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Messenger SSR System

Description of the radar set, tactical-technical characteristics

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Figure 1: The S-1095 antenna on a marconi-tower

frequency: 1030 / 1090 MHz
pulse repetition time (PRT):
pulse repetition frequency (PRF):
pulsewidth (τ):
receive time:
dead time:
peak power: up to 2 kW
average power:
instrumented range:
range resolution:
hits per scan:
antenna rotation:

The S 1095 antenna is a large vertikal aperture antenna of open planar array construction. The antenna can either in be used on its own turning gear and tower, or co-mounted with a primary radar antenna and has a gain of 29 dB.

The S 2101 interrogator-responser used in the Messenger- system, is a single rack mounted unit which includes the offboresight azimuth measurement system. The interrogator section uses solid state devices throughout, including the output stages. The latter are modular in format, each module having a peak power of 500 W. Up to 4 modules may be used in an interrogator, the choice depending upon the required range performance and the length of coaxial cable between the antenna and the interrogator.

The decoder-extractor S 7204 used in Messenger is a hybrid hardware/firmware design whitch not only cannot be overloaded but also provides considerable functional flexibility by use of the bit-slice processing technique. The hardware element provides the basic real-time decoder, the firmware dealing with more complex corrupted replies.

The Messenger has been designed to be easily updated to the full Mode-S system and to fulfil ICAO and STANAG 5017 requirements.