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“Fly The Plate and You Won’t Get Hurt”
A pilot flying a GPS approaches to Runways 5 at Saratoga Springs Airport with a VDP on the published approach plate is assured a margin of obstacle clearance. The subsequent tree survey showed the tree [that the aircraft struck] extended well into the 20:1 glideslope far in excess of the 34:1 required by this type of approach. The VDP feature of this type of approach assures the pilot that a 34:1 slope from the VDP to the runway threshold is free of obstructions. (www.ainonline.com) Ещё...Sort type: [Top] [Newest]
Glad that it all worked out safely and the root cause was addressed. Did you end up getting a little mud on the tires?
I have news for you all: the Russian GPS system is better by a factor of four. No one in the USA will accept this fact. NASA know.
Now, now guys. Let's please leave out the we are better than you stuff. The USA has problems--yes. Do the other countries have problems?--Yes. Let's just all work for better world wide aviation for everybody. Roland, this was a non-precision approach. Horizontal guidance was not a factor. I always used the distance from touchdown and calculated 300 feet per nautical mile for a point where a 3 degree ILS glide slope would intercept. As a backup to verify you are doing OK, it works every time.
Yea my bad, thanks for the advice.
No harm, Roland. Just my thoughts. There are holes all over in the system. Gotta watch out!
Erm, better than what? Than it was several years ago? Well, yeah, but that's not saying much. In the early part of the 2000s their constellation was down well below minimum operational capacity, I think as low as 6 space vehicles (the nominal design is 21 + 3 spares).
But better than GPS? Not. Not even by a long shot. GLONASS clocks are much noisier than the Rb and Cs standards used by GPS, and until the modernized (CDMA) K-type satellites are launched (scheduled for 2013, but may slip) the range accuracy and UDRE will continue to be quite a bit worse.
Perhaps you should do just a little bit of reading before making such asinine, unsubstantiated, and flat-out wrong comments.
But better than GPS? Not. Not even by a long shot. GLONASS clocks are much noisier than the Rb and Cs standards used by GPS, and until the modernized (CDMA) K-type satellites are launched (scheduled for 2013, but may slip) the range accuracy and UDRE will continue to be quite a bit worse.
Perhaps you should do just a little bit of reading before making such asinine, unsubstantiated, and flat-out wrong comments.
I can't read Russian. My Bulgarian pal can. He designed some software fot a commercial company. The Russian system was four times more accurate. If I make a mistake I acknowledge it. He designed this 3 years ago. It was part of his degree..physics. Was awarded PhD. Seems you guys are xenophobic hence all those names you called me. Thank God for the visas that let these talented prople to stufy here. They cancel out arrogant nuggets.
A handful of responses:
1) I _can_ read Russian (fluently). But you don't need to know any Russian at all to be able to check the constellation status of GLONASS and GPS, or to learn about current system performance. A simple web search on the phrase "GLONASS constellation status" will take you to (http://www.glonass-center.ru/en/GLONASS/), which is perfectly readable in English. You could also have just checked the Wikipedia page (http://en.wikipedia.org/wiki/GLONASS) for basic details.
2) You've now written "better by a factor of four" and "four times more accurate" in successive posts, but in neither case do you describe the specific metric you're talking about. Do you mean pseudorage accuracy? 2D or 3D position accuracy? 2Drms? Or some related aviation-relevant performance figure, like integrity or availability?
For what it's worth, GLONASS is not even close to "four times more accurate" than GPS by _any_ metric meaningful to aviation (which is, after all, the point of this thread), including those listed above. Apart from extreme northerly or southerly latitudes, standalone GPS consistently outperforms standalone GLONASS at present (and that has been the case at any time over at least the past ten years).
If you're honestly interested in learning about this stuff, you could start by reading either of van Diggelen's informative articles on satnav accuracy (http://http://old.gpsworld.com/columns/9805innov.html and http://www.gpsworld.com/gps/gnss-accuracy-lies-damn-lies-and-statistics-1134). Then perhaps you can make a claim that is somehow verifiable, debatable, or at least in the same postal code as reality.
3) You seem to be confusing my pointed comments about your misinformed claims with "all those names [I] called [you]." Please don't mischaracterize my response by claiming it to be something it's not. And your suggestion of xenophobia is quite the ironic ad hominem attack -- particularly since I'm one of those very "proble [sic]" who came here to "stufy [sic]" (albeit many years ago).
As for "arrogant nuggets," I can only observe that, in addition to being wrong, your statement, "No one in the USA will accept this fact," is rather more arrogant than anything I wrote.
4) There's little point in debating one's qualifications on a pseudonymous Internet forum like FA, but based on your comments above, I am quite confident in saying that I am rather better informed on this topic than you. If, however, you wish to have a _substantive_ technical discussion on the merits and drawbacks of satnav for aviation, such as the issues touched upon in Jim Huddleston's parent article, I will be happy to do so with specificity.
-J
1) I _can_ read Russian (fluently). But you don't need to know any Russian at all to be able to check the constellation status of GLONASS and GPS, or to learn about current system performance. A simple web search on the phrase "GLONASS constellation status" will take you to (http://www.glonass-center.ru/en/GLONASS/), which is perfectly readable in English. You could also have just checked the Wikipedia page (http://en.wikipedia.org/wiki/GLONASS) for basic details.
2) You've now written "better by a factor of four" and "four times more accurate" in successive posts, but in neither case do you describe the specific metric you're talking about. Do you mean pseudorage accuracy? 2D or 3D position accuracy? 2Drms? Or some related aviation-relevant performance figure, like integrity or availability?
For what it's worth, GLONASS is not even close to "four times more accurate" than GPS by _any_ metric meaningful to aviation (which is, after all, the point of this thread), including those listed above. Apart from extreme northerly or southerly latitudes, standalone GPS consistently outperforms standalone GLONASS at present (and that has been the case at any time over at least the past ten years).
If you're honestly interested in learning about this stuff, you could start by reading either of van Diggelen's informative articles on satnav accuracy (http://http://old.gpsworld.com/columns/9805innov.html and http://www.gpsworld.com/gps/gnss-accuracy-lies-damn-lies-and-statistics-1134). Then perhaps you can make a claim that is somehow verifiable, debatable, or at least in the same postal code as reality.
3) You seem to be confusing my pointed comments about your misinformed claims with "all those names [I] called [you]." Please don't mischaracterize my response by claiming it to be something it's not. And your suggestion of xenophobia is quite the ironic ad hominem attack -- particularly since I'm one of those very "proble [sic]" who came here to "stufy [sic]" (albeit many years ago).
As for "arrogant nuggets," I can only observe that, in addition to being wrong, your statement, "No one in the USA will accept this fact," is rather more arrogant than anything I wrote.
4) There's little point in debating one's qualifications on a pseudonymous Internet forum like FA, but based on your comments above, I am quite confident in saying that I am rather better informed on this topic than you. If, however, you wish to have a _substantive_ technical discussion on the merits and drawbacks of satnav for aviation, such as the issues touched upon in Jim Huddleston's parent article, I will be happy to do so with specificity.
-J
Oh OK...thanks for reply.
Boy, you rang a bell with Haywood! That brought the "lurkiness" out of him. I now know more about GPS than I care to. Turn it on and it works---wow. The plane I flew had GPS as the primary nav source. It came on with the batteries--no switch. If it wasn't OK for navigation, the FMS would tell you (RAIM). As for approaches--most GPS approaches are about non-precision mins. Until we can routinely fly GPS down to 200/ 1/2, I'm not impressed.