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Topic: Point an antenna at a static GPS location (Read 1 time) previous topic - next topic

jack wp

#15
Aug 24, 2013, 01:23 am Last Edit: Aug 24, 2013, 01:28 am by jackwp Reason: 1
Questions:
1. Is the arduino/beam antenna, the transmitter, or the receiver, or both?
2. Will you always have line of sight for the transmissions? Does altitude really matter that much?
3. What is the goal here, or is it a secret?
4. Which moves monthly, the arduino/beam, or the other end?
Good luck, Jack

Receo

Awsome, This forum is a near perfect script of my internal dialog before adding "compass" to my initial post.


I think it's safe to say that a gps with an integrated gps would definitely work for my project (Any suggestions folks?)

I'll try to clarify the specifics.

I'd like the device to be as "hands off" as possible.  Once I've  plugged in a lat/long/alt I want to turn on the device,  have it initialize to the gps sattelites and then point to my predesignated location.

My device will need to host a receiving and transmitting antenna (approximate 2 pounds), the terrain is mostly flat but it will be mounted on 30' tower in the wilderness with trees that are less than 20' tall.   The static location antenna has a projection width of 60 degrees.   The mobile arduino antenna pointer has a 8 degree beam.

I'm assuming that if I can get the device to point to all three points..lat/long/alt then I will have better signal strength then lat/long alone.

I'm positive there are easier ways to point one antenna to another by ones self, but I've always had a passive interest in robotics and have finally found a project that would help me accomplish what is currently an exhaustive task autonomously.    Furthermore, I've 2 young children who I suspect will benefit from having a dad that can help out with electronics projects down the road.

Many thanks. 








AWOL

Quote
I think it's safe to say that a gps with an integrated gps would definitely work for my project
Is there another kind?
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

jack wp

I don't think a GPS, and a compass will be very accurate. If your beam is 8 degrees, you want to point it pretty accurately. To increase your accuracy, you can check the signal received, and make fine adjustments of your beam  at the highest signal strength.
Good luck, Jack

Receo

Ooops, I meant to type integrated compass not gps.   

Robin2

I believe you can identify direction with a pair of static GPS receivers that are a distance apart - like 2 to 3 metres. Each of them reports a different position and you can calculate the direction from one to the other.

...R

jack wp

Your compass will not point true north (in most locations). It can be off as much as 20 degrees, well more than your bean angle.
google "magnetic declination". Maybe you should stick with the beam angle of 60 degrees, if you can't sample the reception strength for the fine tuning.

I still don't think altitude will help any. What angle difference do you expect there, 5 degrees? If it is not more than 30 degrees, forget it.
Good luck, Jack

AWOL

Quote
Your compass will not point true north (in most locations). It can be off as much as 20 degrees, well more than your bean angle.

What does it matter?
Declination is well documented for most parts of the planet, and the stated problem is likely to be confined to a well-defined area.
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

jack wp

@AWOL, great point.
As I understood it, the OP did not indicate they were aware of this. I was trying to bring it to their attention in case they were not aware. Once they determine their location on this earth, and make the calculations needed, then their direction will be a bit more accurate. But All in all, I don't think all of their GPS, compass, recalculations, will get the accurate to 4 degrees. What do you think?
Good luck, Jack

AWOL

I think that +/- 4 degrees is a pretty challenging spec, but I don't think we've been told what other performance specifications are relevant.
What is the speed of the moving part of the system?
What are the consequences of LOS?
And, most importantly - what is the budget?
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

jack wp

Quote
What is the speed of the moving part of the system?

I don't see that as an important issue, as the thing only changes about once a month.

Quote
What are the consequences of LOS?
, Sorry, I don't know what "LOS" means.

Quote
And, most importantly - what is the budget?
, yes, that would be great info. A $50,000 budget could do a lot more than a $500 budget. It didn't sound like he was with the CIA tho, so I just assumed a smaller budget. I have been wrong before tho.
the OP is still holding secret the overall system, so, I may be wrong again.
Good luck, Jack

AWOL

Quote
Sorry, I don't know what "LOS" means.

Loss Of Signal
"Pete, it's a fool looks for logic in the chambers of the human heart." Ulysses Everett McGill.
Do not send technical questions via personal messaging - they will be ignored.

123Splat

My bad, guys,,, I was digging in my code to prove the world wrong and found that I was interogating a magnatometer on I2C to find heading delta,, My gps modules are spi, not I2C.  Particular appologies to Grumpy Mike.

I may not know what I'm doing, but it eventually works.... well, sometimes.

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