Method for locating an aircraft relative to a runway, control method and associated devices

Abstract

Method for locating an aircraft relative to a runway, control method and associated devices. The present invention relates to a method for locating an aircraft (2) relative to a runway (4) extending mainly along a longitudinal direction (X) and comprising at least one group of reflective elements (6A, 6B), each group comprising one or more reflective elements (8A, 8B, 10A, 10B), the method comprising the following steps: - transmission of a radio signal from the aircraft (2), - reception of a signal reflected by the runway (4), - extraction of at least one pattern from the received reflected signal, each pattern being the evolution over time of the radio signal reflected by at least one reflective element (8A, 10A), - calculation of a lateral distance (D) and a longitudinal distance (M) from the received radio signal.- Determination of the aircraft's location (2) based on the lateral distance (D) and the longitudinal distance (M). Figure for the abbreviation: Figure 1,

Description

Title of the invention: Method for locating an aircraft relative to a runway, control method and associated devices

[0001] The present invention relates to a method for locating an aircraft relative to a runway. The present invention also relates to a method for controlling an aircraft implementing the locating method. The present invention also relates to the associated devices, namely a locating device, a control device, and a runway.

[0002] The invention relates to the field of aircraft, in particular airplanes, more particularly to the field of localization of the latter during takeoff and landing.

[0003] It is essential to be able to locate an aircraft in relation to the runway on which it can land or take off in order to guarantee a satisfactory level of safety during the takeoff and landing phases.

[0004] Typically, runways have a width of around 30 meters to 100 meters and a length of between 600 meters for the shortest and 5,500 meters for the longest. For safety reasons during landing and takeoff, it is necessary to be able to efficiently locate said aircraft in relation to the runways.

[0005] ILS (Instrument Landing System) technology is known to be a reference system for the location of an aircraft relative to a runway during the landing phase.

[0006] This technology uses transmitting antennas located at the end of the runway, the sum of the signals received by the aircraft being characterized by a carrier and a modulation, themselves direct functions of the lateral and longitudinal offsets of the aircraft relative to the reference approach axis in the vertical and horizontal plane.

[0007] However, this technology is expensive and therefore moderately deployed and does not allow the detection of the possible presence of obstacles on the track.

[0008] Furthermore, this technology is not used for takeoff.

[0009] There is therefore a need for a method of locating an aircraft relative to a runway for takeoff and / or landing that is easy to implement.

[0010] To this end, the description describes a method for locating an aircraft relative to a runway on which aircraft can land or take off, the runway extending mainly in a longitudinal direction, a first transverse direction being perpendicular to the first transverse direction, the runway comprising a main area delimited by two edges and at least one group of reflective elements for a radio signal, each group comprising one or more reflective elements arranged on one edge of the track or on both edges of the track, each reflective element being composed of at least one reflector, the method comprising the following steps:

[0011] - transmission of a radio signal from the aircraft to the runway,

[0012] - reception of a signal reflected by the track,

[0013] - extraction of at least one pattern in the received reflected signal, each pattern being the evolution over time of the radio signal reflected by at least one reflective element composing a group of reflective elements, called a tracking group,

[0014] - calculation of a lateral distance and a longitudinal distance from the signal radio received, the lateral distance being the distance between the aircraft and the runway along the first transverse direction, and the longitudinal distance being the distance between the aircraft and the tracking group along the longitudinal direction, and

[0015] - determination of the aircraft's location based on lateral distance and of the longitudinal distance.

[0016] According to other advantageous aspects, the localization method comprises one or more of the following features, taken individually or in all technically possible combinations:

[0017] - the step of calculating the lateral distance comprises the following sub-steps:

[0018] - estimation of the distance between the aircraft and each of the reflective elements of the spotting group, and

[0019] - calculation of the aircraft's lateral distance based on the two estimated distances and of the position of the two reflective elements of the spotting group.

[0020] - The step of calculating the lateral distance comprises the following sub-steps:

[0021] - estimation of a phase shift between the two motifs, and

[0022] - calculation of the lateral distance by applying a function to the estimated phase shift, the function associating a lateral distance with a phase shift between the two patterns.

