RU2565158C1 - Aircraft radar signature minimising method - Google Patents

Abstract

FIELD: aviation.

SUBSTANCE: method of decrease of the aircraft radar signature consists in placement of a homing head antenna in a tight cavity of a radiotransparent fairing, filling of the cavity with plasma-forming gas mix with the pressure 1-100 kPa and injection of the beam of electrons into the plasma-forming gas mix with formation of absorbing plasma volume. The aircraft flies at the height with ambient pressure less than the size of pressure of gas mix in the fairing cavity. During the flight an additional supply of plasma-forming gas mix into the fairing cavity is provided in view of degree of its tightness.

EFFECT: reduction of necessary degree of tightness of the front fairing at the same radar cross section.

2 cl, 1 dwg

Description

The invention relates to aircraft (LA), to their devices for absorbing waves emitted by the antenna.

Known, adopted as a prototype, a method for reducing the radar visibility of an object equipped with at least one antenna, RU patent No. 2469447, which consists in the fact that a sealed radio-transparent cavity is installed in the antenna location area, the cavity is filled with a gas mixture, a beam is introduced into the gas mixture electrons, control the composition of the gas mixture, the electron energy and the beam current so that they form an absorbing plasma volume and / or reflecting plasma volume, the profile of which provides a smaller radar the visibility of the plasma volume than the radar visibility of the antenna. A sealed radiolucent cavity is installed in front of the antenna. The antenna is placed directly inside the sealed radiolucent cavity. For a number of reasons, it is preferable to use an absorbing plasma with a high collision frequency. Among the reasons include, in particular, protection from promising systems of multi-position location. To ensure absorption, the plasma formation must have an electron concentration below the critical and a high collision frequency (comparable to the frequency of the probing signal), which is realized in medium and high pressure gases (1-100 kPa). In the case of a decrease in the visibility of the aircraft’s onboard antennas, a nose fairing or other compartment used to place the antenna can be used as such a cavity.

The essential features of the proposed method, which coincide with the features of the prototype, are as follows: a method of reducing the radar visibility of an aircraft, which consists in placing the homing antenna in a sealed cavity of a radiolucent fairing, filling the cavity with a plasma-forming gas mixture with a pressure of 1-100 kPa, and introducing an electron beam into the plasma-forming gas mixture with the formation of an absorbing plasma volume.

The implementation of the known method significantly reduces the effective dispersion surface (EPR, radar visibility, the main contribution of which is made by the antenna) of the aircraft during the passage of the irradiation zone by means of an air defense (air defense) location. However, the plasma formation and the efficiency of absorption of radio waves by the generated plasma depends on the parameters of the gas mixture (pressure and ratio of components), both during storage and during long-term flight. For the stability of the parameters of the gas mixture and a significant reduction in the EPR, a high degree of tightness of the radome antenna is required, which increases the complexity and cost of the aircraft, and reduces its reliability. During storage of the aircraft, it is necessary to control the parameters of the gas mixture in the cavity of the fairing and, if necessary, restore them, which increases the complexity of maintenance and the cost of operating the aircraft.

The technical result, the solution of which the invention is directed, is to reduce the required degree of tightness of the radome antenna, the complexity and cost of manufacturing and operating the aircraft while maintaining an effective reduction of its EPR.

To solve the problem in a method of reducing the radar visibility of an aircraft, which consists in placing the homing antenna in an airtight cavity of a radio-transparent fairing, filling the cavity with a plasma-forming gas mixture with a pressure of 1-100 kPa and introducing an electron beam into the plasma-forming gas mixture with the formation of an absorbing plasma volume, flight of an aircraft the apparatus is carried out at a height with environmental pressure less than the pressure of the gas mixture in the cavity of the fairing and in p Flight otsesse provide additional supply of the plasma-forming gas mixture into the shroud cavity with the degree of tightness. To reduce the variation in performance before introducing the electron beam into the gas mixture, the cavity of the cowling is surrounded by a plasma-forming gas mixture.

Distinctive features of the proposed method is that the flight of the aircraft is carried out at an altitude with environmental pressure less than the pressure of the gas mixture in the cavity of the fairing and during the flight provide additional supply of plasma-forming gas mixture into the cavity of the fairing, taking into account the degree of tightness; before introducing the electron beam into the gas mixture, purge the cavity of the fairing with a plasma-forming gas mixture.

Due to the presence of these distinctive features, together with the known ones, the following technical result is achieved: the required degree of tightness of the aircraft antenna cowl and the cost of its manufacture, the complexity of maintenance and the cost of operating the aircraft are reduced, the stability of the technical characteristics of the aircraft and the reliability of its intended use are increased.

The proposed technical solutions can find application in the development of, mainly, unmanned aerial vehicles that provide increased reliability of the intended use, while reducing the cost of funds and time for the manufacture and operation of the aircraft.

