CZE - 1L22-1/IFF Parol (identifikační systém - modernizace)

1L22-1/IFF Parol
Upgraded 1L22-1/IFF radar

Already during the first considerations of the Czech Republic's accession to NATO, it was obvious that one of the main tasks the Czech army would have to deal with would be to ensure the compatibility of airborne target recognition systems. In the former Czechoslovakia, as in all Warsaw Pact states, the NRZ Kremnij system, different from the IFF-NATO system and incompatible with ICAO standards, was used for this purpose.

In 1994, ELDIS installed the AN/TPX-54 interrogator into an existing radar and, in cooperation with Hazeltine, Allied Signals and Aviation Service, organised the first operational demonstration of the IFF MODE 4 system for representatives of the Czech Ministry of Defence.

At the same time, the MoD developed a project to build a NATO-compatible IFF system using existing Russian-made 1L22-1 radars designed to work in the NRZ Kremnij system. Due to the proven ability of ELDIS to successfully solve such problems, the task of reconstructing the IL22-1 radar was entrusted to ELDIS. In 1998, a complete upgrade of three Soviet 1L22-1 systems was carried out. The result is secondary surveillance radars fully compliant with ICAO standards and IFF systems compatible with NATO standards.

The radar reconstruction consisted of a complete replacement of all control electronics and an upgrade of the antenna system. The result is a radar equipped with an AN/TPX-54(V) interrogator, operating unmanned, with remote control and the ability to synchronize transmission and antenna rotation with the attached primary radar.

The original 1L22-1 radar interrogator was designed for an impedance of 75 and two frequency bands of approximately 670 MHz and 1400 MHz. The purpose of the RF refurbishment was to adapt the most expensive original parts, i.e. the antenna system and rotary coupler, to an impedance of 50 and ICAO frequencies of 1030/1090 MHz.

The reconstructed SSR antenna system forms two standard beams SUM (main) and CON (control). The CON beam is a combination of the DIF, OMNI and BACK beams. The purpose of the CON beam is to overlap the side lobes of the SUM beam.

Only the mirror from the original antenna system has been used, which with the new primary radiator forms the SUM and DIF beams.

The SUM beam has a narrow fan shape with an azimuth width of 4.6° and a shaped characteristic in elevation. The DIF beam has a sharp minimum in the 0° direction, which is also the maximum of the SUM beam. In the vertical plane, the beam has a similar shape to the SUM beam. The purpose of the DIF beam is to increase azimuth accuracy and to contribute to the suppression of side lobes.

The suppression beam (OMNI) is formed by a separate omnidirectional antenna with two vertical rows of dipoles placed on the side of the main antenna mirror. The return beam (BACK) is formed by a dipole with a small reflector placed on the back of the mirror. Its function is to suppress the queries due to the influence of the side lobes of the SUM beam in the back direction.

The correct amplitude and phase ratios on the individual elements of the antenna system are ensured by a set of dividers, made by strip-line technology and connected by coaxial cables. The manufacturing technology used guarantees high resistance to outdoor environment.

The original five-channel rotary coupler with an impedance of 75 & Omega; was designed for Kremnij system frequencies. The modified rotary coupler has three channels with an impedance of 50 & Omega; and is tuned to the frequency band 1.0 to 1.1 GHz.

The reconstructed 1L22-1 radar has successfully passed military trials and has been deployed into operational service with the 26th Command, Control and Reconnaissance Brigade.

1) ELDIS s.r.o.
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1L22/IFF in the company of altimeter PRV-17 equipment of 26. the brigade's command, control and survey..
CZE - 1L22-1/IFF Parol (identifikační systém - modernizace) - (26. brigáda velení, řízení a průzkumu  -

(26. brigáda velení, řízení a průzkumu -
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