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An active disturbance rejection guidance and control scheme for homing missiles with three-dimensional impact angle constraints is proposed. The six-degree-of-freedom dynamical and kinematical models containing model uncertainties and disturbances are established. A strict feedback relative dynamics between the target and homing missile in three-dimensional space are deduced. A reconstructed reduced-order attitude controller design model is proposed. A two-loop control structure with respect to the centroid guidance loop and rotational control loop is conducted to implement the six-degree-of-freedom guidance and control system with the help of second-order sliding mode approach and extended state observers. The tracking loop of the Euler angles of the missile can be elided and the number of six-degree-of-freedom control parameters can be reduced. Finally, the effectiveness and robustness of the newly proposed guidance and control scheme are investigated and verified via six-degree-of-freedom nonlinear simulation studies.

The observability problem of binocular vision measurement system in spacecraft relative navigation is studied in this paper. The Fisher information matrix of system estimation is derived and the method for observability analysis based on the rank analysis of Fisher information matrix is proposed. The interrelationships among the number and distribution of characteristic points, the rank of Fisher information matrix, and the system observability are studied. The conclusion is that at least 2 characteristic points are needed to insure the fully observation. At last, the observabilities of both monocular vision and binocular vision measurement system are compared according to differences of measurement equations under the same number of characteristic points. Simulation results of position and attitude determination for single picture confirm the conclusion obtained from the rank analysis of the Fisher information matrix. [ABSTRACT FROM AUTHOR]

Based on drag acceleration profile, a predictor-corrector guidance law which can guide longitudinal motion and lateral motion synergistically is proposed in this paper. The drag acceleration profile is designed through interpolating between upper drag boundary and lower drag boundary, and then corrected to eliminate the range error. The altitude error is eliminated by adjusting attack angle. The lateral error is eliminated by regulating the reversal time of bank angle. Comparing with the traditional methods, the proposed one can correct the 3-dimensional motion of the vehicle. Using interpolated drag acceleration profile, the flight constraints can be easily dealt with. Moreover, in a correction cycle, the method in this paper only needs twice trajectory predictions, which is favorable for on-board calculation. The simulation results indicate that the proposed guidance law has a high precision and robustness. [ABSTRACT FROM AUTHOR]

Two typical flight modes of hypersonic glide vehicles, equilibrium glide and skip glide, are researched in the paper. Firstly longitudinal kinematic models for hypersonic glide vehicle are established. Relative functions between velocity, height and fight path angle are deduced, and the changing laws of dynamic pressure, total load factor and heating rate with velocity are analyzed in the equilibrium glide mode. In addition, analytical equations between state parameters are presented under the condition of constant lift-drag-ratios. Numerical simulation method is applied to explain the effect of the initial parameters on the skip glide trajectory. The study can help improve the understanding and provide guidance for missions like trajectory prediction, planning and guidance. [ABSTRACT FROM AUTHOR]

Double Lunar-Swingby (DLS) trajeclories have received much attention due to its wide applications in the trajectory design of Multi-Mission and Multi-Purpose'. First, the DLS orbits are divided into two classes named Plane type and Backflip type according to their space configuration and characteristics. Then, the basic theory of swingby is shown based on two dynamics models of Zero-Sphere-of-Influence and CR3BP. Furthermore, both dynamics and modeling of Plane type DLS trajectory are discussed in two categories of application, and the principle and solution methods of Backflip type orbit is also summarized in detail. This study and survey about DLS trajectories could provide a new insight and reference for the interplanetary' mission of China. [ABSTRACT FROM AUTHOR]