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Topic: Azimuth and Elevation project help (Read 1 time) previous topic - next topic

gilberttkd

Hi, I am making a satellite positioning control and I am currently making the azimuth and elevation monitoring.

I have made a compass using HMC5883L that can give me azimuth shown in a LCD 20x4 screen.
I also have made a elevation Pitch and roll using MPU6050 also shown in LCD.
Both above are from youtube reference.

But I need a sensor that can measure both Azimuth (reference from magnetic north) and elevation.

Does anybody made a project before for azimuth and elevation? What kind of sensor do I need to do this?

Thanks.

jremington

#1
Sep 19, 2017, 01:42 am Last Edit: Sep 19, 2017, 04:42 am by jremington
You can buy single chips that combine an accelerometer, a magnetometer and a rate gyro, often called a 9DOF sensor.

MarkT

Normally such a mount would have rotary encoders to display orientation.  MEMS magnetometers are typically
noisy, hard to calibrate well, and not suited if there's moving steelwork in the vicinity (rather obviously).

Can you describe the mechanical arrangement of this antenna control (its not positioning a satellite,
that's more advanced!)
[ I DO NOT respond to personal messages, I WILL delete them unread, use the forum please ]

gilberttkd

Hi MarkT, my satellite dish positioning has a 2 servo motors controlled by arduino. I use my mobile phone to control it with the use of a bluetooth receiver. Its working perfectly. The only problem is that I need to have a elevation and azimuth monitoring.

gdsports

#4
Sep 21, 2017, 08:39 am Last Edit: Sep 21, 2017, 09:20 am by gdsports
9DOF sensors can give attitude (pitch=elevation? and roll) and heading (azimuth?). Checkout Adafruit and Sparkfun for 9DOF boards. There are several boards so I suggest reading the tutorials to get an idea of the differences. The BNO055 works well with slow CPUs because it does all the computation. But it is expensive. Cheaper boards require the host CPU read raw sensor values then crunch numbers to get attitude and heading.

EDIT: I forgot to mention Arduino sells a 9DOF shield based on the BNO055.

https://store.arduino.cc/usa/arduino-9-axis-motion-shield

MarkT

MEMS magnetometers are not great, and this is an application with moving metalwork, so I think
that rules them out.  Thus you'd need encoder for the yaw component anyway.  An 2DoF accelerometer
is all you need for elevation.

What servomotors does it have? Do they have built-in encoders perhaps?
[ I DO NOT respond to personal messages, I WILL delete them unread, use the forum please ]

gilberttkd

Hi gdsports, Thank you for your recommendation. I will check it out.

gilberttkd

Hi MarkT, I am using Hitec HS-5485HB servo motors, yes it has a built in encoder. I will check the 2D as well. Thank you for your advise.

jremington


Johan_Ha

Do you really need a magnetometer? Are you moving the device around places, where you have no means of finding North by eye sight and Google maps in your phone? In that case it could be convenient. Otherwise, just paint a red arrow on your device, which you manually adjust to point to North.
Magnetic North differs from geographical North by several degrees almost everywhere on Earth.
____________________

If you ask for help and write 'u' instead of 'you' because you think it's convenient, I will write 'no' instead of 'yes'. For same reasons.

marcinszumilo

Hi Gilbert
I am wondering if you have found solution for satellite tracking. I theory it should be enough to have magnetometer readings. It shows you 3axis data. Anyway I am wondering if you can share your code since I am struggling with the same problem. How accurate is your positioning? Are any filters required?

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