How does artificial horizon display work?

[davensocal]

Anyone know how the PC display gets the artificial horizon data? Is this a function of speed and rate of climb?

Anyway, just kind of curious.. :D

[Wulf_Flieger]

Artificial Horizon works on a Gyro. Either self conatined as in a standby attitude direction indicator or from a seperate Vertical Gyro or an Inertial Navigation unit which senses attitude changes by the use of a laser and mirrors in a self contained unit. The Apollo moon missions used a Delco "Carousel" an Inertial navigation unit developed by Delco a subdivision of General motors. That used a mechanical Gyro and calculated within its self contained computer Unit, weighed about 90 pounds without its emergency battery back up unit.

Airspeed is computed by Pitot and static pressures. Rate of climb on older planes computed by Static pressure. On newer aircraft vs is computed from a Inertial refererence unit which uses mirrors and a laser. And altitude is computed from static pressures.

Not sure what you mean as its applied with a computer display.

[camship]

Anyone know how the PC display gets the artificial horizon data? Is this a function of speed and rate of climb?

Anyway, just kind of curious.. :D

When I asked the same question the response was it is derived from the GPS data, (if attached) so it is extrapolated and an approximation. I am going to be testing it's usefulness real soon.

Hope this helps,

Camship

[davensocal]

Hi Wulf-
Sorry, I was referring to the artificial horizon as provided by the Eagle Tree system.. With this system , there is an option to have all data transmitted to a PC, and a live view of this data.. This includes an artificial horizon. With the lack of inertial nav eq and gyros, I couldn't understand how the software was determining a possible artificial horizon..

I must say, I learned a lot about avionics from your post!

Camship..
Hmm, I wonder how GPS data could give us an artificial horizon.. It seems any sink could give a false horizon, and high attitude flight (hover, harriers) would really through it for a loop..

Let us know how your testing goes, I would be curious.. I did some bench testing, and I was getting intermittent 90 deg rotations of the horizon, I assume it is some noise for that data point.

[Wulf_Flieger]

Sorry no idea on that one. Gps provides cordinates, altitude, GMT and from knowing where it is and how long it took to get to say the next waypoint or fix then ground speed and course can be computed. I don't see how the GPS on its own can compute attitude. I'm thinking it has some kind of circuitry built into the unit for sensing changes in attitude.

I'd be real interested in learning how it basically does it.

[camship]

Camship..
Hmm, I wonder how GPS data could give us an artificial horizon.. It seems any sink could give a false horizon, and high attitude flight (hover, harriers) would really through it for a loop..

Let us know how your testing goes, I would be curious.. I did some bench testing, and I was getting intermittent 90 deg rotations of the horizon, I assume it is some noise for that data point.

When I spoke to Bill and asked about it he was a bit vauge. I noted in your image that the GPS data was all 0's. It will do very weird things, (intermittent 90 degree changes at random) if there is no GPS data. Now you have me wondering.

I don't know if there is anything else involved in this device calculating attitude so maybe Mr. Bill will chime in here and get us straightened out. I may be completely wrong.

Wulf, check out some of the GPS only attitude systems being developed. They are using segmented antennas, like a bugs-eye view of the sky and once initialized they calculate attitude by simply checking which satellites it was seeing and which "fields" the satellites are in at any given moment. Simple but effective.

Have a good one,

Camship

[Wulf_Flieger]

Camship, thanks for the heads up on the gps attitude being developed. I don't keep up on the new stuff being developed. After 30 years, I kinda lost interest and just want to retire and play with my "Real" airplanes.

[camship]

Camship, thanks for the heads up on the gps attitude being developed. I don't keep up on the new stuff being developed. After 30 years, I kinda lost interest and just want to retire and play with my "Real" airplanes.

After 30 years I'm just getting started. If you haven't been keeping up with new developments you may be surprised to find the definition of "real" gets a bit blurry these days.:)

Have fun and keep 'em turning

Camship

[billpa]

Hi All,

I wanted to give a brief description of what we support now and what we will do in future.

Right now, the Artifical Horizon (AH) gauge that's available for display in the software is a simulation, based on climbrate and aileron movements. It does not represent true attitude. So, in short, we do not offer any real display of attitude presently.

To display attitude with available technology, an IMU (Inertial measurement unit) is required. IMU's are very expensive ($800 minimum for something that has the required compensation and degrees of freedom).

We do support logging/transmitting of data with a couple of IMU's from 3rd parties, but have not done the (significant) work to plumb this into our artifical horizon gauge.

Going forward, we plan on doing this software plumbing, and also will likely have a lower cost hardware solution for attitude. But, the cost will not be trivial at least for the coming few years, until the underlying parts get a LOT cheaper.

I'd love to hear feedback from the community about how we should prioritize this project!

Regards,

Bill, for Eagle Tree

[Wulf_Flieger]

Bill, I kinda was thinking that it may have used Aileron servo travel for the roll axis but knew it would be an approximation. Still pretty neat stuff though.

I'd like to see for the v3 logger computaion and graph plotting of motor or prop efficiency and thrust. It would require a data base of prop k factors which are like top secret held by the prop manufacturers. Dr. Kiwi, I believe has quite a bit of that info.

My 2 cents

[davensocal]

Hi Bill-
Thanks for posting in this one.. I just picked up a Pro system, and was playing with it..

For me, as a recreational sailplane and gas pilot, it has almost no use.. Just another cool toy.

I wanted your system primarily for its' vario capability, and RX voltage. Alititude and airspeed were next on my list. Servo logging, GPS, current, temperature, etc.. are all bonus items for me..

If I were in a position to request anything, I think I would ask for PCM and PPM signal quality (I know Spektrum link quality is available), and a smaller sailplane specific recorder.

I have lost planes because of signal loss in which no cause was ever found (I still think it was an invisible alien UFO).. Anything that would either alert me to an issue (noise levels rising), or at least log the event would be of high value for me.

Thanks, and keep up the good work!

[camship]

I wonder if I were to add a 2 axis inertial device using the analog adapter could that data be used to update the artificial horizon display?
Camship

[billpa]

Hi Camship,

We are researching how best to do this at a reasonable cost.

It is unfortunately more complex than having 2 axes. A full IMU + some very complex software is required to get accurate and consistent readings, I believe.

Dave, PPM/PCM signal quality would be very easy if the receiver reported the data via some public protocol. Right now none made by the "big 3" do. JR/Spektrum is blazing the trail with this IMO.

Regards,

Bill, for Eagle Tree