Airbus A320 GPS and navigation display VOR
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Airbus A320 GPS and navigation display VOR
Hi!
1) Could anyone explain me where the GPS signals goes after the MMR?
2) I imagine that it goes to the FMGS to calculate. So does the FMGS sends the next step (he knows where we are with the GPS) to the F/D which sends it to the A/P which sends it to the ELAC computer, right?
3) But I imagine that it won't be the same "route" in selective mode (or if FMGS has failed). So which computer decides in selective mode the next step? Is it the ELAC? So basically A/P is sending to the ELAC what we have entered in the FCU and ELAC is receiving data from the GPS so it knows what to do to satisfy our demand? But in managed mode, the FMGS calculates the next step not the ELAC...
Check this please:
3) Here we can see VOR2. Airbus autotunes VOR's and we can enter it in the RAD NAV page of the FMGC. Just one question: When it autotunes or when we enter VOR1, does it use the VOR antenna's to display it? Or is it the GPS that sends the position to the FMGS that calculates on which CRS of the VOR we are? Because, in any case, when we enter a TRK/CRS and the frequency of a VOR, it still uses GPS (GPS sends signal to the MMR which sends signal to the FMGS, then to the F/D, to the A/P and the ELAC computer and finally to the hydraulic jack)
Please help!
1) Could anyone explain me where the GPS signals goes after the MMR?
2) I imagine that it goes to the FMGS to calculate. So does the FMGS sends the next step (he knows where we are with the GPS) to the F/D which sends it to the A/P which sends it to the ELAC computer, right?
3) But I imagine that it won't be the same "route" in selective mode (or if FMGS has failed). So which computer decides in selective mode the next step? Is it the ELAC? So basically A/P is sending to the ELAC what we have entered in the FCU and ELAC is receiving data from the GPS so it knows what to do to satisfy our demand? But in managed mode, the FMGS calculates the next step not the ELAC...
Check this please:
3) Here we can see VOR2. Airbus autotunes VOR's and we can enter it in the RAD NAV page of the FMGC. Just one question: When it autotunes or when we enter VOR1, does it use the VOR antenna's to display it? Or is it the GPS that sends the position to the FMGS that calculates on which CRS of the VOR we are? Because, in any case, when we enter a TRK/CRS and the frequency of a VOR, it still uses GPS (GPS sends signal to the MMR which sends signal to the FMGS, then to the F/D, to the A/P and the ELAC computer and finally to the hydraulic jack)
Please help!
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Ok... No, let me ask the question this way:
First I would like to confirm this:
1) The VOR 1 and VOR2 displayed on that photo are coming from the VOR antenna. So when we see VOR1 ---, it means that the VOR is not in the range of what can "see" the antenna.
2) We say to the ELAC: we are here. We want to go there. Right?
Now comes my question: when we enter a CRS and the frequency of the VOR, we tell the plane that we want to be in this radial of this VOR. ELAC knows where we are (GPS) but it should know where is the VOR. Because when we enter x HDG, it means that we want to be HDG x from where we are. So the ELAC knows where we are.
So for a CRS, is the antenna VOR connected with the ELAC to tell him? Or has airbus peogrammed each and every VOR in ELAC so that it knows directly where to go?
Thanks
First I would like to confirm this:
1) The VOR 1 and VOR2 displayed on that photo are coming from the VOR antenna. So when we see VOR1 ---, it means that the VOR is not in the range of what can "see" the antenna.
2) We say to the ELAC: we are here. We want to go there. Right?
Now comes my question: when we enter a CRS and the frequency of the VOR, we tell the plane that we want to be in this radial of this VOR. ELAC knows where we are (GPS) but it should know where is the VOR. Because when we enter x HDG, it means that we want to be HDG x from where we are. So the ELAC knows where we are.
So for a CRS, is the antenna VOR connected with the ELAC to tell him? Or has airbus peogrammed each and every VOR in ELAC so that it knows directly where to go?
