DE102007014878A1 - Method for all-around collision warning for helicopters - Google Patents

Abstract

The invention relates to a method for detecting all obstacles within the range of motion of a helicopter using radar and laser and / or ultrasound sensors assigned to the helicopter, the ranges of the sensors used being dependent on the movement space to be monitored and the installation locations the sensors are selected on the helicopter and the sensors predetermined, on the sample space related scanning movements are impressed and all received by reflections measuring signals of the sensors with their absolute positions according to individual ordered by Abtasträumen signal evaluation in each case with respect to distance and direction together, based on the position of the helicopter be supplied as a received reflection field of a common database for the purpose of fusion of all reflection fields and comparison with stored in the database patterns, by means of subsequent algorithmic evaluation Ges determined in the office situation of the movement space to be monitored and in the cockpit of the helicopter is displayed as an overall image, see. Fig. 4.

Description

The The invention relates to a method for all-around detection of obstacles inside the travel space of a helicopter using from, associated with the helicopter, active radar and / or laser sensors and / or infrared or ultrasonic sensors.

It is known with a scanning radar or laser beam from one Helicopters to detect obstacles and distances to the Ground with a radar altimeter to determine. Obstacle detection systems based on laser technology, are satisfactory in terms of recognizing small objects, in particular but strongly weather dependent in terms of their detection steps. Radar systems are reversed a great weather robustness, but low resolution out.

helicopter are the regular Risk of collision with objects on the ground, especially during takeoff, Landing and hovering suspended. This danger is exacerbated in desert areas by dust / sand turbulence = "Brown Out" or in snowy areas through Snow Whirling = "White Out "when through the turbulences the external view is very limited.

The known obstacle warning sensors on laser and radar base, in the Flying ahead in a limited field of view of typically about 30 ° · 40 ° objects along the trajectory, have a sensor range of about 1000 m in good visibility. Because they each have a sensor principle are either limited in terms of all-weather capability or the detection ability small objects, eg. B. thinner Wires from 5-10 mm on.

To A non-prior art proposal will become Detecting obstacles individual to different wavelengths for different Distances (short-range and long-range) working radar sensors assigned to predetermined Abtastsektoren the helicopter surrounded sphere and these are integrated into an overall system that provides complete coverage the relevant helicopter environment performs what with a single scanning radar beam not possible is. This makes the safety at take-off and landing difficult terrain under adverse visibility, the operational spectrum by warning of collisions during the Landing the helicopter in poor visibility and situational awareness the pilot increased in complicated maneuvers. These radar sensors work as Transmit and receive units and deliver their with an identifier provided signals to an identification and evaluation unit, which the display units installed in the cockpit, the so-called cockpit displays provided. This can be either directly or through an intermediary Symbol generator done.

aid Although such a radar-based warning system is a singular Obstacle detection also of power lines and mountain edges possible, however, it requires recognizing small objects, especially about existing overland power lines a vertical impact of the radar beams on this. this applies also for the lateral distance detection of larger stones, rocks, mountain edges and the like.

Of the Invention is based on the object, a new method for all-around collision warning under To use an active system for helicopters, which is suitable for all weather conditions and better than hitherto obstacles and terrain formations, especially overhead power lines and other obstacles as well as mountain edges and the pilot can show.

These The object is solved by the features of claim 1.

Further Features of the invention will become apparent from the dependent claims.

The Invention is based on the principle that the defined range of motion a helicopter free of reflections of the sensor signals of potential Objects to ensure collision freedom, d. H. So, so long not sent in a defined range of motion sensor signals reflected by objects, is the movement within this Movement space collision free. The range of motion of the helicopter defines resulting from the rotor diameter, the maximum length of the helicopter - blade leading edge main rotor to sheet edge tail rotor - and one about it beyond safety corridor.

