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Questions tagged [ekf]

the extended Kalman filter, a filter for nonlinear state estimation.

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How is the GPS fused with IMU in a kalman filter?

I've been trying to understand how a Kalman filter used in navigation without much success, my questions are: The gps outputs latitude, longitude and velocity. While the IMU outputs acceleration and ...
Diamondx's user avatar
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2 votes
1 answer
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Frequency Limitation in robot_localization's EKF Node

I'm using version 2.7.4 of the robot_localization package for ROS Noetic. I'm currently utilizing two nodes of the package: EKF Local Node: Fuses data from an IMU (100Hz) and wheel encoders (4Hz). ...
user2454945's user avatar
2 votes
1 answer
269 views

robot_localization GPS causing large drift/covariance spike

I am trying to implement the dual ekf navsat example on my real-world robot. The local EKF with wheel odometry and IMU works quite well and has no issues. As far as I can tell, my global EKF ...
Leetfail's user avatar
2 votes
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50 views

Why is the EKF approximated this way?

I'm a student that recently started taking a course on cognitive robotics. The book I use is Probabilistic Robotics by Thrun Burgard and Fox. In the EKF algorithm, we linearized the action model in ...
Essam's user avatar
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Need help in implementing EKF based SLAM

I just started learning about slam and I have been trying to simulate a robot moving around a set of landmarks for the past 3 days. The landmarks have known correspondences. My problem is, if I add ...
harish satishchandra's user avatar
1 vote
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[Slam Toolbox]Map is overlapping and doesn't make loop_closure

Required Info: Operating System: Ubuntu 22.04 Installation type: binaries ROS Version : ROS2 Humble Version or commit hash: release version Laser unit: RP Lidar We mapped it on the map above and ...
zarqu0n's user avatar
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robot_localization EKF covariance exploding with absolute pose input

Firstly, I have had a look at other questions targeted around exploding covariances, yet I still cannot figure out what is wrong with my setup. I have multiple static cameras that detect a moving AR ...
b0xermatt's user avatar
1 vote
1 answer
46 views

EKF filter node not working correcty

I'm using a two-fixed-wheeled differential robot with Nav2 on ROS2 Humble, I succesfully achieved to code a standard odom publisher which publishes on /odom and /tf topics like this: ...
Jesús 's user avatar
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localization in pivot turn

I have a question about position estimation when a robot performs pivot turn. In pivot turn, it is ideal for only the robot's yaw angle to change, while the x and y positions remain constant. But, I ...
mamoru's user avatar
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1 vote
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682 views

robot_localization not fusing imu data

According to the documentation in : http://docs.ros.org/en/noetic/api/robot_localization/html/state_estimation_nodes.html I was able to transform the imu data header fram from "imu_link" ...
sdu568's user avatar
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robot_pose_ekf won't publish any messages

I am having trouble getting the robot_pose_ekf package to publish messages. I launch it with this launch file. ...
Doug's user avatar
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SLAM - Angle calculation failure ?-EKF

i am currently building up a EKF SLAM. I dont know where my mistake is but i think it has something to do with the angle my robot is driving towards but im not completly sure. First i thought it could ...
muller135's user avatar
1 vote
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81 views

EKF linearization using Taylor expansion and absence of operating point

If we consider the first-order Taylor expansion of a general nonlinear function at the operating point $x=x_0$, then we have the following, $$f(x) \approx f(x_0) + \frac{\partial{f}}{\partial{x}}|_{x=...
indigoblue's user avatar
1 vote
0 answers
356 views

How to calculate observation matrix Jacobians in EFK based mono slam? What are projection Jacobians?

I have been trying to understand an implementation of monoSLAM 1. But my question is generic to EKF based single camera SLAM. My Jacobian calculation leads to complex and lengthy expressions while ...
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Kalman filter and ekf main difference in elaborate way

I am studying about various filtering techniques for Robot pose esitimation. I came to know two very well known filter technique Kalman Filter and Extended Kalman Filter. To know about this two ...
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265 views

EKF based SLAM, marginalization and key-frames

I have a couple of tightly related questions regarding EKF-based visual SLAM. It is common in the Kalman based VSLAM litterature to marginalize 3d points and past poses. Condsidering the EKF as a ...
Ash's user avatar
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Kalman filter localisation equations

I am doing mobile robot localisation as a project. Now I stuck in obtaining the equations of EKF localisation. My robot moves straight for 10 seconds parallel to x-axis and robot equipped with 2 ...
Nekromant's user avatar
1 vote
0 answers
136 views

Strange EKF localization covariance behavior during prediction only

I've implemented a simple robot simulation based on the equations from EKF localization with known correspondence found in Probabilistic Robotics by Thrun et. al. Everything seems to be working but I ...
Nghia's user avatar
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194 views

EKF localization is approaching singularity. Are my sensors too noisy?

