DIY AHRS HUD

Discussion in 'Instruments / Avionics / Electrical System' started by cDuck28Z, Apr 25, 2017.

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  1. Apr 25, 2017 #1

    cDuck28Z

    cDuck28Z

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    Hey guys! I was paging through the forums and had what could be an awesome idea (I'm sure some of you have thought of it already). I'm by no means a aerospace engineer nor a computer scientist, but I was trying to figure out how hard it would be to take a standalone AHRS system like the iLevil 3 Sport, and display it on something like the Epson BT-300. Im sure it would have to be a simplified display, but in theory couldn't we get something like a fighter jet HUD directly in front of your face?!



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  2. Apr 25, 2017 #2

    cluttonfred

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    It's an interesting idea but I think it would be pretty disorienting in some circumstances. I'd prefer a fixed and simplified HUD.
     
  3. Apr 25, 2017 #3

    gtae07

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    Things like that are sort of in the works, to varying extents.

    It's already in service at the high end:
    f35-helmet-news__main.jpg
    It not only displays HUD info but also IR sensor feeds and has a night vision camera built in. The image is space-stabilized so wherever you're looking, you see what's "actually there".

    Of course, that one's $400k.


    There are some people already working on this in the light aircraft segment, using glasses and an AHARS like you suggest. AeroGlass posted some concept shots a couple years ago and they had a demo unit going at Oshkosh last year. I didn't sit through the demo ride because the line was too long but I talked to a couple of their developers. Theirs is more of a high-end type unit but it holds a lot of promise, IMO (more below).

    GRT has a system like you suggest, that works with their avionics packages. However, theirs is not space-stabilized so I could see the potential for disorientation. I'm interested to hear from users.

    I think the biggest challenges with such a display are (1) stabilizing the image and keeping it synced to the outside without disorienting latency (which was a problem on the early F-35 HMD), and (2) optimizing the display so it gives the information you want without too much clutter or overloading.

    Assuming it can be made reliable enough, I think there are enormous benefits to IFR flying. Imagine being able to shoot an approach in Cat III conditions like you're flying the pattern on a sunny Saturday afternoon, with full awareness of the terrain and other traffic?
     
  4. Apr 25, 2017 #4

    cluttonfred

    cluttonfred

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    For an amateur pilot flying for fun, there is definitely such a thing as too much information becoming a distraction and even a danger to safety. Add that to the cost of these units and I don't think you'll seem them much in light aviation anytime soon. I do think that a small HUD, fixed or wearable, providing basic info could be useful, but you definitely need the "less is more approach" more like the Recon Instruments products, for example.

    dims.jpg
     
  5. Apr 25, 2017 #5

    Chris In Marshfield

    Chris In Marshfield

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    I would certainly love to have indicated airspeed projected somewhere on my windscreen, just like I have in my car. Good situational awareness on approach, I think, when you have a fine line between sink and float like my plane does.

    Granted, experience improves performance and lessens the need for such a device, but still worthy.
     
  6. Apr 25, 2017 #6

    Hephaestus

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    There's a bunch of options - Google Glass gave us the framework. I don't think a full HUD is needed in GA but you could definitely have some more basic info displayed. (I quickly touched on my thoughts in a previous post)

    Most depends on which glasses system you choose to use - but largely expect to stream data from a smartphone to the glasses. Getting some actual measured data might be a bit more challenging - but not out of the world impossible.

    One of the big issues is not overloading yourself with useless info that blocks things you need to see. But there's something to be said for being able to hit a button and accessing a tail mounted camera on landing in certain aircraft ;)
     
  7. Apr 25, 2017 #7

    gtae07

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    I think what would be "useful" but not "distracting" or "dangerous" in a VFR application depends on type of installation (fixed HUD vs. wearable) and phase of flight.

    On a fixed HUD, basic airspeed/altitude/heading/AOA, or a pitch ladder with FPM, would be enough.

    For a wearable, I could see a lot of value in 3D airspace when you're flying in close proximity to such (e.g. Socal or close to a TFR or class B). I also see a lot of value in highlighting detected traffic. Yes, yes, I know... use your eyeballs, not a gadget. But frankly, the human eye/brain combination sucks at scanning for traffic. That doesn't mean you don't continue your scan, as there will continue to be NORDO traffic, birds, etc. for a long time to come, but as ADS-B gets cheap and ever more popular, the system is going to call out traffic that the vast majority of pilots would never see (or at least not see till it was a lot closer), no matter how diligent their scans. A traffic callout based on this system would at least have the advantage that you'd be looking out, rather than down at a display.

    Another interesting application would be a "panic" button that would declutter everything else and show only the following: glide ring (overlaid on the out-the-window view), AOA/FPM, and maybe optimized glide paths to runways in range. Maybe it's a crutch, but if I lose an engine every little bit would help. I'd rather it be there and possibly not work when I wanted it, than never have it at all.

