Radar altitude measuring method and radar altitude measuring device

Abstract

The present disclosure provides a radar altitude measurement method and a radar altitude measurement device. The method comprises: performing ionosphere correction on detection data acquired from the radar to obtain a correction coefficient and a target pulse pressure coefficient corresponding to the correction coefficient, wherein the detection data is obtained by the radar detecting the surface of a star; performing pulse compression on the detection data according to the target pulse pressure coefficient to obtain compressed data, wherein the resolution of the compressed data meets the preset resolution requirement; finding the target echo position in the compressed data based on a preset selection rule; determining the radar altitude information according to the time delay corresponding to the target echo position, the sampling rate of the detection data, and the window height at which the radar receives the detection data.

Description

Technical Field

[0001] The present disclosure relates to the field of computer technology, and more specifically, to a radar altitude measurement method, a radar altitude measurement device, equipment, medium and computer program product. Background Art

[0002] Radar detection is convenient, fast, and has high resolution, so it is widely used in archaeology, construction, geological exploration, astronomical exploration, and other fields. Since the radar's transmission signal is omnidirectional, it can not only receive the reflected signal directly below the radar, but also receive the reflected signal within a specific range that deviates from directly below, so it can be used in the field of imaging.

[0003] In the process of implementing the concept of the present disclosure, the inventors found that there are at least the following problems in the related art: the measurement accuracy of radar altitude is poor, resulting in poor quality of images generated by the radar. Summary of the invention

[0004] In view of this, the embodiments of the present disclosure provide a radar altitude measurement method, a radar altitude measurement device, a device, a medium and a computer program product.

[0005] One aspect of an embodiment of the present disclosure provides a method for measuring radar altitude, including:

[0006] Performing ionospheric correction on the detection data obtained from the radar to obtain a correction coefficient and a target pulse pressure coefficient corresponding to the correction coefficient, wherein the detection data is obtained by the radar detecting the surface of a celestial body;

[0007] According to the target pulse pressure coefficient, pulse compressing the detection data to obtain compressed data, wherein the resolution of the compressed data meets the preset resolution requirement;

[0008] Based on a preset selection rule, finding the target echo position in the compressed data from the compressed data;

[0009] The altitude information of the radar is determined according to the time delay corresponding to the target echo position, the sampling rate of the detection data and the window height at which the radar receives the detection data.

[0010] According to an embodiment of the present disclosure, the radar altitude measurement method further includes:

[0011] The target position information and elevation information of the sub-satellite point of the radar on the celestial body are determined based on the altitude information and the radar data packet obtained from the radar, wherein the radar data packet includes the initial position information of the radar in the celestial body inertial coordinate system and multiple attitude angles of the radar.

[0012] According to an embodiment of the present disclosure, the method of determining the position information and elevation information of the sub-satellite point of the radar on the star body according to the altitude information and the radar data packet obtained from the radar includes:

[0013] Determining the direction information of the radar according to the attitude angle;

[0014] Determine the sub-satellite point and the target position information of the sub-satellite point according to the pointing information, the vector length, the initial position information and the latitude and longitude coordinate system of the star body, wherein the vector length represents the altitude information;

[0015] The elevation information of the sub-satellite point is determined based on the distance information between the radar and the center of the star and the altitude information obtained from the radar.

[0016] According to an embodiment of the present disclosure, the ionospheric correction is performed on the detection data obtained from the radar to obtain a correction coefficient and a target pulse pressure coefficient corresponding to the correction coefficient, including:

[0017] According to the initial pulse pressure coefficient and multiple phase estimation error models, multiple estimated values ​​of the above-mentioned target pulse pressure coefficients are obtained; the target pulse pressure coefficient estimated value refers to the pulse pressure coefficient with ionospheric phase estimation error, and the correction coefficient refers to the phase compensation item that can correct the ionospheric phase error.

[0018] According to each of the target pulse compression coefficient estimation values ​​and the detection data, the target pulse compression coefficient corresponding to the detection data is determined. The target pulse compression coefficient refers to the pulse compression coefficient with an accurate ionospheric error estimation value correction amount.

