New energy aircraft flight profile continuous descending vertex prediction method

Abstract

The invention provides a new energy aircraft flight profile continuous descending vertex prediction method, and belongs to the technical field of airborne flight management systems, and the method comprises the steps: obtaining the flight plan aircraft cruise height and the latitude and longitude information of a landing airport; acquiring a flight glide angle, calculating a horizontal distance D from a horizontal projection of a descent point to an airport, and forming an equation 1 by the horizontal distance D and the longitude and latitude of the projection point of the descent point on the horizontal plane according to a distance formula; acquiring the current magnetic course angle of the aircraft, and forming an equation 2 by combining the latitude and longitude of the landing airport and the magnetic course angle calculation method; the first equation and the second equation are combined and combined to solve the longitude information of the horizontal projection P'of the descent point, the solved longitude information of the P 'is substituted into the first equation, the latitude value of the P' point is inversely solved, the latitude value of the P 'point is a descent latitude value, and the three-dimensional position coordinates of the descent point P are obtained through analysis in combination with aircraft cruise height information.

Description

Technical Field

[0001] The present application relates to the field of airborne flight management systems, and in particular to a method for predicting the continuous descent apex of a flight profile of a new energy aircraft. Background Art

[0002] The continuous descent vertex of the flight profile is a virtual waypoint on the flight route, and is a transition point for the aircraft to change from the cruising state to the descent state. The descent vertex is calculated by the onboard flight management system and displayed to remind the pilot that it is about to enter the descent state; for new energy aircraft, especially for new energy aircraft with composite wings, the conventional descent methods are continuous descent and vertical descent, but the energy consumed by vertical descent is greater than that of continuous descent. For detailed analysis, see the paper <Flight Performance Estimation of eVTOL Aircraft Using Synthesis ofAerodynamics Theories of Rotorcraft and Fixed-Wing Aircraft> Therefore, for electric new energy aircraft, the advantages of using energy-saving and safe descent methods during the descent phase are obvious: Advantage 1 can increase the range, and advantage 2 energy-saving methods can indirectly ensure safety. Therefore, continuous descent point prediction becomes very necessary. Summary of the invention

[0003] In view of this, the present application provides a method for predicting the continuous descent apex of a new energy aircraft flight profile, which solves the problems in the prior art and improves the reliability and versatility of the prediction.

[0004] The present application provides a method for predicting the continuous descent apex of a new energy aircraft flight profile using the following technical solutions:

[0005] A method for predicting the continuous descent apex of a new energy aircraft flight profile, comprising:

[0006] Step 1, obtain the cruising altitude H of the flight plan aircraft and the longitude and latitude information L (Nl, El) of the landing airport L, where Nl represents latitude and El represents longitude;

[0007] Step 2: Establish a spherical coordinate system with the center of the earth as the origin, and convert the latitude and longitude information of the airport location into coordinates in the spherical coordinate system;

[0008] Step 3, obtain the flight glide angle, and combine it with the cruising altitude H to calculate the horizontal distance D of the horizontal projection of the aircraft's descent point P from the airport, and obtain the horizontal projection P' of the descent point P;

[0009] The longitude and latitude of the predicted descent point are P(N,E), and the longitude and latitude of the projection point of the descent point on the horizontal plane are P′(N′,E′). In the spherical coordinate system, the horizontal distance D and the longitude and latitude of the projection point of the descent point on the horizontal plane P′(N′,E′) are combined into equation 1 according to the distance formula, where N and N′ represent latitude, and E and E′ represent longitude;

[0010] Step 4, obtain the current magnetic heading angle of the aircraft, and in the spherical coordinate system, combine the longitude and latitude of the landing airport and the magnetic heading angle calculation method to form equation 2;

[0011] Step 5, Equation 1 and Equation 2 are combined and solved to calculate the latitude information of the horizontal projection P' of the descent point P, and after screening, the latitudes of the horizontal projection P' of the continuous descent points are determined;

[0012] Step 6, bring the calculated P' latitude information into equation 1, and inversely solve the longitude value of point P'. The longitude and latitude values ​​of point P' are the longitude and latitude values ​​of the descending point P;

[0013] Step 7, combining the aircraft cruising altitude information, analyzing and obtaining the three-dimensional position coordinates of the descent point P;

[0014] Step 8: After predicting the longitude and latitude of the continuous descent points, mark them in the flight plan.

[0015] Optionally, the equation 1 in step 3 is:

[0016] sin N l sin N′+cos N l cos N′cos(El-E′)=cos w;

[0017] In the formula, w = D / R, R is the radius of the earth.

