METHOD AND DEVICE FOR ESTIMATING THE POSITION AND SPEED OF AN AIRCRAFT DURING AN AUTOMATIC LANDING TAKE-UP PHASE

Description

Technical domain

[0001] The present invention relates to a method and device for estimating the position and speed of an aircraft during an approach phase enabling an automatic landing. State of the art

[0002] The automatic landing of an aircraft on a runway imposes severe constraints on the implementation of the aircraft's navigation systems.

[0003] For each airport runway, there is generally one or more predefined approaches, published on aeronautical charts. Each approach corresponds to a reference approach path, which is characterized in particular by a reference approach axis for the runway in question. This reference approach axis can be defined by a lateral component and a vertical component. The lateral component is generally aligned with a longitudinal axis of the runway. The vertical component of the approach axis is generally at an angle of 3° to the runway.

[0004] During the approach phase to an airport runway, following a predefined approach path, an aircraft can be guided to land on the runway by a radio navigation system. This radio navigation system may be an Instrument Landing System (ILS). The radio navigation system includes at least one ground-based transmitting station configured to transmit guidance signals that allow the aircraft to approach the predefined approach path. Among these signals is a lateral guidance signal that allows the aircraft to determine its lateral deviation from the reference approach path (deviation from the lateral component of the approach path). This lateral guidance signal is generally called a "localizer signal."There is also a vertical guidance signal that allows the aircraft to know its vertical deviation from the reference approach path (deviation from the vertical component of the approach axis). This vertical guidance signal is generally called a "glide signal" or "glide slope signal".

[0005] There are several approach and landing procedures using an ILS system, designated CAT I, CAT II, ​​and CAT III. Category III includes subcategories CAT IIIa, CAT IIIb, and CAT IIIc and allows for an automatic landing potentially without a decision altitude setting for the aircraft pilot. Category I (CAT I) is a procedure that allows the aircraft to automatically descend to a decision altitude of 200 feet (61 m), provided the runway visual range (RVR) is sufficient.

[0006] Currently, only CAT II and CAT III categories (and associated CAT II / III ILS facilities) meet the necessary requirements (primarily accuracy and integrity) to perform a complete automatic landing to touch.

[0007] Category CAT I does not currently allow for such an automatic landing.

[0008] Document FR 3 111 710 A1 describes a method for estimating an angular deviation of a reference guidance axis, a position and a speed of an aircraft during an approach procedure for landing on a runway. Description of the invention

[0009] The present invention aims to remedy the problem by proposing a method and a device enabling the use of a CAT I type ILS installation for automatic landing operations.

[0010] For this purpose, it relates to a method for estimating, during an aircraft approach procedure for landing on a runway according to a predefined approach to said runway, a deviation from a reference guidance axis corresponding to said predefined approach to the runway, and a speed of an aircraft relative to the runway, the approach procedure being carried out using a landing aid device, the landing aid device comprising at least one transmitting station configured to emit at least one reference guidance signal defining the reference guidance axis,

[0011] According to the invention, the method comprises at least the following steps repeated iteratively: a first acquisition stage, implemented by a first acquisition unit, to acquire at least one current position of the aircraft determined by a geopositioning system; a second acquisition stage, implemented by a second acquisition unit, to acquire current inertial data of the aircraft in an inertial frame of reference, including at least one current acceleration determined by an inertial measurement unit; a third acquisition stage, implemented by a third acquisition unit, to acquire a current lateral deviation and a current vertical deviation from the reference guidance signal(s) emitted by the landing aid device; a first filtering stage, implemented by a first filtering unit,to estimate, using an extended Kalman filter, an unbiased aircraft velocity in the inertial frame from at least the aircraft's current position acquired in the first acquisition step and the aircraft's current inertial data acquired in the second acquisition step; a first frame-change step, implemented by a first frame-change unit, to determine the aircraft's unbiased velocity in a runway-linked frame from the unbiased velocity in the inertial frame estimated in the first filtering step; a second frame-change step, implemented by a second frame-change unit, to determine the aircraft's current position in the runway-linked frame from the current position acquired in the first acquisition step and runway location information from a database.a second filtering step, implemented by a second filtering unit, to estimate, using at least one extended Kalman filter, a lateral position and a vertical position of the aircraft in the runway-linked frame, from the current lateral deviation, the current vertical deviation, the unbiased velocity in the runway-linked frame, and the current position of the aircraft in the runway-linked frame determined in the second frame-change step, a determination step, implemented by a determination unit,to determine the current lateral deviation and current vertical deviation of the aircraft in the runway-linked frame, as well as the current lateral velocity and current vertical velocity of the aircraft in the runway-linked frame, estimated in the second filtering step from the lateral and vertical position of the aircraft and the unbiased velocity in the estimated inertial frame, a transmission step, implemented by a transmission unit, to transmit to a user device the current lateral deviation and current vertical deviation of the aircraft in the runway-linked frame, as well as the current lateral velocity and current vertical velocity of the aircraft in the runway-linked frame.

[0012] Thus, thanks to the filtering units, sufficient accuracy is obtained for the current lateral deviation, the current vertical deviation of the aircraft in the reference frame linked to the runway, as well as for the current lateral velocity and the current vertical velocity of the aircraft in the reference frame linked to the runway, for an automatic landing.

[0013] Furthermore, the extended Kalman filter of the first filtering stage presents: a state vector including the estimated unbiased velocity of the aircraft in the inertial frame, the estimated position of the aircraft and an acceleration bias in the inertial frame, a measurement vector including a position of the aircraft determined by the geo-positioning system in the first acquisition stage; the first filtering step comprising an update substep implemented by an update unit to update the estimated position using the current aircraft position determined by the geopositioning system in the first acquisition step, the extended Kalman filter of the first filtering step further presenting a dynamic evolution model comprising the following equations: dV n / dt = a n − 2 Ω e V e sin lat + V n V Z M lat + h − V e 2 tan lat N lat + h dV e / dt = a e + 2 Ω e V n sin lat + V Z cos lat + V e N lat + h V Z + V n tan lat dV d / dt = a Z − 2 Ω e V e cos lat − V n 2 M lat + h − V e 2 N lat + h + g D dlat / dt = V n M lat + h dlon / dt = V e N lat + h cos lat dh / dt = − V d dba n / dt = dba e / dt = dba Z / dt = 0 ; and an observation model comprising the following equation: lat GNSS = lat + v lat , GNSS lon GNSS = lon + v lon , GNSS h GNSS = h + v h , GNSS , in which: Ω and corresponds to the Earth's rotation speed, M corresponds to the meridian radius of curvature, N corresponds to the radius of curvature of the Earth's first vertical axis. gd corresponds to the acceleration due to gravity, latcorresponds to an estimated latitude coordinate of the aircraft's position within the geographic coordinate system. lon corresponds to an estimated longitude coordinate of the aircraft's position in the geographic coordinate system. h corresponds to an estimated height coordinate of the aircraft's position in the geographic coordinate system. GNSS lat< corresponds to a latitude coordinate of the aircraft's position as measured by the geopositioning system in the geographic coordinate system. on GNSS< corresponds to a longitudinal coordinate of the aircraft's position as measured by the geopositioning system in the geographic coordinate system. h GNSS< corresponds to a height coordinate of the aircraft's position as measured by the geo-positioning system in the geographic coordinate system. v lat , GNSS corresponds to white noise of the latitude coordinate measured by the geo-positioning system in the geographic coordinate system, v lon,GNSScorresponds to white noise from the measurement of the longitude coordinate measured by the geo-positioning system in the geographic coordinate system. vh,GNSS corresponds to white noise from the measurement of the height coordinate measured by the geo-positioning system in the geographic coordinate system, the corresponds to a coordinate of the aircraft's current acceleration in a North direction in the inertial frame of reference, ae corresponds to a coordinate of the aircraft's current acceleration in an East direction in the inertial frame of reference, to Z corresponds to a coordinate of the aircraft's current acceleration in a direction of Earth's gravity in the inertial frame of reference, for n corresponds to a coordinate of the bias of the aircraft's current acceleration in a North direction in the inertial frame of reference, bay corresponds to a coordinate of the bias of the aircraft's current acceleration in an East direction in the inertial frame of reference, to Z corresponds to a coordinate of the bias of the aircraft's current acceleration in a direction of Earth's gravity in the inertial frame of reference, V n corresponds to a coordinate of the aircraft's unbiased velocity in a North direction in the inertial frame of reference, V and corresponds to a coordinate of the aircraft's unbiased velocity in an East direction in the inertial frame of reference, VZ corresponds to a coordinate of the unbiased velocity of the aircraft in a direction of Earth's gravity in the inertial frame of reference.

