Abstract
Increasing data bandwidth requirements from spacecraft systems is beginning to pressure existing microwave communications systems. Free-Space optical communications allows for larger bandwidths for lower relative power consumption, smaller size and weight when compared to the microwave equivalent. However optical communication does have a formidable challenge that needs to be overcome before the advantages of the technology can be fully utilized. In order for the communication to be successful the transmitter and receiver terminals need to be pointed with a high accuracy (generally in the order of ≤10 μradians) for the duration of communication. In this paper we present a new concept for the precise pointing of optical communications terminals (termed the Precise Pointing Mechanism). In this new concept we combine the separate pointing mechanisms of a conventional optical terminal into a single mechanism, reducing the complexity and cost of the optical bench. This is achieved by electromagnetically actuating the whole telescope assembly in 6 degrees-of-freedom with an angular resolution of less than ±3 μradians within a 10 (Az. El.) field of view and linear resolution of ±2 μm. This paper presents the new pointing mechanism and discusses the modelling, simulation and experimental work undertaken using the bespoke engineering model developed.
Highlights
Communication is an ever growing and advancing field that is driven by many factors
In this paper we present a new concept for the precise pointing of optical communications terminals
Using the Precise Pointing Mechanism (PPM) as the actuation mechanism for optical terminals, it is envisaged that the field of view of the PPM would require that the telescope assembly element be mounted on each spacecraft and Pre-set (As shown in Figure 1) to point in the direction of the spacecraft to allow communications with the target satellite
Summary
Communication is an ever growing and advancing field that is driven by many factors. As space borne instrumentation and data gathering/processing systems advance, an inherent increase in the data rate and bandwidth of the communications system follows. In the ISLFE terminal the FPA consists of a single mirror that is connected to Lorentz force actuators that manipulate it using capacitive sensors to control the angular position [4] Another major requirement of the pointing system is to overcome spacecraft disturbances and maintain the optical link for the duration of communication. An engineering model that can completely magnetically levitate and actuate a 60 mm telescope antenna in all 6 degrees of freedom has been developed and used to demonstrate the use of magnetic levitation to provide two pointing resolutions (±10 mRadians and ±3 μRadians) for application to an optical communications scenario This mechanism is developed to be an enabling technology for use in terrestrial and free-space optical communications, or applications where active anti-vibration and precise pointing would be advantageous. This paper discusses an example application of the engineering model developed, gives an overview of the control strategy used and presents some results to demonstrate the resolution of the terminal
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
