DE102012007147B3 - Method for determining horizontal wind on flying aircraft, involves determining the cross-wind and longitudinal wind components exclusive of velocity of aircraft above ground, according to magnitude, direction and heading of aircraft - Google Patents

Abstract

The horizontal wind is defined by the cross-wind and longitudinal wind components related to the heading of aircraft. The components are determined exclusive of the velocity of the aircraft above the ground, according to the magnitude, direction and the heading of aircraft. The ground speed and the heading are provided by a navigation system of the aircraft. The navigation system is a global positioning system (GPS) and/or global navigation satellite system (GLONASS) and/or Galileo and/or Indian remote sensing (IRS) system and/or flight management computer (FMC) system of airplane. An independent claim is included for a device for determining horizontal wind on flying aircraft.

Description

The invention relates to a method and a device for determining the horizontal wind on board a (flying) aircraft.

Accurate measurement of the horizontal wind aboard an aircraft is among other things essential for the control and navigation of the aircraft. In the prior art, the horizontal wind is detected on board aircraft, such as in the WMO manual: "Aircraft Meteorological Data Relay (AMDAR) Reference Manual", Paintinq D., World Meteorological Organization (WMO) No 958, 2003, CHAPTER 3 described.

Aircraft in flight thus determine the horizontal wind speed V → _W on the basis of the variables: heading ψ of the aircraft ("heading", HDG, ψ), velocity V → _{F of} the aircraft relative to the surrounding air, the direction of velocity V → _{F is} at a shift angle = 0 is identical to the heading ψ and the amount of speed | V → _F | is given by the true speed of the aircraft relative to ambient air ("True Air Speed", TAS) and the speed V → _{G of} the aircraft over ground ("Groundspeed", GS). The variables: heading ψ and the velocity V → _G are in aircraft today typically from a navigation system comprising, for example, a GNSS receiver (GNSS = Global Navigation Satellite System) and / or a VOR / ADF / DME receiver and / or an inertial navigation system (IRS = "Inertial Reference System") determined and provided. The magnitude of the velocity | V → _F | is determined on the basis of the measured variables: dynamic pressure (total pressure), static pressure and temperature (TAT = "total air temperature"). The horizontal wind V → _W then results as a vector difference: V → _W = V → _G - V → _F (1)

In order to keep errors in the determination of the horizontal wind V → _W small, the vectors V → _G and V → _F must be determined as accurately as possible, since the amount of wind speed | V → _W | is small, ie typically in the range of 0-30 m / s, while the amounts of velocities | V → _G | and | V → _F | typically be in the range of 200-300 m / s for modern commercial aircraft.

It is known that the determination of the speed V → _F , in particular the determination of the amount | V → _F |, ie the so-called true airspeed, can be faulty since calibration errors, calibration drift, random and static errors in the sensor positioning and Alignment, errors in determining the Mach number or the angle of attack, etc. received. Furthermore, it is known that the measurement of the wind velocity V → _W can be considerably improved by measuring and taking into account the sliding angle β (see "Swinging determination from flight measurement data of a scheduled airliner", cf. Meteorological Review 37, pp. 72-81, 1984.

The horizontal wind is thus in the prior art as the difference between two speeds: V → _G and V → _F , which are both typically an order of magnitude greater than the desired horizontal wind V → _W. In addition, since the errors in the determination of the airspeed V → _{F can be} relatively large, sometimes resulting in the difference formation large errors. The above-mentioned AMDAR Reference Manual gives as a typical error in the determination of the wind vector 2-3 m / s.

From the operating manual "Zander SR940 - Operating Instructions" a method for determining the horizontal wind V → _W aboard an aircraft is disclosed.

The object of the invention is to enable the determination of the horizontal wind V → _W aboard an aircraft with improved accuracy.

The invention results from the features of the independent claims. Advantageous developments and refinements are the subject of the dependent claims. Other features, Applications and advantages of the invention will become apparent from the following description, as well as the explanation of embodiments of the invention, which are illustrated in the figures.

A procedural aspect of the object is achieved with a method for determining the horizontal wind V → _W aboard an aircraft, in which the horizontal wind V → _{W is} defined by a relative to a heading ψ of the aircraft transverse wind component V and a longitudinal wind component U, and the transverse wind component V is determined exclusively from the speed V → _{G of} the aircraft over ground in magnitude and direction and the heading ψ.