[0019] According to an embodiment of the present disclosure, the phase estimation error model includes the following formula:

[0020]

[0021]

[0022] δa 2 =0.1Δa 2 ,

[0023] 1≤k≤n

[0024]

[0025]

[0026]

[0027] The second formula is the Taylor expansion expression of the first formula; ai is the coefficient of different products after Taylor expansion, i is a positive integer; k is an integer, n is a preset value, and when the value of k changes, multiple phase error estimation values ​​are obtained according to the above estimation error model and the above detection data The estimated value of the pulse pressure coefficient; f is the frequency of the detection data, the range is the working frequency band of the radar, f 0 is the center frequency of the radar; z is the height of the radar in the ionosphere; n(z) is the ionosphere reflection coefficient, f p (z) is the ionospheric plasma frequency, c is the wave speed, H 1 is the estimated altitude of the radar; L eq is the equivalent thickness of the ionosphere; B is the bandwidth of electromagnetic waves emitted by the radar.

[0028] According to an embodiment of the present disclosure, the target pulse pressure coefficient h(t) is expressed by the following formula:

[0029]

[0030] Where A(t) is the initial pulse pressure coefficient; j is a complex unit; fft and ifft are Fourier transform and inverse Fourier transform, respectively.

[0031] According to an embodiment of the present disclosure, the step of finding the target echo position in the compressed data based on a preset selection rule includes:

[0032] Based on the parameters of each echo position in the compressed data, the echo position with the largest parameter value is determined as the target echo position, wherein the parameters include at least one of the following: amplitude and intensity.

[0033] According to an embodiment of the present disclosure, the pulse compression of the detection data is performed according to the target pulse pressure coefficient to obtain compressed data, including:

[0034] Performing Fourier transform on the target pulse pressure coefficient and the detection data respectively to obtain first frequency domains corresponding to the target pulse pressure coefficient and the detection data respectively;

[0035] Obtaining a second frequency domain according to the first frequency domains respectively corresponding to the target pulse pressure coefficient and the correction data; and

[0036] The second frequency domain is converted into the time domain to obtain the compressed data.

[0037] According to an embodiment of the present disclosure, the height information H 2 The calculation is shown in the following formula:

[0038]

[0039]

[0040] Among them, h is the window height of radar receiving target compressed data, F s is the sampling rate of the target compressed data, c is the speed of light, x is the sampling point number corresponding to the maximum value in the target compressed data, T is the delay of the target compressed data, and PW is the pulse width emitted by the radar.

[0041] Another aspect of the embodiments of the present disclosure provides a radar altitude measuring device, including:

[0042] A correction module, used for performing ionospheric correction on the detection data obtained from the above radar to obtain a correction coefficient and a target pulse pressure coefficient corresponding to the above correction coefficient, wherein the above detection data is obtained by the above radar detecting the surface of a celestial body;

[0043] A compression module, used for performing pulse compression on the detection data according to the target pulse pressure coefficient to obtain compressed data, wherein the resolution of the compressed data meets the preset resolution requirement;

[0044] A selection module, used for finding the target echo position in the compressed data from each of the compressed data based on a preset selection rule; and

[0045] The determination module is used to determine the altitude information of the above-mentioned radar according to the time delay corresponding to the above-mentioned target echo position, the sampling rate of the above-mentioned detection data and the window height of the above-mentioned radar receiving the above-mentioned detection data.

[0046] Another aspect of an embodiment of the present disclosure provides an electronic device, comprising: one or more processors; and a memory for storing one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors implement the method described above.

[0047] Another aspect of an embodiment of the present disclosure provides a computer-readable storage medium storing computer-executable instructions, which are used to implement the method described above when executed.

[0048] Another aspect of an embodiment of the present disclosure provides a computer program product, wherein the computer program product includes computer executable instructions, and the instructions are used to implement the method described above when executed.

