For small GA what kind of non GPS based RNAV systems are actually available?
There is the old KNS 80 VOR/DME based RNVA system.
Then there are inertial navigation systems but did anybody ever see one actually available for small aircraft? I have only read about them for proper airline type FMS but nothing for the typical Garmin/Avidyne panels most smaller GA planes use?
Sebastian_G wrote:
Then there are inertial navigation systems but did anybody ever see one actually available for small aircraft? I have only read about them for proper airline type FMS but nothing for the typical Garmin/Avidyne panels most smaller GA planes use?
I think the integrated Garmin G5000 uses Northrop Grumman LITEF LCR-100N as an internal navigator with GNSS cross-check/verification.
Nothing that I know for modular GA.
There is no certified product but you could build one using one of the boxes in the $10k area which input a GPS antenna and output NMEA, and contain a triple FOG.
I thought about doing that some years ago but all one could do is drive an android tablet since no certified avionics take in NMEA and neither does anything from Apple.
A DME-DME RNAV box would be easy enough to build. The worldwide DME database is/was downloadable from various places and a single remotely tuned DME (KN63) is all you need. The problem, as I say above, is there is no legal connection to avionics even if you did emulate a GPS signal.
Peter wrote:
There is no certified product but you could build one using one of the boxes in the $10k area which input a GPS antenna and output NMEA, and contain a triple FOG.
That box I’ve mentioned above costs around $80K, just for reference…
Of course, big jet avionics do exist.
You might get a DME DME box for 80k but I am sure you won’t get a FOG box for that. And integration might be fun because the sizes are different and AFAIK jet avionics are mostly based on the avionics bay system which doesn’t exist in modern GA anymore. The EFIS40 in a TBM or KA is similar.
If you have GPS then there is zero need for any of this.
I guess Sebastian would ideally like to be independent from the frequent GPS outages in the northeast of Europe these days.
Peter wrote:
You might get a DME DME box for 80k but I am sure you won’t get a FOG box for that.
Sorry, you are right – it is now around $180K.
https://aeroval.com/ref/381758/145130-3000/
“Unit Price Reference: $182,997.00”
boscomantico wrote:
I guess Sebastian would ideally like to be independent from the frequent GPS outages in the northeast of Europe these days.
Years ago I did not thing about this much but now I had two occasions where I did consider a sudden loss of GPS as an option. First flying to Cyprus. It di dnot happen to us but the weather down there is so good with a clear coastline that simple visual navigation seemed like a good backup plan. Second we did a RNAV departure out ot LSZS. Without GPS there is no VOR backup or similar and mountains on both sides. My backup plan with little wind was to use heading and timing and hope we would not be blown of course too much for the few minutes required to outclimb the terrain. In addition I did consider using the weather radar to track the valley and simply keep in the middle using the radar screen in a worst case scenario.
So with more and more GPS issues I started to wonder if any products are actually available and if there is actually a market for them. After all the the airlines seem to still spend large amounts on FMS system with INS capabilities.
Peter wrote:
since no certified avionics take in NMEA
True but you could feed the data as GDL90 to popular apps and then navigate using those apps. That would probably be enough in many cases.
Sebastian_G wrote:
For small GA what kind of non GPS based RNAV systems are actually available?
Anything with Proline21 will do DME/DME, VOR/DME. King Air, Piaggio, CJ. That is the light category, so counts as small GA, right?
I think the lightest plane with inertial navigation as an option is the PC-24. It’s in the commuter class.
@ Sebastian_G
You would need some kind of micro IRS platform calculating positioning with the second law of Newton (re-aligned corrected with DME, VOR or whatever) then to spit it out in NMEA or a GDL format to make this work. Initial positioning could be on data base.
Don’t think it exists for GA.. E-LORAN?
https://www.ursanav.com/product/un-151b/