The method according to the invention thus provides that, when determining the transverse wind component V, no measurement of the velocity | V → _F | (TAS) is needed and thus the largest source of error of the wind measurement is avoided. For the determination of the transverse wind component V, it is sufficient according to the invention to determine the lateral drift of the aircraft, preferably by means of navigation data which are determined, for example, by measurements of the Global Positioning System (GPS) and / or the Inertial Reference System (IRS). This enables a considerable improvement in the accuracy in determining at least one component of the horizontal wind V → _W to be determined.

The determination of the longitudinal wind component U (wind speed V → _W in the direction of the control course ψ) is furthermore carried out conventionally, ie taking into account the magnitude of the velocity | V → _F | (TAS). Due to the resulting increased accuracy of a (V) of the two components (U, V) of the horizontal wind V → _W is also the resulting horizontal wind V → _W more accurately. As the following exemplary embodiment will show, with the method according to the invention the error in the determination of the horizontal wind V → _{W can be} considerably reduced.

A preferred embodiment of the method according to the invention is characterized in that the speed V → _G and the heading ψ are provided by a navigation system of the aircraft, the navigation system preferably a GPS and / or a GNLONASS and / or a Galileo and / or or an IRS and / or FMS system of the aircraft.

A particularly preferred development of the method is characterized in that the transverse wind component V is determined according to the following formula: V = V → _GE · cos (ψ) - V → _GN · sin (ψ) (2) where V → _{GE is} the east component (from west to east) of speed V → _G , V → _{GN is} the north component (from south to north) of speed V → _G , and ψ is the heading of the aircraft. The information "north" and "east" components relate preferably to the geographic north pole of the earth.

A further preferred embodiment of the method according to the invention is characterized in that the longitudinal wind component U of the horizontal wind V → _W from the speed V → _{G of} the aircraft over ground in magnitude and direction, the heading ψ, and the amount of airspeed | V → _F | is determined. Preferably, the longitudinal wind component U is determined according to the following formula: U = V → _GE · sin (ψ) + V → _GN · cos (ψ) - | V → _F | (3) where V → _{GE is} the east component of the speed V → _G , V → _{GN is} the north component of the speed V → _G , ψ is the heading of the aircraft, and | V → _F | the amount of airspeed V → _F is (TAS).

A further improvement in the accuracy of the method according to the invention for determining the horizontal wind V → _W can be achieved if the horizontal wind V → _{W is determined} only in those cases in which the roll angle Φ of the aircraft is <10 ° or <7 ° or <5 ° or <3 °. As a result, errors in the horizontal wind determination, which are caused by flying maneuvers, especially dynamic maneuvers, significantly reduced.

A further improvement in the accuracy of the method for determining the horizontal wind V → _W can be achieved if the heading ψ in each case by a shift angle β (if any) is corrected. In the present case, the slip angle β (lateral slip angle, crab angle) designates the drift angle between the longitudinal axis of the aircraft (heading ψ) and the direction of the flow (relative wind). The sliding angle β is aerodynamically of interest. If it is different from zero, the wings are flown unbalanced. In the normal flight condition of an aircraft, it is zero.

An apparatus-related aspect of the object is achieved with a device for determining the horizontal wind V → _W aboard an aircraft, wherein the horizontal wind V → _{W is} defined by a relative to a heading ψ of the aircraft transverse wind component V and a longitudinal wind component U. The device according to the invention comprises a first means with which the speed V → _{G of} the aircraft over ground in magnitude and direction can be provided, a second means with which the heading ψ of the aircraft can be provided, a third means with which the amount of the airspeed | V → _F | of the aircraft, a fourth means adapted to determine the transverse wind component V exclusively in terms of the aircraft's speed V → _G in magnitude and direction and the heading ψ, and a fifth means adapted to the longitudinal wind component U from the Velocity V → _G in magnitude and direction, the heading ψ, and the airspeed | V → _F | to investigate.

Preferably, the first means and the second means are or include a GPS and / or a GNLONASS and / or a Galileo and / or an IRS and / or FMS system.

The method according to the invention and the device according to the invention make it possible to determine the horizontal wind V → _W aboard aircraft in a more accurate manner than in the prior art. For special applications, such as the on-board forecast of wake wake vortices, the crosswind component V is even the most important meteorological input. As a result of the significantly improved crosswind measurement, considerably more accurate forecasts of wake transport can be realized.

