scholarly journals Second-Order Relative Motion Equations

2003 ◽  
Vol 26 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Christopher D. Karlgaard ◽  
Frederick H. Lutze
2000 ◽  
Vol 180 ◽  
pp. 242-247
Author(s):  
Cheng-li Huang ◽  
Wen-jing Jin ◽  
Xing-hao Liao

AbstractBy integrating the truncated complex scalar gravitational motion equations for an anelastic, rotating, slightly elliptical Earth, the complex frequency dependent Earth transfer functions are computed directly. Unlike the conventional method, the effects of both oceanic loads and tidal currents are included via outer surface boundary conditions, all of which are expanded to second order in ellipticity. A modified ellipticity profile in second order accuracy for the non-hydrostatic Earth is obtained from Clairaut’s equation and the PREM Earth model by adjusting both the ellipticity of the core-mantle boundary and the global dynamical ellipticity to modern observations. The effects of different Earth models, anelastic models, and ocean models are computed and compared. The atmospheric contributions to prograde annual, retrograde annual and retrograde semiannual nutation are also included as oceanic effects. Finally, a complete new nutation series of more than 340 periods, including in-phase and out-of-phase parts of longitude and obliquity terms, for a more realistic Earth, is obtained and compared with other available nutation series and observations.


Author(s):  
Di Zhou ◽  
Sheng Sun ◽  
Jing Yang Zhou ◽  
Kok Lay Teo

Based on the discrete form of the target-missile relative motion equations in plane, a discrete sliding-mode guidance (DSMG) law is proposed. All previous missile seeker's measurements are used in the design of the DSMG law to estimate the target acceleration such that noises in the seeker's measurements are effectively being smoothened. It is proved that the proposed DSMG law is finite time convergent. Quasi sliding-mode bands of the DSMG law are discussed, and the formula for calculating the terminal miss distances of the missile under the DSMG law are presented. Simulation results from a space interception process verify the effectiveness of the proposed method.


2019 ◽  
Vol 11 (4) ◽  
pp. 123-131
Author(s):  
Roxana Alexandra PETRE ◽  
Ion STROE ◽  
Andrei CRAIFALEANU

The relative motion of a robotic arm formed by homogeneous bars of different lengths and masses, hinged to each other is investigated. The first bar of the mechanism is articulated on a platform, considered for three cases: placed on the surface of the Earth, so it is fixed; located on Earth, but in rotation with respect to it and in the final case, located on a space station, moving around the Earth. For all the analyzed cases the motion equations are determined using the Lagrangian formalism.


2006 ◽  
Vol 97 (2) ◽  
pp. 101-129 ◽  
Author(s):  
Prasenjit Sengupta ◽  
Srinivas R. Vadali ◽  
Kyle T. Alfriend

2017 ◽  
Vol 71 (1) ◽  
pp. 44-64 ◽  
Author(s):  
Ranjan Vepa

In this paper we develop the nonlinear motion equations in terms of the true anomaly varying Tschauner–Hempel equations relative to a notional orbiting particle in a Keplerian orbit, relatively close to an orbiting primary satellite to estimate the position of a spacecraft. A second orbiting body in Earth orbit relatively close to the first is similarly modelled. The dynamic relative motion models of the satellite and the second orbiting body, both of which are modelled in terms of independent relative motion equations, include several perturbing effects, such as the asymmetry of the Earth gravitational field resulting in the Earth's oblateness effect and the third body accelerations due to the Moon and the Sun. Linear control laws are synthesised for the primary satellite using the transition matrix so it can rendezvous with the second orbiting body. The control laws are then implemented using the state estimates obtained earlier to validate the feedback controller. Thus, we demonstrate the application of a Linear Quadratic Nonlinear Gaussian (LQNG) design methodology to the satellite rendezvous control design problem and validate it.


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