Using experimental data on geotrajectory function and checking trajectory dynamics with lookuPose function (SATCOM toolbox)

Hello everyone,

Im using SATCOM toolbox to evaluate a SATCOM link.

I have experimental flight profile data with a samplerate of 100Hz, that im using in the geotrajectory function

trajectory = geoTrajectory(Waypoints=[lat lon alt],TimeOfArrival=time,Velocities=[vnedx vnedy vnedz],ReferenceFrame="NED",Orientation=Euler);

then im using the lookupPose function to extract dynamical information

[position,orientation,velocity,acceleration,angularVelocity] = lookupPose(trajectory,time); 

Finally, Im comparing the experimental data with the information provided by lookupPose.

Position, orientation and velocity matched the experimental data that was provided in the geotrajectory function.

I derived experimental acceleration using a forward difference numerical derivative of the experimental velocity data. When I compared this experimental acceleration data to the acceleration provided by the lookupPose, the results did not match exactly for velocity in x and y, but they were comparable. This is expected since the lookupPose might be using a different derivative method (see Figure below). However the velocity in z did not match at all.

The results shown above are derived using a sample rate of 1Hz ( I downsampled the experimental data). The problem arises when I increase the sample rate for example to 10 Hz. As seen in the images below the acceleration provide by the lookupPose function goes bersek.

My questions are:

1. Does the lookupPose function has a minimum sample rate limit (1Hz).
2. What is the numerical derivative used by the lookupPose function to calculate acceleration from velocity?
3. Is there a way to change the numerical derivative used by lookupPose to calculate acceleration?
4. Why does the Z component of acceleration does not match for a sample rate of 1Hz (even worse for 0.1 Hz).

As a reference these are the comparitions between experimental data of velocity ( given to geotrajetory ) and what the lookuppose outputs, (this comparisson is for 10Hz). The results are exactly the same.

Any help or guidance you could provide would be greatly appreciated. Thank you in advance for your assistance!.

Answer 1

[Umar]

Hi @Diego,

Let me paraphrase, Have you collaborated with developers or experts in SATCOM toolbox usage, they can offer valuable insights and guidance in resolving these issues effectively.

[Diego]

Hi umar.

This looks like an answer from chat GPT. Im looking for an answer from the developers of SATCOM tool box or somone that has experienced the same problem.

Thank you.

[Diego]

Nots sure if you are asking or this is a statement, either way, no I havent been able to get in contact with them.

Thank you.