Design, implementation and demonstration of a laser beam steering system for free space optical communications
Project funded by Innovate UK. Hyperion started in February 2013 and is forecast to end in August 2015
A partnership between Airbus Group and the University of Oxford
Future UAVs, aircraft and satellites will require high speed data links to rapidly offload mission and system health monitoring data. Communication systems using laser offer a high speed, license-free alternative and are not vulnerable to interception or jamming.
Free Space Optical (FSO) communications systems use directed visible or invisible light from a laser to establish a data link. FSO communications systems are potentially capable of datarates up to Gbps and provide an attractive alternative to Radio Frequency (RF). Here, the challenge is about the range involved, the variable weather and atmopheric conditions, but also about keeping the laser light directed onto the target. The Hyperion project focuses on a method to steer a laser beam using a hologram for use in a free space optical communications system. In this project, a UAV to ground link is used. The project will create an eye safe optical data link from a UAV in flight to a ground station using low power retro reflective technology. The project has the potential to change the way we create our data links, and offers the precision tracking required to implement these free space links with aircraft on approach, mission data from UAVs and data from low earth orbit satellites; it could therefore allow safer travel, more efficient UAV operations and reduce the cost of space assets, as well as the creation of new services.
The Hyperion project started in February 2013 and is currently due to finish in August 2015. The main motivations behind the project are:
Increasing numbers of aircraft, UAVs and satellites occupying the sky
The RF spectrum is over allocated – high data rates cannot easily be achieved
Across sectors, higher and higher data transmission rates are required for communications and download of operational data
The use of light from lasers is currently unlicensed
1550nm light does not focus on the human retina – this wavelength can be used in an eye-safe manner
Laser pointing systems are heavy, power hungry and expensive – they are not suitable for small UAVs and small satellites (e.g. CubeSats)
Relatively high data rates have been achieved using a Modulated Retro Reflector (MRR), where the high power laser source and the bulky optics required for the communication link remain on the ground
MRRs are lightweight and low power devices able to modulate an incoming laser beam with data and reflect it back to its source. Aiming a laser beam at a such a device carried by a flying object, such as a UAV or a satellite, requires high precision pointing and tracking. Existing beam steering systems use fast steering mirrors that are fragile and could be damaged during a UAV mission or a satellite launch. The Hyperion project will deliver a fine pointing and tracking capability using a solid state device: A Spatial Light Modulator (SLM). This robust device will allow precise horizontal and vertical steering of a laser beam as well as control of the beam divergence or focus.
A communications link is demonstrated using a laser beam directed onto a UAV using the SLM. A MRR on the UAV modulates the laser light and sends it back to the ground station. The signal is detected and decoded into the transmitted data. Learn about individual aspects of the Hyperion system by clicking on the captions below.
MRRs based on liquid crystal (LC) technology and multiple quantum wells (MQW) technology will soon be tested outdoors at a range of 1.2km.
Our MRR based on Multiple Quantum Well (MQW) technology was recently tested in our labs and achieved a data rate of 40Mbps over a range of 5m.
The fine tracking system was tested at range of 1.2km and could potentially operate with a range of 3km+ depending on atmospheric conditions.
Click here to download our most recent high resolution movie
Click here to download our slightly older high resolution movie
If you have any questions about the project, do not hesitate to get in touch using our web form or by email.