Questions tagged [localization]

Localization is the problem of estimating a robot's pose relative to a map of its environment.

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Likelihood field sensor model (Probabilistic Robotics, Thrun et al., p.169-174)

I am currently working on the "likelihood field" sensor model (aka "endpoint model") by Thrun et al. (book: Probabilistic Robotics, Thrun et al., p.169-174) In this context I have ...
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1answer
60 views

building a grid map from gps trajectory poses

I am trying to create a feature grid map with Images from camera mounted to the top of the car. Novatel ProPak RTK gps poses Beforehand, I've checked to ensure that the standard deviations of the ...
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2answers
127 views

EKF SLAM : Missing older landmarks in new observation

I am a beginner to SLAM and robotics in general and I have been trying to implement SLAM on my GoPiGo3 robot car kit using primarily Chapter 10 from Probabilistic Robotics by Sebastian Thrun as ...
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1answer
156 views

SEIF ,online version of Graph slam create doubt in Motion Update state

I have a thesis work about Graph Slam The GraphSLAM Algorithm with Applications to Large-Scale Mapping of Urban Structures I try to implement it with the help of this paper but during the ...
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1answer
80 views

What's the correct approach to merging of localization and odometry data?

We've got a mobile platform with a source of odometry and an IMU, which are merged in an EKF filter (robot_localization node), producing continuous odom->base_link transform. The robot is also ...
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34 views

How does loop closure backpropagate the robots states into prior times?

I have read some about loop closure and I am somewhat confused. Suppose we implement something like EKF slam using LIDAR and suppose loop closure is aided by computer vision based features so that if ...
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55 views

Kalman Filter for 2d pose

I'm really sorry if this is a dumb question, but I don't have a clue on how to do this. I'm trying to write a kalman filter with a State vector of : {x, y, ẋ, ẏ, ẍ, ÿ } To estimate the 2 dimensional ...
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40 views

How do you handle angle discontinuities in estimation problems?

When one is implementing a state estimator in a system that involves kinematics, will inevitably face the problem of angle discontinuities, i.e., the fact that the angles have to be wrapped between ...
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1answer
222 views

How to synchronise data for fusion in Kalman from multiple sensors with different timestamp information?

I'm using Kalman filter to track the position of a vehicle and receive position data from 2 sensors: A GPS sensor and an Ultrasonic sensor for which I want to implement sensor fusion into the Kalman. ...
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30 views

Fiducials in conjuction with AMCL

I'm having some trouble getting fiducials (using aruco_detect) to work alongside amcl. The goal here is to use normal amcl localization when a fiducial is not present, and to switch to localization ...
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71 views

EIF slam algorithm implementation as per Probabilistic Robotics

I want to implement EIF slam from Probabilistic Robotics Table 11.2. This is the algorithm for EIF slam. To construct $\Omega and \xi$ matrix I write down a Java code. Here is my code ...
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203 views

Introducing new particles in particle filters for localization

Standard particle filters can produce bad localization result if the initial particle generation step produces no particle that is close to location (and bearing) of tracked object. The accuracy ...
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144 views

Random number generation for Particle Filter

I implemented a bootstrap Particle filter on C++ by reading few Papers and I first implemented a 1D mouse tracker which performed really well. I used normal Gaussian for weighting in this exam. I ...
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Self localization for 3 wheeled omnidirectional robot

I am trying to self localize a 3 wheeled omni directional robots using just motor encoders I followed the odometry method mentioned in equations 5,8,9 of https://bibliotecadigital.ipb.pt/bitstream/...
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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 ...
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12 views

Getting the new heading after a Transformation

Lets say I have 2d poses as such (angles in degrees): world_to_robot = {0, 4, 45} robot_to_object = {4, -4, -45} From a graph it would be easy to see that: world_to_object = {4, 8, theta}, what goes ...
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2answers
71 views

LiDAR Feature Extraction

I'd like to extract "features" of an environment scanned with a 2D LiDAR. I tried to create a temporary occupancy map to extract "corners" with the Harris Corner Detector. However ...
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36 views

Determining Orientation of a Robot Relative to a Line on Table

I am currently busy with a robot that needs to obtain it's orientation relative to a line seen by a camera. At the moment, I am using Hough lines to obtain a gradient for the line, but the gradient ...
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Hint regarding Localization & Map Scaling

I just started with mobile robotics. I'm trying to do a collaborative system between a mobile robot and a ceiling camera (Raspberry). They should do all tasks as a "team". Means Calibration, ...
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1answer
70 views

Effect of platform speed (how fast it is moving) on the quality of SLAM

I want to know how big of on an impact does the speed of the platform on which your sensors are mounted have on the quality of the outcome of a SLAM solution. Are there are any methods that are better ...
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79 views

Sensorfusion of odometry, accelerometer and gyroscope using Indirect Kalman Filter

I'm trying to implement an indirect Kalman for pose estimation of a wheeled robot. I found two papers that describe this approach. CMU. Journal (2006) Vol. 5(1) IFAC Conference on Embedded Systems ...
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18 views

Problem with UKF weights when calculating predicted state

I'm having troubles implementing a UKF during the calculation of $\overline{\mu_t}$, specifically in this step: $$\overline{\mu_t} = \sum_{i=0}^{2n}w_m^{[i]}\chi_t^{*[i]}$$ My problem I'm facing is ...
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56 views

hand_eye_calibration, surface normal by stereo vision

I'm a graduate student at mechanical engineering. I took computer vision(stereo vision) last semester but I'm still fairly new to this area. I wonder if I may ask 3 questions related to computer ...
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171 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 ...
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38 views

Resampling step for MC variation reduction

I am reading particle filtering for robot localisation and specifically the resampling step to avoid particle degeneracy. Can anyone explain me what MC (Monte Carlo) variation means? I saw it couple ...
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138 views

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 ...
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122 views

Help with fusing multiple measurements with known covariances

I am working on an estimation application for multiple robots, each of which uses measurements from various sources to calculate position and orientation data. For now, I am looking at about three ...
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119 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 ...
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131 views

How does a measurement model for camera based PNP work?