[0023] - The step of calculating the lateral distance comprises the following sub-steps:

[0024] - determination of a sub-motif extracted from one of the reflected motifs for which a The correlation with a theoretical pattern is maximal, and

[0025] - calculation of the lateral distance by applying a function to the sub-pattern extracted, the function associating a lateral distance with an extracted sub-pattern.

[0026] - the method includes a step of obtaining the aircraft height according to a second transverse direction relative to the runway and in which, during the determination stage, the location is a three-dimensional location of the aircraft, the location also being a function of the height.

[0027] - the radio signal has a frequency belonging to the X band or to the W band.

[0028] The description also relates to a method for controlling an aircraft comprising the following steps:

[0029] - localization of the aircraft by implementing a localization method such as previously described,

[0030] - estimation of the risk of an obstacle being present on the track based on a pattern of ground, the ground pattern being the radio signal reflected by the runway ground, and

[0031] - performing an action to interrupt the landing or takeoff depending on of the determined location and the estimated risk of presence.

[0032] The description also relates to a device for locating an aircraft relative to a runway on which aircraft may land or take off, the runway extending mainly in a longitudinal direction, a first transverse direction being perpendicular to the longitudinal direction, the runway comprising a main area delimited by two edges and at least one group of reflective elements for a radio signal, each group comprising at least one reflective element disposed on one edge of the runway or on both of its edges, said locating device comprising a computer configured to:

[0033] - to transmit a radio signal from an aircraft towards the runway,

[0034] - receive a signal reflected by the track,

[0035] - extract at least one pattern from the received reflected signal, the patterns being the evolution over time of the radio signal reflected by the reflective elements composing a group of reflective elements, called the tracking group,

[0036] - calculate a lateral distance and a longitudinal distance based on the patterns, the Lateral distance being the distance between the aircraft and the runway along the first transverse direction, and longitudinal distance being the distance between the aircraft and the spotting group along the longitudinal direction, and

[0037] - determine the aircraft's location based on the lateral distance and the longitudinal distance.

[0038] The description also relates to a device for controlling an aircraft relative to a runway on which aircraft can land or take off, the runway extending mainly in a longitudinal direction, a first transverse direction being perpendicular to the longitudinal direction, the runway comprising a main area delimited by two edges and at least one group of reflective elements for a radio signal, each group comprising at least one reflective element arranged on one edge of the runway or on both of its edges, said control device comprising:

[0039] - an aircraft location device according to the invention, and

[0040] - a controller configured for:

[0041] - estimating a percentage risk of the presence of an obstacle on the track from of a ground pattern, the ground pattern being the radio signal reflected by the runway floor; and

[0042] - to perform an automatic interruption of the landing or takeoff action by function of the location determined by the location device and the estimated risk percentage of presence.

[0043] The description also describes a runway on which aircraft can land or take off, the runway extending mainly in a longitudinal direction, a first transverse direction being perpendicular to the longitudinal direction, and comprising at least one group of reflective elements for a radio signal, each of the at least one group comprising at least one reflective element arranged on one edge of the runway or on both of its edges.

[0044] Following other advantageous aspects, the track comprises one or more of the following features, taken individually or in all technically possible combinations:

[0045] - the spacing between groups is between 100 meters and 500 meters, the spacing between groups being the projection onto the longitudinal direction of the distance between the two nearest points within two adjacent groups,

[0046] - a transverse distance is between 25 meters and 100 meters, the distance transverse being the distance between the nearest point of a reflective element and a point in a main area of ​​the runway,

[0047] - a reflective element comprises at least two trihedral reflectors.

