RU2416822C2 - Improved system for positioning aircraft on parking area - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: system has apparatus for determining distance, which is configured to determine at least distance between the system and the aircraft using apparatus for receiving an electromagnetic radiation signal. The apparatus for determining distance is configured to measure at least one property of the signal of the receiver, which is received by the signal reception apparatus, compare the said measurement of at least one property of the reception signal with a threshold value and depending on that comparison, output a signal which indicates whether visibility is sufficiently good at the parking area for safe parking of the aircraft. The property is associated with visibility on the parking area. The method of controlling positioning of the aircraft on the parking area is meant for application of the said system. The system and method are meant for controlling operations on an airport.

EFFECT: determining the possibility of automatic parking of aircraft on parking area.

19 cl, 6 dwg

Description

Technical field

The invention relates to a system for placing an aircraft in a parking position located at a parking position, said system comprising a distance determination means configured to determine at least a distance between the system and the aircraft.

Description of the Related Art

In recent years, the need for efficient operation has increased at airports, and at the same time, at many airports there has been a need to replace manual control of the movement of the aircraft to the place of embarkation and disembarkation by an automatic system for placing the aircraft in the parking position.

Automatic parking systems are usually based on techniques that are more or less affected by limited visibility, for example, due to fog and precipitation. The expression "visibility" should be understood as atmospheric transmission of electromagnetic radiation at the appropriate wavelength. One example of such a system is disclosed in US patent No. 6563432, in which a system for detecting and determining the distance to the aircraft scans the area of the landing and landing using laser pulses. Reflected laser pulses are analyzed to detect solid objects, as well as distinguish solid objects from fog or precipitation.

Another example of an automatic parking position system that is affected by visibility conditions is disclosed in US Pat. No. 6,542,086. The system in US Pat. No. 6,542,086 uses a video camera as a sensor.

The disadvantage of such systems is that they do not always make it possible to park at all weather conditions during which the airport is open for transportation. The aircraft may need guidance at a distance of 80-100 meters from the nearest location where a parking system can be installed, usually at the boarding and landing site, while the airport may still be open for transportation with visibility less than 80- 100 meters. As a result of this, in conditions when automatic parking position is not possible due to fog or precipitation, parking position must be carried out manually by signalmen. The problem in this situation is that the need for manual control of movement on the ground may not be obvious until the aircraft approaches the landing and disembarkation sites and it turns out that the fog or precipitation is too strong for the parking system to give guidance. At a large airport, this can happen simultaneously at several places of embarkation and disembarkation and, as it is not planned, can cause disruption of the airport and related problems such as additional costs or reduced security.

Although the system disclosed in US Pat. No. 6,563,432 detects, identifies, and parks aircraft and also determines whether the detected object is a solid object or there is fog or precipitation, it does not determine whether automatic parking is possible or impossible. .

Typically, visibility measurements are carried out at airports using visibility meters located close to runways. However, the output from existing visibility meters usually does not provide complete information about the conditions near the parking positioning systems, since they are usually located at the pick-up and drop-off points in the immediate vicinity of the terminal buildings and since the fog density usually varies significantly at the airport. In addition, the installation of such a visibility meter at each landing and disembarkation point is not an optimal solution. The output of the meter will still not be able to provide complete information about the conditions that determine the performance of the parking system, since the fog is often present in small areas and since the working area for the system is a sector that extends about 100 meters from the system. Another disadvantage of this solution is the additional cost of providing many expensive visibility meters.

SUMMARY OF THE INVENTION

Therefore, from the above description of the disadvantages related to systems of the prior art, it turns out that in the technical field there is a need for a system for placing an aircraft in a parking position with the ability to determine whether visibility conditions allow the installation of a aircraft in a parking position using the system or not.

Therefore, the objective of the present invention is how to perform a parking position system with the ability to determine visibility conditions within its working area and give a signal when these conditions no longer allow parking position using the system.

To accomplish this task, the present invention provides, in a first feature, a system for staging an aircraft at a parking position, configured to be placed at a parking position. The system comprises distance determining means configured to determine, using the electromagnetic radiation signal receiving means, at least the distance between the system and the aircraft. The distance determining means is further configured to measure at least one property of the receiver signal received by said signal receiving means, said property related to visibility at a parking place, compare said measure of at least one property of the receiver signal with a threshold value, and depending on the comparison, to give a signal indicating whether the visibility at the parking place is good enough to be able to safely put into the parking place using systems s.

