Analysis method of the impact of terrain in front of glide path antenna on its structure based on sideband reference

Abstract

The present invention discloses a method for analyzing the structural influence of terrain ahead of a sideband reference glide path antenna, belonging to the field of civil aviation. The method comprises: calculating a spatially synthesized CSB and a synthesized SBO based on an amplitude and phase distribution diagram of a sideband reference glide path beacon antenna and generating a curve; determining the shielding angle of terrain objects relative to the sideband reference glide path beacon antenna based on the relative position of the terrain objects and the sideband reference glide path beacon antenna and the height difference between the terrain objects and the sideband reference glide path beacon antenna installation location; obtaining the beam curvature BBP corresponding to the shielding angle based on the calculated terrain object shielding angle and combining it with the spatially synthesized CSB and synthesized SBO curves; calculating the modulation index difference DDM; converting the modulation index difference DDM into a glide path structure deviation value CDI, and determining the degree of influence of the terrain objects on the glide path structure by comparing it with a glide path structure threshold value. The method of the present invention is simple, efficient, easy to master, and has wide application.

Description

Technical Field

[0001] The present invention relates to the field of civil aviation technology, and more specifically, to an analysis method for the influence of terrain in front of a sideband reference glide path antenna on its structure. Background Art

[0002] The Instrument Landing System (ILS) is a widely used precision approach and landing guidance system. It consists of three components: a localizer, a glide path beacon, and a marker beacon or distance measuring instrument (DME). These provide approaching aircraft with horizontal azimuth, vertical altitude, and distance information, respectively, and are essential for ensuring a safe landing. Glide path beacon antennas primarily come in three types: zero reference antennas, sideband reference antennas, and capture effect antennas (also known as "M-type" antennas). Glide path beacons operate in the 328.6MHz to 335.4MHz frequency band and work in conjunction with airborne receivers to provide glide path guidance information to approaching aircraft. Glide path beacons are typically located 280m to 350m behind the runway threshold and 120m from the runway centerline.

[0003] The multipath interference caused by the reflection and re-radiation of the signal transmitted by the terrain and objects in front of the glide path beacon antenna can distort its radiation pattern, causing the glide path structure to bend, swing and shake, which in turn causes the glide angle to change, directly affecting the landing safety of the aircraft. Therefore, it is necessary to analyze and evaluate the possible impact of the terrain and objects in front of the glide path beacon on the glide path beacon space signal, especially the impact on the glide path structure, to ensure the safe landing of the aircraft. However, the glide path beacon signal has many transmission paths and the signal synthesis method in space is complex. Currently, it mainly relies on professional third-party assessment agencies to provide space signal assessment services, which is time-consuming, expensive, and has great limitations. Those skilled in the art urgently need to solve this problem. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the existing technology and provide an analysis method for the influence of the terrain in front of the sideband reference glide path antenna on the structure, which is simple, efficient, easy to master and has a wide range of application scenarios.

[0005] The object of the present invention is achieved through the following solutions:

[0006] A method for analyzing the influence of the terrain in front of a sideband reference glide path antenna on its structure includes the following steps:

[0007] Step 1: Calculate the spatial composite carrier and sideband wave CSB and composite sideband wave SBO according to the sideband reference glide path beacon antenna amplitude and phase distribution diagram and generate a curve;

[0008] Step 2: Determine the shielding angle of the terrain feature relative to the sideband reference glide path beacon antenna based on the relative position of the terrain feature and the sideband reference glide path beacon antenna and the height difference between the terrain feature and the installation location of the sideband reference glide path beacon antenna;

[0009] Step 3: Calculate the terrain and object shielding angle according to step 2, and then combine it with the CSB curve and SBO curve obtained in step 1 to obtain the beam curvature BBP corresponding to the shielding angle;

[0010] Step 4: Calculate the modulation difference DDM based on the beam curvature BBP calculation result in step 3;

[0011] Step 5: Convert the modulation depth difference DDM obtained in step 4 into the glide path structure deviation value CDI, and compare it with the glide path structure threshold value to determine the degree of influence of the terrain and objects on the glide path structure.

