WFIRST low order wavefront sensing and control (LOWFS/C) performance on line-of-sight disturbances from multiple reaction wheels

Abstract:On-line intelligent monitoring, diagnosis, and control of dynamic systems such as patients in intensive care units necessitates the context-dependent acquisition, processing, analysis, and interpretation of large amounts of possibly noisy and incomplete data. The dynamic nature of the process also requires a continuous evaluation and adaptation of the monitoring strategy to respond to changes both in the monitored patient and in the monitoring equipment. Moreover, real-time constraints may imply data losses, the importance of which has to be minimized. This paper presents a computer architecture designed to accomplish these tasks. Its main components are a model and a data abstraction module. The model provides the system with a monitoring context related to the patient status. The data abstraction module relies on that information to adapt the monitoring strategy and provide the model with the necessary information. This paper focuses on the data abstraction module and its interaction with the model.

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On-Line Identification, Model Structure Reduction, and Control Using NARX Models

1992 American Control Conference ◽

10.23919/acc.1992.4792345 ◽

1992 ◽

Author(s):

Thomas Proll ◽

M. Nazmul Karim

Keyword(s):

Model Structure ◽

Line Identification ◽

On Line ◽

Narx Models ◽

And Control ◽

Identification Model

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Performance of 4G-LTE Communication and Navigation System in Blended Wing-Body UAS

International Journal of Recent Technology and Engineering - 2 ◽

10.35940/ijrte.d9910.118419 ◽

2019 ◽

Vol 8 (4) ◽

pp. 9538-9542

Keyword(s):

Satellite Communication ◽

Line Of Sight ◽

Multiple Factors ◽

The World ◽

New Type ◽

Blended Wing Body ◽

4G Lte ◽

The Right ◽

And Control ◽

Technology Demonstrator

In vision of searching for the right Unmanned Aerial System (UAS) for a specific mission, there are multiple factors to be considered by the operator such as mission, endurance, type of payload and range of the telemetry and control. This research is focusing on extending control range of the UAS by using 4G-LTE network to enable beyond-line-of-sight flying for the commercial UAS. Major UAS such Global Hawk, Predator MQ-1 are able to fly thousands of kilometers by the use of satellite communication. However, the satellite communication annual license subscription can be very expensive. With this situation in mind, a new type of flight controller with 4G-LTE communication has been developed and tested. Throughout the research, blended-wing-body (BWB) Baseline B2S is used as the platform for technology demonstrator. Result from this analysis has proven that the proposed system is capable to control a UAS from as far as United Kingdom, with a latency less than 881 ms in average. The new added capability can potentially give the commercial UAS community a new horizon to be able to control their UAS from anywhere around the world with the availability of 4G-LTE connection

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A Tip–Tilt and Piston Detection Approach for Segmented Telescopes

Photonics ◽

10.3390/photonics8010003 ◽

2020 ◽

Vol 8 (1) ◽

pp. 3

Author(s):

Shun Qin ◽

Wai Kin Chan

Keyword(s):

Error Detection ◽

Phase Retrieval ◽

Dynamic Range ◽

Detection Accuracy ◽

Wavefront Sensing ◽

Next Generation ◽

Large Aperture ◽

Detection Approach ◽

Segmented Mirror ◽

And Control

Accurate segmented mirror wavefront sensing and control is essential for next-generation large aperture telescope system design. In this paper, a direct tip–tilt and piston error detection technique based on model-based phase retrieval with multiple defocused images is proposed for segmented mirror wavefront sensing. In our technique, the tip–tilt and piston error are represented by a basis consisting of three basic plane functions with respect to the x, y, and z axis so that they can be parameterized by the coefficients of these bases; the coefficients then are solved by a non-linear optimization method with the defocus multi-images. Simulation results show that the proposed technique is capable of measuring high dynamic range wavefront error reaching 7λ, while resulting in high detection accuracy. The algorithm is demonstrated as robust to noise by introducing phase parameterization. In comparison, the proposed tip–tilt and piston error detection approach is much easier to implement than many existing methods, which usually introduce extra sensors and devices, as it is a technique based on multiple images. These characteristics make it promising for the application of wavefront sensing and control in next-generation large aperture telescopes.

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