0
$\begingroup$

Assuming no GPS is available, what can be used to measure the horizontal speed of a hypothetical drone? Sensor mass and size don't need to be taken into account. Could small Doppler radars , maybe placed in an off-nadir angle measure it?

Thank you in advance for your help!

$\endgroup$
0
$\begingroup$

You could use an IMU to measure the speed and position. You just have to:

  1. Calculate the quaternion that represents your drone orientation, using a filter like the Madwick or Mahony filters.
  2. Strip the gravity from your accelerometer raw data readings, the quaternion you calculated is what you will be using for this. It's not the only way, you could also use a low pass filter. I asked this question some time ago here . You can also read this explanation about how to compensate gravity from your accelerometer readings.
  3. Calculate the acceleration vector with the following formula: sqrt((ax * ax) + (ay * ay) + (az * az))
  4. Finally, you integrate this acceleration value to get velocity, and then you integrate it a second time to get the position but.......

You are not supposed to be doing this. Your data will be extremely inaccurate. When you integrate you are getting an approximate value, and you will be integrating this not-so-precise data over time. If you want to read a really good explanation about this I suggest you this article. You can also read this question, someone asked about speed measurement with an IMU.

| improve this answer | |
$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.