[0048] The invention will become clearer upon reading the following description, given solely by way of non-limiting example and with reference to the drawings in which: - [Fig. 1] [Fig. 1] is a schematic representation of a top view of an aircraft equipped with a positioning device and landing on a runway, - [Fig.2] [Fig.2] is a schematic representation of a side view of the elements shown in [Fig.1]. - [Fig.3] [Fig.3] is a flowchart illustrating an example of the implementation of a method for locating an aircraft relative to a runway, - [Fig. 4] [Fig. 4] is a schematic representation of a top-down view of an aircraft with a control device landing on a runway, and - [Fig.5] [Fig.5] is a flowchart illustrating an example of the implementation of an aircraft control process.

[0049] An aircraft 2 and a runway 4 are schematically represented in [Fig.1].

[0050] An aircraft is a means of transport capable of rising and moving at altitude within the Earth's atmosphere.

[0051] For example, an aircraft is an airplane, a helicopter or a drone.

[0052] Aircraft 2 seeks to land on runway 4.

[0053] Alternatively, runway 4 can also be used for the takeoff of aircraft 2.

[0054] Runway 4 thus presents a rectangular surface adapted and reserved for the take-off and landing of aircraft.

[0055] Thus, as shown in [Fig. 1], track 4 has a main area delimited by two edges.

[0056] In this respect, the main area is the rectangular surface adapted (in terms of dimensions and coating in particular) for an aircraft to take off or land.

[0057] Runway 4 extends mainly along a longitudinal direction corresponding to the direction along which aircraft 2 takes off or brakes during a landing.

[0058] The longitudinal direction is represented by an X axis on [Fig.1] so that

[0059] the longitudinal direction is referred to as the longitudinal direction X in the following.

[0060] A first transverse direction is also defined as a direction perpendicular to the longitudinal direction and contained in the plane of the track.

[0061] The first transverse direction is represented by an axis Y on the [Fig.1], so that the first transverse direction is referred to as the first transverse direction Y in the following.

[0062] Furthermore, with reference to [Fig.2], a second transverse direction is defined as a direction perpendicular to the longitudinal direction and contained in a plane perpendicular to track 4. The second transverse direction is referred to as the second transverse direction Z in the following.

[0063] As seen in [Fig.1], track 4 comprises at least one group of reflective elements 6A.

[0064] In the example described, only two groups are represented but this number is not limiting, the number of groups can be limited to a single group or be as high as desired.

[0065] According to the case represented, the distance between each group of neighboring reflective elements along the longitudinal direction X is the same.

[0066] This distance is the projection onto the longitudinal direction X of the distance between the two closest points of a group of neighboring reflective elements and is called spacing between groups in the following.

[0067] For example, the spacing between groups is between 100 meters (m) and 500 m.

[0068] Preferably, the spacing between groups is equal to 250 m.

[0069] Each group 6A or 6B comprises a first reflective element 8A or 8B and a second reflective element 10A or 10B.

[0070] Each reflective element 8A, 8B, 10A or 10B can be arranged on either side of the main area of ​​the runway, as illustrated, but the elements of the same group can also be arranged on the same side.

[0071] A transverse distance is defined for each reflective element 8A, 8B, 10A or 10B as the distance between the nearest point of a reflective element 8A, 8B, 10A or 10B with a point in the main area of ​​the runway.

[0072] The transverse distance is between 25 m and 100 m.

[0073] Advantageously, the transverse distance is equal to 50 m.

[0074] According to the example described, the transverse distance is the same for each reflective element 8A, 8B, 10A or 10B.

[0075] Each reflective element 8A, 8B, 10A or 10B is an element having the property of reflecting a radio signal, and more specifically a radar signal from aircraft 2.

[0076] Each reflective element 8A, 8B, 10A or 10B comprises at least one reflector.

[0077] A reflector is a device that allows an incident electromagnetic wave, and especially a radar signal, to be reflected.

[0078] Each reflector can be a trihedral reflector.

[0079] A trihedral reflector is well suited for radar waves because it has the property of generating radar echoes of relatively high amplitude.

[0080] However, any form of reflector is conceivable here, including parabolic, planar or elliptical reflectors, as well as reflectors using passive, active electronic components, or those with frequency-selective properties, such as Van Atta type reflectors.