[0014] According to a first embodiment, the current position of the aircraft determined by the geo-positioning system and the estimated position of the aircraft of the state vector of the extended Kalman filter of the first filtering stage are defined in the geographic coordinate system.

[0015] Furthermore, the second filtering stage implements a first extended Kalman filter and a second extended Kalman filter, the first extended Kalman filter having: a state vector comprising a lateral position of the aircraft in the frame linked to the runway, an angular alignment bias of a lateral guidance signal delivered by the landing aid device and a sensitivity factor bias of the lateral guidance signal; a measurement vector comprising the lateral position in the frame linked to the runway and a current lateral deviation measured in microamperes from the lateral guidance signal, the second extended Kalman filter having: a state vector comprising a vertical position in the frame linked to the runway,an angular alignment bias of a vertical guidance signal delivered by the landing aid device and a sensitivity factor bias of the vertical guidance signal; a measurement vector comprising the vertical position in the runway-linked frame and a current vertical deviation measured in DDM from the vertical guidance signal; the second filtering step comprising a first update substep implemented by a first update unit to update the aircraft's lateral position estimated by the first extended Kalman filter in the runway-linked frame using the aircraft's current position in the runway-linked frame determined in the second frame-change step,the second filtering step includes a second update substep implemented by a second update unit to update the aircraft's vertical position estimated by the first extended Kalman filter in the runway-linked frame using the aircraft's current vertical position in the runway-linked frame determined in the second frame-change step, the first extended Kalman filter implemented in the second filtering step having a dynamic evolution model comprising the following equations: , dY rwy / dt = V y rwy db LOC Sensi / dt = db Align / dt = 0 , and an observation model comprising the following equation: η loc = L 0 , 7 + b LOC Sensi ⋅ Y rwy − sin b Align ⋅ L − X rwy L − X rwy + ν loc , in which: η control corresponds to a current lateral deviation in microamperes acquired from the reference guidance signal(s) emitted by the landing aid device, v loccorresponds to a measurement noise of the current lateral deviation L corresponds to a distance between the threshold of the landing runway and the transmitting station which emits the reference lateral guidance signal. b LOCSense corresponds to a sensitivity factor bias of the reference lateral guidance signal relative to a standardized reference lateral signal of 0.7, b Align corresponds to the angular alignment bias of the lateral guidance signal, X king corresponds to a longitudinal position of the aircraft in the reference frame linked to the runway, Y rwy corresponds to a lateral position of the aircraft in the reference frame linked to the runway, V yrwy corresponds to an unbiased lateral velocity of the aircraft in the frame of reference linked to the runway; the second extended Kalman filter implemented in the second filtering stage presents a dynamic evolution model comprising the following equations: dZ rwy / dt = V z rwy db GLD Sensi / dt = db GPA / dt = 0 , and an observation model comprising the following equation: η GLD = 0 , 0875 GPA − b GPA ⋅ 0 , 12 − b GLD Sensi ⋅ atan Zrwy X rwy + dX − GPA − b GPA + ν GLD , in which: η GLD corresponds to a current vertical deviation in DDM acquired from the reference guidance signal(s) emitted by the landing aid device, v GLD corresponds to a measurement noise of the current vertical deviation, b GLDSense corresponds to a sensitivity factor bias of the reference vertical guidance signal relative to a standardized vertical guidance signal of 0.12, GPA corresponds to an angle between the vertical guidance axis defined by the vertical guidance signal and the landing runway, b GPA corresponds to the angular alignment bias of the vertical guidance signal, v GLD corresponds to a measurement noise of the current vertical deviation, dX corresponds to a longitudinal distance between the threshold of the landing runway and the transmitting station that emits the reference vertical guidance signal, Z kingcorresponds to the vertical position of the aircraft in the reference frame linked to the runway, V zrwy corresponds to an unbiased vertical speed of the aircraft in the reference frame linked to the landing runway.

[0016] Furthermore, the current lateral deviation is equal to the aircraft's lateral position estimated by the first extended Kalman filter in the runway-linked frame of reference; the current lateral velocity is equal to the lateral velocity estimated by the first extended Kalman filter in the runway-linked frame of reference. and the aircraft's current vertical deviation corresponds to the following expression: DZ = Z rwy − X rwy + dX ⋅ tan GPA − b GPA , the aircraft's current vertical speed corresponds to the following expression: DVZ = V g ⋅ tan GPA − b GPA − V Z rwy .

[0017] According to a second embodiment, the current position of the aircraft determined by the geo-positioning system and the estimated position of the aircraft of the state vector of the extended Kalman filter of the first filtering stage are expressed in pseudo-distance.

[0018] The invention also relates to a device for estimating, during an aircraft approach procedure for landing on a runway according to a predefined approach to said runway, a deviation from a reference guidance axis corresponding to said predefined approach to the runway, and a speed of an aircraft relative to the runway, the approach procedure being carried out using a landing aid device, the landing aid device comprising at least one transmitting station configured to emit a reference guidance signal defining the reference guidance axis,

[0019] According to the invention, the device comprises at least: a first acquisition unit configured to acquire at least one current position of the aircraft determined by a geopositioning system, a second acquisition unit configured to acquire current inertial data of the aircraft in an inertial frame including at least one current acceleration determined by an inertial measurement unit, a third acquisition unit configured to acquire a current lateral deviation and a current vertical deviation from the reference guidance signal(s) emitted by the landing aid device, a first filtering unit configured to estimate, using an extended Kalman filter, an unbiased velocity of the aircraft in the inertial frame from at least the current position of the aircraft acquired by the first acquisition unit and the current inertial data of the aircraft acquired by the second acquisition unit,a first reference frame change unit configured to determine the unbiased velocity of the aircraft in a reference frame linked to the runway from the unbiased velocity in the inertial reference frame estimated by the first filtering unit, a second reference frame change unit configured to determine the current position of the aircraft in the reference frame linked to the runway from the current position acquired by the first acquisition unit and runway location information from a database, a second filtering unit configured to estimate, using at least one extended Kalman filter, a lateral position and a vertical position of the aircraft in the reference frame linked to the runway, from the current lateral deviation, the current vertical deviation,the unbiased velocity in the runway-linked frame and the current aircraft position in the runway-linked frame determined by the second frame-change unit, a determination unit configured to determine the current lateral deviation and current vertical deviation of the aircraft in the runway-linked frame as well as the current lateral velocity and current vertical velocity of the aircraft in the runway-linked frame estimated by the second filtering unit from the lateral and vertical position of the aircraft as well as the unbiased velocity in the estimated inertial frame,a transmission unit configured to transmit to a user device the current lateral deviation and current vertical deviation of the aircraft in the reference frame linked to the runway, as well as the current lateral velocity and current vertical velocity of the aircraft in the reference frame linked to the runway,

[0020] The invention also relates to an aircraft comprising an estimation device, such as that specified above. Brief description of the figures

[0021] The accompanying figures will clearly illustrate how the invention can be implemented. In these figures, identical reference numerals designate similar elements. There figure 1 represents a schematic view of the estimation device. figure 2 represents a schematic view of the estimation process. figure 3 This represents a top-down view of an aircraft during an approach procedure in preparation for landing on a runway. figure 4 This represents a profile view of an aircraft during an approach procedure for landing on a runway. figure 5 represents a profile view of an aircraft carrying the estimation device. Detailed Description

[0022] There figure 1 represents the device for estimating S of a deviation DY, DZ relative to a reference guide axis A and a speed DVY, DVZ of an AC aircraft relative to a runway RWY during an approach procedure of an AC aircraft for landing on the runway RWY according to a predefined approach to said runway RWY. The reference guidance axis A corresponds to a predefined approach to the runway RWY ( figure 3 ).

