8
votes
Accepted
What is a good approach for outlier rejection during real time data filtering?
It is both acceptable and standard to use camera observations with a Kalman filter if you are talking about landmark positions in pixel or real-world space. Pixel space observations are usually ...
- 902
4
votes
Accepted
Noisy magnetometer data
First, let's look at if your findings seem reasonable given the datasheet specifications for the sensor.
For this, I'll assume that Wikipedia is generally correct and that the strength of Earth's ...
- 15.9k
4
votes
Accepted
Practicality of using magnetometer inside AUV
Mags are used in almost all UAVs. It will be useful and it will be a unique source of information.
Adding a some shielding between the mag and your computers and power lines will greatly reduced the ...
- 1,853
4
votes
Can I write the seperation principle for LQG controllers in this state space form?
Both state space representations are equivalent. For example the eigenvalues of the two closed-loop system matrices should be the same. However when implementing LQG you only have access to the ...
- 941
3
votes
Accepted
Can I write the seperation principle for LQG controllers in this state space form?
This is really a lot to look at, but the most glaring issue I noticed off the bat is your definition of the control signal $u(t)$.
What is the input to your controller? What should be the input to ...
- 15.9k
2
votes
Accepted
Wheel odometry simulation using ground truth
You can't just take the ground truth states and get wheel encoder positions, or vice-versa, because the robot is nonholonomic. Nonholonomic is a fancy word that means "path dependent," essentially, ...
- 15.9k
2
votes
EKF singularity problem when measurement noise R is zero
I think you need to step back a bit and think beyond the math. An (E)KF is used to estimate the true value of a signal in the presence of noise; it's only because of this noise that we even need the ...
- 2,814
2
votes
Accepted
What would be a way to estimate IMU noise covariance matrix?
Usually, IMU manufacturers implement some kind of filter to remove the noise these days, therefore the probability is your IMU is not throwing raw values. Nevertheless, you can initiate the sensor ...
- 536
2
votes
Eliminating drift generated from double integration of acceleration signal using Envelope Method
It looks like you are adding a constant for noise, so it makes sense the envelope output is a constant offset from the clean. I would think you need to add gaussian noise to simulate more realistic ...
- 356
2
votes
accelerometer and gyroscope fusion using extended kalman filter
You should be using quaternions for fusion for good behaviour. Addition and multiplication for quaternions will be swapped out by rotation composition operations for quaternions and your orientation ...
- 128
1
vote
Converting IMU random walk, bias instability to stddev, bias stddev, etc
Kalibr library has a good tutorial on how to calibrate an IMU with respect to a camera. It also has explanations of parameter data used in IMU calibrations.
From the kalibr wiki:
The parameters for ...
- 111
1
vote
What is the noise in this PWM signal?
After a bit more reading and thinking, I think I’ll answer my own question. I’d like feedback on my logic if you have it.
My logic is this:
the PWM signal from the MCU is clean (evidenced by the ...
- 339
1
vote
Accepted
Understanding import attributes of electronics speakers, by example
A small speaker like this one should be able to play tunes as you have mentioned. You can use an arduino or a raspberry-pi to stream audio over as shown in this link.
- 535
1
vote
Practicality of using magnetometer inside AUV
As mentioned in the previous answer, many small, low-cost underwater (and aerial) vehicles use a magnetic compass. You need a good procedure for both hard-iron and soft-iron calibration of your ...
- 126
1
vote
Odometry motion model for Kalman filter, but is the error zero mean?
The noise term will always be zero mean. If you believe the odometry equations will not accurately capture wheel slip and you believe the filter will not adequately track your state then the solution ...
- 1,853
1
vote
Accepted
Should the kalmanfilter have disturbance as input?
I don't like the format you're using, with $\tilde{x}$, because it masks the fact that it is actually $x-\hat{x}$. In generally, you don't actually care about the state error; what you really should ...
- 15.9k
1
vote
Accepted
Why doesn't this kalmanfilter filter anything? Reduce disturbances and noises with LQG controller
I'm not sure if this answers the question but I think there is a mismatch between the block diagram and the state equations.
In the first block of the state transition matrix (top-left $A-BL$) you ...
- 26
1
vote
Accepted
Why does one IMU axis influence another?
The problem is estimating angles in regions of instability.
Let us look at equations used for estimation of pitch and roll angles. For aerospace rotation sequence e.g. $xyz$:
$\tan(roll)=\frac{G_{y}...
- 297
1
vote
Kalman filter: 3D measurement error to individiual components
Take a bunch of measurements of your system while states are static and compute the noise matrix yourself. As long as recording measurements is relatively straightforward this should be a painless ...
- 1,853
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