The Experts below are selected from a list of 1830 Experts worldwide ranked by ideXlab platform

James P. Mclellan - One of the best experts on this subject based on the ideXlab platform.

  • Formation control of High-Altitude Balloons experiencing real wind currents by discrete-time distributed extremum seeking control
    2017 American Control Conference (ACC), 2017
    Co-Authors: Isaac Vandermeulen, Martin Guay, James P. Mclellan
    Abstract:

    In this paper, a discrete-time method for the formation of High-Altitude Balloons is developed. The Balloons float passively along the Earth's wind currents. For actuation, a balloon can change its Altitude to enter a different wind current and move in a different direction. The control objective is to steer a fleet of Balloons into a configuration where they are evenly distributed around the Earth. The control approach is a discrete-time distributed extremum-seeking controller. This controller works to minimize a measured cost function. It only requires a measurement of this cost function and does not require a model of the nonlinear time-varying wind currents. For the problem of balloon formation control, the cost function is based on a Voronoi partition resulting in an algorithm similar to Lloyd's algorithm. The control architecture is fully distributed. There is no central coordinator and each balloon receives all the information it needs by communicating to nearby Balloons over a network whose structure is the Delaunay triangulation with the Balloons as vertices. The resulting distributed control algorithm is computationally efficient as the burden of computation is shared between all of the Balloons. Several simulations involving 1200 Balloons are used to verify the effectiveness of this approach. The simulations use realistic nonlinear time-varying models which are obtained by interpolating gridded weather data obtained from the National Oceanic and Atmospheric Administration.

  • formation control of High Altitude Balloons by distributed extremum seeking control
    Advances in Computing and Communications, 2016
    Co-Authors: Isaac Vandermeulen, Martin Guay, James P. Mclellan
    Abstract:

    In this paper, a method for the formation control of High-Altitude Balloons is developed. This method uses a distributed extremum seeking controller implemented at each balloon. The controller works to minimize a cost function based on the number of users connected to each balloon. This cost function is designed so that the Balloons tend to spread themselves out evenly over Earth. The control approach is fully distributed and requires no central coordinator. Balloons communicate over a network via a consensus algorithm providing all Balloons with an accurate estimate of the total cost. Since extremum seeking is a model-free approach, it does not require a complex wind model. The resulting algorithm is efficient as the burden of computation is shared between all Balloons. A simulation study involving 20 Balloons is used to verify the effectiveness of this approach.

Isaac Vandermeulen - One of the best experts on this subject based on the ideXlab platform.

  • Formation control of High-Altitude Balloons experiencing real wind currents by discrete-time distributed extremum seeking control
    2017 American Control Conference (ACC), 2017
    Co-Authors: Isaac Vandermeulen, Martin Guay, James P. Mclellan
    Abstract:

    In this paper, a discrete-time method for the formation of High-Altitude Balloons is developed. The Balloons float passively along the Earth's wind currents. For actuation, a balloon can change its Altitude to enter a different wind current and move in a different direction. The control objective is to steer a fleet of Balloons into a configuration where they are evenly distributed around the Earth. The control approach is a discrete-time distributed extremum-seeking controller. This controller works to minimize a measured cost function. It only requires a measurement of this cost function and does not require a model of the nonlinear time-varying wind currents. For the problem of balloon formation control, the cost function is based on a Voronoi partition resulting in an algorithm similar to Lloyd's algorithm. The control architecture is fully distributed. There is no central coordinator and each balloon receives all the information it needs by communicating to nearby Balloons over a network whose structure is the Delaunay triangulation with the Balloons as vertices. The resulting distributed control algorithm is computationally efficient as the burden of computation is shared between all of the Balloons. Several simulations involving 1200 Balloons are used to verify the effectiveness of this approach. The simulations use realistic nonlinear time-varying models which are obtained by interpolating gridded weather data obtained from the National Oceanic and Atmospheric Administration.

  • formation control of High Altitude Balloons by distributed extremum seeking control
    Advances in Computing and Communications, 2016
    Co-Authors: Isaac Vandermeulen, Martin Guay, James P. Mclellan
    Abstract:

    In this paper, a method for the formation control of High-Altitude Balloons is developed. This method uses a distributed extremum seeking controller implemented at each balloon. The controller works to minimize a cost function based on the number of users connected to each balloon. This cost function is designed so that the Balloons tend to spread themselves out evenly over Earth. The control approach is fully distributed and requires no central coordinator. Balloons communicate over a network via a consensus algorithm providing all Balloons with an accurate estimate of the total cost. Since extremum seeking is a model-free approach, it does not require a complex wind model. The resulting algorithm is efficient as the burden of computation is shared between all Balloons. A simulation study involving 20 Balloons is used to verify the effectiveness of this approach.

Caitlyn A K Singam - One of the best experts on this subject based on the ideXlab platform.