[0023] In the remainder of the description, this device is referred to as the "S estimation device".

[0024] The RWY runway defines a coordinate system in which the origin of said system corresponds to a threshold T of the RWY runway, the x-axis of said system is driven by a unit vector parallel to the longitudinal axis B1 of the RWY runway, the y-axis is driven by a unit vector perpendicular to the longitudinal axis B1 of the runway, and the elevation axis is driven by a unit vector perpendicular to the plane comprising the x-axis and the y-axis. In the following description, this coordinate system is referred to as the "RWY runway coordinate system".

[0025] The S estimation device can be integrated into flight control computers on board the aircraft AC in software form.

[0026] The approach procedure is carried out using a landing aid device, such as an ILS system. The landing aid device includes at least one transmitting station 22 configured to transmit a reference guidance signal defining the reference guidance axis A.

[0027] One transmitting station emits a lateral reference guidance signal corresponding to a "localizer signal." Another transmitting station emits a vertical reference guidance signal corresponding to a "glide slope signal." The lateral reference guidance signal defines the lateral component of the reference guidance axis A. The vertical reference guidance signal defines the vertical component of the reference guidance axis A.

[0028] The estimation device S includes at least: a first acquisition unit 1, a second acquisition unit 2, a third acquisition unit 3, a first filtering unit 4, a first reference frame change unit 5, a second reference frame change unit 6, a second filtering unit 7, a determination unit 8, a transmission unit 9.

[0029] The first acquisition unit 1 is configured to acquire at least one current position ( GNSS lat< , GNSS lon< , h GNSS< ) of the AC aircraft determined by a GNSS geo-positioning system.

[0030] The geo-positioning system can correspond to a geolocation and navigation system by a GNSS satellite system (“Global Navigation Satellite System” in English), such as a GPS system (“Global Positioning System” in English).

[0031] For example, the GPS system can be used with a Satellite-Based Augmentation System (SBAS). This variant allows for obtaining a current position ( GNSS lat< , GNSS lon< , h GNSS< ) of the AC aircraft more precisely.

[0032] In other examples, the GPS system can be replaced by a Galileo, Glonass or Beidou system.

[0033] In a first embodiment, the current position ( GNSS lat< , GNSS lon< , h GNSS< The position of the AC aircraft can be determined by the GNSS geopositioning system in a geographic coordinate system. In the geographic coordinate system, the current position ( GNSS lat< , GNSS lon< , h GNSS< ) is defined by a latitude coordinate (in degrees) GNSS lat< , a longitude coordinate (in degrees) on GNSS< and a height coordinate (in meters) h GNSS< .

[0034] In a second embodiment, the current position of aircraft AC determined by the GNSS geopositioning system is expressed in pseudo-distances. A pseudo-distance corresponds to an indirect value of the distance between a transmitting satellite of the geopositioning system and the GNSS geopositioning system by comparing the time of reception of a signal received by the GNSS geopositioning system and the time of transmission of the signal by the transmitting satellite without taking into account the synchronization of the clocks of the GNSS geopositioning system and the transmitting satellite.

[0035] The second acquisition unit 2 is configured to acquire current inertial data of the AC aircraft in an inertial frame of reference of which at least one current acceleration ( the , ae , az ) determined by an IRS (Inertial Reference System) unit on board the aircraft AC.

[0036] The inertial frame of reference corresponds to a North-East-Down (NED) frame. The NED frame is defined by a plane tangent to the Earth's surface. The NED frame includes a unit vector on the x-axis coinciding with the North direction, a unit vector on the y-axis coinciding with the East direction, and a unit vector at the elevation point coinciding with the direction of gravity. The origin of this frame is chosen so that it coincides with the aircraft's center of gravity.

[0037] For the current acceleration ( the , ae , az ), the coordinate (in m / s 2< ) the is carried by the unit vector coinciding with the North direction. The coordinate (in m / s²) ae is carried by the unit vector coinciding with the East direction. The coordinate (in m / s²) as is carried by the unit vector coinciding with the direction of gravity.

[0038] The third acquisition unit 3 is configured to acquire a current lateral gap η LOC and a current vertical gap η GLD from the reference guidance signal(s) emitted by the landing aid device 22.

[0039] The current lateral gap η LOC is determined from the reference lateral signal defining the lateral component of the reference guide axis A.

[0040] The current vertical gap η GLD is determined from the reference vertical guidance signal defining the vertical component of the reference guidance axis A. The first filtering unit 4 is configured to estimate, using an extended Kalman filter, an unbiased velocity ( V n , V e , V d ) of the aircraft AC in the inertial frame of reference from at least the current position ( GNSS lat< , GNSS lon< , h GNSS<) of the AC aircraft acquired by the first acquisition unit 1 and current inertial data of the AC aircraft acquired by the second acquisition unit 2.

[0041] In the inertial frame of reference, the coordinate (in m / s) V n is carried by the unit vector coinciding with the North direction. The coordinate (in m / s) V and is carried by the unit vector coinciding with the East direction. The coordinate (in m / s) V z is carried by the unit vector coinciding with the direction of Earth's gravity. The extended Kalman filter of the first filtering unit 4 can exhibit a state vector including the unbiased velocity ( V n , V e , V d ) estimated position of aircraft AC in the inertial frame of reference, (lat, long, h) estimated AC aircraft and an acceleration bias ( for n , for e , for Z ) in the inertial frame of reference.

[0042] In the geographical coordinate system, the position (lat, long, h)The estimated altitude of aircraft AC is therefore defined by a latitude coordinate (in degrees). lat, a longitude coordinate (in degrees) lon and a height coordinate (in meters) (or altitude) h. In the inertial frame of reference, the current acceleration bias ( for n , for e , for Z ) is defined by a coordinate (in m / s 2< ) for n in a North direction, a coordinate (in m / s 2< ) bay in an East direction and a coordinate (in m / s 2< ) to Z in a direction of Earth's gravity.

[0043] According to the first embodiment, the position (lat, long, h) The estimated AC aircraft of the state vector of the extended Kalman filter of the first filtering stage E4 is defined in the geographic coordinate system.

[0044] In the continuation of the description of the estimation device S, the current position ( GNSS lat< , GNSS lon< , h GNSS< ) of the AC aircraft and the position (lat, long, h) The estimated values ​​of the AC aircraft are defined in the geographic coordinate system.

[0045] The said extended Kalman filter of the first filtering unit 4 may also have a measurement vector comprising a position ( GNSS lat< , GNSS lon< , h GNSS< ) of the aircraft AC determined by the GNSS geopositioning system in the first acquisition step E1. The first filtering step E4 may include an update substep E41 to update the position (lat, long, h) estimated using the current position ( GNSS lat< , GNSS lon< , h GNSS< ) of the aircraft AC determined by the GNSS geo-positioning system in the first acquisition stage E1.

