Gps
Joined: May 2001
Posts: 10,804
Likes: 1
I down loaded the almanac today in the cruise.
Seems there are 30 sats online just now 24 good 2 bads and the rest spare.
Did they ever sort out that registry overflow problem with them? I seem to remember a New scientist article on the subject of the life span of said network.
MJ
Seems there are 30 sats online just now 24 good 2 bads and the rest spare.
Did they ever sort out that registry overflow problem with them? I seem to remember a New scientist article on the subject of the life span of said network.
MJ
Joined: Oct 2001
Posts: 3,832
Likes: 115
From: UK
I come to this discussion late. I too come from the radio range days/SBA/Consol/Loran/Sun Gun/Decca/Doppler etc etc right through to triple INS and Omega.
In my current day job, we use 2xGPS with UNS1K FMAs as the primary BRNAV requirement. It works very well.
It is categorised as RNP5 equipment. This means that for 95% of a flight, the equipment is guaranteed to keep the aircraft within 5 nms of track.
My fun aeroplane is equipped with a Garmin 430 which I love but when I am crawling round the London TMA, I assume that even if it is as good as the kit I use in my day job, it is only guaranteed to the above limits. I therefore try to give everything a miss by at least 5 nms just in case I'm in the 95% of the time and not when the error could be in excess of 5 nms for 5% of the time if you see what I mean!
Looking out of the window helps enormously.
In my current day job, we use 2xGPS with UNS1K FMAs as the primary BRNAV requirement. It works very well.
It is categorised as RNP5 equipment. This means that for 95% of a flight, the equipment is guaranteed to keep the aircraft within 5 nms of track.
My fun aeroplane is equipped with a Garmin 430 which I love but when I am crawling round the London TMA, I assume that even if it is as good as the kit I use in my day job, it is only guaranteed to the above limits. I therefore try to give everything a miss by at least 5 nms just in case I'm in the 95% of the time and not when the error could be in excess of 5 nms for 5% of the time if you see what I mean!
Looking out of the window helps enormously.
Joined: Aug 2000
Posts: 3,648
Likes: 2
From: UK
Isn't it the most accurate and reliable bit of equipment that even a simple UK PPL can use for navigation... Then why does the mighty US Air Force put restrictions on it's use above the restriction thay place on a simple VOR or ILS?
Availability vs integrity is a trade off. The higher the standard you insist on (and for GPS for even NPAs, the ICAO standard is many orders of magnitude higher than for conventional navaids) the lower the availability. With an NDB, if it's radiating, it's available. That's because the integrity of the navigational output derived from ADF/NDB is so poor.
If your point is that a pilot should never rely on the availability of a single navaid in a mission critical situation, I'm with you 100%. If you're suggesting that the USAF policy brings other aspects of the "reliability"of GPS into question, or its accuracy, then you need to rethink your understanding of failure modes.
Joined: May 2001
Posts: 10,804
Likes: 1
New Scientist
http://www.newscientistspace.com/article.ns?id=dn8051
Article in the latest additions to the fleet.
Gives the upgrade over the next few years.
Does anyone know about this new exra freq. I take it won't be available until quite far into the replacement program.
And all you needed to know about gps
http://www.colorado.edu/geography/gc...gps/gps_f.html
Article in the latest additions to the fleet.
Gives the upgrade over the next few years.
Does anyone know about this new exra freq. I take it won't be available until quite far into the replacement program.
And all you needed to know about gps
http://www.colorado.edu/geography/gc...gps/gps_f.html
