Demonstration of High-Rate Laser Communications From a Fast Airborne Platform

Abstract

In this paper, we report on the demonstration of a high-rate free-space optical communication downlink from a fast airborne platform to a ground station. The flight platform used was a Panavia Tornado with a laser communication terminal installed in an attached avionic demonstrator pod. A transportable optical ground station equipped with a free-space receiver frontend was used as the receiver station. Downlink wavelength for communication and uplink wavelength for beacon laser were chosen to be compatible with the C-band DWDM grid. New opto-mechanical tracking systems were developed and applied on both sides for link acquisition and stabilization. The flight tests were carried out at the end of November 2013 near the Airbus Defence & Space location in Manching, Germany. The campaign successfully demonstrated the maturity and readiness of laser communication for aircraft downlinks at a data rate of 1.25 Gbit/s. We outline the experiment design based on link budget assessments, the developed opto-mechanical terminal technology, and the results of the flight campaign. The experiment itself focused on the tracking performance of the airborne terminal and the ground station. Performance could be measured at aircraft speeds up to Mach 0.7 and video data from an onboard camera was transmitted. Tracking accuracies of up to 20 µrad rms for the airborne terminal and the ground station were achieved at instantaneous tracking errors below 60 µrad and 40 µrad, respectively. The tracking link worked up to a horizontal distance of 79 km and data transmission was possible up to 50 km.

Preparing for Satellite Laser Uplinks and Downlinks

“…Demonstrations on Fast-Moving Platforms Not to belittle the work done in orbit, but very little of the above experimentations examined the impacts of terminals moving at greater speeds (low-Earth orbit at 7 km per second versus geosynchronous orbit at 3 km per second) or being affected by in-atmosphere turbulence; this is changing. The German Aerospace Center (Deutsches Zentrum fur Luft-und Raumfahrt, i.e., DLR) is conducting experiments using their optical space infrared downlink system, a small laser communications terminal orbiting in low-Earth orbit, demonstrating the requirements for high-precision alignment between stations [49,50]. Additionally, in 2013, DLR went on to successfully demonstrate laser communications from a jet aircraft.…”

Aerospace laser communications technology as enabler for worldwide quantum key distribution

“…The Transportable Optical Ground Station (Figure 6, right) has a higher degree of integration and is therefore meant for semi-operational use and technology demonstrations, e.g. for satellite-and aircraft-ground communications [19], [28][29][30].…”

“…The feasibility of air-GEO links was demonstrated within the LOLA project [17]. Direct optical air to ground links were demonstrated for data download from airborne sensors in the former DLR projects Argos [18] and DODfast [19]. Free-space optical links are also considered for aeronautical networks by exploiting multiple air to air FSO and radio frequency links as investigated in [20].…”

RF-Assisted Free-Space Optics for 5G Vehicle-to-Vehicle Communications

“…Furthermore, the extremely high directivity of laser sources allows to establish dense networks of high-capacity, high-security links with minimized mutual interference and eavesdropping. As such, FSO is emerging as an attractive candidate to interconnect fixed base stations by point-to-point links in next-generation cellular networks, as well as dynamic devices such as drones [7], vehicles [8] and airplanes [9].…”