[0018] Optionally, the equation 2 in step 4 is:

[0019] sin N l sin N′-sin N l ocs N′cos(El-E′)=cos A sin w

[0020] Where A is the current magnetic heading angle of the aircraft, w = D / R, and R is the radius of the earth.

[0021] Optionally, in step 5, the latitude N′ of point P′=arcsin(sin N l cos w+cos A sin w cos Nl).

[0022] Optionally, in step 6, the longitude of point P'

[0023] Optionally, the three-dimensional position coordinates of point P are

[0024]

[0025] In summary, this application includes the following beneficial technical effects:

[0026] The method of the present application is different from the existing method of iteratively predicting the descent point by weight change. It converts the longitude and latitude coordinates of the descent point to be predicted into a spherical three-dimensional coordinate system, and performs reverse calculation based on the known information of the traditional great circle route distance and the magnetic heading to be flown. The method is reliable and has strong versatility.

[0027] The method of the present application abstracts and mathematizes the problem by deriving formulas in a strict three-dimensional coordinate system. The reasoning logic is rigorous and practical, and it provides a new idea for calculation.

[0028] The present application provides a new solution for predicting the descent point during a continuous descent approach of a new energy aircraft with a small weight change. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 This is a flow chart of a method for predicting the continuous descent apex of a new energy aircraft flight profile in this application;

[0031] Figure 2 This is a schematic diagram of the flight phase of the new energy aircraft according to the embodiment of the present application;

[0032] Figure 3 This is a schematic diagram of the prediction of the glide path point of continuous descent of the new energy aircraft in the embodiment of the present application;

[0033] Figure 4 It is a schematic diagram of the relationship between longitude and latitude coordinates and spherical coordinates;

[0034] Figure 5 Schematic diagram of the relationship between great circle route distance and earth radius. DETAILED DESCRIPTION

[0035] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0036] The following describes the implementation methods of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific implementation methods, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the following embodiments and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work belong to the scope of protection of the present application.

[0037] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement the device and / or practice the method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this device and / or practice this method.

[0038] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show the components related to the present application rather than being drawn according to the number, shape and size of the components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed at will, and the component layout may also be more complicated.

[0039] Additionally, in the following description, specific details are provided to facilitate a thorough understanding of the examples. However, it will be understood by those skilled in the art that the aspects described may be practiced without these specific details.

[0040] An embodiment of the present application provides a method for predicting the continuous descent apex of a new energy aircraft flight profile.

[0041] A method for predicting the continuous descent apex of a new energy aircraft flight profile, comprising:

[0042] like Figures 1 to 3 As shown, step 1 is to obtain the flight plan aircraft cruising altitude H and the latitude and longitude information L (Nl, El) of the landing airport L; Nl is the latitude value of the landing airport, and El is the longitude value of the landing airport.

[0043] Step 2: Establish a spherical coordinate system with the center of the earth as the origin, such as Figure 4 As shown, the airport location latitude and longitude information is converted into coordinates in the spherical coordinate system. Where R is the radius of the earth; θ l and It is obtained by the following formula:

[0044] θ l =90°-Nl (N latitude, north latitude is positive, south latitude is negative);

[0045] (East longitude, E takes positive value);

[0046] (West longitude, E takes a negative value).

[0047] Step 3, obtain the flight glide angle a, and combine it with the cruising altitude H to calculate the horizontal distance D of the horizontal projection of the aircraft's descent point P from the airport, and obtain the horizontal projection P' of the descent point P;

[0048] The longitude and latitude of the predicted descent point are P(N,E), and the longitude and latitude of the projection point of the descent point on the horizontal plane are P′(N′,E′), where N is the latitude value of the descent point P, E is the longitude value of the descent point P, N′ is the latitude value of the descent point P′, and E′ is the longitude value of the descent point P′; in the spherical coordinate system, Figure 3 and Figure 5 As shown, the horizontal distance D and the latitude and longitude P′(N′, E′) of the projection point of the descending point on the horizontal plane are combined into equation 1 according to the distance formula, where N and N′ represent latitude, and E and E′ represent longitude; equation 1 is:

[0049] sin N l sin N′+cos N l cos N′cos(El-E′)=cos w;

[0050] Wherein, w = D / R, R is the radius of the earth; w is the angle in radians between the longitude and latitude coordinates of point P′ and point L in the spherical coordinate system.

[0051] Step 4, obtain the current magnetic heading angle of the aircraft, and in the spherical coordinate system, combine the longitude and latitude of the landing airport and the magnetic heading angle calculation method to form equation 2; equation 2 is: sin N l sin N′-sin N l cos N′cos(El-E′)=cos Asin w;

[0052] Where A is the current magnetic heading angle of the aircraft, w = D / R, and R is the radius of the earth.