[0046] Furthermore, the extended Kalman filter of the first filtering unit 4 can implement an evolution model comprising the following equations: dV n / dt = a n − 2 Ω e V e sin lat + V n V z M lat + h − V e 2 tan lat N lat + h dV e / dt = a e + 2 Ω e V n sin lat + V z cos lat + V e N lat + h V z + V n tan lat dV d / dt = a z − 2 Ω e V e cos lat − V n 2 M lat + h − V e 2 N lat + h + g d dlat / dt = V n M lat + h dlon / dt = V e N lat + h cos lat dh / dt = − V d dba n / dt = dba e / dt = dba Z / dt = 0 ; and an observation model comprising the following equation: lat GNSS = lat + ν lat , GNSS lon GNSS = lon + ν lon , GNSS h GNSS = h + ν h , GNSS . in which: Ω and corresponds to the Earth's rotation speed (in rad / s). M corresponds to the meridian radius of curvature (in meters). N corresponds to the radius of curvature of the Earth's first vertical axis (in meters). gd corresponds to the acceleration due to gravity (in m / s²). lat corresponds to an estimated latitude coordinate of the position of aircraft AC in the geographic reference frame (in degrees). lon corresponds to an estimated longitude coordinate of the position of aircraft AC in the geographic coordinate system (in degrees). h corresponds to an estimated height coordinate of the position of aircraft AC in the geographic coordinate system (in degrees). GNSS lat< corresponds to a latitude coordinate of the position of the aircraft AC measured by the GNSS geo-positioning system in the geographic coordinate system (in degrees). on GNSS<corresponds to a longitude coordinate of the position of the aircraft AC measured by the GNSS geo-positioning system in the geographic coordinate system (in degrees). h GNSS< corresponds to a height coordinate of the position of the aircraft AC measured by the GNSS geo-positioning system in the geographic coordinate system (in degrees). v lat , GNSS corresponds to white noise from the latitude coordinate measurement lat (in degrees). v lon,GNSS corresponds to white noise from the measurement of the longitude coordinate lon (in degrees). vh,GNSS corresponds to white noise from the height coordinate measurement h (in degrees). the corresponds to a coordinate of the current acceleration of aircraft AC in a North direction in the inertial frame of reference. ae corresponds to a coordinate of the current acceleration of aircraft AC in an East direction in the inertial frame of reference. to Zcorresponds to a coordinate of the current acceleration of aircraft AC in a direction of Earth's gravity in the inertial frame of reference. for n corresponds to a coordinate of the bias of the current acceleration of aircraft AC in a North direction in the inertial frame of reference. bay corresponds to a coordinate of the bias of the current acceleration of aircraft AC in an East direction in the inertial frame of reference. to Z corresponds to a coordinate of the bias of the current acceleration of aircraft AC in a direction of terrestrial gravity in the inertial frame of reference. V n corresponds to a coordinate of the unbiased velocity of aircraft AC in a North direction in the inertial frame (in m / s). V and corresponds to a coordinate of the unbiased velocity of aircraft AC in an East direction in the inertial frame (in m / s). VZcorresponds to a coordinate of the unbiased velocity of the aircraft AC in a direction of terrestrial gravity in the inertial frame of reference (in m / s).

[0047] The first unit of frame change 5 is configured to determine the unbiased velocity ( V xrwy , V yrwy , V zrwy ) of aircraft AC in the reference frame linked to the landing runway RWY from the unbiased speed ( V n , V e , V d ) in the inertial frame estimated by the first filtering unit 4.

[0048] Once the current position ( GNSS lat< , GNSS lon< , h GNSS< ) of aircraft AC is estimated and the unbiased speed ( V n , V e , V d ) in the inertial frame is estimated, the first unit of frame change 5 determines the unbiased velocity ( V xrwy , V yrwy , V zrwy ) V zrwy ) of aircraft AC in the frame of reference linked to the runway RWY using the following equations: V x rwy = cos ψ r V n + sin ψ r V e V y rwy = sin ψ r V n − cos ψ r V e V z rwy = − V d in which ψ rcorresponds to the orientation (in rad) of the runway (“runway heading” in English) which corresponds to the orientation of the longitudinal axis B1 of the runway RWY with respect to the North direction.

[0049] V xrwy corresponds to the coordinate of the unbiased velocity (in m / s) carried by the unit vector parallel to the longitudinal axis B1 of the RWY landing runway (longitudinal unbiased velocity).

[0050] V yrwy corresponds to the coordinate of the unbiased velocity (in m / s) carried by the unit vector perpendicular to the longitudinal axis B1 of the RWY landing runway (lateral unbiased velocity).

[0051] V zrwy corresponds to the coordinate of the unbiased velocity (in m / s) carried by the unit vector carried perpendicular to the plane comprising the x-axis and the y-axis (vertical unbiased velocity).

[0052] The orientation of the runway ψ r can be provided by a NAVDB navigation database.

[0053] The second unit of reference frame change 6 is configured to determine the current position ( X rwy GNSS , Y rwy GNSS , Z rwy GNSS ) of aircraft AC in the reference frame linked to runway RWY from the current position GNSS lat< , GNSS lon< , h GNSS< acquired by the first acquisition unit 1 and RWY runway location information from the database, such as the NAVDB navigation database.

[0054] The current position ( X rwy GNSS , Y rwy GNSS , Z rw GNSS ) of aircraft AC in the reference frame linked to runway RWY includes: the coordinate X rwy GNSS which corresponds to the coordinate of the current position (in meters) carried by the unit vector parallel to the longitudinal axis B1 of the RWY runway (longitudinal position acquired by the first acquisition unit 1), the coordinate Y rwy GNSS which corresponds to the coordinate of the current position (in meters) carried by the unit vector perpendicular to the longitudinal axis B1 of the RWY runway (lateral position acquired by the first acquisition unit 1), the coordinate Z rwy GNSS which corresponds to the coordinate of the current position (in meters) carried by the unit vector carried perpendicular to the plane comprising the x-axis and the y-axis (vertical position acquired by the first acquisition unit 1).

[0055] The second filtering unit 7 is configured to estimate a lateral position using at least one extended Kalman filter F king and a vertical position Z king of aircraft AC in the reference point linked to the runway RWY from the current lateral deviation η LOC , the current vertical gap η GLD , unbiased speed ( V xrwy , V yrwy , V zrwy ) in the reference frame linked to the RWY runway and the current position ( X rwy GNSS , ) Y rwy GNSS , Z rwy GNSS ) of aircraft AC in the reference frame linked to the landing runway RWY determined by the second reference frame change unit 6,.

[0056] The second filtering unit 7 can implement a first extended Kalman filter and a second extended Kalman filter.

[0057] The first extended Kalman filter of the second filtering unit 7 can have a state vector with a lateral position Y rwy (in meters) of aircraft AC in the reference frame linked to runway RWY, an angular alignment bias b Align (in radians) of a lateral guidance signal delivered by the landing aid device and a sensitivity factor bias b LOCSense of the lateral guidance signal.

[0058] The sideways position Y rwy corresponds to the coordinate of the aircraft's position along the ordinate axis in the coordinate system linked to the RWY runway.

[0059] The angular alignment bias of the lateral guidance signal b Align This corresponds to an angular deviation of the lateral guidance signal (Localizer signal) that defines a lateral guidance axis relative to the lateral component of the reference approach axis corresponding to the longitudinal axis of runway RWY. The longitudinal axis B1 of runway RWY corresponds to an axis that divides runway RWY into two substantially identical parts along the length of runway RWY.

[0060] The first extended Kalman filter of the second filtering unit 7 can also present a measurement vector including the current lateral position Y rwy GNSS (in meters) in the reference frame linked to the RWY runway and a current lateral deviation η LOC measured in microamperes or DDM from the reference lateral guidance signal and acquired by the third acquisition unit 3.

[0061] The current lateral gap η LOC Measured in DDM (Difference in Depth Modulation), it means that it is measured as a difference in modulation rates. In practice, it is expressed as a percentage. The lateral guidance signal has two parts. Each part is transmitted at a different frequency. The DDM corresponds to the difference between the modulation rate of one part transmitted at one frequency and the modulation rate of the other part transmitted at a different frequency. The lateral deviation is zero if the aircraft AC is following a trajectory aligned with the lateral guidance axis.

