Frigate Tests


The main purpose of the testing was to check the fuze’s immunity against the electronic emissions of the different weapon systems and emitters on board the frigate. Pursuant to this objective, 12 shots were fired over the sea (one from the F-104 “Méndez Nuñez”, and eleven from the F-103 “Blas de Lezo” frigates) in which different emissions with all parameters were being incorporated gradually, so that during the last shots all emitters were activated at maximum power and their antennas pointing the projectile trajectory. Some important aspects to point out were:

·    Success of the testing is achieved if the fuze activates itself after a full trajectory illuminated by the frigate’s emitters. Explosion over the sea shows that the proximity fuze worked properly, enduring the dense electronic disturbance.

·    If the projectile does not explode or explodes by impact with the sea, is not possible to get any conclusion about the immunity of the fuze, because it may not have activated itself or the pyrotechnic train may have failed. Not exploding by impact on the sea denotes a failure on the pyrotechnic train. Explosion by contact with the sea denotes a failure in the proximity fuze or in the battery.

  • Premature explosion would denote undue activation of the fuze due to the disturbance of the external radioelectrical sources.

 ·   Checkout of behavior over the sea was done from the frigate using the IR camera of the Fire Direction System DORNA and from an observer ship about 3000 yards from the impact point, using optical devices and a FLIR camera. This professor had access to the DORNA camera and was able to ascertain that it was possible to determine with reliability the “explosion type”, but not with much precision on its altitude over the sea. As a reminder, the fuze radiates frontally, therefore a explosion a few meters over the sea is to be expected.

·    Total flight time was about 23 seconds, which means that all the emitters illuminated the fuze for a long time. Not always the SPY-1D radar was able to define the track on the projectile (shift to tracking mode on this target) but this does not invalidate the testing because on volumetric exploration and horizon exploration modes, this radar illuminates many times the fuze with similar signals, particularly because the surveillance sector was pointed to the flight zone.

·    Testing was performed, surprisingly pleasing this professor, with great efficiency and accuracy. Shots were fired without interruptions and at a very high rate. The frigate’s crew controlled all the aspects of the operation at all times, ensuring the reliability of the conclusions.

Finally, it is worth to mention that the following are the handwritten notes and impressions of an external observer with a limited knowledge of the frigate’s systems, and the weapons operations. Therefore there may have mistakes on the interpretation of these aspects.

The testing has allowed us to verify the effectiveness of the new fuze design, which includes specific circuits to avoid disturbing effects by interfering signals and electronic countermeasures, thus ensuring immunity to radioelectrical systems incorporated on the ships.