scholarly journals Real-time trajectory replanning for MAVs using uniform B-splines and a 3D circular buffer

2017 ◽  
Author(s):  
Vladyslav Usenko ◽  
Lukas von Stumberg ◽  
Andrej Pangercic ◽  
Daniel Cremers
Keyword(s):  
Real Time ◽  
B Splines ◽  
Circular Buffer

Real-Time Cooperative Trajectory Planning Using Differential Flatness Approach and B-Splines

2013 ◽  
Vol 333-335 ◽  
pp. 1338-1343 ◽  
Author(s):  
Xue Qiang Gu ◽  
Yu Zhang ◽  
Jing Chen ◽  
Lin Cheng Shen
Keyword(s):  
Optimal Control ◽  
Real Time ◽  
Trajectory Planning ◽  
Differential Flatness ◽  
Planning Problem ◽  
Receding Horizon ◽  
B Splines ◽  
Battlefield Environment ◽  
Planning Space ◽  
Spatial Trajectories

This paper proposed a cooperative receding horizon optimal control framework, based on differential flatness and B-splines, which was used to solve the real-time cooperative trajectory planning for multi-UCAV performing cooperative air-to-ground target attack missions. The planning problem was formulated as a cooperative receding horizon optimal control problem (CRHC-OCP), and then the differential flatness and B-splines were introduced to lower the dimension of the planning space and parameterize the spatial trajectories. Moreover, for the dynamic and uncertainty of the battlefield environment, the cooperative receding horizon control was introduced. Finally, the proposed approach is demonstrated, and the results show that this approach is feasible and effective.

Real-time regional VTEC modeling based on B-splines using real-time GPS and GLONASS observations

2021 ◽  
Author(s):  
Eren Erdogan ◽  
Andreas Goss ◽  
Michael Schmidt ◽  
Denise Dettmering ◽  
Florian Seitz ◽  
...  
Keyword(s):  
Kalman Filter ◽  
Real Time ◽  
Carrier Phase ◽  
Background Information ◽  
Electron Content ◽  
Vertical Total Electron Content ◽  
Total Electron ◽  
B Spline ◽  
B Splines ◽  
Cycle Slips

<p>The project OPTIMAP is at the current stage a joint initiative of BGIC, GSSAC and DGFI-TUM. The development of an operational tool for ionospheric mapping and prediction is the main goal of the project.</p><p>The ionosphere is a dispersive medium. Therefore, GNSS signals are refracted while they pass through the ionosphere. The magnitude of the refraction rate depends on the frequencies of the transmitted GNSS signals. The ionospheric disturbance on the GNSS signals paves the way of extracting Vertical Total Electron Content (VTEC) information of the ionosphere.</p><p>In OPTIMAP, the representation of the global and regional VTEC signal is based on localizing B-spline basis functions. For global VTEC modeling, polynomial B-splines are employed to represent the latitudinal variations, whereas trigonometric B-splines are used for the longitudinal variations. The regional modeling in OPTIMAP relies on a polynomial B-spline representation for both latitude and longitude.</p><p>The VTEC modeling in this study relies on both a global and a regional sequential estimator (Kalman filter) running in a parallel mode. The global VTEC estimator produces VTEC maps based on data from GNSS receiver stations which are mainly part of the global real-time IGS network. The global estimator relies on additional VTEC information obtained from a forecast procedure using ultra-rapid VTEC products. The regional estimator makes use of the VTEC product of the real-time global estimator as background information and generates high-resolution VTEC maps using real-time data from the EUREF Permanent GNSS Network. EUREF provides a network of very dense GNSS receivers distributed alongside Europe.</p><p>Carrier phase observations acquired from GPS and GLONASS, which are transmitted in accordance with RTCM standard, are used for real-time regional VTEC modeling. After the acquisition of GNSS data, cycle slips for each satellite-receiver pair are detected, and ionosphere observations are constructed via the linear combination of carrier-phase observations in the data pre-processing step. The unknown B-spline coefficients, as well as the biases for each phase-continuous arc belonging to each receiver-satellite pair, are simultaneously estimated in the Kalman filter.</p><p>Within this study, we compare the performance of regional and global VTEC products generated in real-time using the well-known dSTEC analysis.</p>

Force Field-Based Control of Dynamic Particles with User-Specified Paths

2015 ◽  
Vol 15 (03) ◽  
pp. 1550009
Author(s):  
Muhammad Rusdi Syamsuddin ◽  
Jimwook Kim ◽  
Sung-Hee Lee
Keyword(s):  
Force Field ◽  
Real Time ◽  
Target Location ◽  
Attraction Force ◽  
B Splines ◽  
Human Figure ◽  
Physics Based Animation ◽  
Steering Force ◽  
Animation System ◽  
Number Of Particles

We present a framework to design force fields that drive particles to follow a path under the physics-based animation system. In this framework, a user interactively specifies the desired path, represented by a Bezier curve using a GUI and the attraction force that drives a particle toward the target location. Then, the framework automatically defines the steering force to make a particle follow the desired path. To this end, we use B-splines to define the steering force that best approximates the user-specified path. We demonstrate the effectiveness of our method by showing a large number of particles following the desired path and forming an animated human figure. Our method creates a stable behavior of particles and is fast enough to run in real time.