[0062] The first extended Kalman filter of the second filtering unit 7, which can be implemented in the second filtering unit 7, can implement an evolution model comprising the following equations: dY rwy / dt = V y rwy db LOC Sensi / dt = db Align / dt = 0 , and an observation model comprising the following equation: η loc = L 0 , 7 + b LOC Sensi ⋅ Y rwy − sin b Align ⋅ L − X rwy L − X rwy + ν loc .

[0063] η controlcorresponds to a current lateral deviation acquired by the third acquisition unit 3 from the reference guidance signal(s) emitted by the landing aid device 22.

[0064] v loc corresponds to a measurement noise (in microamps) of the current lateral deviation L corresponds to a distance (in meters) between the threshold T of the landing runway RWY and the transmitting station which emits the reference lateral guidance signal.

[0065] b LOCSense corresponds to a sensitivity factor bias of the reference lateral guidance signal (Localizer) relative to a standardized lateral signal of 0.7.

[0066] The standardized sensitivity factor of 0.7 corresponds to a sensitivity factor that complies with the standards of the International Civil Aviation Organization (ICAO).

[0067] b Aligncorresponds to the angular alignment bias of the lateral guidance signal. X king corresponds to the longitudinal position (in a direction parallel to the longitudinal axis of the RWY runway along the x-axis) of the aircraft AC in the reference frame linked to the RWY runway (in meters).

[0068] Y rwy corresponds to the lateral position of aircraft AC in the reference frame linked to runway RWY (in meters).

[0069] V yrwy corresponds to an unbiased lateral velocity of aircraft AC in the reference frame linked to the landing runway RWY (in m / s).

[0070] The second extended Kalman filter of the second filtering unit 7 can exhibit a state vector with a vertical position Z king (in meters) in the coordinate system linked to the RWY runway, an angular alignment bias b GPA(in radians) of a vertical guidance signal delivered by the landing aid device and a sensitivity factor bias b GLDSense of the vertical guidance signal.

[0071] The vertical position Z king corresponds to the coordinate of the aircraft's position along the axis of the dimensions in the reference frame linked to the RWY landing runway.

[0072] The angular alignment bias of the vertical guidance signal b GPA corresponds to an angular deviation of the vertical guidance signal (Glide Slope signal) which defines a vertical guidance axis A with respect to the vertical component of the reference approach axis B2 making a predetermined angle with the runway RWY. Without limitation, the predetermined angle is equal to 3° ( figure 4 ). The predetermined angle can also be provided by the NAVDB navigation database.

[0073] The second extended Kalman filter of the second filtering unit 7 can also present a measurement vector including the vertical position Z rwy GNSS of the aircraft in the reference frame linked to the RWY landing runway and a current vertical deviation η GLD measured in DDM or microamps from the reference vertical guidance signal.

[0074] The current vertical gap η GLD measured in DDM (Difference in the Depth Modulation), as for the current lateral deviation η LOC , This means it is measured as a difference in modulation rates. The vertical guidance signal has two parts. Each part is transmitted at a different frequency. The DDM (Difference in Modulation Rate) corresponds to the difference between the modulation rate of one part transmitted at one frequency and the modulation rate of the other part transmitted at a different frequency. The vertical deviation is zero if the aircraft AC (Aircraft Control) follows a trajectory aligned with the vertical guidance axis.

[0075] The second extended Kalman filter of the second filtering unit 7, which can be implemented in the second filtering unit 7, implements an evolution model comprising the following equations: dZ rwy / dt = V z rwy db GLD Sensi / dt = db GPA / dt = 0 , and an observation model comprising the following equation: η GLD = 0 , 0875 GPA − b GPA ⋅ 0 , 12 − b GLD Sensi ⋅ atan Zrwy X rwy + dX − GPA − b GPA + ν GLD .

[0076] η GLD corresponds to a current vertical deviation acquired (in DDM) by the third acquisition unit 3 from the reference guidance signal(s) emitted by the landing aid device 22.

[0077] v GLD corresponds to a measurement noise (in DDM) of the current vertical deviation η GLD . b GLDSense corresponds to a sensitivity factor bias of the reference vertical guidance signal (Glide slope) relative to a standardized vertical guidance signal of 0.12 (by ICAO).

[0078] GPAcorresponds to an angle (in radians) between the vertical guidance axis defined by the vertical guidance signal (Glide Slope signal) and the RWY landing runway.

[0079] b GPA corresponds to the angular alignment bias of the vertical guidance signal (in radians).

[0080] v GLD corresponds to a measurement noise (in DDM) of the current vertical deviation η GLD . dX corresponds to a distance (in meters) between the threshold T of the RWY landing runway and the transmitting station which emits the reference vertical guidance signal.

[0081] dX can be determined from the following equation: dX = TCH / tan( GPA ) in which TCH corresponds to the height (in meters) relative to the threshold T of the RWY runway at which the vertical deviation is zero (in meters).

[0082] Z kingcorresponds to the vertical position of aircraft AC in the reference frame linked to the landing runway RWY (in meters).

[0083] V zrwy corresponds to an unbiased vertical velocity of aircraft AC in the reference frame linked to runway RWY (in m / s).

[0084] The second filtering unit 7 may include a first update unit 71 configured to update the lateral position F king of aircraft AC estimated by the first extended Kalman filter in the reference frame linked to runway RWY using the current lateral position Y rwy GNSS of aircraft AC in the reference frame linked to the landing runway RWY determined by the second reference frame change unit 6.

[0085] The second filtering unit 7 may also include a second update unit 72 configured to update the vertical position Z kingof aircraft AC estimated by the first extended Kalman filter in the reference frame linked to the runway RWY using the current vertical position Z rwy GNSS of aircraft AC in the reference frame linked to the landing runway RWY determined by the second reference frame change unit 6.

[0086] The unit of determination 8 is configured to determine the lateral deviation DY current and vertical deviation DZ current aircraft AC in the reference frame linked to the runway RWY as well as the lateral speed DVY current and vertical speed DVZ current position of aircraft AC in the reference point linked to the runway RWY from the lateral position Y rw and the vertical position Z king of the AC aircraft as well as the unbiased speed ( V n , V e , V d ) estimated in the inertial frame of reference.

[0087] Lateral deviation DY current is equal to the lateral position F king of aircraft AC estimated by the first extended Kalman filter in the reference frame linked to runway RWY. Lateral velocity DVY current is equal to the lateral velocity V Yrwy estimated by the first extended Kalman filter in the frame linked to the RWY landing strip.

[0088] The vertical deviation DZ The current state of aircraft AC corresponds to the following expression: DZ = Z rwy − X rwy + dX ⋅ tan GPA − b GPA .

[0089] Vertical speed DVZ The current state of aircraft AC corresponds to the following expression: DVZ = V g ⋅ tan GPA − b GPA − V Z rwy .

[0090] V g corresponds to the ground velocity of the aircraft AC.

[0091] The said ground speed is equal to the following expression: V g = V e 2 + V n 2 .

[0092] The transmission unit 9 is configured to transmit the lateral deviation to a user device 10 DY current and vertical deviation DZ current aircraft AC in the reference frame linked to the runway RWY as well as the lateral speed DVY current and vertical speed DVZ current of aircraft AC in the reference frame linked to the landing runway RWY estimated by the second filtering unit 7.

[0093] The user device 10 may correspond to an automatic landing system configured to pilot the aircraft AC for landing on the runway RWY.

[0094] The invention also relates to an estimation method ( figure 2 ), during an approach procedure of an AC aircraft for landing on a runway RWY according to a predefined approach to said runway RWY, of a deviation DY, DZ relative to a reference guidance axis A corresponding to said predefined approach to the RWY runway, and at a speed DVY, DVZof an aircraft AC relative to the runway RWY, the approach procedure being carried out using a landing aid device, the landing aid device comprising at least one transmitting station 22 configured to transmit a reference guidance signal defining the reference guidance axis A.

