Abstract: A field unit for warning of a danger of collision between an aircraft and an obstacle, in particular a topographical ground obstacle or an obstacle formed by a mast, building or aerial cable structure, comprises a multi-part tubular mast having devices for fixing a solar panel and a radar antenna; an elongate radar antenna in an environment-protective casing, which, with an electronics unit, forms a radar system for synthesized radar detection of an aircraft in a radar coverage area; a central processing unit for identifying on the basis of information from the radar system an aircraft which is in a zone of the radar coverage area and which on the basis of radar information such as direction, distance and/or speed computes a collision danger area; and a high-intensity light system and radio transmitter system that can be activated by the central processing unit upon detection of an aircraft in a collision danger area.

Abstract: A Raman amplifier includes a Raman gain fiber comprising a length of high-dispersion gain fiber and operable to receive at least one optical signal. The Raman amplifier also includes at least one pump source capable of generating at least one pump signal that co-propagates within the Raman gain fiber with at least a portion of the at least one optical signal received by the Raman gain fiber. The length of the high-dispersion gain fiber is at least ten (10) times a walk off length between the at least one pump signal and at least one wavelength of the at least one optical signal received by the Raman gain fiber. In addition, the length of high-dispersion gain fiber is at least two (2) times a walk off length between at least two optical signal wavelengths of the at least one optical signal received by the Raman gain fiber.

Abstract: A radar detector (10) includes a first period detector (76, 122), a second period detector (96, 120) and a third period detector (86, 124) within a multi-period periodicity validator 38. The first period detector (76, 122) detects radar pulses exhibiting one-half of an expected pulse period (48), the second period detector (96, 120) detects radar pulses exhibiting the expected pulse period (48), and the third period detector (86, 124) detects radar pulses exhibiting twice the expected pulse period (48). A plurality of pulse-train records (40) can simultaneously track a plurality of possible pulse trains. A control element (84, 136, 138) accounts for missing pulses and corrects the expected pulse period when missing pulses have caused the expected pulse period to be inaccurate.

Abstract: The disclosed method uses the ancillary antennas of a radar, and consists in determining the positions of the phase centers of these ancillary antennas, compensating for the difference in optical path between the reflection lobe of the processed channel and that of the ancillary channel, and generating a synthetic channel by an SLO type processing in performing a coherent subtraction between the processed channel and the ancillary channels used, on the desensitized zone of the doppler distance/frequency ambiguous domain of each of the processed channels.