[0081] Preferably, as is the case for [Fig.1], each reflective element 8A, 8B, 10A or 10B comprises several reflectors (two in the case of [Fig.1]).

[0082] The reflectors are arranged according to a specific spatial arrangement, so that the reflection of an incident wave by the reflectors forms a single signal.

[0083] Indeed, as will be detailed later, the presence of a plurality of reflectors generates interference between the signals reflected by the different reflectors, resulting in a reflected signal that is a function of the distance between the emitter of the incident radiation and the reflecting element.

[0084] The signal reflected by the reflecting element thus exhibits a unique evolution at during the aircraft's approach that could serve as a recognition signature.

[0085] In this sense, the reflectors form an n-tuple characteristic of the reflective element considered 8A, 8B, 10A or 10B, n being an integer designating the number of reflectors of a reflective element.

[0086] Aircraft 2 includes a location device 20 configured to transmit a radio signal towards runway 4 and receive a signal reflected by runway 4 (and more specifically, at least one reflective element 8A, 8B, 10A or 10B in order to deduce a position of aircraft 2).

[0087] Depending on the case, the position of an object refers either to the geographical position or to a location relative to track 4.

[0088] The geographical position is given by the three coordinates of the object in the X, Y and Z coordinate system with center O.

[0089] The center O, corresponding to the intersection of the three axes X, Y and Z, has coordinates (0, 0, 0).

[0090] In the remainder of this description, the location of an object relative to track 4 is defined as the coordinates of the object's projection onto the (X, Y) plane. Thus, point O has coordinates (0,0) when referring to location.

[0091] In the rest of the description, the center O also represents a start of track 4.

[0092] The location device 20 includes a radio transceiver 28 and a computer 30.

[0093] The radio transceiver 28 is configured to transmit a signal radioelectric from aircraft 2 towards runway 4 and to receive a signal reflected by runway 4.

[0094] For example, the radio transceiver 28 is a radar.

[0095] According to a preferred embodiment, the radar is a continuous wave radar.

[0096] Such a radar is more often referred to as an FMCW radar, which refers to the corresponding English name for “Frequency Modulated Continuous Wave”.

[0097] Such a radar operates here with millimeter or centimeter waves.

[0098] Preferably, the radio transceiver 28 is suitable for transmitting or receiving signals with a frequency between the X and W bands, i.e. between 8 Gigahertz (GHz) and 110 GHz.

[0099] Advantageously, the signals emitted or received by the radar have a frequency of 15 GHz, 24 GHz or 95 GHz.

[0100] In the example of [Fig.1], the localization device 20 includes a computer 30 comprising, for example, a processor 32 and a memory 34 associated with the processor 32.

[0101] The computer 30 is configured to process signals from the radio transceiver 28.

[0102] The calculator 30 is an electronic circuit designed to manipulate and / or transform data represented by electronic or physical quantities in registers of the calculator and / or memories into other similar data corresponding to physical data in register memories or other types of display devices, transmission devices or storage devices.

[0103] As a specific example, calculator 30 is a graphic calculator.

[0104] The operation of the localization device 20 is now described with reference to [Fig.3] which illustrates an example of the implementation of a localization method (90).

[0105] The localization process comprises an emission step 100, a reception step 200, an extraction step 300, a calculation step 400 and a determination step 600.

[0106] During the first transmission stage 100, the radio transceiver 28 transmits a radio signal from aircraft 2 to runway 4.

[0107] The radio signal thus emitted interacts with the reflective elements 8A. 8B, 10A or 10B which returns a reflected signal towards aircraft 2 and more specifically towards radio transceiver 28.

[0108] Generally, it is a group of reflective elements 6A or 6B that interacts with the incident signal.

[0109] In this sense, the group of reflective elements 6A or 6B which is called upon serves as a locating group.

[0110] However, the spotting group may change during landing or takeoff depending on the evolution of the distance between runway 4 and aircraft 2.

[0111] The spotting group is usually the nearest group in the direction of progress of aircraft 2, in the field of vision of radio transceiver 28.

[0112] In the following description, the locating group 6A is composed of the reflective elements 8A and 10A.