The necessary sensor range is determined by the low translational speed of the helicopter of approx. 10-20 kts during takeoff / landing / hover and the necessary reaction times of Pilot (typically: 3 sec.) Helicopter (typically: 4 sec.) And evaluation unit (2 sec to the next detection) for safe detection (typically about 8 seconds for these components). By way of example, the detection range is determined for a horizontal speed of 10 kts. X detection = 5.14 m / s · (3 + 4 + 2) sec. = 46.26 m

This results in a rotor radius of z. B. 11 m and a selected safety distance of 10 m, a maximum required sensor range of: R Smax = R rotor + X safety + X detection = 11 m + 10 m + 46.26 m = 67.26 m

to Safe detection of such obstacles are inventively each two different types of sensors adapted to the range of motion used simultaneously, namely Radar and laser or radar and ultrasonic sensors or others Combinations of high resolution and all-weather Sensors whose measuring signals caused by reflections on obstacles are individual after scanning rooms ordered in terms of distance and direction together on the Position of the helicopter combined related to reflection fields and after determining the reflection density in the space of movement of the helicopter be merged into a database and after reconciliation with in the Database stored patterns by algorithmic evaluation as the overall situation of the monitored Movement space of the helicopter representing consolidated overall picture in the cockpit of the helicopter. Thereby can z. B. an approach warning or collision warning done on time.

The used radar, laser and ultrasonic sensors are small, reliable working components - like For example, from the distance warning of vehicle technology known - and allow a simple and flexible attachment to the helicopter structure.

are the sensors for execution the method according to the invention for example, constructed from a radar sensor and a laser sensor, detect these sensors due to their physical properties Objects different good. Laser sensors are capable of small size and thin Objects such. B. wires easier to detect than radar sensors. On the other hand, a radar has one size Ranging capabilities also under different atmospheric Conditions such as dust, rain, snow and fog.

Both Sensors send their signals according to the given measuring points out, so over the runtime the distance as well as the orientation of the sensor determines the direction of the received reflection in the respective sensor becomes. For Each sensor type is done according to his physical characteristics an individual signal evaluation of the received reflection field. Also done for each one Sensor type a pattern recognition, so that from the arrangement of the reflections as well as their distance to defined objects are closed can. The objects thus detected by the sensor pairs are in a database with its absolute positions. This results get a first overall picture the situation where both sensor types are the same or the same may have detected different objects. Another algorithmic Evaluation checks in the next Step based on the sensor-specific positioning accuracy and the object type, whether one and the same or different, possibly closely spaced objects. by virtue of The sensor properties described above can be such a radar and a Laser sensor the Identify the same high voltage pylons, using the algorithm even identified as a mast. The laser sensor is however additionally able to recognize even the associated lines, the one Radar sensor insufficiently reliably detected. As long as no Reflection patterns occur that are potentially hazardous Objects indicate that the room is classified as safe. This will be metallic Objects, larger stones and woods as endangering Looking at objects. Are the same or similar at a position range Reflections detected by both sensors, so evaluates the algorithm this as a hindrance. Are the reflections unstructured and in very low density, which is adjustable as a threshold, in Distributed observation room, this is considered as a collision-free space. With The evaluation algorithm is a uniform "overall picture" over the object situation is stored in the database and can then be stored in different form in the cockpit for display.

A second form of collision warning is based on the approach that the detected and verified by sensor data fusion be positively identified as obstacles and as forbidden waypoints be shown to the crew.

The Sensor data fusion according to the invention results for the first time a clear and clear presentation of the situation. Previous approaches only know the superimposed optical, pictorial representation of z. B. video and infrared image, with which an abstract fusion, which also does not use pictorial Allows sensors, not possible is.

The Invention is described below in conjunction with the drawings. In detail show:

1a . 1b the helical scanning sectors of the method for an all-around warning system according to the invention;

2 the safe movement space of an example helicopter according to 1 ;

3a . 3b the display of a cockpit display for the method according to the invention in strong abstraction for "acute danger of collision front"; and

4 a functional diagram of the all-around warning system according to the invention.

Since the components and groups required for carrying out the method according to the invention are known per se, their representation has been dispensed with. The paired sensors may be pivotable or, if sufficiently large antenna apparatuses are present, also fixed to the helicopter. They are - like that 1a and 1b - Front, rear and arranged on the sides of the helicopter and the scanning A, B, C, D, and E assigned. Each installation point so two different sensor types, namely radar and laser sensors or radar and ultrasonic sensors are assigned. Below the helicopter such sensor pairs are also arranged in a pivotable or fixed form. The coverage area of the sensors below the helicopter grips the leading edge of his fuselage and the outer tip of his tail boom; see. 1a ,

The measurement signals of the various sensors are related in terms of distance and direction together on the position of the helicopter by means of the evaluation of the database, not shown. Due to the common reference to a coordinate system, objects can be detected with the different sensors and the detected detections can be verified. If both sensor types each detect different objects, these objects are also detected as potential hazards. If the system is made up of a radar sensor and a laser sensor, these sensors detect objects differently due to their physical properties. The laser sensor is capable of small and thin objects, such. As wires, easier to detect than the radar sensor. By contrast, the radar sensor has a longer range, even under dust, rain and fog. The ranges are how 2 shows, selected around the helicopter and amount in the present embodiment, a maximum of 67.26 meters, of which 10 meters embody the required safety distance.

