Practical results of a coherent optical free space transmission experiment through the atmosphere, including a PAT subsystem and its relevance for future space applications

Abstract This paper presents a new algorithm to navigate robots in dynamically cluttered environments. The proposed algorithm uses basic concepts of space attraction (hence the term Agoraphilic) to navigate robots through dynamic obstacles. The new algorithm in this paper is an advanced development of the original Agoraphilic navigation algorithm that was only able to navigate robots in static environments. The Agoraphilic algorithm does not look for obstacles (problems) to avoid but rather for a free space (solutions) to follow. Therefore, it is also described as an optimistic navigation algorithm. This algorithm uses only one attractive force created by the available free space. The free-space concept allows the Agoraphilic algorithm to overcome inherited challenges of general navigation algorithms. However, the original Agoraphilic algorithm has the limitation in navigating robots only in static, not in dynamic environments. The presented algorithm was developed to address this limitation of the original Agoraphilic algorithm. The new algorithm uses a developed object tracking module to identify the time-varying free spaces by tracking moving obstacles. The capacity of the algorithm was further strengthened by the new prediction module. Future space prediction allowed the algorithm to make decisions considering future growing/diminishing free spaces. This paper also includes a bench-marking study of the new algorithm compared with a recently published APF-based algorithm under a similar operating environment. Furthermore, the algorithm was validated based on experimental tests and simulation tests.

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Low-Noise InGaAs/InP Single-Photon Avalanche Diodes for Fiber-Based and Free-Space Applications

IEEE Journal of Selected Topics in Quantum Electronics ◽

10.1109/jstqe.2021.3104962 ◽

2021 ◽

pp. 1-1

Author(s):

Fabio Signorelli ◽

Fabio Telesca ◽

Enrico Conca ◽

Adriano Della Frera ◽

Alessandro Ruggeri ◽

...

Keyword(s):

Free Space ◽

Single Photon ◽

Low Noise ◽

Space Applications ◽

Avalanche Diodes ◽

Single Photon Avalanche Diodes

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Record-sensitivity Gb/s receiver for free-space applications based on phase-sensitive amplification

Conference on Lasers and Electro-Optics ◽

10.1364/cleo_at.2019.jth5b.1 ◽

2019 ◽

Cited By ~ 2

Author(s):

Ravikiran Kakarla ◽

Jochen Schröder ◽

Peter A. Andrekson

Keyword(s):

Free Space ◽

Space Applications ◽

Phase Sensitive ◽

Phase Sensitive Amplification

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Membrane Modular Structures With Inflatable Tubes and Connective Cables for Future Space Applications

Volume 2: Multifunctional Materials; Enabling Technologies and Integrated System Design; Structural Health Monitoring/NDE; Bio-Inspired Smart Materials and Structures ◽

10.1115/smasis2009-1480 ◽

2009 ◽

Author(s):

Nobuhisa Katsumata ◽

Ryoko Fujii ◽

M. C. Natori ◽

Hiroshi Yamakawa

Keyword(s):

Conceptual Models ◽

Space Structure ◽

Modular Structure ◽

Membrane Structures ◽

Large Space ◽

Space Applications ◽

Cable Networks ◽

Large Space Structure ◽

Future Space ◽

Modular Structures

Spirally folded hexagonal membrane structures with inflatable tubes and connective cable networks are presented aiming to establish possible construction scenarios of future large space structure systems over hundreds meters scale and corresponding structures based on the hierarchical modular structure concept using deployable membrane modules. Laboratory scale hand-made conceptual models are manufactured, and their deployment experiments are carried out to show their applicability to the hierarchical modular structures systems.

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Analysis and Test of a Proton Exchange Membrane Fuel Cell Oxidant System

10.1115/imece2000-1323 ◽

2000 ◽

Author(s):

Arturo Vasquez ◽

Donald E. Varanauski ◽

Robert W. Clark

Keyword(s):

Fuel Cell ◽

Proton Exchange Membrane ◽

Cell System ◽

Proton Exchange ◽

Published Data ◽

Space Applications ◽

Future Space ◽

Water Separator ◽

Component Models ◽

Exchange Membrane

Abstract An effort is underway to develop a Proton Exchange Membrane (PEM) Fuel Cell system for future space applications. A breadboard system has been constructed and includes the following: reactant pressure regulators, ejector-based reactant pumps, a 4-kW fuel cell stack, and a passive, membrane-based oxygen / water separator. A computer model is being developed concurrently to analytically predict fluid flow in the oxidant reactant system. Preliminary data obtained from tests performed with the breadboard system, as well as other published data, has been used to validate the analytical component models. These components have been incorporated into an integrated oxidant fluid system model. Results obtained from both the performance tests and the analytical model are presented.

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