RU2392191C1 - Early radar detection airplane - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: early radar detection airplane has two wings arranged at airframe top part. Sweep-forward front wing is arranged at airframe nose section. Normal-sweep rear wing is arranged at airframe rear section that allows lateral antennas to occupy larger part of airframe side surfaces.

EFFECT: longer range, higher accuracy of detection and noise immunity, reduction in carrier plane weight.

3 cl, 6 dwg

Description

The device relates to the field of radar, and in particular to the design of the aircraft, which allows to improve the placement of antennas.

The most common design of early warning radar aircraft (AWACS) is the scheme with the antenna in the "mushroom" above the fuselage. Such an aircraft, E3 of the AWACS system, is depicted in Figure 1 [Military aircraft. Book 1, Minsk: Potpourri, 1999].

The disadvantages of this scheme are:

- “mushroom” affects the aerodynamics of the aircraft;

- the area of the antenna placed in the "mushroom" is insufficient to detect targets at ranges corresponding to the range of the radio horizon;

- the tail keel obscures the sector in the rear hemisphere and does not allow to obtain a circular view;

- the antenna and the “mushroom” rotate mechanically, which increases the mass of equipment, reducing the duration of the patrol.

The prototype of the proposed device is a newer aircraft DRLO with radar PHALCON [Military aircraft. Book 1. Minsk: Potpourri, 1999, p. 505], which has an antenna in the form of several rectangular active phased array antennas (PAR). Depending on the project, such headlights can be from 3 to 6. The placement of the side radar antennas shown in the form of rectangles is shown in Figure 2. The disadvantage of this scheme is that the same Boeing-707 aircraft was used as the carrier, as at AWACS. As a result:

- the location of the wing in the middle of the fuselage does not allow you to place the antenna along the entire side of the carrier, i.e. the antenna has approximately the same area as the AWACS radar antenna;

- due to the presence of a wing in the middle of the hull and engines located on the wing, the front side antenna can only scan with a beam in the front hemisphere and a small part of the rear hemisphere (all angles mentioned in this application are counted in the coordinate system associated with the aircraft body) . When the beam approaches the wing and the engines, the beam is distorted, and the radar becomes impossible. As a result, to review the rest of the rear hemisphere, a second antenna is installed behind the wing, which increases the mass of the radar;

- the roundness of the shape of the fuselage does not allow placing the antenna of the required height on it. As a result, the beam width in the vertical plane is ≈8 °. When targets are detected at ranges of 500-700 km, the beam size in height is equal to 60-100 km. Given that the altitude of the targets does not exceed, as a rule, 12-15 km, we find that most of the energy in the beam is emitted in vain, since it irradiates a space in which there are no targets. As a result, the detection range of a typical target is reduced to ≈300 km.

The aim of the invention is to increase the detection range and reduce the mass of the aircraft.

This goal is achieved by the fact that instead of a civilian carrier, a specialized one is used, the shape of which allows you to place antennas, the area of which is as close as possible to the area of the corresponding surface of the fuselage. To do this, the side surfaces of the fuselage are made flat, and the wing is divided into two, and one of the wings is installed in the front upper, and the second in the rear upper part of the fuselage. So that the front wing does not obscure the sector of view of the side antenna, it has the opposite sweep.

The maximization of the area of the side antenna was made by occupying almost the entire side surface of the fuselage. In this case, the extreme parts of the antennas are under the wings, which allows them to be used only when scanning the lower hemisphere, when scanning the upper hemisphere they are turned off.

In Fig.1 shows a General view of the aircraft AWACS, Fig.2 - PHALCON aircraft, Fig.3 - top, side and front views of the proposed aircraft, where:

1 - fuselage

2 - front wing

3 - rear wing

4 - left side antenna

5 - front antenna

6 - right side antenna

7 - rear antenna

8 - keel

9 - engines.

Figure 4 shows the functional block diagram of the radar, where

4 - left side antenna

5 - front antenna

6 - right side antenna

7 - rear antenna

10 - antenna beam control unit

11 - receiving and forming unit

12 - switches.

The proposed aircraft consists of a fuselage 1 and two wings 2 and 3 (Figure 3). Wing 2 is installed in the bow, and wing 3 in the rear of the aircraft. The front wing has a reverse sweep, and the rear has a normal sweep. The wings are deflected upward from the fuselage by an angle exceeding the antenna beam width in elevation.

Four antennas are installed in the fuselage - two side 4 and 6, front 5 and rear 7. There are keel 8 and engines 9 on the fuselage.

Each side antenna has a rectangular shape and is divided along the fuselage into three parts: the two extreme ones are under the wings, and the middle part is in the fuselage-free part of the wings. Each of the parts is an independent active PAR. HEADLIGHTS consist of transceiver modules that operate on either reception or transmission. The block diagram of the connection of the HEADLIGHT to the remaining blocks of the radar is shown in Figure 4.

All three parts of the side headlights have a single beam control system 10 and a receiving-forming unit. 11, to which the middle parts are connected directly, and the extreme parts through the switch 12.