In a second aspect, the invention provides a method for controlling the positioning of an aircraft in a parking position in a system for staging an aircraft in a parking position located at a parking position. The system comprises a distance determining means configured to determine, using the electromagnetic radiation signal receiving means, at least the distance between the system and the aircraft, and the distance determining means performs the steps of measuring at least one property of the receiver signal received by said signal receiving means, said property related to visibility at a parking place, said measure of at least one property of a receiver signal is compared threshold value and depending on said comparison output a signal indicating whether sufficient good visibility on the parking place to be able to secure the parking place with the system.

In a third aspect, the invention provides a computer program comprising program instructions that, when executed on a computer, perform the method described above.

In a fourth aspect, the invention provides the use of an aircraft parking position system for controlling operations at an airport.

In other words, the system in accordance with the present invention is configured to check visibility conditions of the working area of the parking position system in front of and / or while the aircraft is parked. The system measures characteristics that are relevant to on-site visibility and which limit system performance. The measurement results are used as a determining factor in determining whether the conditions of visibility allow a safe setting to a parking place or not.

An advantage of the present invention, therefore, is that it provides the airport operator with enhanced capabilities to determine whether it is possible to perform a parking position operation when visibility is reduced to such an extent that there is uncertainty whether a safe parking position is possible or not. For example, prior art systems are typically unable to distinguish between dense fog or precipitation from parts of an approaching aircraft. Needless to say, such a lack of discrimination ability can lead to dangerous situations. On the other hand, prior art systems can be configured to take into account such a lack of discrimination and simply signal that parking is not possible when the system is uncertain. However, this means that the suitability of prior art systems is not as high as the suitability of a system in accordance with the present invention.

In addition, the advantage is that it is possible in real time and continuously determine whether the density of fog or precipitation makes it impossible to automatically place the parking lot, and inform the dispatchers about it. The need for manual control of movement on the ground can be foreseen, and thus, the signalmen can be in place when the aircraft arrives, and violations in the form of delays in the parking position can be avoided. Thus, the effective operation of the airport is achieved, which is expressed, for example, in a smaller amount of waiting time for the aircraft and faster and, therefore, more efficient placement of the arriving aircraft at the places of embarkation and disembarkation and terminals, when automatic parking is possible.

Another advantage of the invention is that by providing the solution to the problems discussed above, an existing parking position system can be adapted to provide a signal showing visibility conditions at the parking position. Typically, an implementation will entail only reprogramming the management software in the system, which means greater cost savings compared to a situation in which a separate visibility system would be needed. It is not necessary to adapt any hardware of the existing parking position system, since the wavelength range in which the parking system operates is also suitable for operation in connection with the determination of visibility conditions.

In embodiments of the invention, the distance determination means is configured to measure reception signal properties with respect to electromagnetic radiation scattering. For example, the distance determination means may comprise a laser ranging means, and then the distance means may be configured to measure the dispersion of the laser radiation.

Alternatively, the distance determination means may comprise a radar rangefinder, and then the distance determination means may be configured to measure radar radiation dispersion. In further embodiments, electromagnetic backscattering radiation, or more precisely the distribution of backscattering radiation power, indicates scattering.

In further embodiments, the distance sensing means comprises a signal receiving means comprising imaging means configured to provide two-dimensional images of the parking position, the distance determining means being configured to measure at least one property of the receiver signal, at least related to the difference in contrast, at least between two areas within the image. These image areas may correspond to predetermined parking locations, preferably at the same distance from the system.

In other words, when the parking system uses a two-dimensional imaging technique, the measure of visibility is image contrast. The analysis of the image signal used to determine the location of the aircraft and the deterioration of this signal caused by fog or precipitation provides a good indication as to whether the deterioration of visibility exceeds that level above which parking is dangerous or even impossible.

The imaging tool may be configured to detect electromagnetic radiation either in the optical wavelength range or in the infrared wavelength range, and also to detect electromagnetic radiation in both of these wavelength ranges.

Brief Description of the Drawings

The invention will now be described in more detail with reference to the attached drawings.

Figure 1 schematically illustrates parking lots on which parking systems according to the invention are placed.

Fig. 2a schematically illustrates a parking position system in accordance with a first embodiment of the present invention.