[0049] According to an embodiment of the present disclosure, ionospheric correction is performed on detection data that meets preset resolution requirements to reduce amplitude and phase errors in the detection data when passing through the ionosphere, thereby obtaining second data with higher accuracy, thereby making it possible to more accurately calculate the altitude information using the selected target second data. Therefore, using radar altitude information that is more accurate and has a larger data volume facilitates subsequent radar data imaging processing. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The above and other objects, features and advantages of the present disclosure will become more apparent through the following description of the embodiments of the present disclosure with reference to the accompanying drawings, in which:

[0051] Figure 1 An exemplary system architecture of a method for measuring radar altitude according to an embodiment of the present disclosure is schematically shown;

[0052] Figure 2 A flowchart of a radar altitude measurement method according to an embodiment of the present disclosure is schematically shown;

[0053] Figure 3 A flowchart for determining the position information and elevation information of a sub-satellite point of a radar on a star body according to an embodiment of the present disclosure is schematically shown;

[0054] Figure 4 A block diagram schematically shows a radar altitude measuring device according to an embodiment of the present disclosure; and

[0055] Figure 5 A block diagram of an electronic device for implementing a radar altitude measurement method according to an embodiment of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0056] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present disclosure. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present disclosure.

[0057] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0058] All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification, and should not be interpreted in an idealized or overly rigid manner.

[0059] When using expressions such as "at least one of A, B, and C, etc.", they should generally be interpreted according to the meaning of the expression commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0060] The electromagnetic waves emitted by the radar are generated by the transmitter, emitted by the antenna, reflected by the surface and subsurface interface, received by the antenna, and converted by the receiver. During this process, the radar's transceiver channel and antenna may have a certain impact on the electromagnetic waves. In order to obtain high-resolution radar images, this error must be corrected. Among them, the electromagnetic waves will also undergo amplitude and phase changes when passing through the ionosphere of the celestial body.

[0061] In view of this, the embodiments of the present disclosure provide a radar altitude measurement method and a radar altitude measurement device. The method includes: performing ionospheric correction on the detection data obtained from the radar to obtain a correction coefficient and a target pulse pressure coefficient corresponding to the correction coefficient, wherein the detection data is obtained by the radar detecting the surface of a star; performing pulse compression on the detection data according to the target pulse pressure coefficient to obtain compressed data, wherein the resolution of the compressed data meets the preset resolution requirement; based on the preset selection rules, finding the target echo position in the compressed data; determining the radar altitude information according to the time delay corresponding to the target echo position, the sampling rate of the detection data and the window height of the radar receiving the detection data.

[0062] Figure 1 The exemplary system architecture 100 to which the radar altitude measurement method according to an embodiment of the present disclosure can be applied is schematically shown. It should be noted that: Figure 1 What is shown is merely an example of a system architecture to which the embodiments of the present disclosure can be applied, in order to help those skilled in the art understand the technical content of the present disclosure, but it does not mean that the embodiments of the present disclosure cannot be used in other devices, systems, environments or scenarios.

[0063] like Figure 1As shown, the system architecture 100 according to this embodiment may include terminal devices 101, 102, 103, a network 104, a server 105, and a radar 106. The network 104 is used to provide a medium for communication links between the terminal devices 101, 102, 103 and the server 105. The network 104 may include various connection types, such as wired and / or wireless communication links, etc.

[0064] The user can use the terminal devices 101, 102, 103 to interact with the server 105 through the network 104 to receive or send messages, etc. Various communication client applications can be installed on the terminal devices 101, 102, 103, such as radar height measurement applications, web browser applications, search applications, instant messaging tools, email clients and / or social platform software, etc. (only as examples).

[0065] The terminal devices 101 , 102 , and 103 may be various electronic devices having a display screen and supporting web browsing, including but not limited to smart phones, tablet computers, laptop computers, and desktop computers.

[0066] The server 105 may be a server that provides various services, such as a background management server (only as an example) that provides support for the measurement of radar altitude requested by the user using the terminal devices 101, 102, and 103. The background management server may analyze and process the received data such as user requests, and feed back the processing results to the terminal device.

[0067] The radar 106 may use a transmitting antenna to transmit a transmission signal toward the surface of a celestial body. After the transmission signal is reflected by the surface of the celestial body, the receiving antenna of the radar 106 receives the reflected signal.

