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
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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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1answer
129 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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29 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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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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25 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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2answers
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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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25 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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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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199 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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134 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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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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32 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
125 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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1answer
57 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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48 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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17 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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151 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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36 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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134 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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115 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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106 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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130 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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131 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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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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155 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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28 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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11 views

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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1answer
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How does a Tesla or any self-driving car self-drive to a remote place and align itself to an object?

I am trying to understand the technology/procedure related to one of the trivial functions of a modern self-driving cars. Let us consider the example of Tesla's Model S (or any). The car is parked at ...
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8 views

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
23 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
28 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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1answer
26 views

Applying Rotation & Translation Matrix Obtained from Iterative Closest Point

Suppose I have M lidar contour points from t = k and N lidar contour points from t = k+1. (Some of you might question why I have differing number of contour points, and the reason is that these lidar ...
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29 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
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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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23 views

Robot Localization - Motion and Sense Probability

I'm currently taking Udacity's AI for robotics course and came across a question that stumped me. The problem plays on localization probability given uncertainty in our measurement updates. The first ...
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Bundle Adjustment for Monocular SLAM

I am confused with how monocular BA works in visual-based SLAM. Is there any tutorials I can do in openCV to provide me some visualization aid? Thank You.
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loop closing in grid based fastslam 2.0

I understand how grid based fastslam 2.0 works I just would like to know how to implement a loop closure functionality in a grid-based fastslam 2.0? Since at each state we only consider the last state ...
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Ceiling Camera & robot - SLAM still neded?

I've got a question regarding the topic of SLAM. My composition consists of a mobile robot and a top down looking 2D camera with wide-angle lens. It is comparable to a survaillance camera mounted on ...
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1answer
65 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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MAV drifting away from its takeoff position

I am working on MAV control in GPS denied environment using px4flow and Lidar sensor.While in simulation and during experiments on real vehicle, MAV doesnt stay at its position and drifts in random ...
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1answer
51 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 ...
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Robot localization including the orientation of the boundary

Consider a SLAM system for a mobile robot that is able not only to predict the position wrt the map boundary but also to measure the orientation of the boundary once it is reached. If the measured ...
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Integrating Arduino Cloud Platform into ROS

I have an existing ROS framework used for an autonomous driving vehicle. I am working on tests to understand how localization is affected by light. My existing hardware does not have a lux measurement ...
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22 views

What is the difference between SLAM and cooperative localization?

I need to ask this simple question for my own understanding. I am new to the field and want to differentiate between the two.
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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 ...
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How do I set the weights of an Unscented Kalman Filter?

In most of the papers I have read, calculation of weights is done by the following formula: Where L is the dimensionality of my state and lambda is calculated by: And the usual values for alpha, ...
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25 views

Max angle of beam against surface (ultrasonic sensor)

I am trying to localize a robot within a rectangular room (182cm x 243cm) with completely black walls (so IR sensors and LIDAR are out of the question). I am trying to figure out if I can position ...