# Questions tagged [localization]

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

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### Whats the logic to implement a particle filter for a robot with range sensor?

I am trying to implement a particle filter for a robot in Java. This robot is having a range sensor. The world has 6 obstacles - 3 in the top and 3 in bottom. I am calculating the distance of the ...
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### Why models are not perfect to represent robotic environments?

Sebastian Thrun says in his paper on Particle Filters that - no model however detailed fails to represent the complexity of even the simplest of robotic environment. What does he means by this? Can ...
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### Calculate object distance with camera

Firstly I'm unsure whether this question belongs here or on another SE site (but I'll wing it for now). I've recently been given the job of connecting up a 'smart camera' to a setup where a robotic ...
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### EKF Localization when robot is in parallel with a landmark.

I'm facing a real weird problem with EKF Localization. The filer gives me wrong error every time the robot is in parallel with a landmark. I've debugged the code many times but failed to solve the ...
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### Path comparison

Problem: the cartesian position of an end effector (no orientation) of a robot arm is recorded, say, every millisecond (the time steps can not be changed), during a motion. The robot arm is commanded ...
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### Why should I still use EKF instead of UKF?

The Unscented Kalman Filter is a variant of the Extended Kalman Filter which uses a different linearization relying on transforming a set of "Sigma Points" instead of first-order Taylor series ...
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### innovation step ekf localization?

Let's say we have a bunch of observations $z^{i}$ from sensor and we have a map in which we can get the predicted measurements $\hat{z}^{i}$ for landmarks. In EKF localization in correction step, ...
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### Solutions for Finding Position and Heading in a Multi-Level House

I was wondering if you could reccomend possible solutions for locating a robot within a multilevel house. What seems obvious to me is that need an altitude sensor to derive the story the robot, and a ...
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### How to calibrate differential drive?

I'm building a robot with differential drive. I've reached the point when I can drive it around on remote control and I'm trying to get the localization working. Now I would like to exactly measure ...
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### Accelerometer, gyro, and magnetometer sensor fusion in 2d

I have not yet built this so this is basically a theoretical question. I am still wrestling with some C code to manage i2c ...
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### Using robotic simulator for prediction step in probabilistic localization approaches

Probabilistic localization approaches like Kalman or Monte Carlo benefit from an accurate prediction step. The more accurate the prediction step, the more accurate is the belief of the robots pose. In ...
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### Precision we can expect of an ultrasound-based localisation system

I'm considering building an absolute, indoor robot-positioning system based on ultrasound Time Of Flight. Transducers will be ordinary, narrow-band, 40 kHz ones. Based on your experience, what is the ...
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### Multiple position estimates fusion

I have a system in which I have two separate subsystems for estimating robot positions. First subsystem is composed of 3 cameras which are used for detecting markers the robot is carrying and which ...
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### 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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### SLAM for Autonomous car

I am working on SLAM for autonomous car like vehicles with 2D lasers and IMU (deriving odometry). I would like to know how efficient is using the existing SLAM algorithms (for example: gmapping in ...
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### Motion Model for Holonomic Robot

We are working with an holonomic robot equipped with three (120 degree shifted) omnidirectional wheels. The relative movement is estimated by dead reckoning using wheel encoders. To improve this ...
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### Using vision for Monte-Carlo localization

From each step of my vision code I am able to get around 400 coordinates of where the robot thinks the walls are I want to integrate this into Monte-Carlo observation step. I'm storing the map of ...
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### Monte-Carlo Localization

I'm implementing Monte-Carlo localization for my robot that is given a map of the enviroment and its starting location and orientation. Mine approach is as follows: Uniformly create 500 particles ...
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### How to choose WiFi signal strength detecting sensors

We want to create robot that will localize itself by the signals of wifi routers. Which sensors should we buy to detect strength of 3 WiFi signal? Which of following is necessary for us? http://www....
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### Algebraic and geometric in inverse kinematic

I'm just wondering that is there any case that when algebraic way can't solve the problem while the geometric can ? Cause I'm working on a 2DOF robotics arm This one, I know the length of L1 and L2, ...
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### Defining frames for 5DOF robotics arm

For examples if i have this robotic arm: Example, for the base rotation (5th DOF in the clip at 0:58), we know that the Z axis for that joint will be the same as the Z axis for the base frame{0}, but ...
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### Fake localization using bag file in ROS

I have a bag file that contains couple of topics needed for localization, odometry data, kinect data and /tf. What I want is watching robot's movement path in ...
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### Particle filter implementation in ROS

I'm looking for particle filter implementation in ROS to use in mobile robot localization, but it seems the only available package is amcl (Adaptive Monte Carlo), I'm not sure is it possible to use it ...
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### Calculate covariance matrix from x,y,z data

In ROS I've recorded a bag file from a custom robot (in real world) that does not provide covariance matrix and I want to use /odom to feed an EKF, but covariance ...
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### In EKF-SLAM, why do we even need odometry when there is a more reliable sensor?Also, are all SLAM algorithms feature-based?