2b is a graph of a response curve related to a reflected electromagnetic pulse in a fog.

3 schematically illustrates a parking position system in accordance with a second embodiment of the present invention.

4 and 5 are flowcharts of the methods of the invention.

Preferred Embodiments

Figure 1 schematically illustrates a top view of the situation at the airport. The terminal 101, which may be a passenger terminal and / or a cargo terminal, is equipped with a first aircraft parking system 115 and a second aircraft parking system 117. The first parking position 103 and the second parking position 105 are located near each of the parking systems 115, 117, respectively. Although parking lots are indicated by dashed lines in FIG. 1, these lines should not constitute actual markings on the surface of the earth, but should be taken as an aid to reading the present description.

In addition, although FIG. 1 shows that both parking systems 115, 117 are connected to terminal 101, alternative configurations include cases where the parking system is not directly connected to the terminal but connected to any other suitable to the parking lot. In fact, the parking lot may not be directly tied to a specific terminal and may also be tied to a designated parking spot anywhere in the airport where the airport operates with a parking lot.

The situation illustrated in FIG. 1 is one in which a first aircraft 111 approaches a first parking position 103 along a guide line 107 on the surface of the earth. The second aircraft 113 is located in the second parking position 105 after a successful staging operation has been completed and is connected to the terminal 101 via the passenger bridge 109.

The first parking position 103 is heavily covered by fog 119. The fog 119 extends in three spatial directions in the atmosphere at the parking location and should be recognized as a potential obstacle that could interfere with the safe placement of the first aircraft 111 in the parking position as it approaches the first system 115 parking lots.

As you know, fog or precipitation affects visibility mainly by the fact that the incident electromagnetic radiation is scattered by droplets in the atmosphere. During the scattering process, the luminous droplets re-emit some of the incident electromagnetic radiation in all directions. That is, droplets behave like point sources of re-emitted radiation. Some of the incident electromagnetic radiation is scattered back to the radiation source, depending on the relationship between the droplet size and the radiation wavelength. The relationship between visibility and scattered electromagnetic radiation is widely described in the literature, for example, in the article “Ground-based remote sensing of visual range / Visual-range lidar”, Verein Deutscher Ingenieure VDI 3786, or in the book “Elastic Lidar: Theory, practice and analysis methods” (VAKovalev, WEEichinger, Hoboken, NJ, Wiley, 2004).

For staging systems that rely on electromagnetic radiation, for example, to emit pulses, scattering reduces the amount of energy received reflected by the detected objects. For staging systems that rely on imaging, scattering causes a decrease in contrast in the image used.

2a and 2b, a parking position system 215 that uses electromagnetic radiation in the form of emitting pulses and receiving backscattering radiation of these pulses will be described. The parking position system 215 is configured to determine in real time the distance to the approaching aircraft 240, and is also configured to show whether the visibility at the parking position located between the parking position system 215 and the approaching aircraft 240 is sufficiently good for the possibility of safely placing the aircraft 240 in the parking lot.

The parking system 215 in FIG. 2a, which may be any of the parking systems 115, 117 discussed above in connection with FIG. 1, comprises a control unit 221, a transmitter 223 and a receiver 225. The transmitter 223 is configured to the ability, under the control of control unit 221, to emit electromagnetic radiation pulses in the form of laser radiation (although other embodiments may include a transmitter / receiver pair that is configured to operate with radar pulses). The radiation emanates from the transmitter in the form of a transmission beam 229 along the transmission beam direction 230, as schematically illustrated in FIG. 2a. Accordingly, the receiver is also configured, under the control of the control unit 221, to receive backscattering radiation in the reception beam 231 along the direction of the reception beam 232 and to provide a signal representing backscattering radiation to the control unit 221.

The transmitter 223 and the receiver 225 are configured so that they can be directed in any desired spatial direction through the beam guiding device 226 controlled by the control unit 221. As one skilled in the art understands, the beam guiding device 226 can be implemented as mirrors, stepper motors, etc.

The parking location system 215, as indicated in FIG. 1, can be part of a larger system located in an airport terminal, and can also be connected to an external control system 227 controlled by airport staff.

The following is a description of how the positioning system 221 in FIG. 2 works to provide an indication as to whether a safe positioning is possible in which a transmitter 223 and a receiver 225 are used to emit and receiving electromagnetic pulses in the form of either laser pulses or radar pulses. Reference will also be made to the flowchart of FIG. 4.

