Kerry.

quote:Originally posted by Searching_ut:Okay, I'll bite. What are the facts, that support this speculation, and by what means do you think the powers to be have the capability of improving the accuracy of the system. The facts are actual accuracy figures based on recorded data in the Gulf region and surrounding countries. For the 14 days prior to March 20, the 95% accuracy figure ranged from 8.2 to 11.8m (average 9.8m @ 95%). March 20 accuracy dropped to 5.2m @ 95% (3.1m RMS), which is quite a considerable change to ponder about considering and basically hasn't changed much since. Who "really" knows what capability there is in specifically fine tuning the system although there are apparently means and ways. Also there's currently no planned maintainence or outages, which gives the system maximum capability. The other question might be is, does the operation control simply keep the system within published specifications and hold a little in reserve? Cheers, Kerry. I never get lost everybody keeps telling me where to go

quote:Originally posted by Mopar: quote:Originally posted by Warm Fuzzies - Fuzzy: So one could say that GPS has existed since the launch of the first Block I satellite in 1978. Well, it might have existed, but it sure would have made things interesting as it existed back then! I've been using GPS since around '90 or so, and back then it was only a backup for LORAN, since in my area the system could only be seem for a portion of each day. I suppose after the launch of the first GPS Block I Sat on Feb 22, 1978 (operational March 29, 1978), one satellite really doesn't make a system. Maybe it was a system after SVN#3 became operational Nov 9, 1978 and it's also interesting that SVN#3/PRN#6 (Block I-3) to this day still holds the record for the longest operational time. As far as being a backup for Loran well that might have been where there was Loran chains but they didn't exist everywhere either so for those areas of the world where Loran (and Omega) didn't exist some (GPS) coverage was better than "anything" previous. Certainly many milestones for GPS along the way but probably one of the most important (as tragic as it was) was the shooting down of a Korean Airline (KAL-007) on August 31, 1983. As basically a result of that the perceived use of GPS totally changed from a purely military purpose to a public dual use system as we sort of know it today. So maybe Sept 1, 1983 (there was at least enough Sats to form a crowd ) or maybe it was April 14, 1989 when the first "real" Block II Sat became operational?, but also those 1993 & 1995 dates also have some significance. Cheers, Kerry. I never get lost everybody keeps telling me where to go

Actually based on available data there's every reason to assume (some might call speculate but facts don't speculate ) that accuracy "improved" considerably on day-of-year 079 (March 20, 2003 UTC) in the Gulf region and been consistently lower since that date as well compared to the previous few weeks. That might surprise some but what some were "expecting" was never going to happen. Cheers, Kerry. I never get lost everybody keeps telling me where to go

quote:Originally posted by Dinoprophet:.... and GPS didn't exist .... That's interesting, so if not just what date did GPS exist from then. Cheers, Kerry. I never get lost everybody keeps telling me where to go

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: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:Originally posted by NuclearWinter:.... Please kill the rumor! Your GPS service isn't going to be affected. And the sooner everyone drops this "expectation" that SA will be back the better. From actual data that's available in the Gulf region I'd even hazard a guess that the systems's performance has actually improved "considerably" in the past 48 hours compared to the past few weeks. Still requires trending over the next few days to validate but there's certainly appears an improvement right at this time. Cheers, Kerry. I never get lost everybody keeps telling me where to go

quote:Originally posted by Olar:Your second number could be any one of three possiblities: + 53 deg 62.641 minutes+ or, 53.62641 deg.+ or, 53 deg 62 mins 64.1 sec. now 62.641 MINUTES is bad enough but 62 MINUTES 64.1 SECONDS now that's worse. Cheers, Kerry. I never get lost everybody keeps telling me where to go

quote:Originally posted by solohiker:SA was not turned off during the last (1991) War. SA was not turned off until May 1, 2000. SA was definately de-activated in Sept 1990 specifically as to provide improved capabilities (from an incomplete system at that time) in the Gulf war as a large number of civilian GPS receivers were used in that operation. It was re-activated on July 1, 1991 and implemented to the the SPS level on Nov 15, 1991. As for WAAS being useful, well the "Emergency Military Mode" that's built into WAAS will quell any expectation with WAAS, but this won't happen either. Cheers, Kerry. I never get lost everybody keeps telling me where to go

One would appear to be a Geodetic format and the other UTM but unless one also knows the datum (and the zone with regards UTM formats) one can't convert either of those to anything. Cheers, Kerry. I never get lost everybody keeps telling me where to go

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.]

