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Dec 25, 2016, 01:13 PM
Dark Side of the Red Merle
Curtis Suter's Avatar
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Aerobtec Altis GPS


So I got an Aerobtec Altis GPS from Mrs Santa.

The first photo is a test plot of the baro altitude. I put this in the downstairs breakfast nook window. Then I held it above my head at about two minutes and put it back on the window sill. Then I carried it upstairs to the computer room. It shows all that! Impressive!

The Google Maps photo is the GPS position test. The initial Start point is a bit off, but only by 3-4 feet. Then you can see the color change to orange/yellow as I walk through the house (speed) and up the steps and then back across the house to the dark blue which is where my computer desk is. Neat! The software must have a Google Earth plugin as all I did was download the Alti GPS data into the AerobTec Flight Manager software and then click on the Map View tab and there it was! Super easy!

http://www.aerobtec.com/products/rc-...ics/altis-gps/

I would like to make this a stand alone unit; anyone have an idea what the current draw is as the specs don't give that.
Edit: I answered my own question as I put an amp meter on it and it's about 45ma. So lets round that to 50ma and with a 300mah battery your should get six hours but it'll be probably like five hours.

Thanks
Curtis
Montana
Last edited by Curtis Suter; Dec 25, 2016 at 02:47 PM.
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Dec 26, 2016, 01:38 PM
Registered User
tkallev's Avatar
I've been playing with mine for over a year, so much fun!

You must have an internet connection when you download or else the Google Earth features don't work.
Dec 26, 2016, 02:13 PM
Dark Side of the Red Merle
Curtis Suter's Avatar
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Quote:
Originally Posted by tkallev View Post
I've been playing with mine for over a year, so much fun!

You must have an internet connection when you download or else the Google Earth features don't work.
Good point as well as having the free Google Earth installed.

Curti
Dec 28, 2016, 12:33 PM
Registered User
Aaro's Avatar
Hi,

I got mine today. What I really like is how the unit integrates to Jeti EX telemetry, providing all the data needed down to transmitter. Just configure the com setting to "Jeti EX" and plug the wire to receiver. Nothing more to do Of course you have to select what to do with all the data down in the transmitter.
In video it is shown how I configured some gps-based data fieds to one display page, and then, if a switch is pulled, altitude and distance are read as voice. This took maybe 5 minutes

I'm intending to use this in F3J/F5J -gliders when measurement data (eg. velocity) is needed, either to trim something or just because of common interest.

jeti altisgps telemetry (0 min 12 sec)


Aaro
Dec 28, 2016, 12:46 PM
Flying = Falling (Slowly)
dharban's Avatar
One of these days we will get over our "telemetryphobia" and discover that these devices can open up a whole new world of interesting flying opportunities. I have been experimenting with the RC-Electronics GPS Triangle Racing setup in a normal ALES plane and it is pretty amazing.

Right now there are latency issues with things like the Altis GPS playing back through Taranis (and I assume Jeti), but I am sure that those issues will be solved before we get over our phobia of new electronic possibilities.

Happy Landings,

Don
Dec 28, 2016, 01:32 PM
Registered User
Aaro's Avatar
GPS Triangle and it's versions are a very good example of how new (technological) possibilities can be utilized. I guess the "small" class will in future be something worth trying, as there are lot's of more or less suitable gliders (F5J) which are easily equipped.

In my (planned) use I don't think that latency will be an issue. Anyway, it is easy to measure the latency because I have the same position data from both ends of the link; Altis-log and Jeti telemetry recording, including the transmission time. By comparing those the delay can be calculated, as long as the transmitter's clock is correctly set (which can be difficult so maybe what you easily can get is jitter/variation of latency).

Aaro

Quote:
Originally Posted by dharban View Post
One of these days we will get over our "telemetryphobia" and discover that these devices can open up a whole new world of interesting flying opportunities. I have been experimenting with the RC-Electronics GPS Triangle Racing setup in a normal ALES plane and it is pretty amazing.

Right now there are latency issues with things like the Altis GPS playing back through Taranis (and I assume Jeti), but I am sure that those issues will be solved before we get over our phobia of new electronic possibilities.

