellar object (such as a certain longitudes of the earth)? Quote Link to comment
+PDOP's Posted May 4, 2010 Share Posted May 4, 2010 http://en.wikipedia.org/wiki/http://en.wik.../wiki/Libration doesn't that only relate to points between two stellar objects (such as sun/earth or earth/moon), and not to points relative to only one stellar object (such as a certain longitudes of the earth)? That's what I understand a Lagrangian point is too. The wikipedia explanation of "Libration" doesn't seem to apply either.http://en.wikipedia.org/wiki/Libration As a guess it might be that variations in the earths gravity (due to mass concentrations) might cause satellites to be attracted to certain points in the orbit. Quote Link to comment
+EraSeek Posted May 4, 2010 Share Posted May 4, 2010 Yes, confusing. Obviously there is some reason for this "libration points at 105 degrees west and 75 degrees east" and I have seen several references to it but I have not found an explanation of it yet. Quote Link to comment
jholly Posted May 4, 2010 Share Posted May 4, 2010 Yes, confusing. Obviously there is some reason for this "libration points at 105 degrees west and 75 degrees east" and I have seen several references to it but I have not found an explanation of it yet. Because that is the way Q wants it? Quote Link to comment
+EraSeek Posted May 4, 2010 Share Posted May 4, 2010 Aw, maybe this will answer it: Quote Link to comment
+Knight2000 Posted May 4, 2010 Share Posted May 4, 2010 I need someone to explain this (in small words)It means that steering wheel fell off the satellite, and that since it won't stay in its own lane it tends to create problems for other drivers, and eventually, geosync satellites whose steering wheels fall off all wind up in basically the same parking lot. Did you mean? It means that steering wheel fell off the satellite, and that since it won't stay in its own lane it tends to create problems for other drivers, and eventually, geosync satellites whose steering wheels fall off all wind up in basically the same parking lot. Quote Link to comment
+Knight2000 Posted May 4, 2010 Share Posted May 4, 2010 Things are not looking good for G-15. Good article from space.com: Out of Control Satellite Very interesting. Thanks. Quote Link to comment
+PDOP's Posted May 4, 2010 Share Posted May 4, 2010 Yes, confusing. Obviously there is some reason for this "libration points at 105 degrees west and 75 degrees east" and I have seen several references to it but I have not found an explanation of it yet. FWIW I asked about this on an Astronomy forum (link) and this was explained as follows: "The Earth is lumpy, and if I am not mistaken the resulting irregularities in the gravitational field give us these sweet spots where the satellites are more resistant to perturbations from the Sun and the Moon. Those perturbations cause the satellites to drift away from their original longitudes in the first place when they run out of station-keeping fuel." and "Yes, these points are directly opposite each other on Earth's equator, and reflect the slight elliptical nature of the mass distribution around the equator. Geostationary satellites positioned elsewhere are on the slope of a very slight potential well, and will trickle "downhill" without regular station-keeping." Quote Link to comment
+Redwoods Mtn Biker Posted May 4, 2010 Share Posted May 4, 2010 Good info here. I imagine most of the participants are aware of it, but for any who are not, I'll point out that GPS satellites are not geostationary. Quote Link to comment
+ecanderson Posted May 4, 2010 Share Posted May 4, 2010 Good info here. I imagine most of the participants are aware of it, but for any who are not, I'll point out that GPS satellites are not geostationary. Life would be surely be easier if that were possible. My TomTom wouldn't need to download their QuickGPSFix data weekly to keep ahead of the almanac info. Imagine a world without ephemeris data. Wouldn't it be nice if every spot above the earth could be a geostationary position? Shame about that physics stuff... always getting in the way of our fun. That said, the WAAS satellites were indeed expected to "stay put" with a little help, unlike the regular GPS constellation which wanders all over the place. Quote Link to comment
+PDOP's Posted May 5, 2010 Share Posted May 5, 2010 Info on shutdown attempt at spacenews.com Quote Link to comment
+Minimike2 Posted May 6, 2010 Share Posted May 6, 2010 Good info here. I imagine most of the participants are aware of it, but for any who are not, I'll point out that GPS satellites are not geostationary. Two are, or were at least. This one is now un-geostationary. The WAAS satellites are the geostationary ones. The rest of the GPS constellation, in three orbital altitudes, are lower and not geostationary. Quote Link to comment
+Redwoods Mtn Biker Posted May 6, 2010 Share Posted May 6, 2010 Ah, right you are. That'll teach me not to make such "global" statements! Quote Link to comment