Both sensor types of each pair send out their measuring pulses, so that over the term of the distance and the orientation of the sensor, the direction of the received reflections in each sensor is determined by means of a Auswerteelektro electronics. From this, in each case a reflection field and the reflection density in the range of motion of the aircraft Lfz are derived and these data are fed to a database, cf. 5 ,

For each Sensor type is thus according to his physical characteristics an individual signal evaluation of the received reflection field. Also done for each one Sensor type a pattern recognition, so that from the arrangement of the reflections as well as their distance to defined objects are closed can. The thus detected by a sensor objects are in the Database with its absolute positions filed. This results get a first overall picture the situation where both sensor types are the same or different May have detected objects. Another algorithmic evaluation checks in the next step using the sensor-specific Positioning accuracy and the object type, whether it is a and the same or different, possibly close to each other standing objects acts. Due to the described sensor properties can such a radar and a laser sensor the same pylons recognize that with the help of the algorithm also only identified as a mast becomes. However, the laser sensor is also able to do the same Detecting lines that detects a radar insufficient reliable.

With The evaluation algorithm thus becomes a uniform "overall picture" of the object situation in one Database stored and can subsequently in different form be displayed in the cockpit.

The presentation of the collision warning or approach warning in the cockpit shows the 3a and b. The presentation of the measurement results of the sensors is carried out after preparation of the measurement signals supplied by them with a hazard classification of the determined distances, preferably here with differently colored, here hatched areas designated with 10 . 11 and 12 and a colorless arc 13 the display in the form of the helicopter HS surrounding circular arcs, for the center of about the geometric center of the helicopter is selected, and that within a common display, respectively 3a and 3b includes. In this way, the entire spatial hazard image of the helicopter for the pilot is displayed clearly and immediately recognizable. As an example, an acute danger of collision at the front is recognizable by a red (right, thick hatched), a yellow (left, thick hatched) and a green (left, thin hatched) arc, a slight danger of collision is recognizable by a colorless, so not hatched , and each a yellow and a red circular arc, missing collision danger left recognizable by colorless circular arcs and small danger of collision opposite the ground recognizable represented by two colorless and a green circular arc.

10

"Yellow" (thick hatched on the right) arc

11

"Red" (thick hatched left) arc

12

"Green" (thin hatched) arc

13

Colorless arc

A

scanning

B

scanning

C

scanning

D

scanning

e

scanning

HS

helicopter

Claims (5)

Method for detecting obstacles all around inside the travel space of a helicopter using radar and laser and / or ultrasonic sensors associated with the helicopter with the following steps: - The Ranges of the sensors used are dependent to be monitored Movement space and installation locations of the sensors on the helicopter selected - the sensors be predetermined, related to the sample space scanning movements imprinted, - all through Reflections received measuring signals of the sensors with their absolute Positions are organized according to individual, order by department Signal evaluation in each case in terms of distance and direction together based on the position of the helicopter and after determining the Reflection density in the space of movement of the helicopter as received Reflection field of a common database supplied for the purpose of fusion of all reflection fields and comparing with patterns stored in the database, wherein by means of subsequent algorithmic evaluation the overall situation to be monitored Movement space detected and in the cockpit of the helicopter as a whole picture is displayed. Method according to claim 1, characterized in that that for the measuring signals of each sensor type according to the physical Properties and the associated reflection field an individual Signal evaluation of each object detection is performed before this in the Database is stored. Method according to claim 1, characterized in that that is checked in the occurrence of reflection patterns in one of the movement spaces, whether in a post area the distance and direction determined, both types of sensors detected the same or similar reflections have that over The algorithm can be determined as an obstacle, while unstructured Reflections this is considered a collision-free space. Method according to claim 1, characterized in that that after filing a reflection field in the database by further algorithmic evaluation tested whether the detected object is one and the same or whether they are different or closely related Objects acts. Method according to claim 1, characterized in that that the overall situation determined as in direction and relative Removal of the reflective objects in the space of movement of the helicopter as color-coded circular arc sections whose center of gravity of the helicopter is presented in the cockpit.