Happy Landings,

Don
Dec 28, 2016, 02:30 PM
Flying = Falling (Slowly)
dharban's Avatar
Quote:
Originally Posted by Aaro View Post
GPS Triangle and it's versions are a very good example of how new (technological) possibilities can be utilized. I guess the "small" class will in future be something worth trying, as there are lot's of more or less suitable gliders (F5J) which are easily equipped.

In my (planned) use I don't think that latency will be an issue. Anyway, it is easy to measure the latency because I have the same position data from both ends of the link; Altis-log and Jeti telemetry recording, including the transmission time. By comparing those the delay can be calculated, as long as the transmitter's clock is correctly set (which can be difficult so maybe what you easily can get is jitter/variation of latency).

Aaro
Several over here have experimented with these systems where the telemetry is built into the transmitter/receiver system and the problem is that with somewhat smaller courses appropriate for F5J sized planes latency IS a problem. It is not uniform (apparently data rates vary with the density of control signal rates) and it is material. That is to say, that two planes with identical systems flying identical courses may be "guided" over paths that are materially different in their length. This would probably not be a problem if the errors were uniform and repeatable, but right now they are not.

One of the experiments I tried was to compare three different GPS transducers -- a Taranis high resolution, a SM Modelbau GPS Logger 2 that talk directly to the Taranis transmitter and the RC Electronics setup that uses a separate transmitter/receiver setup. I took them all side by side in the car over a course and compared the tracks that each recorded both internally and the track recorded by the transmitter. The 2.4 stuff would vary inconsistently by 20-30 meters at any particular turn point. The RC Electronics, much less so.

I am sure, though that this will ultimately be worked out.

Happy Landings,

Don
Dec 29, 2016, 01:26 AM
Registered User
Aaro's Avatar
There are many variables resulting in the end the feeling of real time or lack of it:
  • Amount of data delivered over the link vs link speed
  • GPS update rate vs. number of channels used - it seems to be so that higher rate -> less satellites -> slower fix and worse accuracy. A field test in my backyard showed following: f=10 Hz --> 6 satellites, f=5 Hz --> 8 satellites, f=1 Hz --> 12 satellites. The location is shady but this gives a clue...
  • There is always a kinematics calculation/estimation/prediction process in the gps-module: some kinematics model, or some of models, is fitted to position measurements. This is why accuracy can be (and often is) better when moving, but depending on model implementation and parameters, it does might not suit to behavior of our planes. Eg. acceleration constrains may cause the "track" to continue straight on while the plane is turning (a traditional case).

I was about to start building a gps/telemetry module of my own, as the modules are quite cheap and there is a Jeti EX telemetry library (c++) available for Arduino. And weather is poor Might still do that, but first I would like to make some measurements with the Altis module. I'm interested in optimizing the amount of data required to form track that "feels" ok. The main idea is to use the Arduino to parse the module's NMEA and to send only the relevant data down in very compact binary format. Actually, the Altis does this, but there is lots of excess/non relevant information also consuming the bandwith.

Aaro

Quote:
Originally Posted by dharban View Post
Several over here have experimented with these systems where the telemetry is built into the transmitter/receiver system and the problem is that with somewhat smaller courses appropriate for F5J sized planes latency IS a problem. It is not uniform (apparently data rates vary with the density of control signal rates) and it is material. That is to say, that two planes with identical systems flying identical courses may be "guided" over paths that are materially different in their length. This would probably not be a problem if the errors were uniform and repeatable, but right now they are not.

One of the experiments I tried was to compare three different GPS transducers -- a Taranis high resolution, a SM Modelbau GPS Logger 2 that talk directly to the Taranis transmitter and the RC Electronics setup that uses a separate transmitter/receiver setup. I took them all side by side in the car over a course and compared the tracks that each recorded both internally and the track recorded by the transmitter. The 2.4 stuff would vary inconsistently by 20-30 meters at any particular turn point. The RC Electronics, much less so.

I am sure, though that this will ultimately be worked out.

Happy Landings,

Don
Last edited by Aaro; Dec 29, 2016 at 04:55 AM.


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