[0068] It should be noted that the radar altitude measurement method provided in the embodiment of the present disclosure can generally be performed by the server 105. Accordingly, the radar altitude measurement device provided in the embodiment of the present disclosure can generally be arranged in the server 105. The radar altitude measurement method provided in the embodiment of the present disclosure can also be performed by a server or server cluster different from the server 105 and capable of communicating with the terminal devices 101, 102, 103 and / or the server 105. Accordingly, the radar altitude measurement device provided in the embodiment of the present disclosure can also be arranged in a server or server cluster different from the server 105 and capable of communicating with the terminal devices 101, 102, 103 and / or the server 105. Alternatively, the radar altitude measurement method provided in the embodiment of the present disclosure can also be performed by the terminal devices 101, 102, or 103, or can also be performed by other terminal devices different from the terminal devices 101, 102, or 103. Correspondingly, the radar altitude measuring device provided in the embodiment of the present disclosure may also be arranged in the terminal device 101 , 102 , or 103 , or in other terminal devices different from the terminal device 101 , 102 , or 103 .

[0069] It should be understood that Figure 1 The number of terminal devices, networks, servers and radars in the embodiment is only for illustration. Any number of terminal devices, networks, servers and radars may be provided as required.

[0070] Figure 2 The flowchart of the radar altitude measurement method according to the embodiment of the present disclosure is schematically shown.

[0071] like Figure 2 As shown, the method includes operations S201 to S204.

[0072] In operation S201, ionospheric correction is performed on detection data acquired from a radar to obtain a correction coefficient and a target pulse pressure coefficient corresponding to the correction coefficient, wherein the detection data is obtained by the radar detecting the surface of a celestial body.

[0073] In operation S202, pulse compression is performed on the detection data according to the target pulse pressure coefficient to obtain compressed data, wherein the resolution of the compressed data meets a preset resolution requirement.

[0074] In operation S203, based on a preset selection rule, the target echo position in the compressed data is found from each compressed data.

[0075] In operation S204, the altitude information of the radar is determined according to the time delay corresponding to the target echo position, the sampling rate of the detection data, and the windowing altitude of the radar receiving the detection data.

[0076] According to an embodiment of the present disclosure, the detection mode of the radar includes a low-frequency detection mode and a high-frequency detection mode, wherein the high-frequency mode may refer to a mode in which a resolution in the distance direction is a preset distance length and a high-frequency electromagnetic wave (e.g., 30-50 MHz) is emitted to detect data. Among them, the radar may include but is not limited to a zero-offset ground penetrating radar and a multi-offset ground penetrating radar, such as the Mars Orbiter Subsurface Investigation Radar (MOSIR).

[0077] According to an embodiment of the present disclosure, the preset resolution requirement may refer to the detection data of the radar in the high frequency mode. The celestial body may include a planet with an ionosphere, such as Mars.

[0078] According to an embodiment of the present disclosure, the preset selection rules may include but are not limited to selecting the maximum value, minimum value or intermediate value of the amplitude or intensity in multiple echo positions of the compressed data. The specific selection rules can be set according to requirements. The embodiment of the present disclosure is exemplified by selecting the maximum value.

[0079] According to the embodiments of the present disclosure, electromagnetic waves emitted and received by the radar will have certain amplitude and phase errors when passing through the ionosphere of a celestial body, which is particularly serious in the low-frequency band. Therefore, it is necessary to perform ionospheric correction on the detection data to reduce the error.

[0080] According to an embodiment of the present disclosure, the detection data in the high-frequency mode is ionosphericly corrected to obtain the target pulse pressure coefficient of the corresponding detection data. The detection data corresponding to the target pulse pressure coefficient is compressed to obtain a plurality of compressed data. Based on a preset selection rule, a compressed data point with the maximum amplitude or the maximum intensity is selected from the compressed data as the target echo position, so as to extract the time delay of the target position, so as to calculate the height information of the radar at the current moment according to the sampling rate and the window height when the radar generates the target detection data.

[0081] It should be noted that the selection process can also be performed based on both amplitude and intensity. For example, when there are multiple echoes with the same amplitude value (or intensity value), the echo position with the largest intensity value (or amplitude value) is used as the target echo position.

[0082] According to an embodiment of the present disclosure, ionospheric correction is performed on detection data that meets preset resolution requirements to reduce amplitude and phase errors in the detection data when passing through the ionosphere, thereby obtaining second data with higher accuracy, thereby making it possible to more accurately calculate the altitude information using the selected target second data. Therefore, using radar altitude information that is more accurate and has a larger data volume facilitates subsequent radar data imaging processing.