In the book of SLAM for dummies, why do we even need the odometry when the robot would use the data retrieved from the laser scanner which is more accurate than odometry? Why not just rerly on the ...
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### What is the most appropriate SLAM algorithm for quadrotors with RGB-D camera?

I have been researching on SLAM. I came across EKF SLAM which uses odometry to measure the robot's initial position in the map and as well as landmarks which helps the robot's position to be more ...
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### Does Monte Carlo Localization need a predefined map?

So I'm doing some reading on Monte Carlo Localization, and it sounds like the approach is based on using a predefined map, but I just need to make sure (because I haven't read anywhere that it ...
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I have a question about car-like robot localization using only dead-reckoning. Given: robot position (at current time step) in the form $\begin{bmatrix}x & y & \theta\end{bmatrix}$ (theta is ...
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### What frame of reference is used during Visual Servoing?

I'm new to the whole visual servoing area. I'm now reading the tutorial Visual Servo Control Part I: Basic Approaches" and I don't understand something fundamental - what information is available to ...
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### Localizing a swarm of robots

I have a 300cm x 300cm room with a 25cm high ceiling (yes twenty five centimeters). It contains 50 small wheeled robots (about 20cm x 20cm). A central computer will orchestrate the movements of the ...
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### How to model unpredictable noise in Kalman Filter?

Background: I am implementing a simple Kalman Filter that estimates the heading direction of a robot. The robot is equipped with a compass and a gyroscope. My Understanding: I am thinking about ...
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### How to implement Bounded Angle Vision in Particle Filter?

I have built a Particles Filter simulator and I wanted to add the following functionalities. Limited Range Vision (Robot can see up to 50 meters) Limited Angle Vision (Robot can see within a certain ...
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### laser scanner distance

I'm looking at laser scanners and I see a huge range of detection distances. The furthest I've see are 30m if you exclude the very expensive ones that claim up to 150m. My question is what is the ...
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### How to perform this reference system transformation?

I have two quaternions that indicate the initial orientation of a four wheel robot, each one in relative to one reference systems. The robot's orientation given by a quaternion q is not the same in ...
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### What are human-friendly terms for mobile-robot orientation and relative direction of non-robot objects?

Within robotics programming, orientation is primarily given in terms of x, y, & z coordinates, from some central location. However x, y, z coordinates aren't convenient for rapid human ...
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### How to make an “invisible line following robot”?

I would like to build a robot which follows a virtual path (Not a visible path like a 'black line on a white surface', etc). I'm just enthusiastic by seeing some sci-fi videos which show robots carry ...
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### Local Localisation with particle filter

I am doing Local Localisation with sonar, particle filter (i.e all particles are initially with robot pose). I have grip map of environment. When I execute algorithm in environment (where doors are ...
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### Extended Kalman Filter using odometry motion model

In the prediction step of EKF localization, linearization must be performed and (as mentioned in Probabilistic Robotics [THRUN,BURGARD,FOX] page 206) the Jacobian matrix when using velocity motion ...
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### Using a Sick laser with Matlab in Windows

Is there a Matlab toolbox available to use Sick lasers in Windows? I found one toolbox for Matlab in GNU/Linux. Is there another way to use Sick laser via Matlab in Windows?
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### Can you seed a Kalman filter with a particle filter?

Is there a way of initializing a Kalman filter using a population of particles that belong to the same "cluster"? How can you determine a good estimate for the mean value (compute weighted average ?) ...
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### How To Determine Heading Without Compass

Lets say I drop a robot into a featureless environment and any magnetic field based sensors (magnetometer/compass) are not allowed. What methods are there of determining where north is? Tracking the ...
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### EKF-SLAM Update step, Kalman Gain becomes singular

I'm using an EKF for SLAM and I'm having some problem with the update step. I'm getting a warning that K is singular, rcond evaluates to ...
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### Particle filters: How to do resampling?

I understand the basic principle of a particle filter and tried to implement one. However, I got hung up on the resampling part. Theoretically speaking, it is quite simple: From the old (and ...