Thanks
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Hi..
the moving map screen you see on the A320 comes from IRU inertial reference units using inertial information (coordinates), it fine tunes itself using GPS or VOR or DME in that order, which are all independent sources of navigation, but inertial is the boss.
the bearing pointers (needles) on the screen are using VOR or NDB information only from ground stations.
If you want to fly to a VOR you can select a HDG to it using the needles or you can type it on the MCDU or FMC and the airplane will fly there using inertial reference (coordinates) with a back up from GPS, VOR or DME.
sometimes the map is wrong and you have to use the old system of VORs.
the MMR and all nav info goes to the FMGC (autopilot/ flight director) then the FMGC talks to the ELAC which moves the flight controls of the plane.
I think this is the level of understanding that you have hope it is helpfull.
the moving map screen you see on the A320 comes from IRU inertial reference units using inertial information (coordinates), it fine tunes itself using GPS or VOR or DME in that order, which are all independent sources of navigation, but inertial is the boss.
the bearing pointers (needles) on the screen are using VOR or NDB information only from ground stations.
If you want to fly to a VOR you can select a HDG to it using the needles or you can type it on the MCDU or FMC and the airplane will fly there using inertial reference (coordinates) with a back up from GPS, VOR or DME.
sometimes the map is wrong and you have to use the old system of VORs.
the MMR and all nav info goes to the FMGC (autopilot/ flight director) then the FMGC talks to the ELAC which moves the flight controls of the plane.
I think this is the level of understanding that you have hope it is helpfull.
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Hi! Thanks a lot!
Don't know IRU! What is this exactly? How does it know where we are exactly? Is there an IRU antenna or something?
So IRU is the boss, then you have GPS, and then IRS, right?
Coordinates? Is there an IRU computer which knows each and every coordinate? Or is it the GPS which is giving our position to the IRU? IRU is only used to display our position or something else too? Navigation?
Everyone had said that there were only 2 things: GPS with backup IRS!
Thanks to clear my doubts!
Don't know IRU! What is this exactly? How does it know where we are exactly? Is there an IRU antenna or something?
So IRU is the boss, then you have GPS, and then IRS, right?
Coordinates? Is there an IRU computer which knows each and every coordinate? Or is it the GPS which is giving our position to the IRU? IRU is only used to display our position or something else too? Navigation?
Everyone had said that there were only 2 things: GPS with backup IRS!
Thanks to clear my doubts!
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Wiki: The*IR
*component of an ADIRU gives attitude, flight path vector, ground speed and positional data.The*ring laser gyroscope*is a core enabling technology in the system, and is used together with*accelerometers,*GPS *and other sensors to provide raw data.
The primary benefits of a ring laser over older mechanical*gyroscopesare that there are no moving parts, it is rugged and lightweight, frictionless and does not resist a change in*precession."
Is IRU = GPS + IRS?
*component of an ADIRU gives attitude, flight path vector, ground speed and positional data.The*ring laser gyroscope*is a core enabling technology in the system, and is used together with*accelerometers,*GPS *and other sensors to provide raw data.
The primary benefits of a ring laser over older mechanical*gyroscopesare that there are no moving parts, it is rugged and lightweight, frictionless and does not resist a change in*precession."
Is IRU = GPS + IRS?
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The Air Data and Inertial Reference System (ADIRS) supplies temperature, anemometric, barometric and inertial parameters to the EFIS system (PFD and ND) and to other user systems (FMGC , FADEC, ELAC, SEC, FAC, FWC, SFCC, ATC, GPWS, CFDIU, CPC).
The system includes :
– three identical ADIRU’s (Air Data and Inertial Reference Units).
Each ADIRU is divided in two parts, either of which can work separately in case of failure in the other :
• the ADR part (Air Data Reference) which supplies barometric altitude, airspeed, mach, angle of attack, temperature and overspeed warnings.
• the IR part (Inertial Reference) which supplies attitude, flight path vector, track, heading, accelerations, angular rates, ground speed and aircraft position.