[0083] According to an embodiment of the present disclosure, the radar altitude measurement method may further include the following operations:

[0084] The target position information and elevation information of the radar's sub-satellite point on the celestial body are determined based on the altitude information and the radar data packet obtained from the radar, wherein the radar data packet includes the initial position information of the radar in the celestial body's inertial coordinate system and multiple attitude angles of the radar.

[0085] According to an embodiment of the present disclosure, the sub-satellite point may refer to the intersection of a ray where a certain antenna of the radar is pointed and the surface of a celestial body.

[0086] According to an embodiment of the present disclosure, the radar data packet contains the initial position information and multiple attitude angles of the radar in the inertial coordinate system of the celestial body. Combining the radar data packet with the above-mentioned determined altitude information can determine the target position information and elevation information of the radar's sub-satellite point on the celestial body.

[0087] Figure 3 The flowchart of determining the position information and elevation information of the sub-satellite point of a radar on a celestial body according to an embodiment of the present disclosure is schematically shown.

[0088] like Figure 3 As shown, determining the position information and elevation information of the sub-satellite point of the radar on the star body according to the altitude information and the radar data packet obtained from the radar may include operations S301 to S303:

[0089] In operation S301 , the direction information of the radar is determined according to the attitude angle.

[0090] In operation S302, the sub-satellite point and the target position information of the sub-satellite point are determined according to the pointing information, the vector length, the initial position information and the latitude and longitude coordinate system of the celestial body, wherein the vector length represents the altitude information.

[0091] In operation S303, the elevation information of the sub-satellite point is determined according to the distance information and the height information between the radar and the center of the satellite body acquired from the radar.

[0092] According to an embodiment of the present disclosure, the initial position information in the inertial coordinate system is projected into the latitude and longitude coordinate system, and the antenna of the radar points to the -Z direction, which will point to the star when the radar is in working state. The precise pointing vector of the -Z axis, that is, the pointing information, is determined according to the attitude angle. The vector length is the above-mentioned height information. The end point of the pointing vector is the position of the reflector on the surface of the star that causes the surface echo (the sub-satellite point), thereby determining the target position information of the sub-satellite point.

[0093] According to an embodiment of the present disclosure, when the altitude information of the radar and the distance information between the radar and the center of the star are known, the elevation information of the current sub-satellite point can be calculated.

[0094] According to an embodiment of the present disclosure, performing ionospheric correction on detection data acquired from a radar to obtain a correction coefficient and a target pulse pressure coefficient corresponding to the correction coefficient may include the following operations:

[0095] According to the initial pulse pressure coefficient and the multiple phase estimation error models, multiple target pulse pressure coefficient estimation values ​​are obtained. According to each target pulse pressure coefficient estimation value and the detection data, the target pulse pressure coefficient corresponding to the detection data is determined.

[0096] According to an embodiment of the present disclosure, since a certain parameter value in multiple phase estimation error models is different, multiple estimated values ​​of target pulse pressure coefficients can be obtained when detection data is input, and each correction data corresponds to a value of the variable parameter in a phase estimation error model.

[0097] According to an embodiment of the present disclosure, the estimated value of the target pulse pressure coefficient obtained by processing the phase estimation error model is combined with the detection data to obtain the target pulse pressure coefficient corresponding to the detection data.

[0098] According to an embodiment of the present disclosure, in ionospheric correction, the step of finding compressed data corresponding to the target compression coefficient from the compressed data using different pulse compression coefficient estimation values ​​based on a preset selection rule to determine the target pulse compression coefficient includes:

[0099] Based on the contrast of parameters in the compressed data generated by multiple channels using different pulse pressure coefficient estimation values, the compressed data with the largest contrast is determined as the pulse pressure data corresponding to the target pulse pressure coefficient, and the target pulse pressure coefficient is determined, wherein the parameters include at least one of the following: amplitude and intensity.

