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Gilching, Germany

Griethe W.,G2Aerospace GmbH | Knapek M.,Vialight Communications GmbH | Horwath J.,Vialight Communications GmbH
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

Remotely Piloted Aircrafts (RPA's) and especially Medium Altitude Long Endurance (MALE) and High Altitude Long Endurance (HALE) are currently operated over long distances, often across several continents. This is only made possible by maintaining Beyond Line Of Side (BLOS) radio links between ground control stations and unmanned vehicles via geostationary (GEO) satellites. The radio links are usually operated in the Ku-frequency band and used for both, vehicle command & control (C2) - it also refers to Command and Non-Payload Communication (CNPC) - as well as transmission of intelligence data - the associated communication stream also refers to Payload Link (PL). Even though this scheme of communication is common practice today, various other issues are raised thereby. The paper shows that the current existing problems can be solved by using the latest technologies combined with altered intuitive communication strategies. In this context laser communication is discussed as a promising technology for airborne applications. It is clearly seen that for tactical reasons, as for instance RPA cooperative flying, Air-to-Air communications (A2A) is more advantageous than GEO satellite communications (SatCom). Hence, together with in-flight test results the paper presents a design for a lightweight airborne laser terminal, suitable for use onboard manned or unmanned airborne nodes. The advantages of LaserCom in combination with Intelligence, Surveillance and Reconnaissance (ISR) technologies particularly for Persistent Wide Area Surveillance (PWAS) are highlighted. Technical challenges for flying LaserCom terminals aboard RPA's are outlined. The paper leads to the conclusion that by combining both, LaserCom and ISR, a new quality for an overall system arises which is more than just the sum of two separate key technologies. © 2015 SPIE. Source


Moll F.,German Aerospace Center | Mitzkus W.,Airbus | Horwath J.,Vialight Communications GmbH | Shrestha A.,German Aerospace Center | And 4 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2014

Some current and future airborne payloads like high resolution cameras and radar systems need high channel capacity to transmit their data from air to ground in near real-time. Especially in reconnaissance and surveillance missions, it is important to downlink huge amount of data in very short contact times to a ground station during a flyby. Aeronautical laser communications can supply the necessary high data-rates for this purpose. Within the project DODfast (Demonstration of Optical Data link fast) a laser link from a fast flying platform was demonstrated. The flight platform was a Panavia Tornado with the laser communication terminal installed in an attached avionic demonstrator pod. The air interface was a small glass dome protecting the beam steering assembly. All other elements were integrated in a small box inside the Pod's fuselage. The receiver station was DLR's Transportable Optical Ground Station equipped with a free-space receiver front-end. Downlink wavelength for communication and uplink wavelength for beacon laser were chosen from the optical C-band DWDM grid. The test flights were carried out at the end of November 2013 near the Airbus Defence and Space location in Manching, Germany. The campaign successfully demonstrated the maturity and readiness of laser communication with a data-rate of 1.25 Gbit/s for aircraft downlinks. Pointing, acquisition and tracking performance of the airborne terminal and the ground station could be measured at aircraft speed up to 0.7 Mach and video data from an onboard camera has been transmitted. Link distances with stable tracking were up to 79 km and distance with data transmission over 50 km. In this paper, we describe the system architecture, the flight campaign and the results. © 2014 SPIE. Source


Moll F.,German Aerospace Center | Horwath J.,Vialight Communications GmbH | Shrestha A.,German Aerospace Center | Brechtelsbauer M.,German Aerospace Center | And 4 more authors.
IEEE Journal on Selected Areas in Communications | Year: 2015

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 front end 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 optomechanical 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 optomechanical 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 accuracy of up to 20 μrad rms for the airborne terminal and the ground station were achieved at instantaneous tracking errors below 60 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. © 2015 IEEE. Source

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