Note: Above 73 North and above 60 South, the ADIRU gives true heading
instead of magnetic heading.
– one ADIRS control panel (ADIRS CDU) on the overhead panel for selection of modes (NAV, ATT, OFF) and indications of failures.
The IR is normally initialized through the FMGS, but the ADIRS CDU may be used as a back up.
– four types of sensors :
• pitot probes (3)
• static pressure probes (STAT) (6)
• angle of attack sensors (AOA) (3)
• total air temperature probes (TAT) (2)
These sensors are electrically heated to prevent from icing up.
– eight ADMs (Air Data Modules) which convert pneumatic data from PITOT and STAT probes into numerical data for the ADIRUs.
– a switching facility for selecting ADR3 or IR3 for instrument displays in case of ADIRU 1 or 2 failure.
Separately.
The aircraft has two independent GPS receivers. Each GPS receiver is integrated in a modular avionics unit called MMR (Multi Mode Receiver) (GPS 1 receiver in MMR1, GPS2 receiver in MMR2).
The MMR processes the data received and transfers them to the ADIRUs, which then perform a GP-IRS hybrid position calculation. The FMGCs use the hybrid position. The GPS MONITOR page on MCDU1 or MCDU2 can display pure GPS position, true track, ground speed, estimated position, accuracy level, and mode of operation for the information and use of the flight crew.
Note: Flight crew can use the MCDU NAVAID page to deselect the use of GPS data for calculating position
The system includes :
– three identical ADIRU’s (Air Data and Inertial Reference Units).
Each ADIRU is divided in two parts, either of which can work separately in case of failure in the other :
• the ADR part (Air Data Reference) which supplies barometric altitude, airspeed, mach, angle of attack, temperature and overspeed warnings.
• the IR part (Inertial Reference) which supplies attitude, flight path vector, track, heading, accelerations, angular rates, ground speed and aircraft position.
Note: Above 73 North and above 60 South, the ADIRU gives true heading
instead of magnetic heading.
– one ADIRS control panel (ADIRS CDU) on the overhead panel for selection of modes (NAV, ATT, OFF) and indications of failures.
The IR is normally initialized through the FMGS, but the ADIRS CDU may be used as a back up.
– four types of sensors :
• pitot probes (3)
• static pressure probes (STAT) (6)
• angle of attack sensors (AOA) (3)
• total air temperature probes (TAT) (2)
These sensors are electrically heated to prevent from icing up.
– eight ADMs (Air Data Modules) which convert pneumatic data from PITOT and STAT probes into numerical data for the ADIRUs.
– a switching facility for selecting ADR3 or IR3 for instrument displays in case of ADIRU 1 or 2 failure.
Separately.
The aircraft has two independent GPS receivers. Each GPS receiver is integrated in a modular avionics unit called MMR (Multi Mode Receiver) (GPS 1 receiver in MMR1, GPS2 receiver in MMR2).
The MMR processes the data received and transfers them to the ADIRUs, which then perform a GP-IRS hybrid position calculation. The FMGCs use the hybrid position. The GPS MONITOR page on MCDU1 or MCDU2 can display pure GPS position, true track, ground speed, estimated position, accuracy level, and mode of operation for the information and use of the flight crew.
Note: Flight crew can use the MCDU NAVAID page to deselect the use of GPS data for calculating position
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In the 'old old' days before INS came along, we had conventional instruments that used various gyroscopes and dynamic and static pressure to present attitude, altitude, heading, vertical speed and turn & slip information to the pilots. This basic instrumentatiom was supplemented by navigation techniques using VOR's, DME, ADF, radar, astral navigation, doppler, Loran etc to determine position - we used to navigate around the world like this!
The along came INS (Inertial Navigation system). This used 3 gyros set in a box at 90 deg to each other which sensed gravity and could work out where you were on the planet. Once it knew where you were, it sensed acceleration in the 3 different gyros to work out your vector in 3D and could therefore work out where you were now - the difference between position a and b representing the vector (up/down, left/right, faster/slower) which it translated to attitude, heading, airspeed, groundspeed, VS and position information. You could load about 9 waypoints (manually by lat/long) and it would command the AP to take you there. As you passed a waypoint you had to add another to keep going where you wanted to go - time consuming and prone to error.
