Kerry.
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Posts posted by Kerry.
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But it's the 50th built... which fits the wording. No not really correct either as there were 21 GPSIIR's actually built and 12 of these have been modified as GPS IIR-M's and still sitting in storage as has the other IIR's been sitting waiting to be launched as required, just that sats are remaining healthy and working way past their expected life. Also satellites built are not launched in order and there is also a IIR in storage at Cape Canaveral at all times in case of emergency launch requirements.
Block I sats were SVN's 1 to 12
Block II sats SVN's 13 through 21
Block IIA sats SVN's 22 through 40
Block IIR sats SVN's 41 through 62
PRN's (max for 32) are reallocated but SVN's are not.
All GPS Sats I believe have been launched from Cape Canaveral as this is where a backup GPS monitor station is located, which is primarily used for final vehicle checkout prior to launch.
Cheers, Kerry.
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In a way it's a milestone but the "50th of these marvels is poised for delivery into space Saturday" claim is not really correct. GPS IIR-11 might be the 50th launch but only 48 have ever made it into space as GPS I-7, a block I test satellite and GPS IIR-1 (the first of the IIR's) were both lost in launch failures.
So it's the 50th launch and the 48th in space (if and when it makes it).
Cheers, Kerry.
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The Trimble prediction software is available for download but considering the download is over 20mb and the Leica Satellite availability is less than 1mb and does the same thing then I'd use the download link in T2's post.
There's also a Magellan mission planning software version that is capable of including GLONASS predictions.
Cheers, Kerry.
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Can depend on the actual make/model and some manuals specifically detail how it should be held, horzizontal, vertical, angles etc. One such case study on antenna orientation
Case Study of Antenna Orientation
Also as well as correctly orientating the handheld (for those models where it matters) the general rule for any handheld (for all low to mid latitudes) is always face the equator as this can mximize satellite reception as there are no satellites over the poles, 45 degrees either side of North or south and below 45-60 degrees above the horizon. In other words behind you.
Cheers, Kerry.
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As a Surveyor we report numbers like these on DOT drawing mostly.
What! too five (5) decimal places
Cheers, Kerry.
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Without a Datum then one is a little lost. I do find it strange that a survey map has coordinates to 5 decimal places, that's a bit over the top really.
"DGN" is a Intergraph/Bentley (mapping) file format but has no bearing on the particular units used in the file, and what they mean on this particular map, not sure.
Cheers, Kerry.
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Also important marks are placed in groups as a check for each mark. This can be slightly different and for different reasoning than simply recovery type marks. Level benchmarks and especially junction type marks are important especially considering the amount of time it takes to do level runs so having a group (generally 3 still leaves 2 if one moves or is destroyed) of marks is a check for movement on either of the marks.
With 3 marks one can generally tell if one has moved, with only 2 marks if there's a difference then it's difficult to tell which mark is at fault or even if both marks might be at fault.
Cheers, Kerry.
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Let's be fair.
The U.S. taxpayers already paid for the system. The fairest method would be to tax non-U.S. users.
Yes and thankyou very much for that
As for non US users paying well that's what's called unfair trade tarrifs, isn't it NO actually there's more spin-offs from GPS technology to the economy etc especially in the civil sector, which outstrips military expenditure/requirements by a very large factor.
Cheers, Kerry.
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Rosco, sure all this type of stuff might be fun but really reality must start and stop somewhere. Attempting experiments like this with equipment like this really doesn't prove a thing and I'm sorry but that's simply the way it is and there can be absolutely no conclusions made by doing this.
Technically GPS is affected by weather conditions and weather forecasting actually uses GPS in determining weather conditions but for a similar question asked here then the answer is No.
There has been an extreme amount of work done on issues like this as if there really were major issues with clouds, rain etc then there would be some fairly major problems accepting and using GPs especially in critical safety-of-life situations.
But your right this ............."My GPS was jumping around because it was cloudy"........ comments comes up time and time again similar when a user doesn't have a signal then ....."they must have turned the signal off 'cause of the war" ..... and all these types of comments really need to be squashed before some tturn myth in belief.