[0012] Furthermore, in step 1, the calculation of the spatially synthesized carrier and sideband wave CSB, the synthesized sideband wave SBO and the generation of a curve based on the sideband reference glide beacon antenna amplitude and phase distribution diagram specifically includes the following sub-steps:

[0013] The spatially synthesized carrier and sideband wave CSB are calculated according to formula (1), and the spatially synthesized sideband wave SBO is calculated according to formula (2):

[0014] (1);

[0015] (2);

[0016] in, E CSB_SBR For the sideband reference glide path antenna spatial synthesis CSB, E SBO_SBR The spatial synthesis SBO for the sideband reference glide path antenna; is the installation height of the antenna below the sideband reference antenna; A CSB_SBR_下 is the CSB signal level value radiated by the antenna under the sideband reference glide path antenna; A SBO_SBR_上 、A SBO_SBR_下 are the SBO signal level values ​​radiated by the upper antenna and lower antenna of the sideband reference glide path antenna respectively; λ is the wavelength; α is the elevation angle of the aircraft relative to the sideband reference glide path antenna.

[0017] Furthermore, in step 2, determining the shielding angle of the terrain object relative to the sideband reference glide path beacon antenna based on the relative position of the terrain object and the sideband reference glide path beacon antenna and the height difference between the terrain object and the sideband reference glide path beacon antenna installation location specifically includes the following sub-steps:

[0018] Calculate the terrain and object shielding angle according to formula (3):

[0019] (3);

[0020] in, β 遮蔽角 is the shielding angle of terrain objects relative to the sideband reference glide path beacon antenna;

[0021] h 地形地物 is the height difference between the terrain and the sideband reference glide path beacon antenna;

[0022] d 地形地物 is the distance of the terrain object relative to the sideband reference glide path beacon antenna.

[0023] Furthermore, in step 3, the terrain obstruction angle calculated according to step 2 is combined with the CSB curve and SBO curve obtained in step 1 to obtain the beam curvature BBP corresponding to the obstruction angle, which specifically includes the following sub-steps:

[0024] The beam curvature BBP corresponding to the terrain and object shielding angle is calculated according to formula (4):

[0025] (4);

[0026] in, is the spatial composite SBO amplitude corresponding to the shielding angle θ;

[0027] is the spatial composite CSB amplitude on the glide slope.

[0028] Furthermore, in step 4, the modulation difference DDM is calculated based on the beam curvature BBP calculation result in step 3, which specifically includes the following sub-steps:

[0029] Calculate the modulation difference DDM according to formula (5):

[0030] (5);

[0031] Among them, DDM is the modulation difference between 150Hz and 90Hz; k R is the reflection coefficient of the terrain and objects on the signal transmitted by the sideband reference glide path beacon.

[0032] Furthermore, in step 5, the modulation difference DDM in step 4 is converted into a glide path structure deviation value CDI, and the influence of the terrain and objects on the glide path structure is determined by comparing it with the glide path structure threshold value. The specific steps include:

[0033] The modulation error DDM is converted into the glide slope structure deviation CDI using formula (6):

[0034] (6);

[0035] μA is the unit of current, microampere. The calculated result of the glide path structure deviation value CDI is compared with the allowable threshold of the glide path structure of the glide path beacon specified by ICAO, and then the degree of influence of the terrain and objects on the glide path structure is determined.

[0036] The beneficial effects of the present invention include:

[0037] (1) The method of the present invention is reasonable and scientific. Based on the distribution relationship of the radiation signal of the sideband reference glide path beacon antenna, the basic principles of radio wave propagation, and the working principle of the sideband reference glide path beacon antenna, the method of the present invention derives the calculation formulas for the spatial synthesis CSB and synthesis SBO of the sideband reference glide path beacon antenna. Then, based on the calculation results of the terrain and object shielding angle, the beam curvature BBP and modulation difference DDM corresponding to the shielding angle are calculated. Finally, the modulation difference DDM is converted into the glide path structure deviation value CDI. The analysis method is reasonable and scientific.

[0038] (2) The method of the present invention analyzes the influence of the terrain ahead on the glide path structure jitter of the sideband reference glide path beacon antenna, and can solve the analysis of the influence of the terrain ahead on the glide path structure of the sideband reference glide path beacon antenna, and has a wide range of applications.

[0039] (3) The method of the present invention is simple, efficient and easy to master. Currently, the analysis of the impact of the glide path beacon space signal mainly relies on professional third-party assessment agencies, which usually have long service cycles, high costs and great limitations. The method of the present invention can quickly calculate the beam curvature BBP corresponding to the shielding angle by calculating the terrain and object shielding angle. Finally, based on the terrain and object reflection coefficient, the glide path structure deviation value CDI can be obtained. By comparing it with the glide path structure threshold value, the degree of influence of the terrain and objects on the glide path structure can be determined. General staff can quickly master the quantitative analysis of the impact of terrain and objects on the glide path structure through this method. The method is simple, efficient and easy to master. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0041] Figure 1 The amplitude and phase distribution diagram of the sideband reference glide path beacon antenna;

[0042] Figure 2 It is the amplitude curve of the sideband reference glide path beacon antenna CSB and SBO after spatial synthesis;

[0043] Figure 3 The glide path structure curve of the sideband reference glide path beacon antenna when the obstacle shielding angle is 1.0° and the reflection coefficient is 0.15;

[0044] Figure 4 Flow chart of the steps of the method of the present invention. DETAILED DESCRIPTION

[0045] All features disclosed in all embodiments in this specification, or steps in all methods or processes implicitly disclosed, except for mutually exclusive features and / or steps, can be combined and / or expanded or replaced in any manner.

