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Hi all, this is my second forum I have joined and think I have exhausted the gang on the other due to my lack of knowledge but very eager to learn new tricks.

Background:
I have built a motorised satellite dish mount which has 2 motors to pan for azimuth and tilt for elevation of the satellite dish, I have the model up and running and can control the motors to move the dish around, you would all think what more do you need.

I have purchased an ardunio board along with accelerometer, compass and lcd screen. These I am waiting on being delivered and when they do i am venturing into the unknown for me and going to start with the basics of making an led flash and progress from there.

I want to be able to sit the unit down, press a button and then hopefully let the arduino take over and locate the fixed satellite. the satellite is Astra 2 at 28.2 degrees east. To do this I have an understanding that I need to program the board to work with the compass to pan the unit around to 28.2 degrees east. The hard part which is doing my head in is how to get the elevation code/program correct as I caravan around the country so therefore the dish needs a different elevation depending on where I am.

In a nut shell would it be possible to store a footprint of the UK inside the arduino and use a gps module to identify where i am and let the unit work out the elevation angle?

Someone also suggested using an android phone with the dishpoiner app to control the motors but i think this is a million miles away from my capabilities, although the android phone has everything I need but unsure how I would get the arduino to work hand in hand with the phones hardware to control 2 motors.

Sorry or the long question but I am determined to achieve my goal.

Many thanks for your time and replies if any

Ian
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Massachusetts, USA
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> the satellite is Astra 2 at 28.2 degrees east. To do this I have an understanding that I need to
> program the board to work with the compass to pan the unit around to 28.2 degrees east.

That won't work.  When they say that Astra 2 is at 28.2 degrees East they mean it is in geosynchronous orbit over the intersection of zero degrees Latitude (the equator) and 28.2 degrees East Longitude.  This is not going to be at azimuth 28.2.

You will need a GPS to determine where on Earth you are.  From Latitude and Longitude you can calculate the Azimuth and Altitude of the satellite (Google for that).  You will need the compass to determine Azimuth.  You may need to compensate for local magnetic deviation (magnetic north is not at the North Pole).  After you get close you may need to do a fine sweep to locate the best signal.
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Thanks fo rthat info, I guess that put me right.

Has anyone got any info or links on how to use an app on android phone along side the andruino to control motors as i think this might be the easiest option for me to proceed
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Well more fundamentally do you have some form of position feedback from the antenna mount back to your arduino to tell what position the antenna is at any given position? Without that just moving motors will not get you very far.  smiley-wink

Lefty
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I'm looking to do the same,
I'm using two servos  and a compass module to find in my case 144 degrees at 20 degrees
How are you getting on with your setup.
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You won't get close enough with a magnetic compass and accellerometer alone.  You need to move back and forth to maximize the signal or find it at least.
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Since its a geosynchronous bird, once you found it, well you found it. You'll need some way to know where your mount is pointing, so just record the settings. As said, you'll need to fine tune. Maybe you can get signals from the receiver to even automate this part.

Of course, you do play to be able to locate more than one sat, right?
 
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Interesting project, wondering if the OP or anyone else has gotten anywhere with this? Just overall for the wonder of it. Doesn't seem to me to be too difficult of a project (jsut some math to find the right angle to point at the satellite). I wonder which astra 2 satellite they were going for though cause according to wiki theres 2 of them (and more to come).

Could be nifty though, preset the arduino with a couple dozen satellite positions, hit a button and it would reaim itself as needed. Kinda high tech and lowtech at the same time. Would really suck it the GPS went out though.
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Would really suck it the GPS went out though.

Nothing to stop you from entering the lat/long or grid reference manually, if it came to that.
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Take a look the projects designed to control telescopes finding a satellite is just the same problem as finding a star.

Google "telescope arduino"

Mark
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Finding a satellite is just the same problem as finding a star.

Almost just the same.  smiley

The satellites and MUCH closer so you have to worry about parallax.  In the northern hemisphere the satellites will appear south of the celestial equator.  Here's a paper on the math: http://www.ngs.noaa.gov/CORS/Articles/SolerEisemannJSE.pdf

A Google search for "geosynchronous azimuth elevation" turned up some useful pages:

http://www.codeguru.com/cpp/cpp/algorithms/article.php/c5115/Geographic-Distance-and-Azimuth-Calculations.htm

http://www.satcom.co.uk/article.asp?article=29&section=1
http://www.satcom.co.uk/article.asp?article=29&section=2

Here's some code in some C-like language:
http://www.speqmath.com/repository/files/Aimingata%20Geostatic%20Satellite.html


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Would really suck it the GPS went out though.

Nothing to stop you from entering the lat/long or grid reference manually, if it came to that.

true true. But when was the last time you saw someone who was able to find their lat/long by referancing a map?

(I could probably do it in a city or something with a good map, but i know a lot of people can't even make it to the neighboring town anymore without some phone navigator or a dashboard GPS system)
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Pilots can.
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But when was the last time you saw someone who was able to find their lat/long by referancing a map?

Might not be as convenient as having it set itself automatically, but the point is that it's possible and not especially difficult.
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