Synthesis of the vector spline guidance laws for a land-survey satellite at scanning observation and rotational maneuvers

A new design method for trajectory shaping guidance laws with the impact angle constraint is proposed in this study. The basic idea is that the multiplier introduced to combine the equations for the terminal constraints is used to shape a flight trajectory as desired. To this end, the general form of impact angle control guidance (IACG) is first derived as a function of an arbitrary constraint-combining multiplier using the optimal control. We reveal that the constraint-combining multiplier satisfying the kinematics can be expressed as a function of state variables. From this result, the constraint-combining multiplier to achieve a desired trajectory can be obtained. Accordingly, when the desired trajectory is designed to satisfy the terminal constraints, the proposed method directly can provide a closed form of IACG laws that can achieve the desired trajectory. The potential significance of the proposed result is that various trajectory shaping IACG laws that can cope with various guidance goals can be readily determined compared to existing approaches. In this study, several examples are shown to validate the proposed method. The results also indicate that previous IACG laws belong to the subset of the proposed result. Finally, the characteristics of the proposed guidance laws are analyzed through numerical simulations.

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Administrative Legacy and the River Mura Border Dispute between Slovenia and Croatia

Südosteuropa ◽

10.1515/soeu-2019-0027 ◽

2019 ◽

Vol 67 (3) ◽

pp. 369-392

Author(s):

Marko Zajc

Keyword(s):

Environmental History ◽

Political History ◽

Border Dispute ◽

History Of ◽

Land Survey ◽

Natural Dynamics

Abstract Set at the intersection between political history and environmental history, this article shows the significance of administrative legacy and natural dynamics of rivers in the landscape for creating (and solving) border disputes. In 2006, Slovenia and Croatia engaged in such a dispute regarding the exact course of the border near the River Mura in the vicinity of the villages of Hotiza (Slovenia) and Sv. Martin na Muri (Croatia). After giving an overview of the Slovenian-Croatian border disputes between 1992 and 2019, the author analyses the border dispute around the River Mura. He then shows how the history of the river’s regulations, of the Habsburg and Yugoslav land survey activities, as well as of the previous border disputes on the river are entangled in the current dispute.

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Design of finite-time guidance law based on observer and head-pursuit theory

Proceedings of the Institution of Mechanical Engineers Part G Journal of Aerospace Engineering ◽

10.1177/0954410020984562 ◽

2021 ◽

pp. 095441002098456

Author(s):

Chenqi Zhu

Keyword(s):

Finite Time ◽

Three Dimensional ◽

Hypersonic Vehicle ◽

Two Dimensional ◽

Dimensional Model ◽

Reaching Law ◽

Guidance Law ◽

Fast Power ◽

Simulation Results ◽

Guidance Laws

In order to improve the guiding accuracy in intercepting the hypersonic vehicle, this article presents a finite-time guidance law based on the observer and head-pursuit theory. First, based on a two-dimensional model between the interceptor and target, this study applies the fast power reaching law to head-pursuit guidance law so that it can alleviate the chattering phenomenon and ensure the convergence speed. Second, target maneuvers are considered as system disturbances, and the head-pursuit guidance law based on an observer is proposed. Furthermore, this method is extended to a three-dimensional case. Finally, comparative simulation results further verify the superiority of the guidance laws designed in this article.

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Order Upon the Land: The U.S. Rectangular Land Survey and the Upper Mississippi Country

The American Historical Review ◽

10.2307/1850150 ◽

1977 ◽

Vol 82 (2) ◽

pp. 451

Author(s):

Thomas G. Manning ◽

Hildegard Binder Johnson

Keyword(s):

Land Survey ◽

The U.S

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