Distance movement.

Hello people from arduino world.

I need to do a comunication but I need and advice from other people. Then I will choose the best option.

I have 2 points. One of this is an static point (altitude and distance 0) and the other one its the motion point (altitude and distance variable). The maxim distance will be 700~900 m.

The static point must know in less than 1~2 second where is it the motion point ( altitude and horizontal distance)
I have several ideas …

1rst Idea:
I thought using an 10 DOF IMU ( 3x axis acc, 3x axis compass, 3x axis gyro, 1x altimeter) and comunicate both points with zigbee.

2nd Idea:
Using 3 axis compass, 1 altimeter and RSSI from zigbee

3rd idea
Using GPS

Which of them is the faster and the best option?

In my point of view, I think the faster option is the 2n idea. Because with the RSSI I should know the horitzontal distance, with the compass I should know the direction of the motion point, and finally with the altimeter I should know the height from the point.

thanks for reading. I accept all kind of suggestions and opinions.


What is the nature of the movement of the moving point?

Of the three options listed, GPS is the only one that you could realistically expect to work.

Consumer grade IMUs are too inaccurate to keep track of motion for more than a few seconds, and RSSI is almost useless to measure distance. It depends strongly on the relative orientation of the receiving and transmitting antennas, as well as the presence of nearby absorbing and reflecting objects.

Best, in my opinion, would be GPS, but for best accuracy, both the fixed and moving locations should have a GPS, which eliminates much of the error.

yestarday, I thought about the idea.

And as jremington says, It will be the best option.
I fix the coordinates from the fix point, and then the motion point send via zigbee it position to the fix point.

This is the best solutions

Thanks to all!

Then I will know the distance from the 2 points.