The lateral surfaces of the fuselage are inclined at an angle of 5 ° ÷ 10 ° from the vertical (Figure 3, front view), which provides an improved overview of the lower hemisphere, in which most of the detected targets are located. The front edge of the front wing and the rear edge of the rear wing are deflected from the construction axis of the fuselage by an angle of 45 ° ÷ 60 ° (Figure 3, top view), which provides circular scanning when using all four antennas.

In order that when installing the beam at an elevation angle of 0 °, it would be possible to use all three parts of the side antenna, the wings are deviated from the horizontal upward by an angle exceeding the beam width of the radar antenna in elevation (Figure 3, front view).

The best technical and economic characteristics are obtained with unmanned aircraft. Operators control the flight and operation of the radar via a communication line from a ground command post. Information is transmitted to the receiver of the command post by the radar antenna in the coverage area of which the command post is located. For this, the control unit 10 allocates a special time interval in the sequence diagram of the radar. This method of transmitting information provides high noise immunity due to the directivity of the antennas and high power transmitters.

During radar operation, all 4 antennas operate independently. Each antenna scans the azimuthal sector ± (45-60) °, which provides a circular view. Due to the curvature of the earth, the most distant aerial targets are in the lower hemisphere. When flying along the borders, the most important is the inspection of the side sector, therefore, for example, consider the operation of the side antenna. Each of the three parts of the antenna is an independent active PAR. The input signals received by each transceiver module of the headlamp are summed inside each headlamp and from the output of each headlamp are fed to 3 separate inputs of the receiving-forming unit 11. This block is a typical multi-channel receiver. In addition, in block 11 is the shaper of the emitted signal. The emitted signal is fed from the output of block 11 to the inputs of all three HEADLIGHTS of the side antenna. Commands to turn on the headlamp and control the beam come from the output of unit 10. When scanning, the rays of all three headlamps move in parallel, and a single beam is formed in space that is identical to the beam of an unshared side antenna. Upon receipt, the signals of the three headlamps are summed up inside block 11, forming a similar total beam.

During the scan of the lower hemisphere, the switches 12 open and the extreme headlights cease to work, and the beam forms only the middle headlight. Thus, the beam of this part of the side headlamp passes by the wing, not touching it and not distorting.

The detection range of the target when the extreme headlights are turned off decreases. The decrease is considered acceptable, since in the upper hemisphere due to the curvature of the earth targets appear at shorter ranges than in the lower.

The front and rear headlights work similarly to the middle part of the side headlights, that is, without switching.

The Boeing - 707 PHALCON aircraft with a mass of 150-160 tons has a side antenna with an area of ≈10 m ² . The length of the aircraft is 42 m, the average diameter of the fuselage is 3.5 m, the crew is 15 people.

Assume that to obtain a qualitatively new ranges of detection required to have an antenna side area of 40 m ^2, such as 2.5 · 16 m. Then the proposed fuselage of the aircraft will have a length of 20-21 m and a height of 3-3.5 m, width 2-2 , 5 m. Given the absence of need for an unmanned aircraft to seal the cockpit, the mass of the aircraft can be estimated at 50 tons. At the indicated height of the aircraft, the antenna height will be at least 2.5 m, and the beam in the vertical plane will narrow in 1.5-1 6 times. As a result, with the same radiated power, the detection range will increase 1.6 times. Increasing the size of the antenna allows you to reduce the beam width and the level of the side lobes, which increases the noise immunity of the radar.

In combat conditions, AWACS aircraft fly under the protection of fighters. Increasing the detection range and unmanned execution allows the proposed aircraft to abandon protection, which further significantly reduces operating costs.

The production and operation of an unmanned aircraft weighing 50 tons should cost 3-5 times cheaper than for the prototype. Such indicators will allow to organize its mass production, which will pay back the development costs.

Industrial feasibility is ensured by the fact that the aircraft is manufactured using the same technologies as the prototype, with a change in shape only. A wing with reverse sweep has been known for a long time and is used, for example, in the Su-37 aircraft. The possibility of installing two wings in series is also confirmed by the shape of the Su-37, where the large tail can be considered as a second wing. The reduced cruising speed of the aircraft makes it easier, in comparison with the prototype, to solve aerodynamic problems.

Claims (3)

1. An aircraft of early warning, consisting of a fuselage, wings and a radar with active phased antenna arrays, characterized in that two wings are installed in the upper part of the fuselage, one of which has a reverse sweep in the front of the fuselage and the second in the rear of the fuselage has a normal sweep. 2. The aircraft according to claim 1, characterized in that, the wings are deflected upward by an angle exceeding the width of the antenna beam. 3. The aircraft according to claim 2, characterized in that the side antennas are divided into three parts so that the extreme parts are under the wings, and the middle part is in the fuselage-free part of the wings, the middle part being connected directly to the receiving-forming unit, and extreme - through the switches switched by the antenna beam control unit.

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