I'm getting this warning from Matlab about Kalman Gain. ...
CroCo's user avatar
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1 answer
61 views

Issues while setting up EKF for Ackermann Steered Robot

I have an Ackermann steered robot with optical flow sensor mounted at an offset from base_link x = 0, y = 0.4 , z = 0.15 and ...
Rakshit Soni's user avatar
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Extended Kalman filter + IMU sensor

I'm trying to implement an extended Kalman filter to the accelerometer and gyroscope. However, the result is not good. It seems to have some errors in my codes. I check the equation and code again but ...
davidchu's user avatar
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Velocity based motion model (dead reckoning)

I'm trying to understand the derivation of the velocity based motion model to implement an EKF: But the problem is, that I cannot find any derivation/explanation. Mostly there is only a visualization ...
user39812's user avatar
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62 views

EKF not providing good position estimation

I am working on a robotics project and I am using the package robot_localization in ROS2. I am trying to fuse the wheel odometry and IMU data, but I am struggling a lot to make it work. I've read a ...
João Victor Aguiar's user avatar
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1 answer
42 views

UKF position data closely match slam absolute pose regard wheel odometry

I have a specific question related to a robot localization package. I've been trying to get an answer on the Robot Stack Exchange for quite some time now, but I haven't received a response. I'm ...
Spectra543's user avatar
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74 views

robot_localization package position output is the same as input absolute pose

Hello my question is whether this type of output is a proper output? I fuse absolute pose from slam and fuse linear velocity from wheel odometry, but the filter output position data is the same as the ...
ruj's user avatar
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35 views

Robot Localization pkg / Motion Model prediction step

As I was investigating the transition functions in the prediction step in the ROS Robot Localization pkg (ekf.cpp) . I found for the orientation equations there are as follows: Roll angle is the ...
jf2's user avatar
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2 answers
19 views

seeking clarity regarding the 'world_frame' parameter in ekf_localization node

I have spawned two husky bots (namespaced husky_1 and husky_2) in the Gazebo world. I am ...
skpro19's user avatar
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2 answers
10 views

Not accurate results of yaw when fusing wheel encoders with imu using robot_localization

Hello, I have differential drive Jaguar 4x4 wheel mobile robot. I am trying to fuse wheel odometry data with IMU sensor measurements using robot_localization. The problem is that after some time (...
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1 answer
218 views

EKF of robot_localization have a delay compared to GPS data

I am using ros2 humble and the extended Kalman Filter from the robot_localization package to get both the odom -> base_link and ...
Timothée's user avatar
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29 views

EKFSLAM with LiDAR and IMU + GPS localization module

There are many resources that relate to EKFSLAM based on the presence of only a LiDAR unit, which localize both the vehicle and the detected landmarks. I see that they often use state vectors that get ...
mOSRobots's user avatar
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215 views

MPU6050 providing gyroscope values for linear acceleration

I am using this ROS2 driver to connect my MPU6050 to RPi 4 running ROS2 humble. It outputs an IMU message containing linear acceleration and angular velocity. The linear acceleration values seem to be ...
Redstone's user avatar
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75 views

Nonlinear continuous system function of IMU sensor fusion robot

For my robotics course I have to implement the nonlinear continuous system function for a mobile robot that is equipped with a GPS receiver and an IMU consisting of an accelerometer and a gyroscope. ...
exzoran's user avatar
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0 answers
79 views

EKF Update Step measurement data doesnt fit state vector

I have an EKF SLAM Algorithm which tries to estimate the robots position (X,Y,Theta) + the X,Y coordinates of several landmarks. Like in the posted algorithm i have a range/bearing sensor. I ...
muller135's user avatar
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0 answers
185 views

IMU Vision Fusion using EKF

I am trying to track an object indoors using an IMU (only accel and gyroscope) and a visual marker. This is similar to IMU+GPS fusion, where GPS is effectively replaced by the position that my vision ...
OlorinIstari's user avatar
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69 views

EKF landmark-based help needed

I am new in localization algorithms and EKF is new for me as well. I think that I implemented EKF (the whole code of class is here. I have problems in updating bearing angle of the robot. Basically I ...
Hillbilly Joe's user avatar
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0 answers
61 views

Differences between strapdown inertial navigation and motion models

In a state estimation scheme with a simple IMU/GNSS setup using EKF, I have always thought the prediction step would be done using a motion model and all sensor measurements would be incorporated via ...
vasf's user avatar
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0 votes
0 answers
58 views

EKF based Slam implementation with landmark identification in Global frame

I am working on mobile Robotics. I want to implement Slam. I have a very specific question about EKF Slam. To implement Slam I read the book "Probabilistic Robotics". I read its online version. There ...
user avatar
-1 votes
1 answer
287 views

Calculated yaw angle is not poper (EKF)

I used EKF to observe the quaternion and extract the roll, pitch and yaw angles. The used sensors are Gyro sensor and acceleration sensor. The roll and pitch angle looks like proper but the yaw ...
kkj's user avatar
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