[0095] The estimation process includes at least the following steps repeated iteratively: a first acquisition step E1, implemented by the first acquisition unit 1, to acquire at least one current position ( GNSS lat< , GNSS lon< , h GNSS< ) of the aircraft AC determined by a GNSS geopositioning system, a second acquisition stage E2, implemented by the second acquisition unit 2, to acquire current inertial data of the aircraft AC in an inertial frame of reference of which at least one current acceleration ( and , ae , azdetermined by an inertial measurement unit (IRS), a third acquisition stage E3, implemented by a third acquisition unit 3 to acquire a current lateral deviation η LOC and a current vertical gap η GLD from the reference guidance signal(s) emitted by the landing aid device 22, a first filtering stage E4, implemented by the first filtering unit 4, to estimate, using an extended Kalman filter, an unbiased speed ( V n , V e , V d ) of the aircraft AC in the inertial frame of reference from at least the current position ( GNSS lat< , GNSS lon< , h GNSS< ) of the AC aircraft acquired in the first acquisition stage E1 and current inertial data of the AC aircraft acquired in the second acquisition stage E2, a first reference frame change stage E5, implemented by the first reference frame change unit 5, to determine the unbiased velocity ( V xrwy , V yrwy , V zrwy) of aircraft AC in a reference frame linked to runway RWY from the unbiased speed ( V n , V e , V d ) in the inertial frame estimated in the first filtering step E4, a second frame change step E6, implemented by the second frame change unit 6, to determine the current position ( X rwy GNSS , Y rwy GNSS , Z rwy GNSS ) of aircraft AC in the reference frame linked to runway RWY from the current position ( GNSS lat< , lon GNSS< , h GNSS< ) acquired in the first acquisition step E1 and RWY runway location information from the database, such as the NAVDB navigation database, a second filtering step E7, implemented by the second filtering unit 7, to estimate a lateral position using at least one extended Kalman filter Y rwy and a vertical position Z king of aircraft AC in the reference point linked to runway RWY, from the current lateral deviation η LOC , the current vertical gap η GLD , unbiased speed ( V xrwy , V yrwy , V zrwy ) in the reference frame linked to the RWY runway and the current position ( X rwy GNSS , Y rwy GNSS , Z rwy GNSS ) of aircraft AC in the reference frame linked to the landing runway RWY determined in the second reference frame change step E6, a determination step E8, implemented by determination unit 8, to determine the lateral deviation DY current and vertical deviation DZ current aircraft AC in the reference frame linked to the runway RWY as well as the lateral speed DVY current and vertical speed DVZ current position of aircraft AC in the reference frame linked to the runway RWY estimated in the second filtering stage 6 from the lateral position Y rwy and the vertical position Z king of the AC aircraft as well as the unbiased speed ( V n , V e , V d) in the estimated inertial frame, a transmission step E9, implemented by the transmission unit 9, to transmit the lateral deviation to a user device 10 DY current and vertical deviation DZ current aircraft AC in the reference frame linked to the runway RWY as well as the lateral speed DVY current and vertical speed DVZ current of aircraft AC in the reference point linked to the landing runway RWY.

[0096] The extended Kalman filter of the first filtering stage E4 may exhibit: a state vector including the unbiased velocity ( V n , V e , V d ) estimated position of aircraft AC in the inertial frame of reference, (lat, long, h) estimated of the aircraft AC) and an acceleration bias ( for n , for e , for Z ) in the inertial frame, a measurement vector comprising a position ( GNSS lat< , GNSS lon< , h GNSS<) of the aircraft AC determined by the GNSS geo-positioning system in the first acquisition stage E1.

[0097] The first filtering step E4 may include an update substep E41, implemented by the update unit 41 to update the position (lat, long, h) estimated using the current position ( GNSS lat< , GNSS lon< , h GNSS< ) of the aircraft AC determined by the GNSS geo-positioning system in the first acquisition stage E1.

[0098] The extended Kalman filter of the first filtering stage E4 can implement an evolution model and an observation model as described above for the first filtering unit 4

[0099] The second filtering stage E7 can implement a first extended Kalman filter and a second extended Kalman filter as described above for the second filtering unit 7.

[0100] The second filtering step E7 may include a first update substep E71 implemented by the first update unit 71 to update the lateral position Y rwy of aircraft AC estimated by the first extended Kalman filter in the reference frame linked to runway RWY using the current position Y rwy GNSS of aircraft AC in the reference point linked to the landing runway RWY determined in the second reference point change step E6.

[0101] The second filtering step E7 may include a second update substep E72 implemented by the second update unit 72 to update the vertical position Z king of aircraft AC estimated by the first extended Kalman filter in the reference frame linked to the runway RWY using the current vertical position Z rwy GNSS of aircraft AC in the reference point linked to the landing runway RWY determined in the second reference point change step E6.

[0102] The first extended Kalman filter implemented in the second filtering stage E7 can implement an evolution model and an observation model as described above for the second filtering unit 7.

[0103] The second extended Kalman filter implemented in the second filtering stage E7 can implement an evolution model and an observation model as described above for the second filtering unit 7.

[0104] The estimation device S and the estimation method offer many advantages.

[0105] They allow for an estimation of velocity biases based on a fusion of measurements from a GNSS geopositioning system and measurements from an IRS inertial navigation system. This makes it possible to obtain unbiased velocities before the approach procedure is carried out using an ILS landing aid in order to: serve as input data in the second filtering unit 7, serve as input data for the control laws to capture the reference guidance signals.

[0106] The observation models used in the second filtering unit 7 provide sufficient accuracy for automatic landing thanks to the introduction of estimation: two biases related to the signal transmitting station Localizer b LOCSense And b Align , two biases related to the signal transmitting station of the Glide Slope signal b GLDSense And b GPA .

[0107] Monitoring these estimated values ​​can alert to erroneous reference guidance signals acquired by the third acquisition unit 3.

[0108] Furthermore, a decentralized estimation architecture allows for better analysis, monitoring, and adjustment of the different units of the estimation device S.