The method is illustrated in the drawing, which shows an unmanned aerial vehicle (UAV) implements it. Presented on the drawing, the UAV contains a housing 1 with a sealed radio-transparent front fairing 2, and a control system 3 located in the housing 1, equipped with a homing head 4 with a radar antenna 5 located in the cavity 6 of the front fairing 2, as well as a high voltage starting power source 7 a device 8 and two pairs of electrodes 9, 10 and 11, 12, mounted in front of the radar antenna 5 in the cavity 6 of the front fairing 2, which at the same time contains a line 13 for supplying a plasma-forming mixture of gases in it cavity 6 and line 14 for discharging a mixture of gases from cavity 6, which are equipped with shut-off devices 15 and 16, respectively. The shut-off device 15 can be made in the form of a plug, plug, valve, controlled valve, with a manual or electrically controlled drive. The housing 1 is equipped with an autonomous source 17 of a plasma-forming gas mixture, connected by a line 18 with a cavity 6 of the front cowl 2 through a gas flow limiting device made in the form of a pressure reducer 19 and a starting device 20 connected to the control system 3 of the electric communication line 21. The gas flow limiting device can also be made in the form of a throttle, throttle package, or a system of chokes with their switching valves. Alternatively, the source 17 is made in the form of a high-pressure cylinder and is equipped with a charging device 22. There are other possible versions of the source 17, for example, chemical, thermochemical, desorption. The device 16 overlap in line 14 of the discharge of the mixture of gases from the cavity 6 of the front fairing 2 is made reusable, electrically controlled and connected to the control system 3 of the line 23 of the electrical connection.

Presented on the drawing, the device operates as follows. After manufacturing the UAV, the source of the plasma-forming gas mixture (not shown) is docked to the overlap device 15 and is used to ensure the flow rate of the mixture. The devices 15 and 16 of the overlap are opened, while the plasma-forming mixture of gases through the device 15 through line 13 enters the cavity 6 of the front fairing 2, and the air that is located after manufacturing the front fairing 2 in its cavity 6 is displaced through the line 14 into the environment. After replacing the air in the cavity 6 with a plasma-forming gas mixture, the devices 15 and 16 of the overlap are closed and the UAV is stored until use. When a UAV is flying in front of the UAV entering the irradiation zone with anti-aircraft defense means, the control system 3 on the electric communication lines 21 and 23 opens the shutdown devices 16 and 20, while the plasma-forming gas mixture from the source 17 passes through the pressure reducer 19 through the pressure reducer 19 to the cavity 6, restoring in it, the parameters of the plasma-forming gas mixture, violated due to gas leaks and air entering the cavity, due to leakage of the fairing 2 during storage of the UAV. The stabilization of the parameters of the plasma-forming gas mixture in the cavity 6, after starting the plasma formation, ensures the stabilization of the degree of absorption and reflection by the plasma of the radio waves and the degree of reduction of the radar visibility of the antenna 5 and the UAV as a whole. Excess gas mixtures (including those with deviated parameters) are discharged via line 14 into the environment, which further helps to stabilize the parameters of the gas mixture in the cavity 6. Then, the control system 3 through the electric communication line 23 closes the device 16 at the residual pressure of the gas mixture in the cavity 6, exceeding the ambient pressure, in the range of 1-100 kPa, which ensures the formation of absorbing radio waves of the plasma volume in the cavity 6 between the electrodes 9, 10 and 11, 12 in front of the antenna 5, after which the system 3 is controlled Ia activates the starting device 8 of the high voltage source 7, for the initial breakdown of the gas mixture gap between the electrodes 9, 10 and 11, 12 and the start of the plasma volume in the cavity 6 in front of the antenna 5. The presence of a second pair of electrodes 11, 12 reduces the threshold electric voltage of the source 7 and contributes to an increase in the volume of plasma formation and its stability in the cavity 6 of the front fairing 2 in front of the antenna 5. After starting, the source 7 maintains the plasma volume at low electric values current and voltage (lower electrical power). The presence of gas mixture flow from an autonomous source 17 through line 18 to cavity 6 of cowl 2 during plasma formation allows one to reduce the required degree of tightness of cowl 2. The pressure reducer 19 is selected from the condition of compensation for leakage of gas mixture from cavity 6 of cowl 2 with a reduced degree of tightness. The implementation of the device for limiting the gas flow in line 18 in the form of a pressure reducer 19 allows to reduce the pressure spread of the plasma-forming gas mixture in the cavity 6 of the fairing 2 and thereby reduce the spread of the absorption and reflection of radio waves by the plasma and the degree of decrease in the radar visibility of the antenna 5 and the UAV as a whole. At the moment the homing head is turned on, the control system 3 ensures that the high voltage supply is disconnected from the source 7 to the electrodes 9, 10 and 11, 12 and the plasma volume between them in front of the antenna 5 goes out, which ensures the effective operation of the antenna 5 of the homing head 4 for the efficient performance of the UAV flight mission . The reduced degree of tightness of the fairing 2 simplifies its design and the design of its docking with the housing 1, thereby reducing the cost of manufacturing UAVs. The receipt of the gas mixture from the source 17 through line 18 into the cavity 6 compensates for possible leakages of the gas mixture and ensures a decrease in the spread of the parameters of the gas mixture in it and, accordingly, the spread of the degree of absorption of radio waves by the plasma volume between the electrodes 9, 10 and 11, 12 and the minimum degree of absorption are reduced radio waves (maximum EPR), which increases the reliability of the UAV passing the air defense coverage area and completing the flight mission.

Claims (2)

1. A method of reducing the radar visibility of an aircraft, which consists in placing the antenna of the homing head in an airtight cavity of a radio-transparent fairing, filling the cavity with a plasma-forming gas mixture with a pressure of 1-100 kPa and introducing an electron beam into the plasma-forming gas mixture with the formation of an absorbing plasma volume, characterized in that the flight the aircraft is carried out at a height with environmental pressure less than the pressure of the gas mixture in the cavity of the fairing and in the process field These provide an additional supply of plasma-forming gas mixture into the cavity of the fairing, taking into account the degree of its tightness. 2. The method according to p. 1, characterized in that before the introduction of the electron beam into the gas mixture, the cavity of the cowling is surrounded by a plasma-forming gas mixture.