RU49373U1 - LAP VARIABLE HELICOPTER RADAR STATION CIRCLE REVIEW - Google Patents

Abstract

The utility model relates to antenna systems and is used as part of a helicopter radar station. A useful model is the large-aperture blade antenna of a circular viewing helicopter radar station, mounted on the rotor blades, designed to determine the location of objects and ensure flight safety in conditions of limited visibility (at night and in bad weather). The blade antenna is made in the form of an active phased antenna array, and is a combination of modules (2) located on one of the rotor blades of the helicopter. The active modules are powered by a relatively low voltage, as a result of which the transmission of a powerful signal from the helicopter body to the main rotor is not required. The relative arrangement of the modules is selected from the condition of the formation of one main maximum of the radiation pattern. The dimensions of the blade allow you to form a large-aperture antenna with a high resolution, operating in the wavelength range of more than 5-7 cm to eliminate the effect of precipitation on the range of the radar station. A circular view of the space is ensured by rotation of the rotor. Phasing in the antenna is carried out by means of auxiliary radiation, which is formed by the primary irradiator (3) of the helicopter. With this phasing method, phase shifters are not used; the controlled phase in each module is installed almost instantly independently relative to the other modules of the antenna array, while the information contained in

auxiliary radiation. Moving the modules in space does not violate the directional properties of the antenna system.

Description

The utility model relates to antenna systems and is used as part of a helicopter radar to determine the location of targets and prevent collisions with objects.

Known blade active phased antenna array of a helicopter passive direction finder with auxiliary irradiator on the tail beam, designed to determine the direction of arrival of radio emission in the front hemisphere [1].

The prototype is a linear slot antenna array of a multifunctional radar station mounted on a UH-1 helicopter. The linear slot antenna array is located at the leading edge of the rotor blade, has a carrier frequency of 16.5 GHz and a pulse power of 30 kW, and is used in the mapping and selection of moving targets. This antenna is connected to the transmitter and receiver by a waveguide that passes through the hollow shaft of the rotor and a four-axis rotary joint mounted on the rotor hub [2].

The disadvantages of the system are: insufficient reliability and efficiency of the transmission line of high-frequency energy from the fuselage of the helicopter to the rotor, due to the relatively high power of the transmitted signal; a significant reduction in range when operating in adverse weather conditions, due to absorption of radio waves of the working range by gases and scattering by hydrometeors (fog, rain, snow) [3].

A useful model is the large-aperture active phased array antenna of a circular viewing helicopter radar station mounted on the rotor blades and designed to determine the location of objects and ensure flight safety in conditions of limited visibility (at night and in bad weather).

An active phased antenna array is a collection of modules placed on one of the rotor blades of a helicopter. The active modules are powered by a relatively low voltage, as a result of which the transmission of a powerful signal from the helicopter body to the main rotor is not required. The relative arrangement of the modules is selected from the condition of the formation of one main maximum of the radiation pattern. The dimensions of the blade allow the formation of a large-aperture antenna with high resolution, operating in the wavelength range of more than 5-7 cm to exclude the influence of precipitation on the range of the radar station [3]. Phasing in the antenna is carried out by means of auxiliary radiation, which is formed by the primary irradiator located on one of the rotor blades. With this phasing method, the controlled phase in each module is established almost instantly independently relative to other modules of the antenna array, while the information contained in the auxiliary radiation is used to ensure independent phasing of each emitter. As a result of this, there is no need to use controlled phase shifters and organize a computing process for calculating the coordinates of emitters and adjustable phases. With this phasing method, moving the modules in space due to the oscillatory movements of the blades does not lead to a violation of the directed properties of the antenna system [4]. A circular view of the space is ensured by rotation of the rotor.

Figure 1 presents the blade active phased antenna array of the helicopter radar station of the circular review.

The antenna system contains: blades 1; modules 2 located on the blade, each of which contains a signal transceiver antenna at the operating frequency, an antenna for receiving radiation from the primary irradiator, an amplitude detector, a beating filter, an amplifier, a frequency converter;

primary irradiator 3.

The system operates as follows. The primary irradiator 3 forms auxiliary radiation in space, which is the sum of two spherical electromagnetic waves with spaced centers of curvature. These electromagnetic waves have different but close frequencies. Auxiliary radiation is received by modules 2. In modules 2, using an amplitude detector and a filter, beats are selected whose frequency corresponds to the operating frequency of the radar station. The beats then go to the transmitting path as a master oscillation, and to the receiving path as a local oscillator signal. The master oscillation and the local oscillator signal contain phasing information. In the transmitting path, the master oscillation is amplified, modulated, and radiated into space. The heterodyne signal is mixed in the frequency converter with the received signal reflected from the target. A signal is generated at the output of the frequency converter at an intermediate frequency equal to twice the working frequency of the radar station. Then the signals at the intermediate frequency from the modules are fed to a common adder. A signal is generated in the adder that characterizes the irradiated object. Next is the standard processing of the received signal.

Literature:

1. Application No. 20010123239/09 (004309) dated 02.21.2000 (positive decision 03.17.2003).

2. Gribanov A.S. Radio-electronic surveillance equipment placed on helicopters - Foreign Radio Electronics, 1991, No. 12, p. 15-33.

3. Kalinin A.I., Cherenkova E.L. Radio wave propagation and radio link operation. - M.: Communication, 1971.

4. Bahrakh L.D., Stepanenko S.N., Povarenkin N.V. Methods of phasing non-rigid antenna arrays / Ed. A.A. Lavrova, - M .: VVIA named after Zhukovsky, Faculty of Aviation Radioelectronic Equipment, NMM, 1997, p.139-149.

Claims (1)

The rotary vane antenna of a rotary radar station of circular visibility, comprising modules, a primary irradiator, characterized in that it is made in the form of an active phased antenna array, the modules of which are located on the rotor blades; modules are supplied with a relatively weak signal; working wavelength exceeds 5-7 cm; each module contains a signal transceiver antenna at the operating frequency, an antenna for receiving radiation from the primary irradiator, an amplitude detector, a beating filter, an amplifier, a frequency converter; phasing of the modules is carried out by auxiliary radiation formed by the primary irradiator located on one of the rotor blades of the helicopter; All-round visibility is ensured by rotation of the rotor.