Claims

1. A method for estimating, during an approach procedure for an aircraft (AC) with a view to landing on a landing runway (RWY) following a predefined approach to said landing runway (RWY), a deviation (DY, DZ) relative to a reference guidance axis (A) corresponding to said predefined approach to the landing runway (RWY), and a speed (DVY, DVZ) of an aircraft (AC) relative to the landing runway (RWY), the approach procedure being carried out with the assistance of a landing aid device (ILS), the landing aid device (ILS) comprising at least one transmitter station (22) configured to transmit at least one reference guidance signal defining the reference guidance axis (A), comprising at least the following iteratively repeated steps: - a first acquisition step (E1), implemented by a first acquisition unit (1), for acquiring at least one current position (latGNSS, lonGNSS, hGNSS) of the aircraft (AC) determined by a geo-positioning system (GNSS); - a second acquisition step (E2), implemented by a second acquisition unit (2), for acquiring current inertial data of the aircraft (AC) in an inertial reference frame, including at least one current acceleration (an, ae, az) determined by an inertial unit (IRS); - a third acquisition step (E3), implemented by a third acquisition unit (3), for acquiring a current lateral deviation (ηLOC) and a current vertical deviation (ηGLD) from the one or more reference guidance signals transmitted by the landing aid device (22); - a first filtering step (E4), implemented by a first filtering unit (4), for estimating, using an extended Kalman filter, an unbiased speed (Vn, Ve, Vd) of the aircraft (AC) in the inertial reference frame from at least the current position of the aircraft (AC) acquired in the first acquisition step (E1) and the current inertial data of the aircraft (AC) acquired in the second acquisition step (E2); - a first reference frame changing step (E5), implemented by a first reference frame changing unit (5), for determining the unbiased speed (Vxrwy, Vyrwy, Vzrwy) of the aircraft (AC) in a reference frame linked to the landing runway (RWY) from the unbiased speed (Vn, Ve, Vd) in the inertial reference frame estimated in the first filtering step (E4); - a second reference frame changing step (E6), implemented by a second reference frame changing unit (6), for determining the current position ( X rwy GNSS , Y rwy GNSS , Z rwy GNSS ) of the aircraft (AC) in the reference frame linked to the landing runway (RWY) from the current position (latGNSS, lonGNSS, hGNSS) acquired in the first acquisition step (E1) and from information concerning the location of the landing runway (RWY) originating from a database; - a second filtering step (E7), implemented by a second filtering unit (7), for estimating, using at least one extended Kalman filter, a lateral position (Yrwy) and a vertical position (Zrwy) of the aircraft (AC) in the reference frame linked to the landing runway (RWY), from the current lateral deviation (ηLOC), the current vertical deviation (ηGLD), the unbiased speed (Vxrwy, Vyrwy, Vzrwy) in the reference frame linked to the landing runway (RWY) and from the current position ( X rwy GNSS , Y rwy GNSS , Z rwy GNSS ) of the aircraft (AC) in the reference frame linked to the landing runway (RWY) determined in the second reference frame changing step (E6); - a determination step (E8), implemented by a determination unit (8), for determining the current lateral deviation (DY) and the current vertical deviation (DZ) of the aircraft (AC) in the reference frame linked to the landing runway (RWY), as well as the current lateral speed (DVY) and the current vertical speed (DVZ) of the aircraft (AC) in the reference frame linked to the landing runway (RWY) estimated in the second filtering step (E7) from the lateral position (Yrwy) and the vertical position (Zrwy) of the aircraft (AC), as well as from the estimated unbiased speed (Vn, Ve, Vd) in the inertial reference frame; - a transmission step (E9), implemented by a transmission unit (9), for sending a user device (10) the current lateral deviation (DY) and the current vertical deviation (DZ) of the aircraft (AC) in the reference frame linked to the landing runway (RWY), as well as the current lateral speed (DVY) and the current vertical speed (DVZ) of the aircraft (AC) in the reference frame linked to the landing runway (RWY).

2. The method as claimed in claim 1, characterized in that the extended Kalman filter of the first filtering step (E4) has: - a state vector comprising the estimated unbiased speed (Vn, Ve, Vd) of the aircraft (AC) in the inertial reference frame, the estimated position (lat, lon, h) of the aircraft (AC) and an acceleration bias (ban, bae, baZ) in the inertial reference frame; - a measurement vector comprising a position (latGNSS, lonGNSS, hGNSS) of the aircraft (AC) determined by the geo-positioning system (GNSS) in the first acquisition step (E1); the first filtering step (E4) comprising an updating sub-step (E41) implemented by an updating unit (41) for updating the estimated position (lat, lon, h) using the current position (latGNSS, lonGNSS, hGNSS) of the aircraft (AC) determined by the geo-positioning system (GNSS) in the first acquisition step (E1), the extended Kalman filter of the first filtering step (E4) also having a dynamic evolution model comprising the following equations: dV n / dt = a n − 2 Ω e V e sin lat + V n V Z M lat + h − V e 2 tan lat N lat + h dV e / dt = a e + 2 Ω e V n sin lat + V Z cos lat + V e N lat + h V Z + V n tan lat dV d / dt = a Z − 2 Ω e V e cos lat − V n 2 M lat + h − V e 2 N lat + h + g D dlat / dt = V n M lat + h dlon / dt = V e N lat + h cos lat dh / dt = − V d dba n / dt = dba e / dt = dba Z / dt = 0 ; and an observation model comprising the following equations: lat GNSS = lat + ν lat , GNSS lon GNSS = lon + ν lon , GNSS h GNSS = h + ν h , GNSS , in which: Ωe corresponds to the rotation speed of the earth; M corresponds to the meridian radius of curvature; N corresponds to the radius of curvature of the first vertical of the earth; gd corresponds to the gravitational acceleration; lat corresponds to an estimated latitude coordinate of the position of the aircraft (AC) in the geographical reference frame; lon corresponds to an estimated longitude coordinate of the position of the aircraft (AC) in the geographical reference frame; h corresponds to an estimated height coordinate of the position of the aircraft (AC) in the geographical reference frame; latGNSS corresponds to a latitude coordinate of the position of the aircraft (AC) measured by the geo-positioning system (GNSS) in the geographical reference frame; lonGNSS corresponds to a longitude coordinate of the position of the aircraft (AC) measured by the geo-positioning system (GNSS) in the geographical reference frame; hGNSS corresponds to a height coordinate of the position of the aircraft (AC) measured by the geo-positioning system (GNSS) in the geographical reference frame; νlat,GNSS corresponds to a white noise from the latitude coordinate measured by the geo-positioning system (GNSS) in the geographical reference frame; νlon,GNSS corresponds to a white noise from the measurement of the longitude coordinate measured by the geo-positioning system (GNSS) in the geographical reference frame; νh,GNSS corresponds to a white noise from the measurement of the height coordinate measured by the geo-positioning system (GNSS) in the geographical reference frame; an corresponds to a coordinate of the current acceleration of the aircraft (AC) in a Northern direction in the inertial reference frame; ae corresponds to a coordinate of the current acceleration of the aircraft (AC) in an Eastward direction in the inertial reference frame; aZ corresponds to a coordinate of the current acceleration of the aircraft (AC) in a terrestrial gravity direction in the inertial reference frame; ban corresponds to a coordinate of the bias of the current acceleration of the aircraft (AC) in a Northern direction in the inertial reference frame; bae corresponds to a coordinate of the bias of the current acceleration of the aircraft (AC) in an Eastward direction in the inertial reference frame; baZ corresponds to a coordinate of the bias of the current acceleration of the aircraft (AC) in a terrestrial gravity direction in the inertial reference frame; Vn corresponds to a coordinate of the unbiased speed of the aircraft (AC) in a Northern direction in the inertial reference frame; Ve corresponds to a coordinate of the unbiased speed of the aircraft (AC) in an Eastward direction in the inertial reference frame; VZ corresponds to a coordinate of the unbiased speed of the aircraft (AC) in a terrestrial gravity direction in the inertial reference frame.

3. The method as claimed in any one of claims 1 and 2, characterized in that the current position (latGNSS, lonGNSS, hGNSS) of the aircraft (AC) determined by the geo-positioning system (GNSS) and the estimated position (lat, lon, h) of the aircraft (AC) from the state vector of the extended Kalman filter of the first filtering step (E4) are defined in the geographical reference frame.

