Angular position measurement of pulsars based on X-ray intensity correlation

In this paper, the relationship between direct measurement of X-ray pulsar angular position and second-order correlation is analyzed by classical statistical optics. On this basis, a scheme for measuring pulsar angle position is put forward on account of X-ray band intensity correlation, which is expected to achieve a positioning accuracy of 10 Mas. Finally, the connection between positioning accuracy and complex correlation in the intensity correlation measurement is studied. Also, main factors that affected the measurement are analyzed.

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Study of a high-precision pulsar angular position measuring method

Modern Physics Letters B ◽

10.1142/s0217984918503554 ◽

2018 ◽

Vol 32 (29) ◽

pp. 1850355 ◽

Cited By ~ 2

Author(s):

Yao Li ◽

Tong Su ◽

Lizhi Sheng ◽

Pengfei Qiang ◽

Baosheng Zhao

Keyword(s):

Measurement Accuracy ◽

Angular Position ◽

Measuring Method ◽

Intensity Correlation ◽

X Ray ◽

Long Baseline ◽

Novel Method ◽

The Relationship ◽

Theoretical Analyses ◽

Pulsar Navigation

Currently, very long baseline interferometry technology is widely used in the astronomical measurement areas, providing about 1 [Formula: see text]as pulsar positioning accuracy. However, these conventional methods cannot meet the higher position accuracy requirements of X-ray pulsar navigation. In this paper, we provide a novel method to measure the angular position based on X-ray intensity correlation. First, we show the relationship between the pulsar angular position and the X-ray intensity correlation. Second, we simulate the measurement error within the constraint on the photon energy fluctuations and compensation time. Finally, we propose a way to achieve such measurement. These theoretical analyses will improve the measurement accuracy of the pulsar angular position to a large extent.

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Assessment of the Accuracy of Determining the Angular Position of the Unmanned Bathymetric Surveying Vehicle Based on the Sea Horizon Image

Sensors ◽

10.3390/s19214644 ◽

2019 ◽

Vol 19 (21) ◽

pp. 4644 ◽

Cited By ~ 2

Author(s):

Naus ◽

Marchel ◽

Szymak ◽

Nowak

Keyword(s):

Angular Position ◽

Complementary Metal Oxide Semiconductor ◽

General Concept ◽

Oxide Semiconductor ◽

Position Measurement ◽

The Matrix ◽

Horizon Line ◽

Aerial Vehicle ◽

Line Slope ◽

Further Development

The paper presents the results of research on assessing the accuracy of angular position measurement relative to the sea horizon using a camera mounted on an unmanned bathymetric surveying vehicle of the Unmanned Surface Vehicle (USV) or Unmanned Aerial Vehicle (UAV) type. The first part of the article presents the essence of the problem. The rules of taking the angular position of the vehicle into account in bathymetric surveys and the general concept of the two-camera tilt compensator were described. The second part presents a mathematical description of the meters characterizing a resolution and a mean error of measurements, made on the base of the horizon line image, recorded with an optical system with a Complementary Metal-Oxide Semiconductor (CMOS) matrix. The phenomenon of the horizon line curvature in the image projected onto the matrix that appears with the increase of the camera height has been characterized. The third part contains an example of a detailed analysis of selected cameras mounted on UAVs manufactured by DJI, carried out using the proposed meters. The obtained results including measurement resolutions of a single-pixel and mean errors of the horizon line slope measurement were presented in the form of many tables and charts with extensive comments. The final part presents the general conclusions from the performed research and a proposal of directions for their further development.

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Design of a high-performance optical system for angular position measurement: optical and electronic strategies for uncertainty reduction

Proceedings of the 20th IEEE Instrumentation Technology Conference (Cat. No.03CH37412) ◽

10.1109/imtc.2003.1207939 ◽

2004 ◽

Cited By ~ 1

Author(s):

L. Rovati

Keyword(s):

Optical System ◽

High Performance ◽

Angular Position ◽

Uncertainty Reduction ◽

Position Measurement

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A phase-space beam position monitor for synchrotron radiation

Journal of Synchrotron Radiation ◽

10.1107/s1600577515007390 ◽

2015 ◽

Vol 22 (4) ◽

pp. 946-955 ◽

Cited By ~ 4

Author(s):

Nazanin Samadi ◽

Bassey Bassey ◽

Mercedes Martinson ◽

George Belev ◽

Les Dallin ◽

...

Keyword(s):

Phase Space ◽

Synchrotron Radiation ◽

Incident Angle ◽

Operating Conditions ◽

Photon Beam ◽

Profile Measurement ◽

Beam Position Monitor ◽

Position Measurement ◽

Beam Position ◽

X Ray

The stability of the photon beam position on synchrotron beamlines is critical for most if not all synchrotron radiation experiments. The position of the beam at the experiment or optical element location is set by the position and angle of the electron beam source as it traverses the magnetic field of the bend-magnet or insertion device. Thus an ideal photon beam monitor would be able to simultaneously measure the photon beam's position and angle, and thus infer the electron beam's position in phase space. X-ray diffraction is commonly used to prepare monochromatic beams on X-ray beamlines usually in the form of a double-crystal monochromator. Diffraction couples the photon wavelength or energy to the incident angle on the lattice planes within the crystal. The beam from such a monochromator will contain a spread of energies due to the vertical divergence of the photon beam from the source. This range of energies can easily cover the absorption edge of a filter element such as iodine at 33.17 keV. A vertical profile measurement of the photon beam footprint with and without the filter can be used to determine the vertical centroid position and angle of the photon beam. In the measurements described here an imaging detector is used to measure these vertical profiles with an iodine filter that horizontally covers part of the monochromatic beam. The goal was to investigate the use of a combined monochromator, filter and detector as a phase-space beam position monitor. The system was tested for sensitivity to position and angle under a number of synchrotron operating conditions, such as normal operations and special operating modes where the photon beam is intentionally altered in position and angle at the source point. The results are comparable with other methods of beam position measurement and indicate that such a system is feasible in situations where part of the synchrotron beam can be used for the phase-space measurement.

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Fuzzy Control of an Inverted Pendulum

Volume 6: 16th Computers in Engineering Conference ◽

10.1115/96-detc/cie-1441 ◽

1996 ◽

Author(s):

Tuna Balkan ◽

Mehmet Emin Ari

Keyword(s):

Inverted Pendulum ◽

Fuzzy Controller ◽

Angular Position ◽

Upright Position ◽

Control Signal ◽

Position Measurement ◽

Pendulum System ◽

Inverted Pendulum System ◽

And Performance ◽

The Stability

Abstract An inverted pendulum system has been designed and constructed as a physical model of inherently unstable mechanical systems. The vertical upright position of a pendulum is controlled by changing the horizontal position of a cart to which the pendulum is hinged. The stability of the system has been investigated when a fuzzy controller is used to produce the control signal, while making a single measurement. It has been shown that by using simple fuzzy rules to allow real time computation with a single angular position measurement, the system can not be made absolutely stable. However, the stability and performance of the system have been considerably improved by shrinking the membership functions of angular position, computed angular velocity and control signal when inverted pendulum is very close to the vertical upright position.

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