RU2561496C1 - Radar station for facilitating safe helicopter landing in conditions without or with limited visibility - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: radar station comprises an antenna device, a circular rotation drive with a rotating waveguide adapter, a transceiving device, an information processing unit and a radioparent radome, wherein the antenna device consists of a rotating horn-type antenna deviating from the vertical by a fixed angle and having a counterweight which, with small antenna dimensions, enables to form a narrow antenna beam pattern in the 3 mm wavelength range, and a fixed antenna directed vertically downwards, which operates as an additional channel for data on the environment, connected to a single transceiver through a waveguide switch.

EFFECT: facilitating safe helicopter landing in difficult weather conditions, as well as in conditions with zero or limited visibility, while simultaneously reducing the size and weight of the radar station.

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Description

The invention relates to the field of radar, in particular to radar stations operating in the three-millimeter wavelength range, and can be used to ensure a safe landing of the helicopter in the absence or limited visibility.

It is known (description of patent RU 2497175 C1 “Flight visualization system and cognitive flight indicator of a single-rotor helicopter”, published October 27, 2013, IPC G06F 3/00, B64D 45/00) that currently a number of leading world developers of aviation equipment are actively working to create systems to increase the situational awareness of helicopter pilots in the absence or limited visibility. In particular, the aerospace company Honeywell International has developed a new technology called the Enhanced Flight Visual System / Synthetic Vision System (EFVS / SVS) - an enhanced instrumented cabin visibility / synthesized vision system for the underlying surface. The SVS system provides the crew with a database and graphical 3D visualization of aircraft routes, showing on the indicator in a schematic form the surface of the earth over which the aircraft is flying and possible obstacles on it.

The new EFVS system works with infrared sensors and receives real earth mapping data, superimposing them on SVS data. Together, two data sets allow the crew to observe the terrain in the take-off and landing area of the helicopter.

Information is displayed on Honeywell aerobatic displays (IPED), which are LCD screens mounted on the dashboard in the cockpit.

The main disadvantages of this technology are its dependence on the information received from the satellite navigation system, as well as the limited capabilities of the RF sensor when operating in difficult weather conditions (SMU) and in the conditions of snow (dust) shroud formed during helicopter landing.

Known US patent No. 7642929 B1 (publ. 05.01.2010, IPC G01C 23/00), which discloses a crew information support system for helicopter landing. It owes its origin to military operations in Iraq, Saudi Arabia and Afghanistan. During landing, the helicopter raised a cloud of dust and sand up to 100 feet high so that the landing area was hidden from view. In accordance with the claims, the helicopter is equipped with cameras (for example, an infrared camera) and other sensors that detect the presence of obstacles on the site to prevent collision with them when landing before a dust cloud forms. Signals from the sensors enter the computer's memory. There is also an inertial navigation system (ANN) that processes the output signals of the helicopter control system. Data is displayed on a conventional cathode tube screen, or on indicators on the windshield, or on helmet-mounted indicators.

The main drawback of this system is that information is obtained before landing and during the reduction process, the true location of the objects stored in memory may differ by the value of the ANN accumulated error.

Also known are helicopter radars intended for the survey of the earth and water surface (description of patent RU 2289825 C2 "Radar station for circular viewing for a helicopter", published on December 20, 2006, IPC G01S 13/90):

- AN / APS-94 radar (USA) on the ЕН-60B helicopter of the SOT AS system for detecting ground and air objects in the 180 ° sector;

- Radar "Seyspray 2000", "Searchwater" (UK) for the early detection of surface and airborne objects, respectively, in the 360 ° sector.

Due to the functioning in the X-wavelength range, the common drawbacks of these radars are the significant mass dimensions and low detection efficiency of small objects against reflections from the underlying surface, which makes it impossible to use them for helicopter landing in conditions of limited or no visibility.

Closest to the claimed radar is the radar "Octopus-E" (Russia) for the detection of marine objects in the 360 ° sector, selected as a prototype, 0.95 × 0.45 m in size with circular rotation (description of patent RU 2206903 C2 "Radar station for a helicopter ”, publ. 06/20/2003, IPC G01S 13/00). A magnetron transmitter is used to generate electromagnetic energy. The radar is incoherent, microwave pulses with a given duration and repetition frequency are fed to the location antenna and radiated into space. The echoes reflected from the objects enter the antenna and then, sequentially, to the receiving device, processing device and indicator.

The disadvantage of the prototype is the poor angular resolution of the antenna, operating in the 3-cm range, the reason for which is the limited size of the antenna aperture, which can be realized when placing the antenna in the limited dimensions of the fuselage of the helicopter. This does not allow the use of the indicated radar for landing a helicopter.

The objective of the invention is the creation of a radar with new functions in terms of providing the possibility of landing a helicopter, while reducing weight and size for ease of placement on helicopters of various types.

The solution to this problem is achieved by ensuring the functioning of the radar in the 3 mm wavelength range and its design.