[0100] According to an embodiment of the present disclosure, the phase estimation error model includes the following formulas (1) to (6):

[0101]

[0102]

[0103]

[0104]

[0105]

[0106]

[0107] Wherein, formula (2) is the Taylor expansion expression of formula (1); a iis the coefficient of different products after Taylor expansion, i is a positive integer; k is an integer, n is a preset value, and when the value of k changes, multiple phase error estimation values ​​are obtained according to the estimated error model and the detection data. The estimated value of the pulse pressure coefficient; f is the frequency of the detection data, the range is the working frequency band of the radar, f 0 is the center frequency of the radar; z is the height of the radar in the ionosphere; n(z) is the ionosphere reflection coefficient, f p (z) is the ionospheric plasma frequency, c is the speed of light, H 1 is the estimated altitude of the radar; L eq is the equivalent thickness of the ionosphere; B is the bandwidth of the electromagnetic waves emitted by the radar.

[0108] According to an embodiment of the present disclosure, for formula (2) after Taylor expansion, a 2 The greatest impact on the radar echo pulse compression result (obviously broadened), the contrast method from a 2 To get started, first set up a 2 The specific value of the number of iterations n (preset value) can be used to obtain formula (3).

[0109] According to an embodiment of the present disclosure, the contrast method may be a method for eliminating or reducing the phase error caused by the ionosphere of a stellar body to a radar echo. The method determines whether the generated phase error estimation formula is accurate by comparing the energy concentration of the pulse compression result, and the energy concentration of the pulse compression result uses the magnitude of the contrast of amplitude and / or intensity as an evaluation criterion.

[0110] According to an embodiment of the present disclosure, a 3 , a 4 It will also affect the waveform and can be used 2 By expressing it, we can get formula (4) and formula (5). Where, the equivalent thickness of the ionosphere is L eq It can be set according to the actual situation of the celestial body. For example, the equivalent thickness of the ionosphere of Mars can be 19 km.

[0111] According to an embodiment of the present disclosure, based on formulas (1) to (5), the bit error estimation value expression shown in formula (6) can be determined.

[0112] According to an embodiment of the present disclosure, the target pulse pressure coefficient h(t) is expressed by formula (7):

[0113]

[0114] Where A(t) is the initial pulse pressure coefficient; j is a complex unit; “fft” and “ifft” are Fourier transform and inverse Fourier transform, respectively.

[0115] In an exemplary embodiment, the initial pulse compression coefficient (time domain) is assumed to be A(t) (the transmission signal including the antenna and transceiver channel errors measured by radar calibration can be used as the basis of the pulse compression signal), then the target pulse compression coefficient (time domain) after ionospheric correction is as shown in formula (7), wherein the initial pulse compression coefficient can represent the ideal pulse compression coefficient.

[0116] According to an embodiment of the present disclosure, based on a preset selection rule, finding compressed data corresponding to a target pulse pressure coefficient from compressed data generated using a plurality of pulse pressure coefficient estimation values ​​to determine the target pulse pressure coefficient may include the following operations:

[0117] Based on the contrast of parameters of compressed data generated using multiple pulse pressure coefficient estimation values, the compressed data generated using the pulse pressure coefficient estimation value with the largest contrast is determined as the compressed data corresponding to the target pulse pressure coefficient, and the target pulse pressure coefficient is determined, wherein the parameters include at least one of the following: amplitude and intensity.

[0118] According to an embodiment of the present disclosure, since k in formula (3) is a variable parameter, when detection data is input, as k changes, a plurality of pulse pressure coefficient estimation values ​​corresponding to different k values ​​can be obtained, thereby obtaining a plurality of different compressed data.

[0119] According to the embodiments of the present disclosure, the echo position with the largest amplitude / intensity in the compressed data is used as the target echo position according to the amplitude / intensity of the compressed data to calculate the radar altitude information. The target pulse pressure coefficient obtained by performing ionosphere correction using the first channel of detection data can be directly used for pulse compression of the remaining subsequent detection data without performing ionosphere correction operations on all detection data.

[0120] Based on the energy intensity of the compressed data, the data point with the strongest energy is usually determined as the target echo position. If two peaks with strong energy and close intensity appear in the single-channel data, the optical image can be used to assist in determining the target echo position.