The graph in FIG. 2b shows a typical distribution of the range-corrected system receiver signal power Z (r) when the pulse was emitted in step 401 of emitting in the direction of the uniform fog and backscatter radiation was received by receiver 225 in step 403 of receiving as a receiver signal, having a power distribution P (r). This is followed by calculation step 405, during which the value for visibility V is calculated.

At calculation step 405, the range-corrected power distribution Z (r) is initially calculated as Z (r) = r ² * P (r) to compensate for attenuation of the receiver signal over long distances as 1 / r ² , where r is the distance between the transmitter / receiver and reflective / scattering object.

Then, the visibility V is calculated based on the ranging signal Z (r) of the receiver, for example, using the algorithm disclosed in DE 19642967, or using the so-called asymptotic approximation method. According to this method, the visibility of V can be calculated by expressing

where c is the speed of light

,

,

,

,

r ₀ is the distance at which the field of view of the transmitter and receiver begins to completely overlap,

r ₁ - the distance at which the signal drops to 10% of the maximum value at a distance r ₀ , and

r ₂ = r ₁ -r ₀ .

The integration time for I _r1 is from t ₀ to t ₁ = t ₀ + Δt, and the integration time for I _r2 is from t ₁ to t ₂ = t ₁ + Δt, where t ₀ , t ₁ , t ₂ and Δt refer to r ₀ , r ₁ , r ₂ and Δr, as defined in fig.2b.

Then, in step 407 of the comparison, the calculated visibility V is compared with a predetermined threshold value to give an indication, i.e. signal whether parking is possible. Specific threshold values are determined, for example, empirically. If the visibility of V is greater than the threshold value, an indication is given in indication step 409 that the visibility is good and safe parking is possible. If, on the other hand, the visibility of V is less than the threshold value, an indication is given in indication step 411 that the visibility is poor and safe parking is not possible.

Now, with reference to FIG. 3, a parking position system 315 that uses imaging means in the form of a camera 324 will be described. As in the previous embodiment, the parking position system 315 is configured to real-time determine distances to an approaching aircraft , and also made with the ability to show whether the visibility at the parking place is good enough to be able to safely place the aircraft 340 at the parking position.

The parking system 315 of FIG. 3, which may be any of the parking systems 115, 117 discussed above in connection with FIG. 1, comprises a control unit 321 connected to a camera 324 and connected to an external system 327 control, similar to the situation discussed above in connection with the embodiment in figa.

A camera 324 is controlled to record an image of a contrast test object, illustrated by a dark spot 303 and a bright spot 304, located at a distance d from the parking position system 315. As one skilled in the art understands, test object 304, 305 can be any predetermined object or markup located at the parking place within the field of view of the parking system, for example, part of the applied guide line 107. The fog 305 is illustrated in FIG. 3 as extending in the atmosphere between the parking system 315 and the approaching aircraft 340.

The following is a description of how the parking position system 315 of FIG. 3 works in order to provide an indication as to whether a safe parking position is possible, in which a camera 324 is used to record images when determining the distance of the control unit 321. In the recorded images, the first pixel denoted by i and the second pixel denoted by j contain image data of the corresponding scene point P _i and P _j , which correspond to spots 303, 304 of the calibration object. Reference will also be made to the flowchart of FIG. 5.

After recording the image in the recording step 501, in the calculation step 503, the contrast between the two pixels i and j in the camera image corresponding to the two points of the scene P _i and P _j at the same distance d from the camera is calculated. Then, as will be described below, contrast is used as a measure of performance degradation caused by reduced visibility.

The contrast in the camera image is affected by the scattering of light by atmospheric particles in two ways, as shown in Fig.3. Direct transmission 307 is the attenuated radiation flux density received by the camera sensor from the scene point 303, 304 along the line of sight. Airspace light 309 represents the total amount of ambient lighting 311 (sunlight, sky glow, light from the surface of the earth) reflected into the line of sight by atmospheric particles.

It is known that the following relationships apply:

where E ⁽ⁱ⁾ and E ^(j) are the brightness in two pixels i and j, respectively.

I _∞ - ambient light intensity,

ρ is the normalized radiation flux density of the point 303, 304 of the scene, which is a function of the reflection coefficient of the point of the scene, the normalized spectrum of ambient lighting and the spectral characteristics of the camera 324,

β is the coefficient of backscattering of the atmosphere in front of the camera 324,

d is the distance between the system 315 and the point 303, 304 of the scene.