Then along came FMS capability to store flight plans, navaids, airports and airways etc which you loaded and a whole route could be established.
All that has happened since is to further refine the information acuracy. We now have IRU to replace INS - better gyro technology basically. Air Data sources are fundamentally unchanged, although digital processing is better. GPS merely adds another (albeit it very accurate) source of position information. As such it is secondary to the (AD)IRUs in the hierarchy.
This is not meant as an absolute definitive history but to try and show how history has evolved.
The along came INS (Inertial Navigation system). This used 3 gyros set in a box at 90 deg to each other which sensed gravity and could work out where you were on the planet. Once it knew where you were, it sensed acceleration in the 3 different gyros to work out your vector in 3D and could therefore work out where you were now - the difference between position a and b representing the vector (up/down, left/right, faster/slower) which it translated to attitude, heading, airspeed, groundspeed, VS and position information. You could load about 9 waypoints (manually by lat/long) and it would command the AP to take you there. As you passed a waypoint you had to add another to keep going where you wanted to go - time consuming and prone to error.
Then along came FMS capability to store flight plans, navaids, airports and airways etc which you loaded and a whole route could be established.
All that has happened since is to further refine the information acuracy. We now have IRU to replace INS - better gyro technology basically. Air Data sources are fundamentally unchanged, although digital processing is better. GPS merely adds another (albeit it very accurate) source of position information. As such it is secondary to the (AD)IRUs in the hierarchy.
This is not meant as an absolute definitive history but to try and show how history has evolved.
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Ok so here is the route:
1) GPS- MMR-ADIRU-FMGS. IRS/INS/INU are backups, right?
2) ADIRS is devided in ADR and IR. Both have different sensors which provide informations. Right?
3) What do you mean by GP-IRS?? GPS + IRS? But GPS is primary.
Let's first clear this to continue...
1) GPS- MMR-ADIRU-FMGS. IRS/INS/INU are backups, right?
2) ADIRS is devided in ADR and IR. Both have different sensors which provide informations. Right?
3) What do you mean by GP-IRS?? GPS + IRS? But GPS is primary.
Let's first clear this to continue...
Only half a speed-brake
AF330: sorry, not possible. Your assumptions draw the debate out of tech log.
I really do apologize, but as I see it, you mix apples with camshafts.
But please, keep the enthusiasm going, just wait before playing a game of chess until you are ready to differentiate between what is the board, figures, and the players.
PS: You live in Paris?
I really do apologize, but as I see it, you mix apples with camshafts.
But please, keep the enthusiasm going, just wait before playing a game of chess until you are ready to differentiate between what is the board, figures, and the players.
PS: You live in Paris?
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@Flight Detent: Ha ha! Yes, indeed, it's a great city! I have also been to Prague (you live there, no?). It is great! Loved the Prague castle and the night walk over the Charles Bridge! One of the best cities I have been in Europe! 
"The aircraft has two independent GPS receivers. Each GPS receiver is integrated in a modular avionics unit called MMR (Multi Mode Receiver) (GPS 1 receiver in MMR1, GPS2 receiver in MMR2).
The MMR processes the data received and transfers them to the ADIRUs"
2 GPS receives data. The GPS is inside the MMR. Then the MMR sends the position to the ADIRU.
"....which then perform a GP-IRS hybrid position calculation."
Ah! So GPS is just giving the position, IRS/INS/IRU is capable to calculate the time:
"We now have IRU to replace INS - better gyro technology basically. Air Data sources are fundamentally unchanged, although digital processing is better. GPS merely adds another (albeit it very accurate) source of position information."
Ok so GPS (MMR) +IRS signals (which is capable to calculate with gyro technology the position and the time which the signal will take to reach IR) send their signal to the IR. They get "mixed" and IR (part of ADIRU) figures out our exact position (which is normally the one sent by the IRS/IRU/INS).