As for under tree cover now that's a totally different issue again to weather related matters and probably more of make comparison (as such all things being equal) than a system thing but again GPS being very dynamic unless ALL the users do the trial under the exact same conditions (satellite conditions, satellite geometry, same satellites etc) then what does it really mean? What I'm trying to say is, if someone rolls up with a perfect 10-12 satellite geometry visible through some convienient gaps in/under/through the tree and 30 minutes latter someone rolls up with when only 5 sat are visible and all obstructed by branches etc then what will the deduction be? The tree, the GPS, the User, the System, the Time etc and one reason why system spec's are Signal-In-Space (SIS) as the owners/operators have absolutely no control over some of the things people want/expect to do with GPS.
One of the most important things a user can do especially when working in obstructions (trees, buildings etc) and even out in the open to some extent is being where one has to be (wants to be) at the right time to take advantage of the best conditions possible.
Cheers, Kerry.
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While the GPS signal itself is not hammpered by clouds or rain, it is quite possible that the extra water in and on the overgrowth can cause signals to be blocked more than normal.
So.... while out in the open you should notice no difference, when under a canopy of trees you could very well notice a big difference.
Wet trees and also depending on the type of tree are more reknown for causing multipath issues, even can occur out in the open but again the effects that could/might cause issues with recreational receivers, well that's rather difficult to actually prove with this technology
For something factual, anybody like to list the current equipment that is actually certified for aircraft use for some of the conditions claimed, the spec's might interest some even though there isn't that many to list.
Fun thing to do, might be but really a waste of time, and that's a fact.The study is a good one because it makes no claim at completeness, nor global validity. It seems like it was a fun thing to do for a given set of circumstances.Cheers, Kerry.
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.... characterizes the worst case, one direction effect as being 20mm, or 2cm; far beyond the current capabilities of consumer GPSrs.
That's about it so any conclusions about cloud one way or the other based on consumer receivers is totally irrelevant, meaningless and whatever one wants to label it.
Also, those other guidance systems you refer to are redundant in the case of main navigational failure. Why have 1 system when you can have 2 at twice the price?So what's a main navigation failure? Inertial systems in essence are really the the brains in accurate guidance hence the general term is "GPS aided Inertial Navigation System" and in any case accuracy is one thing but one must also know quite accurately exactly where one wants to actually put the thing.
.... I'll rephrase and say the 2 meters is the current goal of consumer grade GPSThe thing is industry doesn't control the system that provides the signal in the first place. As with all accuracy it comes at a cost be it SBAS augmentation, standard differential or whatever. Consumer grade GPS won't even begin to approach 2 metres until the new civil freq are up and running.
... I mean, they are using GPS to guide airliners down into weather so bad mountains cannot be seen.GPS? no technically they are not and neither can GPS (as such) land a FA-18 on a carrier under auto-pilot but that also can be done but that's not simply "GPS" either and we can go further into that any time.
Cheers, Kerry.
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.... and my current position was indicating an accuracy of +-17 feet, I would know that if I added fifteen clicks (0.00015 degrees, or 0.00001 degree per 1.1 meters) I would know the latitude of the "shaded" position, obviously with the same accuracy of +-17 feet.
A GPS does/can not indicate accuracy as it doesn't know where it is in the first place. Much of this isn't real practical and really has no guarantee of achieving a better end result.
Cheers, Kerry.
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No, U.S policy is to continue providing GPS service free of direct user fees to civil users worldwide and this has been the policy since 1983.
However this revenue generation is one issue with the Interoperability issues of a free open system (such as GPS) with a fee-based encrypted system, which Galileo being a "private" commercial system will charge for some of its services to the civil community.
Cheers, Kerry.
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Yeah but guided missiles of generally all varieties do not solely rely on GPS and actually have several navigation systems, which either co-exist or take over as required.
says who? possibly go take a read of the Global Positioning System Standard Positioning Service Performance Standard, october 2001 2 meters indistry accepted standard, be buggered..... and as a result we have the current, industry accepted 2meter accuracy ...If anybody wants a correct definitive of some of the actual affects then Try this light reading but recreational receivers will certainly not be able to determine cloud type issues one way or another.