The observed contrast between P _i and P _j can be defined as

This shows that contrast deteriorates exponentially depending on the scattering coefficient β and the depth of the points in the scene in a situation where fog 305 is present.

The brightness E of two pixels is measured and the contrast C (i, j) between two points is calculated as

Then, at step 505, the calculated contrast C is compared with a predetermined threshold value to give an indication, i.e. signal whether parking is possible. Specific threshold values are determined, for example, empirically. If the contrast C is greater than the threshold value, an indication is given in indication step 507 that the visibility is good and safe parking is possible. If, on the other hand, the contrast C is less than the threshold value, at step 509 an indication is given that visibility is poor and safe parking is not possible.

Claims (19)

1. A system for placing an aircraft in a parking position, configured to be parked, said system comprises a distance determination means configured to determine, using the electromagnetic radiation signal receiving means, at least the distance between the system and the aircraft, said the distance determination means is further configured to: measure at least one property of a receiver signal received by said reception means with Ignal, the mentioned property is related to visibility at the parking place, compare the said measure of at least one property of the receiver signal with a threshold value, and depending on the said comparison, give a signal indicating whether the visibility at the parking place is good enough for safe setting to the parking spot using the system. 2. The system of claim 1, configured to measure said at least one property of a receiver signal, at least related to scattering of said electromagnetic radiation. 3. The system according to claim 2, in which the means for determining the distance contains a laser rangefinder means, and the means for determining the distance is configured to measure the dispersion of the laser radiation. 4. The system according to claim 2, in which the means for determining the distance comprises a radar ranging tool, and the means for determining the distance is made with the ability to measure the dispersion of the radar radiation. 5. The system according to any one of claims 2 to 4, in which the means for determining the distance is made with the ability to measure electromagnetic radiation backscattering. 6. The system of claim 5, wherein the distance determining means is configured to determine a power distribution of a received backscatter electromagnetic radiation signal. 7. The system of claim 1, wherein said distance determining means comprises a signal receiving means comprising imaging means configured to provide two-dimensional images of the parking position, the distance determining means being configured to measure at least one property of the receiver signal at least related to the difference in contrast between at least two areas within the image. 8. The system of claim 7, wherein said image forming means is configured to determine said difference in contrast between predetermined parking locations, said predetermined locations correspond to said at least two regions within the image. 9. The system of claim 8, wherein said predetermined locations are located at substantially the same distance from the system. 10. The system according to any one of claims 7 to 9, in which the image forming means is configured to detect electromagnetic radiation in at least the optical wavelength range. 11. The system according to any one of claims 7 to 9, in which the image forming means is configured to detect electromagnetic radiation in at least the infrared wavelength range. 12. A method for controlling the positioning of an aircraft in a parking position in a system for positioning an aircraft in a parking position located at a parking position, said system comprises distance determining means configured to determine, using the electromagnetic signal receiving means, at least the distance between the system and an aircraft, wherein said distance determining means performs the steps of: measuring at least one property of a receiver signal received by said signal receiving means, said property is related to visibility at a parking place, said measure of at least one property of the receiver signal is compared with a threshold value, and depending on said comparison, a signal indicating whether the parking visibility is good enough for the possibility of safe parking at the site using the system. 13. The method according to item 12, in which the measurement of at least one property of the signal of the receiver comprises measuring at least the scattering of said electromagnetic radiation. 14. The method according to item 13, in which the measurement includes measuring electromagnetic radiation backscattering. 15. The method according to 14, containing the stage of determining the power distribution of electromagnetic radiation of backscattering. 16. The method according to item 12, in which the said means for determining the distance contains means for receiving a signal containing means for forming images, configured to provide two-dimensional images of the parking lot, and the step of measuring at least one property of the signal of the receiver includes a measurement, at least contrast differences between at least two regions within the image. 17. The method according to clause 16, in which the said definition of the said difference in contrast between the predetermined locations on the parking lot comprises determining the difference in contrast between the predetermined locations corresponding to the said at least two areas within the image. 18. The method of claim 17, wherein said predetermined locations are located at substantially the same distance from the system. 19. The use of the system of placing the aircraft at the parking lot according to any one of claims 1 to 11 for controlling operations at the airport.

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