The technical result is to ensure the safe landing of a helicopter in adverse weather conditions, as well as in the complete absence or limited visibility, while reducing the overall dimensions of the radar.

Ensuring safe landing is understood as eliminating the collision of a helicopter (landing gear, tail boom or main rotor, etc.) with ground-based obstacles (for example, masts, structures, vans, barrels, power lines, large stones, shrubs, trees, large animals, people) when take-off and landing of the helicopter day and night, in difficult weather conditions (fog, haze, rain, snow, dustiness or smoke of the atmosphere), as well as in conditions of dust or snow raised from the ground by its rotary propeller.

At the same time, the determination of the slope of the landing site is provided to avoid exceeding the allowable limit for a particular type of helicopter.

The technical result is achieved in that in a circular radar station for a helicopter containing an antenna device, a circular rotation drive with a rotating waveguide transition, a transceiver device, an information processing unit and a radiotransparent fairing, the antenna device consists of a horn antenna rotatable deflected by a fixed angle from the vertical type with aerodynamic counterweight, which allows for a small antenna size to form a narrow antenna pattern (BOTTOM) in 3 mm diameter a range of wavelengths, and a stationary antenna directed vertically downward, which acts as an additional channel of environmental data connected to a single transceiver through a waveguide switch.

The basic principle of radar operation is to provide a constant view of the earth's surface in the form of a ring under a helicopter by the radiation of a rotating antenna (horn type) with a narrowing of the field of view when the helicopter is lowered or widens upon take-off. At the same time, the height above the landing site is constantly monitored by radiation through a fixed antenna to the landing point or with confirmation of the absence (presence) of obstacles in it.

Switching the emitted / received EHF signal to each specific antenna from the transceiver device is carried out by means of a waveguide-switching path, which alternately with a high frequency connects to the transceiver a rotating or fixed horn antenna through a waveguide switch.

The main advantage of the 3 mm range radar is the possibility of forming a narrow antenna radiation pattern (BOTTOM) and, accordingly, a highly selective overview of the terrestrial situation with insignificant mass and size characteristics of a radar containing small-sized horn antennas.

The essence of the proposed technical solution is illustrated by drawings, graphic materials and drawings:

FIG. 1 - design radar;

FIG. 2 - helicopter landing algorithm;

FIG. 3 is a top view of the inspected area when landing a helicopter on an inclined platform.

The radar circular view is structurally made in the form of a monoblock (Fig. 1), placed in the lower part of the fuselage of the helicopter. The radar contains an antenna device consisting of a horn type 1 antenna rotating around a vertical axis and tilted at a fixed angle from the vertical, and the stationary antenna 2 moving vertically downward. Mobile antenna 1, with low weight and size characteristics, allows forming a narrow antenna radiation pattern (BOTTOM) of 3 mm wavelength range. Fixed antenna 2 acts as an additional channel of data about the environment - the distance to the earth's surface and the presence of dangerous objects. To increase the assigned radar resource, the rotating antenna 1 is connected to a mass-aerodynamic counterweight 3. The radar includes a circular rotation drive 4 with a rotating waveguide transition, a transceiver 5 and an information processing unit 6. Mobile antenna 1 and a stationary antenna 2 through a waveguide switch 7 the waveguide junction connected to a single transceiver device 5. The operation of the radar station provides the power module 8. All radar elements are placed on a single fixed base, for rytom top cover 9, and the bottom - radome 10.

The radar operates as follows.

After switching on, the information processing unit 6 generates a radar operation diagram, commands for turning on the circular rotation drive 4 and the transceiver 5. The circular rotation drive 4 rotates the antenna 1 at a constant angular speed. After turning on the transceiver 5, the information processing unit 6 generates control signals to the transceiver 5, which determine the pulse repetition rate, pulse duration, code sequence by controlling the phase of the signal inside the pulse. The transceiver 5 generates an EHF pulse corresponding to the control signals. The EHF pulse through the waveguide switch 7 through the waveguide path and the rotating transition is transmitted to the rotating horn antenna 1 and is radiated into space. An EHF pulse reflected from a ground object or background element of the earth’s surface enters the antenna 1 and is transmitted through a rotating junction, a waveguide path and a waveguide switch 7 to the input of the receiver (located in the transceiver 5). In the transceiver 5, the reflected EHF pulse is detected and transmitted in analog form to the information processing unit 6, where analog-to-digital conversion, coherent “compression” in range, coherent accumulation, adaptive threshold processing are performed. From the obtained matrix "azimuth-range-speed-level of the reflected signal", an image in the established format is formed on the indicator containing either the X-ray image of the space being inspected, or the X-ray image of the space being inspected together with the generated pictograms of dangerous objects. The image on the indicator is formed taking into account the accumulation of information from several consecutive surveys (rotations of the rotating antenna 1 by 360 °) and is constantly recalculated into the associated coordinate system of the aircraft as it moves spatially.