[0046] Explanation of terms

[0047] CSB, Carrier and Side Bands, carrier and sideband waves.

[0048] SBO, Side Bands Only, sideband wave.

[0049] BBP, Beam Bend Potential, beam curvature.

[0050] In view of the above problems, the present invention aims to provide a simple, fast, and easy-to-understand method for analyzing the impact of terrain and objects on the glide path structure of a sideband reference glide path beacon antenna. The specific implementation process of the present invention is as follows:

[0051] In a preferred embodiment, a method for analyzing the effect of the terrain in front of a sideband reference glide path antenna on the structure is provided, comprising the following steps:

[0052] Step 1: Calculate the spatial composite CSB and composite SBO according to the sideband reference glide path beacon antenna amplitude and phase distribution diagram and generate a curve;

[0053] Step 2: Determine the shielding angle of the terrain feature relative to the sideband reference glide path beacon antenna based on the relative position of the terrain feature and the sideband reference glide path beacon antenna and the height difference between the terrain feature and the installation location of the sideband reference glide path beacon antenna;

[0054] Step 3: Calculate the terrain and object shielding angle according to step 2, and then combine it with the spatially synthesized CSB and SBO curves in step 1 to obtain the beam bend potential (BBP) corresponding to the shielding angle.

[0055] Step 4: Calculate the modulation difference DDM based on the beam curvature BBP calculation result in step 3;

[0056] Step 5: Convert the modulation depth difference DDM obtained in step 4 into the glide path structure deviation value CDI.

[0057] In some embodiments of the present invention, in step 1, the spatial composite CSB is calculated according to formula (1), and the spatial composite SBO is calculated according to formula (2).

[0058] (1);

[0059] (2);

[0060] in, E CSB_SBR For the sideband reference glide path antenna spatial synthesis CSB, E SBO_SBR is the spatial synthesis SBO of the sideband reference glide path antenna; the installation height of the antenna below the sideband reference antenna is (Nominal value is 2.15m), unit is m. The height of the upper antenna is 3 times the height of the lower antenna; A CSB_SBR_下 is the CSB signal level value radiated by the antenna under the sideband reference glide path antenna ； A SBO_SBR_上 、A SBO_SBR_下 are the SBO signal levels radiated by the upper and lower antennas of the sideband reference glide path antenna ;λ is the wavelength in meters; α is the elevation angle of the aircraft relative to the sideband reference glide path antenna, 0≤α≤6°.

[0061] In some embodiments of the present invention, in step 2, the terrain and object shielding angle is calculated according to formula (3).

[0062] (3);

[0063] in, β 遮蔽角is the shielding angle of terrain objects relative to the sideband reference glide path beacon antenna, in degrees (°); h 地形地物 is the height difference between the terrain and the sideband reference glide path beacon antenna, in meters; d 地形地物 The distance between the terrain and the sideband reference glide path beacon antenna, in meters.

[0064] In some implementation schemes of the present invention, in step 3, the beam curvature BBP corresponding to the terrain and object shielding angle is calculated according to formula (4).

[0065] (4);

[0066] in, BBP The potential for the glide path structure to bend, also known as beam curvature; is the spatial composite SBO amplitude corresponding to the shielding angle θ; is the spatial composite CSB amplitude on the glide path. The glide path angle of most civil aviation airports is =3°.

[0067] In some embodiments of the present invention, in step 4, the modulation difference DDM is calculated according to formula (5).

[0068] (5);

[0069] Among them, DDM is the modulation difference between 150Hz and 90Hz; k R is the reflection coefficient of the terrain and objects on the signal transmitted by the sideband reference glide path beacon.

[0070] In some embodiments of the present invention, in step 5, the modulation difference DDM is converted into the glide slope structure deviation value CDI according to formula (6).

[0071] (6);

[0072] The calculated results of the glide path structure deviation (CDI) can be compared with the allowable threshold of the glide path structure of the glide path beacon specified by ICAO, and the degree of influence of the terrain and objects on the glide path structure can be determined.