[0113] During the reception step 200, the radio transceiver 28 receives a signal reflected by track 4.

[0114] Advantageously, in the embodiment in which the radio transceiver 28 is an FMCW radar, the receiving stage 200 is implemented in parallel with the transmitting stage 100.

[0115] During the extraction step 300, the computer 30 extracts at least one pattern from the received reflected signal.

[0116] The at least one extracted motif is the evolution over time of the radio signal reflected by the reflective elements 8A and 10A composing the tracking group 6A.

[0117] Each of the patterns being characteristic of the reflective element and taking, for example, the form of an oscillation of the power received over time when The reflective element consists of two identical reflectors positioned side by side.

[0118] For example, the computing device 20 includes a memory capable of storing a plurality of reference patterns corresponding to a reflected radio signal characteristic of a reflecting element. In particular, the computing device 20 includes a plurality of reference patterns corresponding to specific position conditions of the aircraft 2 relative to the reflecting element.

[0119] The calculator 30 recognizes a pattern in a received signal by comparing it to the plurality of reference patterns.

[0120] During calculation step 400, the calculator 30 obtains a lateral distance D.

[0121] Lateral distance D is defined as the distance between aircraft 2 and runway 4 along the first transverse direction Y.

[0122] Calculator 30 calculates the lateral distance D as a function of the two extracted patterns.

[0123] According to the embodiment of [Fig. 3], calculation step 400 comprises a sub- esthnation step 410 and a calculation substep 420.

[0124] During the esthnation substep 410, the computer 30 estimates two distances: a first distance d between the aircraft 2 and the first reflective element 8A and

[0125] a second distance d2 between the aircraft 2 and the second reflective element 10A.

[0126] The distances dl and d2 are determined by the FMCW radar, from the signal radioelectric received and using classic radar distance measurement algorithms.

[0127] During the calculation substep 420, the calculator 30 calculates the lateral distance D and a longitudinal distance M of the aircraft 2 as a function of the two estimated distances db d2 and the position of the two reflective elements 8A and 10A. This calculation is done by the classical mathematical method of trilateration.

[0128] The longitudinal distance M is defined as the distance between aircraft 2 and tracking group 6A along the longitudinal direction X.

[0129] During the determination step 600, the calculator 30 determines the location of

[0130] aircraft 2 as a function of the lateral distance D and the longitudinal distance M.

[0131] For this purpose, the calculator 30 determines each of the coordinates (XA' in the frame (X,Y).

[0132] The calculator 30 obtains the first coordinate xa as the difference between the longitudinal distance M and the distance x(>a. between the locating group 6A and the beginning of the track O along the longitudinal direction X.

[0133] This can be written mathematically as follows:

[0134] x4 = M-.r6A

[0135] The second coordinate ^4 is the lateral distance D.

[0136]

[0137]

[0138]

[0139]

[0140]

[0141]

[0142]

[0143]

[0144]

[0145]

[0146]

[0147]

[0148]

[0149] ser2 = Or: In summary, calculator 30 obtains the xa and ya coordinates using the following mathematical relationship: The described process thus leads to obtaining the location of aircraft 2. Advantageously, the localization process is simple to implement and involves few constraints for track 4. Indeed, only the reflectors need to be sized according to the frequency of the signals emitted by the radar. In the field of radiocommunications, the radar cross section (RCS) is an inherent physical property of objects indicating the relative importance of the surface area reflecting an electromagnetic beam that they cause. Assuming the following points: - the aircraft includes a radar whose emitted signal is reflected by two reflective elements and then sent back to the said radar - Each reflective element is formed by a pair of trihedral reflectors, - each of the reflectors of the reflecting element is at a distance from the middle of the track ô, and 52, and - each of the reflectors of the reflecting element has sides of length ai and a2; We obtain the following two radar cross-section (RCS) formulas for each of the reflectors: 4n-at4 3 / 4¾4 3 / 2 denotes the wavelength of the signal emitted by the radar, SER denotes the radar cross-section of the first reflector, and SER2 denotes the radar cross-section of the second reflector. Furthermore, the phase of the signal received by the reflector doublet is equal to the distance traveled by the wave during its path radar > reflector > radar, multiplied by 2tt / 3, modulo 2tt, which is mathematically translated by the following equations: = 7 x 2 x ^d 2 + + h 2 mod 2tt tp2= yr x 2 x \Jd^ + ô2 + h mod