Cheers, Kerry.
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I read that heavy storms have been know to effect survey GPS by 2cm.
And considering some countries actually "move" 3 times more than per year, 2cm isn't as much of an issue either, especially considering that for survey type cm accuracy there must be at least 2 receivers and basically what generally affects one affects the other, dependent on separation distance.
Cheers, Kerry.
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No, in a practical sense cloud doesn't, but these types of receivers don't have the capability of measuring any affect either.
Cheers, Kerry.
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Looks like I’ll keep my GPSr set at DDD.DDDDD. Am I right?
No, not really as precision is one thing and accuracy is quite different. Besides decimal degrees isn't really an often used format and those organisations that do use it (like weather forecasts etc) aren't really interested in being precise in the first place and probably only use 1 or 2 decimals. So really if one obtains a position in dDD MM.mmm then simply set the GPS to adopt this format direct as one can't increase the precision of a position by say changing the format from dDD MM.mmm to dDD.ddddd, it is what it is and can't be any better than the original. Going the other way, any difference is probaly more of academic interest than anything practical or really useful.
Any displayed (converted) format can only be as significant as the underlying GPS XYZ coordinate precision.
Also any "difference" in coordinate formats should take into account that positions are at least 2 dimensional.
Cheers, Kerry.
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In simple terms elevation doesn't affect Lat/Long as a point say 10,000 metres vertically (as such) above a ground point of specific lat & long will have the same lat & long.
The XYZ coords that the GPS actually determines prior to conversion to a user friendly format (such as lat/long) is a 3 dimensional determination but not quite the same as pure elevation but is what the lat/long & elevation is determined from.
Cheers, Kerry.
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Recreational CM accuracy from Galileo is another one of those myths, basically rubbish. Not without augmentation and not without a cost and much of the higher accuracy service that will be offered by Galileo will come at a cost, this is what Galileo is, a commercial system and apart from Open Access Service (O.A.S), which is a free for all the commercial side of Galileo will be encrypted and controlled via access keys etc for a fee.
The 95% OAS accuracy for single freq has been quoted as 15 metres horizontal & 35 metres vertical with the dual freq 4 metres horizontal & 8 metres vertical.
.... tests have already taken place in China using EGNOS(the forerunner of Galileo), with what has been reported as good results ....EGNOS is not a forerunner to Galileo as EGNOS is only an augmentation system (similar to WAAS) and relies on a system like GPS and/or Galileo to be operational. Without GPS or Galileo EGNOS is useless.
Cheers, Kerry.
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The GPS SPS performance standards support the terrestrial service volume, where the terrestrial service volume covers the surface of the earth to an altitude of 3,000 kilometres.
The moon
now it's a little further than that.Cheers, Kerry.
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Actually I do realize what a dingo is, pictures and all and like here they are actually still wild and right now there's at least a couple within a few hundered metres of here. You forget Geo oz is where cattle dogs and the dingo actually come from. Once a cattle dog tastes blood you shoot it, with a dingo there preferably shot before they kill and it's not all that long ago that the bounty on dingo's was dropped, however I believe some shires still pay a bounty depending on the season.
Then again not many have actually seen a pure (white socked) dingo as they are getting very rare and any dingo that was bred into cattle dogs back in the early 1800's is a very long distant relative.
Cheers, Kerry.
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Blue Heeler Dingo ??? Can't see any dingo in that dog.
Cheers, Kerry.
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Written like n34° ??.???' then Degrees Minutes & decimal minutes. Degrees Minutes Seconds then it would be something like n34° ??' ??.?"
Cheers, Kerry.
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So do these changes make any difference in the accuracy of handheld GPS recievers? I read the articles but it wasnt very clear.
NO
Cheers, Kerry.
As for non US users paying well that's what's called unfair trade tarrifs, isn't it 
now it's a little further than that.
Gps Satellite #50 To Be Launched
in General geocaching topics
Posted
Well yes, but as of March 18 PRN 31 was sitting in C3.
Cheers, Kerry.