Further advantages, features and details emerge from the following description in which an exemplary embodiment is described with reference to the drawing. Described and / or illustrated features form the subject of the invention, or independently of the claims, either alone or in any meaningful combination, and in particular may additionally be the subject of one or more separate applications. The same, similar and / or functionally identical parts are provided with the same reference numerals.

Show it:

1 a schematic representation of a device according to the invention,

2a -D measurements of the transverse wind component V with the research aircraft Falcon 20 E D-CMET of the DLR-Oberpfaffenhofen, and

3a -D Measurements of the longitudinal wind component U with the research aircraft Falcon 20 E D-CMET of the DLR-Oberpfaffenhofen.

1 shows a schematic representation of a device according to the invention for determining the horizontal wind V → _W aboard an aircraft, wherein the horizontal wind V → _{W is} defined by a reference to a heading ψ of the aircraft transverse wind component V and a longitudinal wind component U. The device comprises a first means 101 , with which the speed V → _{G of} the aircraft over ground can be provided in magnitude and direction, a second means 102 , with which the heading ψ of the aircraft is available, a third means 103 with which the amount of airspeed | V → _F | of the aircraft, a fourth means, which is set up to determine the transverse wind component V exclusively from the speed V → _{G of} the aircraft in magnitude and direction and the heading ψ, a fifth means 105 , which is adapted to the longitudinal wind component U from the speed V → _G in magnitude and direction, the heading ψ, and the airspeed | V → _F | to determine, and a sixth medium 106 which determines and outputs the horizontal wind V → _W on the basis of the transverse wind component V and the longitudinal wind component U.

The first means 101 and the second means 102 include a GPS, an IRS and FMC system of the aircraft.

The improvement in the accuracy of the horizontal wind measurement achievable with the device according to the invention or with the method according to the invention is explained below with reference to measurements made with the research aircraft Falcon 20 E D-CMET by the applicant DIR (German Aerospace Center eV). ) on the occasion of a flight of 7 June 2011. The flight time was 1 hour and 41 minutes.

2a -D each show a graph in which the data obtained during the flight to the transverse wind component V in m / s and the heading ψ (HDG) in degrees over the time t in s are plotted. The 2a -D differ by different measuring times t. So is in 2a the measuring period from t = 0 s to t = 1,250 s, in 2 B the measuring period from t = 1,250 s to t = 2,500 s, in 2c the measurement period from t = 2,500 s to t = 3,750 s, and in 2d the measurement period from t = 3,750 s to t = 5,000 s. The transverse wind component V was determined by three different methods, the results in the 2a Each are denoted as "V_nose_boom", "V_GPS / IRS", and "V_FMC".

In the present case, measurements based on the five-hole probe nasal mast of the research aircraft serve as a reference for the "true" horizontal wind speed V → _W. The transverse wind component V determined therefrom is designated by "V_nose_boom" and in the present case serves as a reference transverse wind component.

This reference transverse wind component V_nose_boom can now be compared, on the one hand, with the transverse wind component V_FMC of the horizontal wind V → _{W provided} by the so-called Flight Management Computer (FMC) of the research aircraft, which corresponds to the method known today for determining the transverse wind component, and furthermore with the transverse wind component V_GPS / IRS, which was determined by means of the method according to the invention. The inventive method for determining the horizontal wind V → _W aboard an aircraft in which the horizontal wind V → _{W is} defined by a relative to a heading ψ of the aircraft transverse wind component V (in this case referred to as V_GPS / IRS) and a longitudinal wind component U is characterized in that the transverse wind component V (= V_GPS / IRS) is determined exclusively from the speed V → _{G of} the aircraft over ground in magnitude and direction and the heading ψ. In this case, the transverse wind component V becomes: V = V → _GE · cos (ψ) - V → _GN · sin (ψ) (2) where V → _{GE is} the east component of speed over ground, V → _{GN is} the north component of speed over ground, and ψ is the heading. The speeds V → _GE and V → _{GN are} determined and provided by means of the GPS and IRS system of the research aircraft. Here, the GPS provides the low-frequency portion of the measured data acquisition, which is supplemented by a high-frequency portion of the IRS. The tax rate ψ is determined and provided by the IRS. Sliding angle measurements are not taken into account in the illustrated embodiment.