scholarly journals Real‐time monitoring of ionosphere VTEC using Multi‐GNSS carrier‐phase observations and B‐splines

Space Weather ◽  
2021 ◽  
Author(s):  
Eren Erdogan ◽  
Michael Schmidt ◽  
Andreas Goss ◽  
Barbara Görres ◽  
Florian Seitz
Keyword(s):  
Real Time ◽  
Carrier Phase ◽  
Real Time Monitoring ◽  
B Splines

Real-time regional VTEC modeling based on B-splines using real-time GPS, GLONASS and GALILEO observations

2020 ◽  
Author(s):  
Eren Erdogan ◽  
Andreas Goss ◽  
Michael Schmidt ◽  
Denise Dettmering ◽  
Florian Seitz ◽  
...  
Keyword(s):  
Kalman Filter ◽  
Real Time ◽  
Carrier Phase ◽  
Background Information ◽  
Electron Content ◽  
Vertical Total Electron Content ◽  
Total Electron ◽  
B Spline ◽  
B Splines ◽  
Cycle Slips

<p>The project OPTIMAP is at the current stage a joint initiative of BGIC, GSSAC and DGFI-TUM. The development of an operational tool for ionospheric mapping and prediction is the main goal of the project.</p><p>The ionosphere is a dispersive medium. Therefore, GNSS signals are refracted while they pass through the ionosphere. The magnitude of the refraction rate depends on the frequencies of the transmitted GNSS signals. The ionospheric disturbance on the GNSS signals paves the way of extracting Vertical Total Electron Content (VTEC) information of the ionosphere.</p><p>In OPTIMAP, the representation of the global and regional VTEC signal is based on localizing B-spline basis functions. For global VTEC modeling, polynomial B-splines are employed to represent the latitudinal variations, whereas trigonometric B-splines are used for the longitudinal variations. The regional modeling in OPTIMAP relies on a polynomial B-spline representation for both latitude and longitude.</p><p>The VTEC modeling in this study relies on both a global and a regional sequential estimator (Kalman filter) running in a parallel mode. The global VTEC estimator produces VTEC maps based on data from GNSS receiver stations which are mainly part of the global real-time IGS network. The global estimator relies on additional VTEC information obtained from a forecast procedure using ultra-rapid VTEC products. The regional estimator makes use of the VTEC product of the real-time global estimator as background information and generates high-resolution VTEC maps using real-time data from the EUREF Permanent GNSS Network. EUREF provides a network of very dense GNSS receivers distributed alongside Europe.</p><p>Carrier phase observations acquired from GPS, GLONASS and GALILEO constellations, which are transmitted in accordance with RTCM standard, are used for real-time regional VTEC modeling. After the acquisition of GNSS data, cycle slips for each satellite-receiver pair are detected, and ionosphere observations are constructed via the linear combination of carrier-phase observations in the data pre-processing step. The unknown B-spline coefficients, as well as the biases for each phase-continuous arc belonging to each receiver-satellite pair, are simultaneously estimated in the Kalman filter.</p><p>Within this study, we compare the performance of regional and global VTEC products generated in real-time using the well-known dSTEC analysis.</p>

scholarly journals A FAST AND FLEXIBLE METHOD FOR META-MAP BUILDING FOR ICP BASED SLAM

2016 ◽  
Vol XLI-B3 ◽  
pp. 273-278
Author(s):  
A. Kurian ◽  
K. W. Morin
Keyword(s):  
Real Time ◽  
Point Cloud ◽  
Sampling Strategy ◽  
Cost Effective ◽  
Point Clouds ◽  
Limited Range ◽  
Map Building ◽  
3D Point Cloud ◽  
Circular Buffer ◽  
Localization And Mapping

Recent developments in LiDAR sensors make mobile mapping fast and cost effective. These sensors generate a large amount of data which in turn improves the coverage and details of the map. Due to the limited range of the sensor, one has to collect a series of scans to build the entire map of the environment. If we have good GNSS coverage, building a map is a well addressed problem. But in an indoor environment, we have limited GNSS reception and an inertial solution, if available, can quickly diverge. In such situations, simultaneous localization and mapping (SLAM) is used to generate a navigation solution and map concurrently. SLAM using point clouds possesses a number of computational challenges even with modern hardware due to the shear amount of data. In this paper, we propose two strategies for minimizing the cost of computation and storage when a 3D point cloud is used for navigation and real-time map building. We have used the 3D point cloud generated by Leica Geosystems's Pegasus Backpack which is equipped with Velodyne VLP-16 LiDARs scanners. To improve the speed of the conventional iterative closest point (ICP) algorithm, we propose a point cloud sub-sampling strategy which does not throw away any key features and yet significantly reduces the number of points that needs to be processed and stored. In order to speed up the correspondence finding step, a dual kd-tree and circular buffer architecture is proposed. We have shown that the proposed method can run in real time and has excellent navigation accuracy characteristics.

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