Trigonometric bearings-only tracking for a single stationary observer

2002 ◽  
Author(s):  
Terry Rea ◽  
Y. T. Chan
Keyword(s):  
Stationary Observer

Estimated Forest Bird Densities by Variable Distance Point Counts

1985 ◽  
Vol 12 (2) ◽  
pp. 307 ◽  
Author(s):  
GH Pyke ◽  
HF Recher
Keyword(s):  
Fixed Time ◽  
Time Interval ◽  
Point Counts ◽  
Fixed Time Interval ◽  
Area Of Interest ◽  
Bird Density ◽  
Significant Movement ◽  
Stationary Observer ◽  
Variable Distance ◽  
Bird Distribution

During variable distance point counts a stationary observer records the species and distance for all birds detected during a fixed time interval. Such counts, repeated throughout the area of interest, can be used to estimate bird density so long as the following assumptions are made: (1) the distribution of birds is unaffected by the observer; (2) observers are certain of detecting near birds; (3) there is no error in measurement or estimation of distances; and (4) birds are stationary. Data collected during the present study indicated that at least two of these assumptions are not satisfied: estimates of distance based on sound are inaccurate and observers do not always detect near birds. No effect of observer presence on bird distribution was detected nor did there appear to be any significant movement of birds during counts. We recommend that bird counts be based only on sight detections and that, when bird movement is significant, instantaneous counts be used.

scholarly journals DISCRETE SPECTRAL SHIFT IN AN ANISOTROPIC UNIVERSE

1994 ◽  
Vol 09 (32) ◽  
pp. 2945-2952
Author(s):  
D. J. LAMB ◽  
A. Z. CAPRI ◽  
M. KOBAYASHI
Keyword(s):  
Particle Creation ◽  
Spectral Shift ◽  
Energy Scale ◽  
Anisotropic Universe ◽  
Discrete Energy ◽  
Massive Scalar Field ◽  
Stationary Observer ◽  
Delta Functions ◽  
Spectrum Shift ◽  
Bogolubov Transformation

In this paper we calculate the particle creation as seen by a stationary observer in an anisotropic universe. By using an observer and geometry dependent time to quantize a massive scalar field we show that a discrete energy spectrum shift occurs. The length scale associated with the geometry provides the energy scale by which the spectrum is shifted. The β(p, q) coefficient for the Bogolubov transformation calculated is proportional to a series of delta functions whose argument contains p and q and half multiples of the root of the curvature.

scholarly journals ON THE ENERGY–MOMENTUM FLUX IN GÖDEL-TYPE MODELS

2013 ◽  
Vol 28 (10) ◽  
pp. 1350039 ◽  
Author(s):  
S. C. ULHOA ◽  
A. F. SANTOS ◽  
R. G. G. AMORIM
Keyword(s):  
General Relativity ◽  
Total Pressure ◽  
Momentum Flux ◽  
Einstein’S Equations ◽  
Einstein's Equations ◽  
Cartesian Coordinates ◽  
Stationary Observer

In this paper, we work in the context of Teleparallelism Equivalent to General Relativity (TEGR) in order to construct the energy–momentum flux for Gödel-type solutions of Einstein's equations. We use an stationary observer, which is settled by the tetrad choice, to obtain the gravitational pressure for each direction of space in cartesian coordinates. Then, we write down the total pressure for each direction in terms of the pressure of the fluid, thus we are able to identify the role of the gravitational pressure.

Research on Total Error of Anti-Radiation Missile against Target Radiation Source Shutdown

2011 ◽  
Vol 63-64 ◽  
pp. 47-50
Author(s):  
Long Jie Zhang ◽  
Xiao Fang Xie ◽  
Jie Liang ◽  
De Dong Li ◽  
Jian Cao
Keyword(s):  
Navigation System ◽  
Radiation Source ◽  
Inertial Navigation System ◽  
Total Error ◽  
Elevation Angle ◽  
Three Dimensional ◽  
Error Model ◽  
Location Error ◽  
Passive Location ◽  
Stationary Observer

This paper established the total error model of Anti-Radiation Missile under condition of target radiation source shutdown, which includes three dimensional passive location error model using information of azimuth and elevation angle as well as their changing rates, and gyroscope drift error model of Strap-down Inertial Navigation System. By analyzing the three dimensional passive location method to moving emitter using single stationary observer, the paper had a research to the hit probability of Anti-Radiation Missile under various flying conditions. If higher hit probability is required, the missile should increase its azimuth and elevation angle as much as possible while not to overstep its attack angle. Simulation result showed that the shutdown occasion of radiation source did much influence to the hit probability of Anti-Radiation Missile, which has great meaning to improve he bat efficiency of Anti-Radiation Missile.

scholarly journals An approach to directly probe simultaneity

2016 ◽  
Vol 31 (26) ◽  
pp. 1650157
Author(s):  
Edward T. Kipreos ◽  
Riju S. Balachandran
Keyword(s):  
Special Relativity ◽  
Lorentz Transformation ◽  
Satellite Communications ◽  
Optical Resonator ◽  
Null Results ◽  
Experimental Strategy ◽  
Light Speed ◽  
Stationary Observer ◽  
The Difference ◽  
Frequency Changes