[0150] Finally, the radar cross-section (RCS) measured by the radar will be equal to the magnitude of the sum of the contributions of the radar cross-sections of the two reflectors, which is mathematically expressed by the following equation:

[0151] SER = WSER^ + SE^é^W

[0152] These calculations were carried out with two reflectors offset from each other along the lateral direction Y, but the principle remains the same when using reflectors offset along the longitudinal direction X or the vertical direction Z, or any other direction.

[0153] In order to clearly distinguish the oscillation from the ground, a 10 dB difference between the low and high values ​​of the oscillation allows for good detection.

[0154] For example, when seeking a radar cross-sectional area (RCA) for the reflector doublet which oscillates between 10 dBm2 and 20 dBm2, in order to clearly distinguish the signal from the ground, and to clearly discern the oscillations for a 24GHz frequency radar, trihedral reflectors with respective dimensions of 202 mm and 213 mm are suitable.

[0155] Such dimensions are dimensions easily achievable in practice.

[0156] Modifying an existing runway thus represents a moderate cost for an airport wishing to equip itself with it and is easy to implement

[0157] Similarly, the cost of installing the location device is also moderate and the modifications to be made are minor, these most often amounting to a simple reprogramming of an already existing computer.

[0158] In addition, the method has a hybrid character since it makes it possible to guarantee a precise localization of the aircraft 2 in the landing and takeoff phases.

[0159] Other embodiments of the process just described are conceivable.

[0160] For example, the steps can be implemented in a different order or in parallel where technically possible.

[0161] According to another example, calculation step 400 is carried out differently.

[0162] In such an example, calculation step 400 comprises an esthnation substep and a calculation substep.

[0163] During the estimation substep, the calculator 30 estimates a phase shift between the two reflected patterns.

[0164] For example, the calculator 30 searches for a sequence of a first reflected pattern in a second reflected pattern, the first reflected pattern being extracted before the second reflected pattern.

[0165] During the calculation substep, the calculator 30 calculates the lateral distance D by applying a function f to the estimated phase shift.

[0166] The function f is a function associating a lateral distance D with a phase shift between the two reflected patterns.

[0167] For example, the associated distance values ​​are contained in a table stored by a memory contained in the locating device 20.

[0168] According to another example, calculation step 400 is carried out differently.

[0169] In such an example, calculation step 400 includes a determination substep and a calculation substep.

[0170] During the determination substep, the calculator 30 determines a sub-motif extracted from one of the reflected motifs for which a correlation with a theoretical motif is maximal.

[0171] During the calculation substep, the calculator 30 calculates the lateral distance D by applying a function f to the sub-motif extracted from one of the reflected motifs.

[0172] The function f is a function associating a lateral distance D with an extracted sub-motif.

[0173] The process may also include additional steps.

[0174] For example, the localization process further includes a step of obtaining a height H of the aircraft 2 relative to the runway 4.

[0175] Height H is defined as the distance between aircraft 2 and runway 4 along the second transverse direction Z.

[0176] The height H is, for example, provided by an altimeter.

[0177] In such a case, during the determination step, the location is a three-dimensional location of the aircraft 2, the location being determined also as a function of the height H.

[0178] More specifically, in addition to the coordinates xa and ^4, the calculator 30 determines a third coordinate za as being the height.

[0179] In summary, the calculator 30 obtains the coordinates xa, and za by using the following mathematical relation: , s K, yA^A)=[M-x6A,D,H)

[0180] The localization method can also be used in other processes, in particular a control method.

[0181] In such a case, aircraft 2 is provided with additional elements as seen in [Fig.4].