I am trying to write an EKF that can estimate the covariance of a pose estimate, where the estimation is being done by a PNP algorithm and 3D-2D correspondences in images. Although EKF based camera ...
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133 views

Using an AR.Drone's IMU to perform PDR

My task is simple: I want to move my drone manually around a room (IMPORTANT: I DO NOT WANT TO FLY IT) and I want to see its position update on a map using IMU data. I've attempted something in ROS ...
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41 views

How to determine the angles between a UAV and a sphere

I have an UAV modeled in three dimensions with let's say position coordinates $p_{uav} = (x_1,y_1,z_1)$ that is moving in a direction $d = (d_x,d_y,d_z)$ and a moving obstacle modeled as a sphere with ...
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161 views

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

I'm getting this warning from Matlab about Kalman Gain. ...
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convert to a reference frame for lidar scan in kitti data

my question is how to convert from lidar scans frame to the reference frame, I'm working with Kitti data set which contain the oxts data (transformation from word frame to imu) and another file like ...
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23 views

Cartographer: What determines how many nodes are added to a trajectory?

I'm testing cartographer using the Deutsches Museum public bag. I'm trying different Lua settings and checking how it affects the mapping process, etc. What I notice is that, no matter what ...
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26 views

multirobot_map_merge package not working properly

I am trying to map a Gazebo environment using 2 husky bots using the multirobot_map_merge package. However, the merged map being produced is wrong and the robots are not being localized correctly ...
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25 views

SLAM Initialize new landmark - specifically the covariance

Im trying to bring an EKF - SLAM to life but it keeps on failing. Specifially, I think, my mistake lies in the initialization of the new cone <-> covariance. I multiply the Jacobian (derived ...
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1answer
30 views

How to handle curved paths in maze

-I have an RPi on Ubuntu with ROS (Kinetic). The task is to solve a maze. I have implemented a left-hand algorithm to navigate through the maze. -The robot is equipped with 3 ultrasonic HC-SR04 ...
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52 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 ...
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1answer
21 views

Extract laser scan from a map and known location

If we have the map of an environment (an occupancy grid for instance) and precisely know the pose of the robot within it. How can one reconstruct what the laser scan should look like at a given ...
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34 views

Fusing cross-correlated measurements for mobile robot's localization using unscented kalman filter (ukf)

I'm currently working on a mobile robot's indoor localization. On the perception side, I can only rely on a 2D lidar and wheel odometry. I have used these sources as input of different localization's ...
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What are the state-of-the-art variants of the basic ICP algorithm for point cloud registration?

The questions is quite straightforward. For the past few days I've been looking into point cloud registration. It looks like it all started with the basic ICP algorithm as described in P. J. Besl and ...
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32 views

Self localization inside machine of interest

I have a type of flight sensor interfaced with Arduino Uno via I2C. The sensor is VL53L0X i am getting the 1D measurement value of distance in mm which i can monitor using serial monitor in Arduino ...
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Improvements over FastSLAM2.0

Are there some papers and/or works that describe improvements for the FastSLAM2.0 algorithm? I'm particularly interested in the following areas: The map is completely unknown at the beginning of the ...
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ECEF postion vs. LAT/LON/Height position with odometry

So I do have a wheeled robot and I want to fuse position data with odometry data. Someone suggested using the position encoded in ECEF rather than using the LAT/LON/Height information I get from the ...
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1answer
56 views

What is the difference between Markov localization and hidden Markov localization?

I just started studying localization for robotics. I started with Markov localization. There was a cool lecture on Udacity. I also came across another localization called hidden Markov localization, ...
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1answer
112 views

Estimate noise covariance matrix of measurements using a ros-bag

I am facing the following issue, and some hint or orientation would be great. I am working on a project in which I was given a ROS bag, and I have to implement a localization node using SLAM. To do so,...
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30 views

Angular movement of a controlled arm relative to an object via Two IMUs

I've been tasked to use two YEI 3-space sensors (IMUs) to detect the azimuth and elevation (altitude in the image below) angle of a moving arm with respect to a fixed object, with a sensor on the end ...
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1answer
35 views

Vehicle Odometry Correction Using Lidar Contour Points (Localization)

I am currently working on a project where... Vehicle travels from point A to B GPS trajectory is used as a reference Vehicle odometry (bicycle model without slip angle beta) was used to estimate a ...
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2answers
80 views

Collaboration of mobile robot and survaillance camera - classic localization (still) needed?

Just started with the topic of mobile robotics.. so I'm still into concept making and little programming, but have not setup everything or tested at all. I got a (differential) mobile robot (lego ...
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1answer
66 views

Localisation of Robot in a Rectangle

I am wondering how to go about localising a robot in a rectangle drawn on a smooth surface. Basically, there is a tape that lines the shape of the rectangle, and the color of this tape is unique in ...