[0073] In other embodiments of the present invention, Figures 1 to 4As shown, a method for analyzing the impact of terrain on the structure ahead of a sideband reference glide path antenna is provided. Specifically, the sideband reference glide path antenna spatially synthesizes the CSB and SBO calculation formulas. Based on the terrain and object shielding angle calculation results, the beam curvature (BBP) and modulation difference (DDM) corresponding to that shielding angle are calculated. Finally, the modulation difference (DDM) is converted into a glide path structure deviation (CDI). By comparing the CDI with the glide path structure threshold, the degree of impact of terrain and objects on the glide path structure can be determined. This method, simple, efficient, and easy to master, can be used by general personnel to quickly and quantitatively analyze the impact of terrain and objects on the glide path structure.

[0074] In a further embodiment, a method for analyzing the influence of terrain and objects in front of a glide path beacon antenna on the glide path structure jitter is provided, comprising the following steps:

[0075] Step 1: According to the amplitude and phase distribution diagram of the glide beacon antenna, Figure 1 As shown, the spatial synthesis CSB and the synthesis SBO are calculated and a curve is generated; in step 1, the spatial synthesis CSB is calculated according to formula (1), and the spatial synthesis SBO is calculated according to formula (2).

[0076] (1);

[0077] (2);

[0078] in, E CSB_SBR For the sideband reference glide path antenna spatial synthesis CSB, E SBO_SBR is the spatial synthesis SBO of the sideband reference glide path antenna; the installation height of the antenna below the sideband reference antenna is (Nominal value is 2.15m), unit is m. The height of the upper antenna is 3 times the height of the lower antenna; A CSB_SBR_下 is the CSB signal level value radiated by the antenna under the sideband reference glide path antenna ； A SBO_SBR_上 、A SBO_SBR_下 are the SBO signal levels radiated by the upper and lower antennas of the sideband reference glide path antenna 。 Sideband reference glide path antenna spatial synthesis CSB signal E CSB_SBR , spatially synthesized SBO signal E SBO_SBR like Figure 2 shown.

[0079] Step 2: Determine the obstruction angle of the terrain feature relative to the sideband reference glidepath antenna based on the relative position of the terrain feature and the sideband reference glidepath antenna, as well as the height difference between the terrain feature and the sideband reference glidepath antenna installation location. In this embodiment, the sideband reference antenna has a lower antenna height of 2.15 meters and an upper antenna height of 6.45 meters. The operating frequency is 333.2 MHz, and the wavelength is approximately 0.9 meters. Aside from the terrain feature to be analyzed (with a reflection coefficient of 0.15), the terrain is flat. The obstacle is located 1000 meters directly in front of the sideband reference glidepath antenna at a height of 17.45 meters.

[0080] In step 2, the obstacle shielding angle is calculated according to formula (3).

[0081] (3);

[0082] Step 3: The terrain and object shielding angle calculated in step 2 is combined with the spatial synthesis CSB and synthetic SBO curves in step 1 to obtain the beam curvature BBP corresponding to the shielding angle. Figure 2 Obtain the spatial composite SBO amplitude corresponding to this angle (masking angle 1.0°). Figure 2 The spatial composite CSB amplitude corresponding to the glide path angle of 3° is obtained. The sideband reference glide path antenna beam curvature BBP corresponding to the shielding angle of 1.0° is calculated according to formula (4).

[0083] (4);

[0084] Step 4: Calculate the modulation difference DDM based on the beam curvature BBP calculated in step 3 and the terrain reflectivity. In step 4, the modulation difference DDM of the sideband reference glide path antenna is calculated using formula (5) when the obstacle shielding angle is 1.0° and the reflection coefficient is 0.15.

[0085] (5);

[0086] Step 5: Convert the modulation error DDM calculated in step 4 into the glide path structure deviation CDI. In step 5, convert the modulation error DDM of the sideband reference glide path antenna calculated in step 4 into the glide path structure deviation CDI according to formula (6).

[0087] (6);

[0088] μA is the current unit of microampere (150μA is the full-scale deflection current value of the instrument). When there is an obstacle with a shielding angle of 1.0° 1000m in front of the sideband reference glide path antenna, according to the calculation result of the glide path structure deviation value CDI in step 5, the glide path structure deviation value CDI is 19.04μA, which is the same as Figure 3 The simulation results of the glide path structure of the sideband reference glide path beacon antenna (maximum jitter value 19.72μA) are basically consistent, verifying the scientificity and rationality of this method.

