A further stage of development of OSIRIS towards higher data rates is OSIRISv3. The terminal now has its own alignment unit with which the data rate can be increased up to 10 Gbit/s.
To increase the data rate well above 1 Gbit/s, the transmission divergence had to be further reduced compared to v2 in order to avoid significantly higher transmission powers. For this purpose, OSIRISv3 no longer relies on the position control of the satellite for beam orientation, but on a dedicated alignment unit instead. This so-called Coarse Pointing Assembly (CPA) enables a hemispheric movement and thus decouples the laser beam from the satellite position. This offers enormous advantages for the operation with other payloads, such as cameras for earth observation, which are also swiveled when the satellite is aligned. In addition, OSIRISv3 has its own on-board computer, which temporarily stores the user data in a large mass storage with several terabytes and encodes it for transmission to the ground. The communication with OSIRISv3 is also protected with an optical uplink and suitable protocols.
OSIRISv3 - Model for serial production at Tesat
The v3 model of the OSIRIS family was developed together with Tesat Spacecom and is to become part of the Tesat product portfolio under the name TOSIRIS.
In its third generation, the OSIRIS laser communication terminal of the DLR Institute of Communications and Navigation has been expanded to include a beam alignment unit that enables a precise alignment of the transmission beam with the ground station and thus reduces the divergence of the transmission beam. This makes it possible to reach a data rate of up to 10 Gbit/s in the downlink of LEO satellites.