The 2a -D it can be seen that the standard transverse wind measurement (V_FMC) deviates significantly from the reference measurement (V_nose_boom). By contrast, the transverse wind component V (= V_GPS / IRS) of the horizontal wind V → _W determined using the method according to the invention agrees very well with the reference measurement (V_nose_boom). During maneuvers, which in this case are indicated by changes in the heading ψ (HDG), the deviations between V_GPS / IRS and V_nose_boom noticeably increase.

3a -D each show a graph in which the data obtained during the flight to the longitudinal wind component U in m / s and the heading ψ (HDG) in degrees over the time t in s are plotted. The longitudinal wind component U was determined by two methods, the results in the 3a -D are each referred to as "U_nose_boom" and "U_GPS / IRS". Heading ψ is determined and provided by the IRS of the research aircraft. The grahpics are otherwise the same as the 2a d.

The longitudinal wind component data "U_nose_boom" serve as a reference and were determined on the basis of the five-hole probe measurements of the research aircraft. The longitudinal wind component data U = "U_GPS / IRS" were determined according to: U = V → _GE · sin (ψ) + V → _GN · cos (ψ) - | V → _F | (3), where V → _{GE is} the east component of the velocity V → _G , V → _GN the north component of the speed V → _G , ψ the heading (HDG), and | V → _F | the amount of airspeed (TAS) is.

| V → _F | was determined by means of the Pitot-Static System and the Air Data Computer of the research aircraft. V → _G , V → _GN , V → _GE , and ψ were determined as above by the research aircraft's GPS and IRS, respectively.

wobei der Index x für FMC (bisherige Methode zur Ermittlung des Windes/der Windkomponente) oder GPS/IRS (erfindungsgemäße Methode zur Ermittlung des Windes, der Windkomponente) steht. Der Index i kennzeichnet jeweils den i-ten von n Messwerten der jeweiligen Windwerte. a) IRS + GPS b) IRS + GPS Φ < 7° c) GPS Φ < 7° d) IRS + GPS Φ < 7°, β RMSE(U_FMC) 1,791 1,412 1,412 1,408 RMSE(V_FMC) 4,065 4,094 4,094 4,095 RMSE(V_GPS/IRS) 1,868 0,799 0,852 0,357 Tabelle 1 Table 1 below shows a statistical evaluation of the in 2a -D and 3a -D shown data. The so-called "Root Mean Square Error" = RMSE was determined. This is defined here as follows:

where the index x stands for FMC (previous method for determining the wind / the wind component) or GPS / IRS (method according to the invention for determining the wind, the wind component). The index i identifies the i-th of n measured values of the respective wind values. a) IRS + GPS b) IRS + GPS Φ <7 ° c) GPS Φ <7 ° d) IRS + GPS Φ <7 °, β RMSE (U_FMC) 1,791 1,412 1,412 1,408 RMSE (V_FMC) 4,065 4,094 4,094 4,095 RMSE (V_GPS / IRS) 1,868 0.799 0,852 0,357 Table 1

The RMSE is thus formed with the reference velocity "V_nose_boom" and the velocity V _{x, i} which stands either for the FMC velocity or for the velocity determined by the method according to the invention. In the configurations a), b) and d), the speed V → _G and the heading ψ are provided by the IRS and the GPS of the research aircraft, high-frequency measurement data being provided by the IRS. In configuration c), however, the speed V → _G and the heading ψ are only provided by the GPS, while IRS data is disregarded. The RMSE is evaluated for the four different configurations a) -d).

It can be seen that the RMSE of the V_FMC (crosswind determined by the Flight Management Computer) is more than twice as large as the RMSE of the U_FMC (longitudinal wind (backwind or headwind) determined by the Flight Management Computer). While the RMSE of the V_FMC remains nearly the same in all four configurations, the RMSE of the U_FMC can be reduced by 21% by excluding flight maneuvers with a roll angle Φ of <7 °.

In configuration a), the RMSE of the transverse wind component V_GPS / IRS determined by the method according to the invention is reduced by 54% compared with the conventional method (V_FMC). If maneuvers with roll angles Φ above 7 ° are excluded (configuration b), the RMSE of V_GPS / IRS is reduced from 1.868 to 0.799. The reduction of the RMS error is now 80%.