[0182] Aircraft 2 further comprises a control device 40 comprising the location device 20 of [Fig.1] and a controller 50.

[0183] The controller 50 is configured to process signals from the locating device 20.

[0184] From a hardware point of view, the controller 50 is similar to the calculator 30 of the locating device 20, so the remarks made for the calculator 30 also apply here.

[0185] Thus, in particular, as with the calculator 30, the controller 50 includes a processor 52 and a memory 54 associated with the processor 52.

[0186] The operation of the control device 40 is now described with reference to [Fig.5] which illustrates an example of the implementation of a control method.

[0187] The control method aims to control aircraft 2, i.e. to ensure its proper progress during a landing or takeoff phase.

[0188] The control process includes a step of locating the aircraft relative to the runway during which the steps of the locating process of the [Fig.3] are implemented.

[0189] The method further comprises an estimation step 700 of the risk of the presence of an obstacle on the track and an alert step 800.

[0190] During the estimation step 700 of a percentage risk of the presence of an obstacle on the runway, a ground pattern is received by the radio transceiver 28, the ground pattern being the radio signal reflected by the ground of runway 4.

[0191] For example, the received floor pattern is compared to a reference floor pattern stored in memory 54 and the percentage of risk is determined based on the differences in amplitude and / or shape of the two patterns.

[0192] During alert step 800, the control device 40 issues an alert to an operator based on the estimated percentage and location of aircraft 2 relative to runway 4.

[0193] For example, the alert takes the form of a notification on a screen for the operator

[0194] The operator here is a pilot, a co-pilot or a member of the flight crew.

[0195] According to another example, the operator is the air traffic control (ATC) service and can authorize or prohibit takeoff or landing depending on the alert received.

[0196] According to another example, the system automatically interrupts the landing or takeoff when the percentage of risk exceeds a certain threshold.

[0197] The control procedure thus makes it possible to guarantee the safety of the aircraft under landing and takeoff conditions while preventing the risk of collision with any obstacles on the runway

[0198] The control procedure remains easy to implement.

Claims

Demands

1. A method for locating an aircraft (2) relative to a runway (4) on which aircraft (2) can land or take off, the runway (4) extending principally in a longitudinal direction (X), a first transverse direction (Y) being perpendicular to the first transverse direction (X), the runway (4) having a principal area bounded by two edges and at least one group of reflective elements (6A, 6B) for a radio signal, each group having one or more reflective elements (8A, 8B, 10A, 10B) arranged on one edge of the runway or on both edges of the runway, each reflective element (8A, 8B, 10A, 10B) being composed of at least one reflector, the method comprising the following steps: - transmitting a radio signal from the aircraft (2) to the runway (4), - receiving a signal reflected by the runway (4), - extracting at least one pattern from the reflected signal received,each pattern being the evolution over time of the radio signal reflected by at least one reflective element (8A, 10A) composing a group of reflective elements, called the tracking group (6A), - calculation of a lateral distance (D) and a longitudinal distance (M) from the received radio signal, the lateral distance (D) being the distance between the aircraft (2) and the runway (4) along the first transverse direction (Y), and the longitudinal distance (M) being the distance between the aircraft (2) and the tracking group (6A) along the longitudinal direction (X), and - determination of a location of the aircraft (2) as a function of the lateral distance (D) and the longitudinal distance (M).

2. A method according to claim 1, wherein the step of calculating the lateral distance (D) comprises the following substeps: - estimation of the distance Qf between the aircraft (2) and each of the reflective elements (8A, 10A) of the locating group (6A), and - calculation of the lateral distance (D) of the aircraft (10) as a function of the two estimated distances (^ and the position of the two reflective elements (8A, 10A) of the locating group (6A).

3. A method according to claim 1, wherein the step of calculating the lateral distance (D) comprises the following substeps: - estimation of a phase shift between the two patterns, and - calculation of the lateral distance (D) by applying a function to the estimated phase shift, the function associating a lateral distance (D) with a phase shift between the two patterns.