[0053] Step 5, Equation 1 and Equation 2 are combined to jointly solve the longitude information of the horizontal projection P' of the descent point P. The magnetic heading angle calculation formula needs to be converted into a spherical coordinate system for calculation. Then, the longitude and latitude values ​​in equations 1 and 2 are further converted into values ​​represented in the spherical coordinate system. The latitude of point P in the spherical coordinate system is represented as θ, and the longitude of point P in the spherical coordinate system is represented as The latitude of point P' is expressed as θ' ​​in the spherical coordinate system, and the longitude of point P in the spherical coordinate system is expressed as That is, equation 1 is converted into Equation 2 is converted to The method for obtaining the representation values ​​of point P and point P′ in the spherical coordinate system is the same as the method for obtaining the representation value of point L in the spherical coordinate system, which will not be repeated here.

[0054] Finally, the joint solution is performed; after screening, the horizontal projection P' latitude of the continuous descending point is determined; P' latitude N'=arcsin(sin N l cos w+cos A sin w cos N l).

[0055] Step 6: Substitute the calculated P' latitude information into equation 1 and solve the longitude value of point P'. The longitude and latitude values ​​of point P' are the longitude and latitude values ​​of the descending point P; the longitude and latitude of point P'

[0056] Step 7: Combine the aircraft cruising altitude information to obtain the three-dimensional position coordinates of the descent point P; the three-dimensional position coordinates of P are

[0057]

[0058] Step 8: After predicting the longitude and latitude of the continuous descent points, mark them in the flight plan.

[0059] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application shall be based on the protection scope of the claims.

Claims

1. A method for predicting the continuous descent vertex of a new energy aircraft flight profile, characterized in that: include: Step 1, obtain the flight plan aircraft cruising altitude H and the latitude and longitude information L (Nl, El) of the landing airport L, where Nl represents latitude and El represents longitude; Step 2: Establish a spherical coordinate system with the center of the earth as the origin, and convert the latitude and longitude information of the airport location into coordinates in the spherical coordinate system; Step 3, obtain the flight glide angle, and combine it with the cruising altitude H to calculate the horizontal distance D of the horizontal projection of the aircraft's descent point P from the airport, and obtain the horizontal projection P' of the descent point P; The longitude and latitude of the predicted descent point are P(N,E), and the longitude and latitude of the projection point of the descent point on the horizontal plane are P′(N′,E′). In the spherical coordinate system, the horizontal distance D and the longitude and latitude of the projection point of the descent point on the horizontal plane P′(N′,E′) are combined into equation 1 according to the distance formula, where N and N′ represent latitude, and E and E′ represent longitude; Step 4, obtain the current magnetic heading angle of the aircraft, and in the spherical coordinate system, combine the longitude and latitude of the landing airport and the magnetic heading angle calculation method to form equation 2; Step 5, Equation 1 and Equation 2 are combined and solved to calculate the latitude information of the horizontal projection P' of the descent point P, and after screening, the latitudes of the horizontal projection P' of the continuous descent points are determined; Step 6, bring the calculated P' latitude information into equation 1, and inversely solve the longitude value of point P'. The longitude and latitude values ​​of point P' are the longitude and latitude values ​​of the descent point P; Step 7, combining the aircraft cruising altitude information, analyzing and obtaining the three-dimensional position coordinates of the descent point P; Step 8: After predicting the longitude and latitude of the continuous descent points, mark them in the flight plan.

2. The method for predicting the continuous descent vertex of the flight profile of a new energy aircraft according to claim 1 is characterized in that: The equation 1 in step 3 is: sinBlsinN′+cosNlcosN′cos(El-E′)=cos w; In the formula, w = D / R, R is the radius of the earth.

3. The method for predicting the continuous descent vertex of the flight profile of a new energy aircraft according to claim 2 is characterized in that: The second equation in step 4 is: sinNl sinN′-sinNl cosN′ cos(El-E′) = cos A sin w Where A is the current magnetic heading angle of the aircraft, w = D / R, and R is the radius of the earth.

4. The method for predicting the continuous descent vertex of the flight profile of a new energy aircraft according to claim 3 is characterized in that: In step 5, the latitude N′ of point P′=arcsin(sin N lcosw+cos A sin w cos N l).

5. The method for predicting the continuous descent vertex of the flight profile of a new energy aircraft according to claim 4 is characterized in that: In step 6, the longitude of point P' 6. The method for predicting the continuous descent vertex of the flight profile of a new energy aircraft according to claim 5, characterized in that: The three-dimensional coordinates of point P are:

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