NCYankee wrote:
Because we have been using the terminology and it has changed for no good reason and we have more RNAV (GPS) approaches (14,000+ procedures on 6400+ charts) than the entire rest of the world put together. It only serves to confuse the issue. We already changed GPS to RNAV (GPS). The US non concurred with the name change for its procedures.
You have only FAA to blame for that I’m afraid. RNAV(GNSS) has been around for what? At least 8 years and probably more.
Peter wrote:
How is this implemented?
It calculates the probability of the aircraft actually being within the specified volume of space (e.g. TSE of RNP-1 is 1 nm) and if it’s less than the required probability (95 % within TSE and 99.999 % within twice the TSE), it alerts you. You should be able to find a paper with details on how this is calculated if that’s what you want.
I was referring to the monitoring bit. AFAIK GPS approaches are not signal-monitored at all. LPV (using EGNOS) are de facto monitored by the ground station(s) but not monitored at each airport. Whereas e.g. an ILS signal is monitored right at the runway.
Peter wrote:
I was referring to the monitoring bit.
Peter wrote:
I was referring to the monitoring bit. AFAIK GPS approaches are not signal-monitored at all. LPV (using EGNOS) are de facto monitored by the ground station(s) but not monitored at each airport. Whereas e.g. an ILS signal is monitored right at the runway.
I suggest you read the PPL/IR PBN manual which explains this well.
Martin wrote:
The renaming is to be done by the December of 2022 IIRC, plenty of time. Until then, even new procedures don’t have to use it. And wasn’t it FAA’s choice to use (continue using) RNAV(GPS) instead of RNAV(GNSS)? RNAV(GNSS) has been around for quite some time, right?
Although the term GNSS may have been around some time, only the US Military GPS system is providing service at this point in time. GPS was declared fully operational in 1995, 21 years ago and in 2000 (16 years ago) it became US policy to not use SA to degrade navigation. Galileo is not to be fully operational until 2019/2020.So what purpose does using GNSS instead of GPS serve. This is another name change for no real purpose other than “not invented here” syndrome. Exactly how many approaches have been flown using other than the US Military provided GPS system to date. The SBAS WAAS augmentation system has been operational since 2003 or 13 years ago. It is nice to see other SBAS systems up and running, but the GPS satellites are what is being used for augmentation. Why should the US change its approach naming conventions just to be politically correct. You guys have fun with your new names. :)
It is not about renaming the “GPS” part to “GNSS”, which would arguably be pretty pointless. But going from “RNAV” to “RNP APCH” changes the underlying definitions. If one day you get eLORAN in the US or a receiver combining multiple sources to achieve resilient navigation, and you have equipment on board that meets the required navigation precision (RNP), you could just use that instead of GPS to fly this approach without asking anybody. Maybe you will be able to increase your position accuracy using WiFi signals, as your phone already does. Who knows. But do we really want to do a new study for a new approach each time that technology evolves, or do we define what performance it should achieve at the minimum to fly a certain approach and then permit all navigators that can do it?
I am sure the US will then choose to permit using eLORAN for a GPS approach and not bother about the naming convention. But it would not make much sense.
NCYankee wrote:
Although the term GNSS may have been around some time, only the US Military GPS system is providing service at this point in time.
You forgot the Russian GLONASS (fully operational by now) and Chinese Beidou (operational over some 20% of the globe?). On my uncertified devices, GLONASS+GPS give a substantially better precision than GPS only.
Ultranomad wrote:
You forgot the Russian GLONASS (fully operational by now) and Chinese Beidou (operational over some 20% of the globe?). On my uncertified devices, GLONASS+GPS give a substantially better precision than GPS only.
So what approach is approved for using GLOSNASS? What certified avionics are available that can be use GLOSNASS? GLOSNASS has only been fully operational for 5 years and has not had a very reliable history. I did not forget GLOSNASS, I ignored it.
NCYankee wrote:
So what approach is approved for using GLOSNASS? What certified avionics are available that can be use GLOSNASS?
GLONASS, not GLOSNASS. UUDD and UUEE Moscow and USTR Tyumen have 4 precision GLONASS approaches each (one for each runway), UNEE Kemerovo, URWW Volgograd and URMM Mineralnye Vody have two each, UHPP Petropavlovsk-Kamchatsky and UIAA Chita have one each. All of them are GBAS-enhanced. Plus a number of non-precision ones. Any certified avionics is obviously Russian-made, but GLONASS reception capability is present in many mass-produced chipsets and uncertified devices. One Russian manufacturer of uncertified GA avionics is planning to move the production to Czech Republic and get their EFIS EASA-certified as soon as they can. Generally speaking, a receiver supporting GPS and GLONASS selects them transparently to the user and can even combine satellites from both systems in a single navigation solution.