[0089] The units involved in the embodiments of the present invention may be implemented in software or hardware, and the units described may also be provided in a processor. In some cases, the names of these units do not limit the units themselves.

[0090] According to one aspect of an embodiment of the present invention, a computer program product or computer program is provided, comprising computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the methods provided in the various optional implementations described above.

[0091] As another aspect, embodiments of the present invention further provide a computer-readable medium, which may be included in the electronic device described in the above embodiments, or may exist independently and not incorporated into the electronic device. The computer-readable medium carries one or more programs, and when executed by the electronic device, the electronic device implements the methods described in the above embodiments.

Claims

1. A method for analyzing the influence of the terrain in front of a sideband reference glide path antenna on its structure, characterized in that: The following steps are involved: Step 1: Calculate the spatial composite carrier and sideband wave CSB and composite sideband wave SBO according to the sideband reference glide path beacon antenna amplitude and phase distribution diagram and generate a curve; Step 2: Determine the shielding angle of the terrain feature relative to the sideband reference glide path beacon antenna based on the relative position of the terrain feature and the sideband reference glide path beacon antenna and the height difference between the terrain feature and the installation location of the sideband reference glide path beacon antenna; Step 3: Calculate the terrain and object shielding angle according to step 2, and then combine it with the CSB curve and SBO curve obtained in step 1 to obtain the beam curvature BBP corresponding to the shielding angle; Step 4: Calculate the modulation index difference DDM based on the beam curvature BBP calculation result in step 3. Calculate the modulation index difference DDM: ； Among them, DDM is the modulation difference between 150Hz and 90Hz; k R is the reflection coefficient of the terrain and objects to the signal transmitted by the sideband reference glide path beacon; Step 5: Convert the modulation index difference DDM obtained in step 4 into the glide path structure deviation value CDI. By comparing it with the glide path structure threshold value, the influence of the terrain and objects on the glide path structure is determined. Convert the modulation index difference DDM into the glide path structure deviation value CDI: ； μA is the unit of current, microampere. The calculated result of the glide path structure deviation value CDI is compared with the allowable threshold of the glide path structure of the glide path beacon specified by ICAO, and then the degree of influence of the terrain and objects on the glide path structure is determined.

2. The method for analyzing the influence of the terrain in front of the sideband reference glide path antenna on the structure according to claim 1 is characterized in that: In step 1, the calculation of the spatial synthetic carrier and sideband wave CSB, the synthetic sideband wave SBO and the generation of a curve based on the sideband reference glide beacon antenna amplitude and phase distribution diagram specifically includes the following sub-steps: The spatially synthesized carrier and sideband wave CSB are calculated according to formula (1), and the spatially synthesized sideband wave SBO is calculated according to formula (2): （1）； （2）； in, E CSB_SBR For the sideband reference glide path antenna spatial synthesis CSB, E SBO_SBR The spatial synthesis SBO for the sideband reference glide path antenna; is the installation height of the antenna below the sideband reference antenna; A CSB_SBR_下 is the CSB signal level value radiated by the antenna under the sideband reference glide path antenna; A SBO_SBR_上 、A SBO_SBR_下 are the SBO signal level values ​​radiated by the upper antenna and lower antenna of the sideband reference glide path antenna respectively; λ is the wavelength; α is the elevation angle of the aircraft relative to the sideband reference glide path antenna.

3. The method for analyzing the influence of the terrain in front of the sideband reference glide path antenna on the structure according to claim 1, characterized in that: In step 2, determining the shielding angle of the terrain object relative to the sideband reference glide path beacon antenna based on the relative position of the terrain object and the sideband reference glide path beacon antenna and the height difference between the terrain object and the sideband reference glide path beacon antenna installation location specifically includes the following sub-steps: Calculate the terrain and object shielding angle according to formula (3): （3）； in, β 遮蔽角 is the shielding angle of terrain objects relative to the sideband reference glide path beacon antenna; h 地形地物 is the height difference between the terrain and the sideband reference glide path beacon antenna; d 地形地物 is the distance of the terrain object relative to the sideband reference glide path beacon antenna.

4. The method for analyzing the influence of the terrain in front of the sideband reference glide path antenna on the structure according to claim 1, characterized in that: In step 3, the terrain obstruction angle calculated according to step 2 is combined with the CSB curve and SBO curve obtained in step 1 to obtain the beam curvature BBP corresponding to the obstruction angle, which specifically includes the following sub-steps: The beam curvature BBP corresponding to the terrain and object shielding angle is calculated according to formula (4): （4）； in, is the spatial composite SBO amplitude corresponding to the shielding angle θ; is the spatial composite CSB amplitude on the glide slope.

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