It then goes to the FMGS.
Sounds good?
"The aircraft has two independent GPS receivers. Each GPS receiver is integrated in a modular avionics unit called MMR (Multi Mode Receiver) (GPS 1 receiver in MMR1, GPS2 receiver in MMR2).
The MMR processes the data received and transfers them to the ADIRUs"
2 GPS receives data. The GPS is inside the MMR. Then the MMR sends the position to the ADIRU.
"....which then perform a GP-IRS hybrid position calculation."
Ah! So GPS is just giving the position, IRS/INS/IRU is capable to calculate the time:
"We now have IRU to replace INS - better gyro technology basically. Air Data sources are fundamentally unchanged, although digital processing is better. GPS merely adds another (albeit it very accurate) source of position information."
Ok so GPS (MMR) +IRS signals (which is capable to calculate with gyro technology the position and the time which the signal will take to reach IR) send their signal to the IR. They get "mixed" and IR (part of ADIRU) figures out our exact position (which is normally the one sent by the IRS/IRU/INS).
It then goes to the FMGS.
Sounds good?
Last edited by AF330; 29th Oct 2014 at 19:53.
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you can download the FMGS manual here
A319 320 321 FMGS
not for operational use,
all the info you're asking about is there.
A319 320 321 FMGS
not for operational use,
all the info you're asking about is there.
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Hmmm....
F-COM says that 3 IRS signals (3 position) come to the FMGS. And then FMGS calculates IRS MIX position. IRS doesn't need satellites. I can understand till here.
But then they talk about GPS position. They say that IRS choses one of the GPS signals which makes it GPIRS!!! Didn't get this one. The IRS choses one of the GPS?? But why? They are 2 different systems to calculate position!
Thanks...
F-COM says that 3 IRS signals (3 position) come to the FMGS. And then FMGS calculates IRS MIX position. IRS doesn't need satellites. I can understand till here.
But then they talk about GPS position. They say that IRS choses one of the GPS signals which makes it GPIRS!!! Didn't get this one. The IRS choses one of the GPS?? But why? They are 2 different systems to calculate position!
Thanks...
Last edited by AF330; 30th Oct 2014 at 09:45.
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AF330
I think part of your mis understanding is the meaning of GPS PRIMARY.
It does not mean that GPS is number 1 and used to determine everything, but just that the GPS position going into the mix IRS/GPS position (GPIRS) complies with an integrity criteria - a reasonableness check.
If it does not comply, then GPS PRIMARY LOST is displayed.
When it again complies, then GPS PRIMARY is redisplayed.
Again, historically, aircraft had been certified without GPS and GPS was the new kid on the block - a bit like you! It was not 'trusted' and was used to supplement existing navigation methods, hence the crew retain to this day the ability to deselect GPS as an input to the navigation processes. Indeed the national governments that put up the satellites retained control over them and could 'modify' the positions they provided to deliberately create inaccuracies for their enemies - remember the satellite network was originally for the military, and you don't want your enemy to be able to use your system against you to accurately bomb targets!
I think part of your mis understanding is the meaning of GPS PRIMARY.
It does not mean that GPS is number 1 and used to determine everything, but just that the GPS position going into the mix IRS/GPS position (GPIRS) complies with an integrity criteria - a reasonableness check.
If it does not comply, then GPS PRIMARY LOST is displayed.
When it again complies, then GPS PRIMARY is redisplayed.
Again, historically, aircraft had been certified without GPS and GPS was the new kid on the block - a bit like you! It was not 'trusted' and was used to supplement existing navigation methods, hence the crew retain to this day the ability to deselect GPS as an input to the navigation processes. Indeed the national governments that put up the satellites retained control over them and could 'modify' the positions they provided to deliberately create inaccuracies for their enemies - remember the satellite network was originally for the military, and you don't want your enemy to be able to use your system against you to accurately bomb targets!