Yeah, lots of useless information from questionable Journo's. Anybody expecting SA to be re-activated will probably be in for rather a long wait. Cheers, Kerry. I never get lost everybody keeps telling me where to go

If there becomes enough reasons to tone down the system (and there is absolutely no reason what so ever to be even thinking along these lines) then WAAS (or dGPS) would also be put in Military mode. Really don't see why there's all this expectation that SA will be back, apart from the attempt by some Journo's at sensationism and scare mongering, 'cause it's certainly not good reporting. Cheers, Kerry. I never get lost everybody keeps telling me where to go

Don't think a "German auto club" is quite the same as the US Government, who really hasn't stated anything of the kind. Some Journo's must be desperate. Cheers, Kerry. I never get lost everybody keeps telling me where to go

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

Doubt if there's such a thing as a simple formula (as such) but have a look at the VERTCON utility which handles the vertical issues as opposed to the NADCON utility, which deals with the horizontal. http://www.ngs.noaa.gov/TOOLS/Vertcon/vertcon.html Cheers, Kerry. I never get lost everybody keeps telling me where to go

quote:Originally posted by jeannine:...but say the GPS is off, is there a way to calibrate it? No I never get lost everybody keeps telling me where to go

In flying school there's a name for that, IFR rules "I Follow Road" but try it in the midlle of the simpson desert, all sand hills (and camels) look the same. Cheers, Kerry. I never get lost everybody keeps telling me where to go

Lots of variables and generally unknowns especially with wet trees as it's not only possibly an obstruction but also can be an interference, with respect multipath as wet trees can tend to act like big mirror balls. Cheers, Kerry. I never get lost everybody keeps telling me where to go

1 foot I'll stay away from some of the reasons I don't wear 1 foot as practical what so ever, regardless of what manufacturers think they can display on a screen. Now apart from what errors are involved from the other end (satellites) before any signals actually reach a receiver it rather difficult to expect an accuracy of 1 foot when being compared to coordinates given to 0.001'. But we're not talking about 10 feet (but I might/could even question that as well) but with the receivers being used (or any other for that matter) here I certainly don't get confused about what accuracy is all about. Cheers, Kerry. I never get lost everybody keeps telling me where to go

quote:Originally posted by Marky:.... Mine was 1 foot off at the measurement location. 1 foot interesting and 1 foot based on coordinates to 3 decimal minutes, was it Cheers, Kerry. I never get lost everybody keeps telling me where to go

Ah but what about tomorrow . Cheers, Kerry. I never get lost everybody keeps telling me where to go

Standard Positioning Service global average vertical accuracy is <=22m [~72 feet) @ 95% SIS and <=77m [~252 feet) worst case scenario so GPS altitude is not all that relevent. Vertical accuracy is also more affected (for the worse) by latitude than horizontal error especially once one is above about 55 degrees N/S latitude where as the higher latitudes generally improve horizontal accuracy. Cheers, Kerry. I never get lost everybody keeps telling me where to go

Where would the media/journo's be without something to write about , right or wrong Funny that this type of stuff comes out of Europe and funny how there's this comparison between their "yet to be developed" system and GPS. Also heard a "rumour" that Galileo's new motto is "Better late than never" , but we'll also have to wait some more to see how true that is. The media is generally very short sighted and last week is forgotten about but then they probably wrote much the same before Afghanistan and shock of all shocks, what happened . But if one keeps dusting the same old story off, different location, then who knows but nothing has changed since Afghanistan and lots have changed since the original Gulf War with the systems capabilities. Cheers, Kerry. I never get lost everybody keeps telling me where to go

Global Positioning System (GPS) is the short name, it's full name is "NAVSTAR GPS" NAVigation Satellite Timing And Ranging Global Positioning System. Cheers, Kerry. I never get lost everybody keeps telling me where to go