4. A method according to claim 1, wherein the step of calculating the lateral distance (D) comprises the following substeps: - determining a sub-motif extracted from one of the reflected motifs for which a correlation with a theoretical motif is maximal, and - calculating the lateral distance (D) by applying a function (f) to the extracted sub-motif, the function (f) associating a lateral distance (D) with an extracted sub-motif.

5. A method according to any one of claims 1 to 4, the method further comprising a step of obtaining the height (H) of the aircraft (2) along a second transverse direction (Z) relative to the runway (4) and wherein, during the determination step, the location is a three-dimensional location ( ) of the aircraft (2), the location also being a function of the height (H).

6. A method according to any one of claims 1 to 5, wherein the radio signal has a frequency belonging to the X band or the W band.

7. Method for controlling an aircraft (2), the control method comprising the following steps: - locating the aircraft (2) by implementation by a locating method (90) according to any one of claims 1 to 6, - estimating the risk of the presence of an obstacle on the runway (4) from a ground pattern, the ground pattern being the radio signal reflected by the ground of the runway (4), and - carrying out an action to interrupt the landing or takeoff according to the determined location and the estimated risk of presence.

8. A location device (20) for an aircraft relative to a runway (4) on which aircraft (2) may land or take off, the runway extending principally along a longitudinal direction (X), a first transverse direction (Y) being perpendicular to the longitudinal direction (X), the runway (4) having a principal area bounded by two edges and at least one group of reflective elements (6A) for a radio signal, each group having at least one reflective element (8A and 10A) disposed on one edge of the runway or on both of its edges, said location device (20) having a computer (30) configured to: - transmit a radio signal from an aircraft (2) to the runway (4), - receive a signal reflected by the runway (4), - extract at least one pattern from the received reflected signal,The patterns being the evolution over time of the radio signal reflected by the reflective elements (8A, 10A) composing a group of reflective elements, called the tracking group (6A), - calculate a lateral distance (D) and a longitudinal distance (M) as a function of the patterns, the lateral distance (D) being the distance between the aircraft (2) and the runway (4) along the first transverse direction (Y), and the longitudinal distance (M) being the distance between the aircraft (2) and the tracking group (6A) along the longitudinal direction (X), and - determine a location ( ) of the aircraft (2) as a function of the lateral distance (D) and the longitudinal distance (M).

9. A control device (40) for an aircraft relative to a runway (4) on which aircraft (2) may land or take off, the runway (4) extending principally in a longitudinal direction (X), a first transverse direction (Y) being perpendicular to the longitudinal direction (X), the runway (4) having a principal area bounded by two edges and at least one group of reflective elements (6A) for a radio signal, each group having at least one reflective element (8A and 10A) arranged on one edge of the runway or on both edges, said control device (40) having: - a localization device (20) of an aircraft (2) according to claim 8, and - a controller (50) configured to: - estimate a percentage risk of the presence of an obstacle on the runway (4) from a ground pattern, the ground pattern being the radio signal reflected by the ground of the runway (4); and - perform an automatic interruption action of the landing or takeoff according to the location determined by the localization device and the estimated percentage risk of presence.

10. Runway (4) on which aircraft can land or take off, the runway (4) extending principally along a longitudinal direction (X), a first transverse direction (Y) being perpendicular to the longitudinal direction (X), and comprising at least one group of reflective elements (6A) for a radio signal, each of the at least one group comprising at least one reflective element (8A and 10A) arranged on one edge of the runway or on both of its edges.

11. Track according to claim 10, wherein a spacing between groups is between 100 meters and 500 meters, the spacing between groups being the projection onto the longitudinal direction (X) of the distance between the two nearest points within two adjacent groups.

12. Runway according to claim 10 or 11, wherein a transverse distance is between 25 meters and 100 meters, the transverse distance being the distance between the nearest point of a reflective element (8A, 8B, 10A JOB) with a point of a main area of ​​the runway.

13. Track according to any one of claims 10 to 12, wherein a reflective element (8A, 8B, 10A JOB) comprises at least two trihedral reflectors.

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