The results for configuration c) show that the use of pure GPS Ground Speed V → _G , ie without enrichment with high frequency IRS data of groundspeed, only slightly degrades the accuracy (from 0.799 to 0.852). In configuration d) the heading ψ is corrected by the shift angle β. This correction reduces the RMSE of the cross wind V_GPS / IRS again, so that a reduction of 91% compared to the standard measurement can be achieved. Configuration d) thus provides an accuracy of the transverse wind measurement on a scale that can otherwise be achieved only with the use of a complex scientific instrument, such as the nose-piece with five-hole probe.

Errors in the determination of the heading ψ affect the measurement of the transverse wind component V of the horizontal wind V → _{W more} than the measurement of the longitudinal wind component U. Therefore, reducing the error of the crosswind component significantly improves the accuracy of horizontal wind V → _W , In the presently evaluated measurement data of the flight, this difference is very pronounced: the error of the longitudinal wind component U is less than half as large as the error of the transverse wind component V.

In configuration b), the error (RMSE) of the horizontal wind V → _W with: [U_FMC ² + V_FMC ² ] ^0.5 = [1.412 ² + 4.094 ² ] ^0.5 = 4.33 m / s (5) be estimated. With the inventively improved determination of the cross wind component V of the horizontal wind V → _W, the error (RMSE) of the horizontal wind V → _W is reduced, however, to: [U_FMC ² + V_GPS / IRS ² ] ^0.5 = [1.412 ² + 0.799 ² ] ^0.5 = 1.62 m / s (6)

This corresponds to a reduction of the error (RMSE) of the horizontal wind V → _W by using the method according to the invention by 62%.

LIST OF REFERENCE NUMBERS

101

first means

102

second means

103

third means

104

fourth means

105

fifth remedy

106

sixth means

Claims (10)

Method for determining the horizontal wind V → _W on board an aircraft, in which the horizontal wind V → _{W is} defined by a transverse wind component V related to a heading ψ of the aircraft and a longitudinal wind component U, and the transverse wind component V exclusively from the velocity V → _{G of} the Aircraft over ground in amount and direction and the heading ψ. The method of claim 1, wherein the speed over ground V → _G and the heading ψ are provided by a navigation system of the aircraft. Method according to Claim 2, in which the navigation system is a GPS and / or a GNLONASS and / or a Galileo and / or an IRS and / or FMS system of the aircraft. Method according to one of claims 1 to 3, wherein the transverse wind component V according to: V = V → _GE · cos (ψ) - V → _GN · sin (ψ) (2) where V → _GE : = east component of speed over ground V → _GN : = north component of speed over ground ψ: = heading. Method according to one of claims 1 to 4, wherein the longitudinal wind component U from the speed V → _G in magnitude and direction, the heading ψ, and the true airspeed | V → _F | is determined. The method of claim 5, wherein the longitudinal wind component U is according to: U = V → _GE * sin (ψ) + V → _GN * cos (ψ) - | V → _F | (3) where V → _GE : = east component of the speed V → _G V → _GN : = north component of the speed V → _G ψ: = heading | V → _F | : = Amount of airspeed is. Method according to one of Claims 1 to 6, in which the determination of the horizontal wind V → _W takes place only in cases in which the roll angle of the aircraft is <10 ° or <7 ° or <5 ° or <3 °. Method according to one of claims 1 to 7, wherein the heading ψ is corrected in each case by a sliding angle. Device for determining the horizontal wind V → _W on board an aircraft, the horizontal wind V → _{W being} defined by a transverse wind component V related to a heading ψ of the aircraft and a longitudinal wind component U, comprising: - a first means ( 101 ), with which the speed V → _{G of} the aircraft over ground can be provided in magnitude and direction, - a second means ( 102 ), which provides the heading ψ of the aircraft, - a third means ( 103 ), with which the amount of airspeed | V → _F | of the aircraft, - a fourth means ( 104 ) arranged to determine the transverse wind component V solely in terms of the aircraft's speed V → _G in terms of magnitude and direction and heading ψ, and - a fifth means ( 105 ), which is adapted to the longitudinal wind component U from the speed V → _G in magnitude and direction, the heading ψ, and the airspeed | V → _F | to investigate. Device according to Claim 9, in which the first means ( 101 ) and the second ( 102 ) is a GPS and / or a GNLONASS and / or a Galileo and / or an IRS and / or FMC system of the aircraft.

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