    AOA would be better than airspeed for this.
     
  8. Apr 25, 2017 #8

    Hot Wings

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    And this is why I'm interested in this kind of hardware. I think it has the potential to significantly de-clutter the data stream for VFR pilots.
    Only display the needed information in the glasses:
    ADS-b targets that are within a 3 minute strike range
    AOA above a set "G" load or below a set speed
    Stall warning
    Vn warning
    Oil pressure warning (or other critical info)
    Altitude warning
    Others as desired...

    Keep the numbers and other non critical info on the panel. Even then don't display it unless it's changing in a critical way. This would let us spend more time flying and less time monitoring stuff - that needs to be monitored, but does not normally need intervention from the pilot.


    They could be portable between aircraft, provided the data stream is standardized in some way. This also has the potential to reduce our overall costs as well. I'd buy a pair to experiment with, but I really don't have the spare time and even if I did someone else will probably come up with a reasonably priced system before I could get a workable/useable one.
     
  9. Apr 26, 2017 #9

    cDuck28Z

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    Coming from a Navy background, the only aircraft I've flown with a real HUD was the T-45 Goshawk throughout flight training. From there I went on to learn and continue to fly the E-2C. I can tell you from first hand experience how much of a DRASTIC difference it makes when all of your pertinent information is displayed directly in front of your face like the 45 vs having to take your eyes inside to the cockpit for information, then refocusing back outside. I know that most basic VFR pilots are not looking for a fully functional, cluttered, or overwhelming display. But if you look at the pic of the fighter HUD posted above, it's really not overwhelming at all. Declutter it a bit and simply display basic horizon and attitude reference, airspeed, altitude, VSI, and heading. All of this information is easy to decipher and is utilized throughout every single phase of flight.

    The reason I have chosen these two pieces of hardware (iLevil 3 Sport and EPSON BT-300) is to try and simplify the problem at hand. Through programs like ixGyro, AHRS Utility by iLevil, and Xavion, to name a few (all of which are compatible with the iLevel, and available to download directly to any Android system), you already have all of the information in tablet form.
    Untitled.png Untitled.png Untitled.jpg

    The AHRS device has all of the hardware required and outputs the information via WiFi. These programs have already proven that this information can be successfully displayed. It seems as through that the only problem now is the GUI. I don't have either of these two products so I can't say for certain, but I'm willing to bet that the BT-300, running Android 5.1, can display this information almost the exact same as on your phone or tablet! I propose that we simply delete the background so you have a true augmented reality while you fly!
     
  10. Apr 26, 2017 #10

    gtae07

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    Hey, my dad flew the E-2! That was back in the 80s though...

    My only HUD experience is with several years of PC flight sims (Falcon 4 primarily), and a little bit of business jet HUD use in the engineering simulators at work. At least to me, that HUD shot in the first pic looks more like a business jet HUD with references to FMS, autothrottle, altitude and speed hold, etc.

    If I were making a fixed homebuilt HUD it would probably look something more like this, at least in the "declutter" state:
    View attachment 34185
     
  11. Apr 26, 2017 #11

    tspear

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    I would rather find the source for something like this: https://www.hudwayglass.com/ or https://www.navdy.com/
    And not have to wear specific glasses. If we could find the source, and if it takes a standard VGA signal interface, I would think it should not be to hard to program.

    Tim
     
  12. Apr 26, 2017 #12

    gtae07

    gtae07

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    Neither of these focuses the symbology at infinity like a "real" HUD. They're just semitransparent reflectors. My mother-in-law's car has something like this on the dash, and it's pretty stupid. For one, it's focused at the dash so you still have to shift your eyes, and for another, it's designed for short people--for me looking through it, the rest of the dash is the background.

    I suspect a "real" fixed HUD is going to require space about the size of a shoebox or maybe a little smaller in order to get all the optics packaged together. It won't be cheap.
     
  13. Apr 26, 2017 #13

    Victor Bravo

    Victor Bravo

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    FWIW, my opinion is that anything which keeps the pilot's eyes outside the aircraft is worth pursuing. All the iPhone and tablet stuff is just fine, I have a GPS/Avare tablet myself. But it does require you to take your focus away form the windshield. The fact is that anything that is actually going to kill you (in a civilian airplane) is going to appear in the windshield some time before it kills you. So if you are always looking at the windshield then you are always going to see the threat sooner. Essentially your windshield is the primary Heads Up Display that you need to pay attention to.

    So a Heads Up Display that also puts the nav, com, and air data "in the windshield" (or on a glass screen through which you are looking at the windshield) is a really good idea.

    That said, I believe it should be fixed rather than helmet mounted.
     
  14. May 5, 2017 #14

    annerajb

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    OP,

    I found this about a year ago. http://glass.aero/

    They are using the same Epson glasses you linked.

    They also use some head tracking camera mounted on top of the cockpit to see where you are rotating your head.
     

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