10 votes
Accepted

How can we use the accelerometer for altitude estimation?

The barometer carried on the pixhawk has an altitude resolution of 10 cm. If that isn't enough, you could write a kalman filter that uses the accelerometer data in the prediction step and the ...
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  • 1,825
7 votes

Open source implementations for GPS+IMU sensor fusion?

Yes. The px4 software for the pixhawk autopilot has an extended kalman filter that uses an accelerometer, a gyroscope, gps, and mag. A paper describing the a smaller ekf which only estimates attitude ...
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  • 1,825
6 votes
Accepted

How to localise a underwater robot?

Localization under water was always a problem in ocean robotics as electromagnetic signals do not propagate very well in water. I think your best localization sensor in that case would be the good old ...
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  • 671
5 votes

Accelerometer, gyro, and magnetometer sensor fusion in 2d

The gyrometer gives you angular velocity about each axis. You simply integrate these values to get the roll, pitch and yaw of the robot. Since this is 2D, all you care about is yaw, and you'll ...
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5 votes

How to track robot position?

How to estimate a robot's position depends on how well you'd like to estimate it. If you just need a rough guess, try odometry, it works OK. For better results, you have to incorporate more sensors. ...
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4 votes

How to localise a underwater robot?

If it's actually underwater, how about a webcam looking at the tile pattern on the floor? (Could be considered "cheating" as it will obviously fail in a natural lake, for example.) You can find a ...
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  • 1,021
4 votes

How to localise a underwater robot?

One of the prime sensors for global localisation on land is GPS. This is not an option underwater because electromagnetic waves get absorbed quickly. There are however alternatives, which provide ...
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  • 2,954
4 votes

How to track robot position?

I am not allowed to comment, so I have to add a reply. By position, do you mean the location in space (so X, Y coordinates), or orientation (tilt, etc)? If position, you can use the accelerometer ...
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  • 169
4 votes
Accepted

Multiple position estimates fusion

What you are describing is essentially a textbook case for using a Kalman filter. First you need a prediction step. Let's assume you are predicting the pose of the robot $(x,y,\theta)$, given the ...
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  • 950
4 votes

Open source implementations for GPS+IMU sensor fusion?

ROS has a package called robot_localization that can be used to fuse IMU and GPS data. This package implements Extended and Unscented Kalman filter algorithms. The package can be found here.
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  • 378
3 votes

Simple Sensor Fusion for pose estimation

So you have acceleration readings from your IMU (linear and angular), and you get velocity readings (linear only) from wheel encoders. Get velocity from linear and angular accelerations with $$ v = ...
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  • 14.7k
3 votes
Accepted

Transforming angular velocity?

I think your diagram is missing an angle for the laser angle with respect to the vehicle body -- I'm going to call that angle $\alpha$, see this diagram for clarity: Since it seems you are tracking ...
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  • 1,357
3 votes
Accepted

Balancing a plate with an IMU offset from the center

Basically it does not matter. But you have to be carefull if the plate is rotating fast, because the rotation of the plate around its center point, with the IMU placed out of center, will cause the ...
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  • 1,647
3 votes

Overcorrecting Kalman Filter

There is an error in your posted equation for the Jacobian $F_J$, so that could be the source of the problem. It should look like this: $F_J = \begin{bmatrix} 1 & 0 & -C \sin \theta \\ C \...
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  • 1,357
3 votes

How to localise a underwater robot?

If you cannot use a camera the task is nearly impossible with your money limitations. Professionals use a scanning sonar like the tritech micron and a particle based localization like [3] based on ...
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3 votes

Accelerometer, gyro, and magnetometer sensor fusion in 2d

Using an IMU you can only measure: acceleration, rate of rotation, and direction of magnetic field. You cannot measure velocity, you can only integrate the acceleration to infer velocity. As you can ...
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  • 6,337
3 votes
Accepted

quaternion implementation

So, as I mentioned in an earlier comment, it looks like you're using a mashup of methods. You're not applying any one method correctly; instead you're mis-using part of one method, then using the ...
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  • 14.7k
3 votes

Need help regarding development of Extended Kalman Filter for sensor-data fusion of odometry and IMU data

Adding to the above, my favorite way to debug a misbehaving filter is to isolate each step. Make sure your prediction step works before correcting it. Your bot should drive straight right with 0,0,0 ...
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2 votes

Controlling a system with delayed measurements

The most straightforward approach is to use a Kalman filter with a memory of recent state history. While waiting for measurements you do the standard time update. When a new measurement arrives, you ...
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  • 2,689
2 votes
Accepted

Measurement and physics model fusion

Kalmnan filters are typically used for sensor fusion. You create a model for what you expect the process to look like, use your sensors as inputs, and the output is the filtered estimate. I'm not ...
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  • 14.7k
2 votes

Open source implementations for GPS+IMU sensor fusion?

A followup on holmeski's reply. It seems those pages have been taken down. I found the old webpages on the 'Way Back Machine'. Pixhawk Attitude Estimator (EKF) Pixhawk ekf_att_pos_estimator (...
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2 votes

Solution for INS and GPS integration

I was in exactly the same boat with my master's thesis; wave-based imaging (sonar and radar) seemed so common that all the papers I read assumed you knew the fundamental concept and they were going to ...
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  • 14.7k
2 votes

Are there off the shelf solutions for GPS+INS (accelerometer,gyro,magneto) sensor fusion for getting filtered/fused location and speed output?

There are many GPS+INS fusion units available on the market. The price, weight and size of the units can vary dramatically depending on the GPS positioning accuracy and rate of drift from the INS. The ...
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  • 21
2 votes
Accepted

Robot positioning using IMU quaternion data?

The quaternion only contains information about the rotation of the vehicle. It will not contain information about the location of you vehicle on a 2-d plane. One method of converting quaternions to ...
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  • 1,825
2 votes

Need help regarding development of Extended Kalman Filter for sensor-data fusion of odometry and IMU data

You should first validate your filter is working before second-guessing your modelling choices. But I agree both those filters look OK (although I did not double check all the maths) and both of your ...
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  • 872
2 votes

Gyro Yaw Drift Compensation With The Aid of Magnetomer

my roll and pitch drifts are corrected with accelerometer inside IMU You mean they're being correct by the IMU, or you're correcting the readings yourself using the accelerometer from the IMU? i ...
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  • 14.7k
2 votes

Is it possible to track position using gyroscope and accelerometer without a magnetometer?

The short answer is that it's possible, but tricky. To estimate position you integrate accelerometer readings over time to get linear velocity estimates, and then integrate the velocities to get ...
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  • 1,266
2 votes
Accepted

EKF sensor fusion

An EKF or any of the variants of the Kalman filter, as you said mainly works in two steps: prediction and correction. The prediction steps gives you a state estimate based on your process model and ...
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2 votes

Bias correction for multiple sensor fusion through Kalman Filtering

Your state vector $x$ is correct. When you do bias estimation(look up IMU kalman filters) you assume that the bias is constant/slowly varying. So your $F$ matrix is just the identity(5x5). Your $H$ ...
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  • 1,581
2 votes
Accepted

GPS Course vs IMU Course

So this probably won't work as course over ground and heading are often 2 different things. Heading is the direction your vehicle is facing, while course over ground is the direction your vehicle is ...
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  • 1,581

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