When operating through a fixed horn antenna type 2, the radar operates in the same way as described above, only the EHF pulse comes from the transceiver 5 through the waveguide switch 7 and the corresponding waveguide path to the stationary antenna 2. The reflected EHF pulse enters the stationary antenna 2 and is transmitted through the waveguide path and a waveguide switch 7 to the input of the receiver (located in the transceiver 5). In the transceiver 5, the reflected EHF pulse is detected and transmitted in analog form to the information processing unit 6, where analog-to-digital conversion, coherent “compression” in range, coherent accumulation, adaptive threshold processing are performed. From the obtained matrix “range-speed-level of the reflected signal” a “height line” is formed in the associated coordinate system of the aircraft, after processing the “height line” the distance to the earth's surface (normal to the horizontal plane of the aircraft) and a signal about the presence dangerous object, if an object with a length of several resolution elements is detected in the "height line".

The received and processed radar information about the environment is reflected on the multifunction indicator (MFI) in the cockpit with the highlighting of the most dangerous objects approaching the helicopter that may collide.

Helicopter landing is as follows.

1. In the case of landing with a preliminary approach to the runway (runway) according to visual landmarks, a preliminary approach to the landing site is made by the pilot in the normal mode according to visual landmarks at altitudes of more than 30 m. After selecting the landing site, the runway hangs and decreases vertically ( helicopter landing without using the influence of an air cushion) (Fig. 2). The control of the reduction process is carried out, inter alia, by including and tracking information from the radar, issued in the form of an image of the inspected surface of the earth with dangerous objects on it (buildings, masts, wires, cars, people, etc.) and their distances from the helicopter. In this case, the central part will be absent in the radar field of view (its size at an antenna tilt angle α = 30 ° and at a height of ~ 35 m can be up to 200 m in diameter). In this case, the diameter of the outer boundary of the surface being inspected will be 340 ... 350 m. With a further decrease in the helicopter, the area under inspection will decrease, however, at the IFI its dimensions may remain the same (including with objects detected and stored in the system memory). In this case, the unobserved “blind” zone will decrease, at a height of 17 m it will be ~ 100 m in diameter, and at a height of 5 m it will be ~ 30 m, respectively. All new objects that fall into the radar inspection zone when reduced will also be displayed on the MFI. In the event of unintentional drift of the helicopter due to loss of visual visibility in dusty (snowy) conditions, it is proposed, along with information displayed to the pilot on the IFI, to provide a quad-stereo sound signaling about objects that pose the greatest danger under such drift conditions, with a change in tone (discontinuity) of the signal as approximations to the object (s). When approaching the surface of the earth, including according to altitude readings from the radar, the required vertical speed and landing are reached.

2. In the case of landing in conditions of limited or lack of visibility - adverse weather conditions (fog, rain, snow, etc.), it is not possible to make a visual approach to the runway (or to a site selected from the air). In this regard, the search for the landing site is carried out according to information from the inertial navigation system (ANN) and the proposed radar. In this case, after reaching the calculated runway location point, according to the navigation system, it is reduced to a height of ~ 30 m (or another safe altitude), the radar is turned on, and the radar survey of the earth's surface occurs. The helicopter moves horizontally without decreasing, the inspection area, respectively, is a moving ring with an external radius of more than 300 m. Detected objects are stored in the system’s memory and displayed on the multi-function indicator even if they fall into the unobserved central zone (~ 200 m in diameter), taking into account the movement helicopter relative to the ground and other objects, that is, the inspection area is a strip with a width of 300 ... 600 m (depending on the flight altitude). With this algorithm of actions, it seems possible to search and detect the runway, or landing site, free from hazardous objects. Next, hovering and landing according to information from the radar is performed similarly to the previous algorithm.

In the case of the existing slope of the site relative to the horizon, the examined area will be an oval with a shift to the side from the calculated landing point (Fig. 3), which, at a known angle of the helicopter from the vertical (according to data from the ANN), will make a decision about the possibility of further landing according operational limitations.

It should be noted that the radar capabilities allow not only to detect objects with the necessary accuracy and resolution characteristics, but also to inform the crew of an unintentional drift of information about movement relative to objects and the background, as well as the speed of such movement. In addition, the crew is constantly informed of the flight altitude according to data from an antenna that is constantly directed downward (in this case, acting as a radio altimeter).

Claims (1)

A rotary radar station for a helicopter comprising an antenna device, a circular rotation drive with a rotating waveguide transition, a transceiver device, an information processing unit, a radiolucent radome, characterized in that the antenna device consists of a horn-type antenna with a counterweight rotating from a vertical angle from the vertical, allowing for small antenna dimensions to form a narrow antenna pattern (BOTTOM) in the 3 mm wavelength range, and a directional vertical down on fixed antennas, acting as an additional channel of the environment data that are connected to a single transceiver through a waveguide switch.

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