One
of the greatest problems facing a successful deployment of an
unmanned vehicle is associated with the reliability and survivability
of the communication system for video, telemetry and command transmission.
Legacy communication systems for UV's, which relied on analog
transmission techniques, are limited by Line-of-Sight (LOS), thus
eliminating the possibility of transmitter or receiver to be located
behind obstacles, buildings or in urban terrains. Furthermore,
the use of the analog video transmission is sensitive in terms
of its encryption/scrambling capabilities, allowing an unauthorized
receiver to decode the transmitted information.
Lightlink datalink communication system, developed by RAFAEL,
is optimized to deliver robust performance in areas saturated
with interference, clutter and multipath, such as in or over an
urban area, forest or jungle. The Lightlink datalink supports
the transmission of multiple video sensors over a single RF frequency,
and operates in Non-Line-of-Sight (NLOS) environments. The system
is designed to co-exist with simultaneous links which operate
in the same coverage area. This is achieved via appropriate allocation
of time and frequency resources among the multiple links via the
C4I network. In addition, the scheme includes certain anti-jam
resistance mechanisms that offer robust performance in the presence
of hostile electromagnetic interference sources.
Lightlink exploits advanced digital video compression and transmission
/ reception techniques to overcome the clutter and obstacles,
transferring video and command data reliably, at compressed, low
latency, high rate, high quality video - a critical capability
for real-time weapons and reconnaissance applications.
The system uses Coded Orthogonal Frequency Multiplexing (COFDM)
modulation with multi-antenna technology which reduces the required
fade margin using spatial-temporal processing algorithms and is
well suited to support fast moving platforms. The system also
provides essential Interoperability between target acquisition
and weapon systems (sensor and shooters).
Designed to support lightweight, man portable and small, unmanned
systems, Lightlink is designed with small form-factor, is lightweight
and has low power consumption. The system has already been deployed
in combat during the 2nd Lebanon War, and is employed on RAFAEL's
multiple Aerial, Ground and Surface platforms.
The low-power (1 - 20 watt) system can be implemented in the
S, L band or UHF, using bandwidth of 6 - 8 MHz.