+PDOP's Posted May 18, 2010 Share Posted May 18, 2010 The saga continues for the Galaxy 15 satellite (PRN 135 / WAAS 48) originally at 133 degrees west. "The stray satellite will pass through the 131 degrees west position around May 31 ..." (link). It's interesting how the other geostationary satellites are being moved around to avoid interference issues. Meanwhile it's still seems to be functioning OK in it's WAAS role according to the WAAS Satellite Status map (link). Quote Link to comment
+Chrysalides Posted May 19, 2010 Share Posted May 19, 2010 I read that they shut down the WAAS relay temporarily to send it a kill signal, but it didn't work. So apparently we still have WAAS for now. Not that my Garmin Oregon knows the difference... Any ideas on if the FAA has a backup WAAS satellite ready? All I've been able to find on the Internet so far is "maybe". Quote Link to comment
+Team CowboyPapa Posted May 19, 2010 Share Posted May 19, 2010 I read that they shut down the WAAS relay temporarily to send it a kill signal, but it didn't work. So apparently we still have WAAS for now. Not that my Garmin Oregon knows the difference... Any ideas on if the FAA has a backup WAAS satellite ready? All I've been able to find on the Internet so far is "maybe". There is no such thing as a WAAS satellite, per se. WAAS is a separate communications package hosted by an Intelsat Galaxy satellite. Therefore, it may be more of an issue of finding another host satellite for another WAAS package. Quote Link to comment
+fizzymagic Posted May 19, 2010 Share Posted May 19, 2010 Good info here. I imagine most of the participants are aware of it, but for any who are not, I'll point out that GPS satellites are not geostationary. But the WAAS relay satellites, of which galaxy 15 is one, are. Quote Link to comment
+ecanderson Posted May 19, 2010 Share Posted May 19, 2010 Meanwhile it's still seems to be functioning OK in it's WAAS role according to the WAAS Satellite Status map (link). Ironic, isn't it? It knows where all of those other satellites are, and hasn't a clue about where IT is! Quote Link to comment
+Chrysalides Posted May 19, 2010 Share Posted May 19, 2010 There is no such thing as a WAAS satellite, per se.WAAS is a separate communications package hosted by an Intelsat Galaxy satellite. Therefore, it may be more of an issue of finding another host satellite for another WAAS package. Does a satellite broadcasting WAAS correction need to have certain hardware on it? I read things like "Galaxy 12 does not have the payload (L-band) necessary to broadcast WAAS corrections" which I assume meant some hardware limitation, but I guess I could be wrong about that. I know it's not dedicated to WAAS only, that is only one of its functions (though now it sounds like it is its only function). So what is the proper terminology for a satellite broadcasting WAAS? Quote Link to comment
+ecanderson Posted May 20, 2010 Share Posted May 20, 2010 I read things like "Galaxy 12 does not have the payload (L-band) necessary to broadcast WAAS corrections" which I assume meant some hardware limitation, but I guess I could be wrong about that.No, you're 100% correct. The WAAS signal uses the 20cm band, just like the rest of the GPS system, and Galaxy 12 doesn't support those frequencies ... it's a C-band only (60cm) satellite. Quote Link to comment
+GPSlug Posted May 25, 2010 Share Posted May 25, 2010 Here's a simulation someone made of how much it will drift. Apparently it will still be broadcasting into July and the new one may be out of test mode as soon as October. Quote Link to comment
+hdarpini Posted May 26, 2010 Share Posted May 26, 2010 I read that they shut down the WAAS relay temporarily to send it a kill signal, but it didn't work. So apparently we still have WAAS for now. I wish someone would tell my Triiton 2000 that. I've had it for three weeks now and have as yet to pick up a WAAS satellite. Or a twelfth GPS satellite. Quote Link to comment
+PDOP's Posted September 16, 2010 Share Posted September 16, 2010 It still lives SpaceFlightNow.com (link) It has drifted to 117.6°W (from 133°W) so far and it looks like it may continue it's WAAS role until the new satellite (PRN133) becomes operational later this year and maybe even later. When Galaxy 15 does power itself down, officials say there is a small chance they could reboot the satellite and recover its functionality. Quote Link to comment
+Hank30721 Posted September 17, 2010 Author Share Posted September 17, 2010 It still lives SpaceFlightNow.com (link) It has drifted to 117.6°W (from 133°W) so far and it looks like it may continue it's WAAS role until the new satellite (PRN133) becomes operational later this year and maybe even later. When Galaxy 15 does power itself down, officials say there is a small chance they could reboot the satellite and recover its functionality. I haven't seen it on any of my GPSr's. It has caused more trouble with CATV head-end reception issues than it is worth!!!! I wish I could shoot it down!! Quote Link to comment