  • implementation of a low cost flight tracking system for High Altitude ballooning
    Journal of Aerospace Information Systems, 2020
    Co-Authors: Caitlyn A K Singam
    Abstract:

    High-Altitude Balloons (HABs) are typically tracked via Global Positioning System (GPS) data sent via real-time radio-based communication systems such as the Automatic Packet Reporting System (APRS...

  • implementation of a low cost flight tracking system for High Altitude ballooning
    arXiv: Signal Processing, 2019
    Co-Authors: Caitlyn A K Singam
    Abstract:

    High Altitude Balloons (HABs) are typically tracked via GPS data sent via real-time radio-based communication systems such as the Automated Packet Reporting System (APRS). Prefabricated APRS-compatible tracker modules have made it trivial to transmit GPS coordinates and payload parameters in compliance with the requisite AX.25 protocol. However, in order to receive and track APRS signals, conventional methodologies call for the use of a Very High Frequency (VHF) receiver to demodulate signals transmitted on the 440/144 MHz APRS frequencies, along with a compatible antenna and custom methodology for visualizing the HAB's location on a map. The entire assembly is typically costly, cumbersome, and may require an internet connection in order to obtain real-time visualization of the HAB's location. This paper describes a low-cost, handheld system based on open-source software that operates independently of an internet connection. The miniaturized system is suited to tracking done either from a vehicle or on foot, and is cost-effective enough to be within the means of nearly any HAB user. The paper also discusses preliminary test results and further applications.

Martin Guay - One of the best experts on this subject based on the ideXlab platform.

  • Formation control of High-Altitude Balloons experiencing real wind currents by discrete-time distributed extremum seeking control
    2017 American Control Conference (ACC), 2017
    Co-Authors: Isaac Vandermeulen, Martin Guay, James P. Mclellan
    Abstract:

    In this paper, a discrete-time method for the formation of High-Altitude Balloons is developed. The Balloons float passively along the Earth's wind currents. For actuation, a balloon can change its Altitude to enter a different wind current and move in a different direction. The control objective is to steer a fleet of Balloons into a configuration where they are evenly distributed around the Earth. The control approach is a discrete-time distributed extremum-seeking controller. This controller works to minimize a measured cost function. It only requires a measurement of this cost function and does not require a model of the nonlinear time-varying wind currents. For the problem of balloon formation control, the cost function is based on a Voronoi partition resulting in an algorithm similar to Lloyd's algorithm. The control architecture is fully distributed. There is no central coordinator and each balloon receives all the information it needs by communicating to nearby Balloons over a network whose structure is the Delaunay triangulation with the Balloons as vertices. The resulting distributed control algorithm is computationally efficient as the burden of computation is shared between all of the Balloons. Several simulations involving 1200 Balloons are used to verify the effectiveness of this approach. The simulations use realistic nonlinear time-varying models which are obtained by interpolating gridded weather data obtained from the National Oceanic and Atmospheric Administration.

  • formation control of High Altitude Balloons by distributed extremum seeking control
    Advances in Computing and Communications, 2016
    Co-Authors: Isaac Vandermeulen, Martin Guay, James P. Mclellan
    Abstract:

    In this paper, a method for the formation control of High-Altitude Balloons is developed. This method uses a distributed extremum seeking controller implemented at each balloon. The controller works to minimize a cost function based on the number of users connected to each balloon. This cost function is designed so that the Balloons tend to spread themselves out evenly over Earth. The control approach is fully distributed and requires no central coordinator. Balloons communicate over a network via a consensus algorithm providing all Balloons with an accurate estimate of the total cost. Since extremum seeking is a model-free approach, it does not require a complex wind model. The resulting algorithm is efficient as the burden of computation is shared between all Balloons. A simulation study involving 20 Balloons is used to verify the effectiveness of this approach.

B J Teegarden - One of the best experts on this subject based on the ideXlab platform.

  • a review of recent results in gamma ray astronomy obtained from High Altitude Balloons
    Astrophysical Journal Supplement Series, 1994
    Co-Authors: B J Teegarden
    Abstract:

    This paper reviews recent results in gamma-ray astronomy obtained from experiments flown on High-Altitude Balloons. New generation balloon-borne imaging experiments have produced the first gamma-ray maps of the Galactic center (GC) region. Balloon flights of new gamma-ray spectrometers with improved sensitivity have provided important new information on the GC annihilation line. For the first time, the narrow 511 keV line as been resolved (FWHM approx. = 3 keV). A very interesting spectral feature at approximately 170 keV has been attributed to backscattered annihilation, probably from the vicinity of a compact object. New results from the Compton Gamma-Ray Observatory (CGRO)/OSSE and Granat/SIGMA experiments on the annihilation line, when considered together with the recent balloon results, have added greatly to our knowledge and understanding of the origin and distribution of this emission. Balloon-borne instruments have made important measurements of gamma-ray continuum and line emission from SN 1987A. The GRIS spectrometer unambiguously resolved the 847 and 1238 keV line emission from radioactive Co-56 synthesized during the explosion. This data indicated that simple spherically symmetric and homogeneous models did not provide an adequate description of the expanding SN shell.