4. The method as claimed in any one of claims 1, 2 and claim 3, characterized in that the second filtering step (E7) implements a first extended Kalman filter and a second extended Kalman filter, the first extended Kalman filter having: - a state vector comprising a lateral position (YRWY) of the aircraft (AC) in the reference frame linked to the landing runway (RWY), an angular alignment bias (bAlign) of a lateral guidance signal supplied by the landing aid device and a sensitivity factor bias (bLOCSensi) of the lateral guidance signal; - a measurement vector comprising the lateral position ( Y rwy GNSS ) in the reference frame linked to the landing runway (RWY) and a current lateral deviation (ηLOC) measured in microamperes from the lateral guidance signal; the second extended Kalman filter having: - a state vector comprising a vertical position (Zrwy) in the reference frame linked to the landing runway (RWY), an angular alignment bias (bGPA) of a vertical guidance signal supplied by the landing aid device and a sensitivity factor bias (bGLDSensi) of the vertical guidance signal; - a measurement vector comprising the vertical position ( Z rwy GNSS ) in the reference frame linked to the landing runway (RWY) and a current vertical deviation (ηGLD) measured in DDM from the vertical guidance signal; the second filtering step (E7) comprising a first updating sub-step (E71) implemented by a first updating unit (71) for updating the lateral position (Yrwy) of the aircraft (AC) estimated by the first extended Kalman filter in the reference frame linked to the landing runway (RWY) using the current position ( Y rwy GNSS ) of the aircraft (AC) in the reference frame linked to the landing runway (RWY) determined in the second reference frame changing step (E6); the second filtering step (E7) comprises a second updating sub-step (E72) implemented by a second updating unit (72) for updating the vertical position (Zrwy) of the aircraft (AC) estimated by the first extended Kalman filter in the reference frame linked to the landing runway (RWY) using the current vertical position ( Z rwy GNSS ) of the aircraft (AC) in the reference frame linked to the landing runway (RWY) determined in the second reference frame changing step (E6); - the first extended Kalman filter implemented in the second filtering step (E7) having a dynamic evolution model comprising the following equations: dY rwy / dt = V y rwy db LOC Sensi / dt = db Align / dt = 0 , and an observation model comprising the following equation: η loc = L 0.7 + b LOC Sensi ⋅ Y rwy − sin b Align ⋅ L − X rwy L − X rwy + ν loc , in which: ηloc corresponds to a current lateral deviation in microamperes acquired from the one or more reference guidance signals transmitted by the landing aid device (22); νloc corresponds to a measurement noise of the current lateral deviation; L corresponds to a distance between the threshold (T) of the landing runway (RWY) and the transmitter station that transmits the reference lateral guidance signal; bLOCSensi corresponds to a sensitivity factor bias of the reference lateral guidance signal relative to a standardized reference lateral signal of 0.7; bAlign corresponds to the angular alignment bias of the lateral guidance signal; Xrwy corresponds to a longitudinal position of the aircraft (AC) in the reference frame linked to the landing runway (RWY); Yrwy corresponds to a lateral position of the aircraft (AC) in the reference frame linked to the landing runway (RWY); Vyrwy corresponds to an unbiased lateral speed of the aircraft (AC) in the reference frame linked to the landing runway (RWY); - the second extended Kalman filter implemented in the second filtering step (E7) having a dynamic evolution model comprising the following equations: dZ rwy / dt = V z rwy db GLD Sensi / dt = db GPA / dt = 0 , and an observation model comprising the following equation: η GLD = 0.0875 GPA − b GPA ⋅ 0.12 − b GLD Sensi ⋅ atan Zrwy X rwy + dX − GPA − b GPA + ν GLD , in which: ηGLD corresponds to a current vertical deviation in DDM acquired from the one or more reference guidance signals transmitted by the landing aid device (22); νGLD corresponds to a measurement noise of the current vertical deviation; bGLDSensi corresponds to a sensitivity factor bias of the reference vertical guidance signal relative to a standardized vertical guidance signal of 0.12; GPA corresponds to an angle between the vertical guidance axis defined by the vertical guidance signal and the landing runway (RWY); bGPA corresponds to the angular alignment bias of the vertical guidance signal; νGLD corresponds to a measurement noise of the current vertical deviation; dX corresponds to a longitudinal distance between the threshold (T) of the landing runway (RWY) and the transmitter station that transmits the reference vertical guidance signal; Zrwy corresponds to the vertical position of the aircraft (AC) in the reference frame linked to the landing runway (RWY); Vzrwy corresponds to an unbiased vertical speed of the aircraft (AC) in the reference frame linked to the landing runway (RWY).

5. The method as claimed in any one of claims 1, 2 and 4 and claim 3, characterized in that the current lateral deviation (DY) is equal to the lateral position (Yrwy) of the aircraft (AC) estimated by the first extended Kalman filter in the reference frame linked to the landing runway (RWY), the current lateral speed (DVY) is equal to the lateral speed (VYrwy) estimated by the first extended Kalman filter in the reference frame linked to the landing runway (RWY), and in that the current vertical deviation (DZ) of the aircraft (AC) complies with the following expression: DZ = Z rwy − X rwy + dX ⋅ tan GPA − b GPA , with the current vertical speed (DVZ) of the aircraft (AC) complying with the following expression: DVZ = V g ⋅ tan GPA − b GPA − V Z rwy .

6. The method as claimed in any one of claims 1 and 2, characterized in that the current position of the aircraft (AC) determined by the geo-positioning system (GNSS) and the estimated position of the aircraft (AC) from the state vector of the extended Kalman filter of the first filtering step (E4) are expressed as pseudo-range.

7. A device for estimating, during an approach procedure for an aircraft (AC) with a view to landing on a landing runway (RWY) following a predefined approach to said landing runway (RWY), a deviation (DY, DZ) relative to a reference guidance axis (A) corresponding to said predefined approach to the landing runway (RWY), and a speed of an aircraft (AC) relative to the landing runway (RWY), the approach procedure being carried out with the assistance of a landing aid device, the landing aid device comprising at least one transmitter station (22) configured to transmit a reference guidance signal defining the reference guidance axis (A), comprising at least: - a first acquisition unit (1) configured to acquire at least one current position (latGNSS, lonGNSS, hGNSS) of the aircraft (AC) determined by a geo-positioning system (GNSS); - a second acquisition unit (2) configured to acquire current inertial data of the aircraft (AC) in an inertial reference frame, including at least one current acceleration (an, ae, az) determined by an inertial unit (IRS); - a third acquisition unit (3) configured to acquire a current lateral deviation (ηLOC) and a current vertical deviation (ηGLD) from the one or more reference guidance signals transmitted by the landing aid device (22); - a first filtering unit (4) configured to estimate, using an extended Kalman filter, an unbiased speed (Vn, Ve, Vd) of the aircraft (AC) in the inertial reference frame from at least the current position of the aircraft (AC) acquired by the first acquisition unit (1) and the current inertial data of the aircraft (AC) acquired by the second acquisition unit (2); - a first reference frame changing unit (5) configured to determine the unbiased speed (Vxrwy, Vyrwy, Vzrwy) of the aircraft (AC) in a reference frame linked to the landing runway (RWY) from the unbiased speed (Vn, Ve, Vd) in the inertial reference frame estimated by the first filtering unit (4); - a second reference frame changing unit (6) configured to determine the current position ( X rwy GNSS , Y rwy GNSS , Z rwy GNSS ) of the aircraft (AC) in the reference frame linked to the landing runway (RWY) from the current position (latGNSS, lonGNSS, hGNSS) acquired by the first acquisition unit (1) and from information concerning the location of the landing runway (RWY) originating from a database; - a second filtering unit (7) configured to estimate, using at least one extended Kalman filter, a lateral position (Yrwy) and a vertical position (Zrwy) of the aircraft (AC) in the reference frame linked to the landing runway (RWY), from the current lateral deviation (ηLOC), the current vertical deviation (ηGLD), the unbiased speed (Vxrwy, Vyrwy, Vzrwy) in the reference frame linked to the landing runway (RWY) and from the current position ( X rwy GNSS , Y rwy GNSS , Z rwy GNSS ) of the aircraft (AC) in the reference frame linked to the landing runway (RWY) determined by the second reference frame changing unit (6); - a determination unit (8) configured to determine the current lateral deviation (DY) and the current vertical deviation (DZ) of the aircraft (AC) in the reference frame linked to the landing runway (RWY), as well as the current lateral speed (DVY) and the current vertical speed (DVZ) of the aircraft (AC) in the reference frame linked to the landing runway (RWY) estimated by the second filtering unit (7) from the lateral position (Yrwy) and the vertical position (Zrwy) of the aircraft (AC), as well as from the estimated unbiased speed (Vn, Ve, Vd) in the inertial reference frame; - a transmission unit (9) configured to send a user device (10) the current lateral deviation (DY) and the current vertical deviation (DZ) of the aircraft (AC) in the reference frame linked to the landing runway (RWY), as well as the current lateral speed (DVY) and the current vertical speed (DVZ) of the aircraft (AC) in the reference frame linked to the landing runway (RWY).

8. An aircraft, characterized in that it comprises an estimation device, such as that specified as claimed in claim 7.