+ecanderson Posted September 17, 2010 Share Posted September 17, 2010 I haven't seen it on any of my GPSr's. It has caused more trouble with CATV head-end reception issues than it is worth!!!! I wish I could shoot it down!! You'd see it as #48, not #133. As it drifts further east, it will actually be a good one for you. I look forward to it moving more to about 104 degrees so it won't be shadowed when I'm up close to the Rockies on the Front Range. Quote Link to comment
+PDOP's Posted October 28, 2010 Share Posted October 28, 2010 "October 25, 2010 – The geostationary (GEO) satellite Intelsat (CRW) will continue broadcasting the WAAS signal at least into December 2010." www.faa.gov Quote Link to comment
+PDOP's Posted October 28, 2010 Share Posted October 28, 2010 .... Apparently it will still be broadcasting into July and the new one may be out of test mode as soon as October. The new one (PRN133) now appears on http://www.nstb.tc.faa.gov/RT_WaasSatelliteStatus.htm Quote Link to comment
+ecanderson Posted October 28, 2010 Share Posted October 28, 2010 Wonder how long until the DNU is dropped? Still on schedule for healthy by December? Quote Link to comment
+ecanderson Posted October 28, 2010 Share Posted October 28, 2010 (edited) FYI: Found this interesting web page the other day that reports "outages" and tracks errors. #27 has been naughty lately... http://adn.agi.com/SatelliteOutageCalendar/SOFCalendar.aspx Edited October 28, 2010 by ecanderson Quote Link to comment
xyzee Posted October 28, 2010 Share Posted October 28, 2010 This is the best that I can come up with. http://www.faa.gov/about/office_org/headqu...gnss/waas/news/ Quote Link to comment
+Hank30721 Posted November 3, 2010 Author Share Posted November 3, 2010 I haven't seen it on any of my GPSr's. It has caused more trouble with CATV head-end reception issues than it is worth!!!! I wish I could shoot it down!! You'd see it as #48, not #133. As it drifts further east, it will actually be a good one for you. I look forward to it moving more to about 104 degrees so it won't be shadowed when I'm up close to the Rockies on the Front Range. Actually it shows up as WAAS 135. Delorme's PN series do not use the SV numbers like Garmin. Quote Link to comment
+ecanderson Posted November 4, 2010 Share Posted November 4, 2010 Actually it shows up as WAAS 135. Delorme's PN series do not use the SV numbers like Garmin. My bad. Got my W133º (old location of PRN-135) mixed up with PRN-133. Quote Link to comment
+PDOP's Posted November 4, 2010 Share Posted November 4, 2010 It looks like the new geo (46 / PRN 133, 98.0°W, Inmarsat 4F3) came out of testing for a while today. Screen shot from Oregon 200 Quote Link to comment
xyzee Posted November 9, 2010 Share Posted November 9, 2010 I just noticed that easterly bound WAAS 48, has almost caught up with 51. 48 is at 107.94 51 is at 107.27 It looks like that 48 will track just south of 51 as it passes it. (if - means south) Can't blame my 60CSx for using 46 for the last few says, as 48 and 51 duke it out. Quote Link to comment
+Hank30721 Posted November 9, 2010 Author Share Posted November 9, 2010 (edited) I just noticed that easterly bound WAAS 48, has almost caught up with 51. 48 is at 107.94 51 is at 107.27 It looks like that 48 will track just south of 51 as it passes it. (if - means south) Can't blame my 60CSx for using 46 for the last few says, as 48 and 51 duke it out. So long 48, and thanks for all the fish.... Edited November 9, 2010 by Hank30721 Quote Link to comment
+ecanderson Posted November 9, 2010 Share Posted November 9, 2010 So long 48, and thanks for all the fish.... Shame the number wasn't 42, eh? Quote Link to comment
+PDOP's Posted December 17, 2010 Share Posted December 17, 2010 PRN 135 is gone - WAAS Intelsat GEO Satellite Ceases Broadcast (link) Quote Link to comment
xyzee Posted December 17, 2010 Share Posted December 17, 2010 My older units are acting as expected, with the "shutdown" of WAAS 48. The Meridian, after more than half an hour, keeps on searching for 48. Too bad that one can't go inside, via 03, and cancel just one WAAS Sat, rather than both, as it's all or nothing. Another hack in the future to change to 46. The GPS 60 grabbed 51 right off, then in the second slot it searched for 48 for about a minute, then to 33 for about a minute, then to 46. The bar never goes solid and the icon flashes, but it has been doing the corrections ok. Sometimes with 14 sats visible, the unit only uses one WAAS slot/bar, and it has kicked 51 off, keeping 46, but the +- accuracy drops from 13 ft to 5 ft, like it does with 51. Side note: I have had the WAAS Sat kicked off of a 60CXs, when there were about 14 sats visible, just like Garmin said that it might, in a back page of the manual. Now I wonder how the new Maggie X10 units will handle the change. Quote Link to comment