The theory of special relativity derives from the Lorentz transformation. The Lorentz transformation implies differential simultaneity and light speed isotropy. Experiments to probe differential simultaneity should be able to distinguish the Lorentz transformation from a kinematically-similar alternate transformation that predicts absolute simultaneity, the absolute Lorentz transformation. Here, we describe how published optical tests of light speed isotropy/anisotropy cannot distinguish between the two transformations. We show that the shared equations of the two transformations, from the perspective of the “stationary” observer, are sufficient to predict null results in optical resonator experiments and in tests of frequency changes in one-way light paths. In an influential 1910 exposition on differential simultaneity, Comstock described how a “stationary” observer would observe different clock readings for spatially-separated “moving” clocks. The difference in clock readings is an integral aspect of differential simultaneity. We derive the equation for the difference in clock readings and show that it is equivalent to the Sagnac correction that describes light speed anisotropies in satellite communications. We describe an experimental strategy that can measure the differences in spatially-separated clock times to allow a direct probe of the nature of simultaneity.

Apparent Rotation of a Line Superimposed upon Radially Expanding and Contracting Backgrounds

Perception ◽  
1981 ◽  
Vol 10 (3) ◽  
pp. 265-271 ◽  
Author(s):  
Michael T Swanston ◽  
Nicholas J Wade
Keyword(s):  
Oblique Line ◽  
Relative Orientation ◽  
Head Movements ◽  
Apparent Rotation ◽  
Stationary Observer ◽  
Horizontal Grating

An oblique line superimposed on a vertical or horizontal grating appears to rotate when the whole pattern is expanded or contracted. The apparent rotation occurs with head movements towards or away from a stationary grating, or with zooming a grating relative to a stationary observer. The magnitude and direction of the apparent rotation is dependent upon the relative inclination of the line to the grating and is most pronounced with a relative orientation of 45°.

Dynamic Occlusion and Motion Parallax in Depth Perception

Perception ◽  
1988 ◽  
Vol 17 (2) ◽  
pp. 255-266 ◽  
Author(s):  
Hiroshi Ono ◽  
Brian J Rogers ◽  
Masao Ohmi ◽  
Mika E Ono
Keyword(s):  
Relative Motion ◽  
Depth Perception ◽  
Motion Parallax ◽  
Three Dimensional ◽  
Depth Order ◽  
Depth Cues ◽  
Small Depth ◽  
Stationary Observer ◽  
Depth Separation ◽  
Condition B

Random-dot techniques were used to examine the interactions between the depth cues of dynamic occlusion and motion parallax in the perception of three-dimensional (3-D) structures, in two different situations: (a) when an observer moved laterally with respect to a rigid 3-D structure, and (b) when surfaces at different distances moved with respect to a stationary observer. In condition (a), the extent of accretion/deletion (dynamic occlusion) and the amount of relative motion (motion parallax) were both linked to the motion of the observer. When the two cues specified opposite, and therefore contradictory, depth orders, the perceived order in depth of the simulated surfaces was dependent on the magnitude of the depth separation. For small depth separations, motion parallax determined the perceived order, whereas for large separations it was determined by dynamic occlusion. In condition (b), where the motion parallax cues for depth order were inherently ambiguous, depth order was determined principally by the unambiguous occlusion information.

scholarly journals Control of vibrational field in an elastic vibration unit with DC motors and time-varying observer

2021 ◽  
pp. 277-286
Author(s):  
Olga P. Tomchina
Keyword(s):  
Control Algorithm ◽  
Closed Loop ◽  
Elastic Vibration ◽  
Synchronization Control ◽  
Time Varying ◽  
Rotor Vibration ◽  
Mechatronic Systems ◽  
Dc Motors ◽  
Stationary Observer ◽  
Drive Dynamics

In the paper the problem of feedback control of vibrational fields in a vibration unit is analyzed taking into account the influence of the elasticity of cardan shafts, the drive dynamics, saturation for control torques. In addition, the synthesized rotor synchronization control algorithm uses the estimates of a non-stationary observer, which makes it possible to implement it practically on a two-rotor vibration unit SV-2. The performance of the closed loop mechatronic systems is examined by simulation for the model of the two-rotor vibration unit SV-2.

Analysis of Self-Excited Longitudinal Vibration of a Moving Tape

1993 ◽  
Author(s):  
Jonathan A. Wickert
Keyword(s):  
Initial Conditions ◽  
Longitudinal Vibration ◽  
Stable Limit Cycle ◽  
Longitudinal Motion ◽  
Stable Limit ◽  
Contact Parameter ◽  
All Solutions ◽  
Stationary Observer ◽  
Axially Moving ◽  
Almost All

Abstract Longitudinal vibration of a moving magnetic tape can be excited by frictional contact with a recording head, or with a guide that defines the path of the tape. The friction force depends on the velocity, relative to a stationary observer, of the tape element that is instantaneously located at the point of contact. The response of a moving tape under such nonlinear dissipation is determined using new methods for the vibration analysis of axially-moving materials. In a particular transport speed range, longitudinal motion of the tape is self-excited through negative (unstable) damping for small amplitude vibration and positive (stable) damping for large amplitudes. Independent of the initial conditions, almost all solutions are attracted to a stable limit cycle, the amplitude of which is sensitive to the transport speed and to the axial location of contact. Parameter combinations that reduce, or eliminate altogether, the self-excited motion are identified. Some of the conclusions differ from those of previous analyses that neglect the effects of convection on the tape’s velocity and acceleration.

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