+Edison.Starfire Posted December 17, 2010 Share Posted December 17, 2010 My older units are acting as expected, with the "shutdown" of WAAS 48. The Meridian, after more than half an hour, keeps on searching for 48. Too bad that one can't go inside, via 03, and cancel just one WAAS Sat, rather than both, as it's all or nothing. Another hack in the future to change to 46. The GPS 60 grabbed 51 right off, then in the second slot it searched for 48 for about a minute, then to 33 for about a minute, then to 46. The bar never goes solid and the icon flashes, but it has been doing the corrections ok. Sometimes with 14 sats visible, the unit only uses one WAAS slot/bar, and it has kicked 51 off, keeping 46, but the +- accuracy drops from 13 ft to 5 ft, like it does with 51. Side note: I have had the WAAS Sat kicked off of a 60CXs, when there were about 14 sats visible, just like Garmin said that it might, in a back page of the manual. Now I wonder how the new Maggie X10 units will handle the change. I responded in the x10 thread in case you don't see it. I'll try and get a good lock with the 610 asap and watch the birdees. 46 has been hit and miss from what I've seen so far but havent got to spend a great deal of time. Last Saturday I was out most of the day but running out of time and ended up grabbing coords with the Garmin since i had several waypoints stored for a friend on the Mag that i didnt want to risk. The 610 is a really nice unit and not sorry I bought it even though it was bought due to temporarily losing the Garmin. Quote Link to comment
+Egnix Posted December 20, 2010 Share Posted December 20, 2010 Just to clear up some misinformation... That said, the WAAS satellites were indeed expected to "stay put" with a little help, unlike the regular GPS constellation which wanders all over the place. GPS satellites do not wander all over the place. Each one is assigned a specific orbital plane and a slot within that plane. Think of a plane as a circle around the earth. A slot is a position on that circle. A GPS satellite will circle the earth roughly twice a day. The WAAS satellites are the geostationary ones. The rest of the GPS constellation, in three orbital altitudes, are lower and not geostationary. As someone else mentioned, "There is no such thing as a WAAS satellite, per se." I just wanted to add that the satellites which carry the WAAS payload are not a part of the NAVSTAR GPS constellation. Quote Link to comment
+PDOP's Posted December 29, 2010 Share Posted December 29, 2010 PRN 135 / WAAS 48 may return.www.intelsat.com Galaxy 15 Status UpdateOn 23 December, the power from the Galaxy 15 battery completely drained during its loss of earth lock and the Baseband Equipment (BBE) command unit reset, as it was designed to do. Shortly thereafter Galaxy 15 began accepting commands and Intelsat engineers began receiving telemetry in our Satellite Operations center. We have placed Galaxy 15 in safe mode, and at this time, we are pleased to report it no longer poses any threat of satellite interference to either neighboring satellites or customer services. After completing initial diagnostic tests, we will load updated commanding software to the satellite. We expect to relocate the satellite to an Intelsat orbital location where engineers at our Satellite Operations Control Center will initiate extensive in-orbit testing to determine the functionality of every aspect of the spacecraft. We will provide an update through normal sales channels, and MyIntelsat, if and when the satellite recovery mission is successful. Quote Link to comment
jholly Posted December 29, 2010 Share Posted December 29, 2010 I guess it was a good thing it didn't have an energizer Quote Link to comment
+G & E Posted December 29, 2010 Share Posted December 29, 2010 News like this really grounds a person. We have so much fun with our sport of geocaching or just getting lost in the woods and using the GSP to get us out that it is easy to forget all of the complexity that goes into making it all possible. It is also somewhat ironic that we are guided by satellites to and from our destination and yet one of those satellites is getting lost. I'm glad there are people whose job it is to keep those satellites in place. Quote Link to comment
+ecanderson Posted December 29, 2010 Share Posted December 29, 2010 Heck of a way to have to perform a reboot, but whatever works, eh? I wonder if it's got enough go juice to return to a stable orbit someplace useful? Wouldn't hurt my feelings if they could find another good place E of the Rockies to park it. Quote Link to comment
+PDOP's Posted December 29, 2010 Share Posted December 29, 2010 ... Wouldn't hurt my feelings if they could find another good place E of the Rockies to park it. It was originally at 133 degrees west so I would guess that it might eventually be returned to that longitude. Quote Link to comment
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