[0121] According to an embodiment of the present disclosure, based on a preset selection rule, finding a target echo position in the compressed data from the compressed data includes:

[0122] Based on the parameters of each echo position in the compressed data, the echo position with the largest parameter value is determined as the target echo position, wherein the parameters include at least one of the following: amplitude and intensity.

[0123] According to an embodiment of the present disclosure, pulse compression is performed on the detection data according to the target pulse pressure coefficient to obtain compressed data, which may include the following operations:

[0124] Fourier transform is performed on the target pulse pressure coefficient and the detection data respectively to obtain first frequency domains corresponding to the target pulse pressure coefficient and the detection data respectively. A second frequency domain is obtained according to the first frequency domains corresponding to the target pulse pressure coefficient and the detection data respectively. The second frequency domain is converted into time domain to obtain compressed data.

[0125] According to an embodiment of the present disclosure, the detection data and the target pulse pressure coefficient are Fourier transformed respectively to obtain the first frequency domain S(f) of the detection data and the first frequency domain H(f) of the target pulse pressure coefficient. The two first frequency domains are dot-multiplied to obtain the second frequency domain Y(f)=S(f).*H(f) of the pulse pressure result. The second frequency domain of the pulse pressure result is transformed back to the time domain y(t)=ifft(Y(f)). After completing the pulse compression, the contrast corresponding to the time domain y(t) can be calculated.

[0126] According to an embodiment of the present disclosure, the dot product may refer to two matrices of the same scale, where elements at the same position in the matrices are multiplied, and the product is also a matrix of the same scale.

[0127] According to an embodiment of the present disclosure, the height information H 2 The calculation of is shown in formula (8) and formula (9):

[0128]

[0129]

[0130] Among them, h is the window height of the radar receiving target detection data, F s is the sampling rate of the target detection data, c is the speed of light, x is the sampling point number corresponding to the maximum value in the target compression data, T is the delay of the target compression data, and PW is the pulse width of the detection data.

[0131] In an exemplary embodiment, the window height may be 2500 m, and the pulse width may be 10 us, and the height information may be calculated according to the above formula.

[0132] According to the embodiment of the present disclosure, the orbiter radar MOSIR uses the radar's own altimetry mode to obtain altitude information to determine the opening time of the detection data receiving window. The altimetry mode outputs the radar's altitude information every 50ms, and the accuracy is low due to on-board data processing and noise. The present disclosure uses the radar's detection data that meets the preset resolution requirements, which intermittently generates the radar's altitude information with the sampling rate. In a unit time, the number of altitude information generated by the present disclosure is higher than the number of altitude information generated by the altimetry mode, which can better meet the requirements of high-precision radar imaging.

[0133] According to the embodiments of the present disclosure, the radar has the characteristics of all-weather, strong penetration and active detection, and the climate environment on the celestial body changes at any time, which has a great impact on optical remote sensing. The radar's altitude information can be obtained more accurately through the radar.

[0134] Figure 4 A block diagram of a radar altitude measurement device according to an embodiment of the present disclosure is schematically shown.

[0135] like Figure 4 As shown, the radar altitude measuring device 400 may include a correction module 410 , a compression module 420 , a selection module 430 , and a determination module 440 .

[0136] The correction module 410 is used to perform ionospheric correction on the detection data obtained from the radar to obtain a correction coefficient and a target pulse pressure coefficient corresponding to the correction coefficient, wherein the detection data is obtained by the radar detecting the surface of a celestial body.

[0137] The compression module 420 is used to perform pulse compression on the detection data according to the target pulse pressure coefficient to obtain compressed data, wherein the resolution of the compressed data meets the preset resolution requirement.

[0138] The selection module 430 is used to find the target echo position in each compressed data based on a preset selection rule.

[0139] The determination module 440 is used to determine the altitude information of the radar according to the time delay corresponding to the target echo position, the sampling rate of the detection data and the window height of the radar receiving the detection data.

[0140] According to an embodiment of the present disclosure, ionospheric correction is performed on detection data that meets preset resolution requirements to reduce amplitude and phase errors in the detection data when passing through the ionosphere, thereby obtaining second data with higher accuracy, thereby making it possible to more accurately calculate the altitude information using the selected target second data. Therefore, using radar altitude information that is more accurate and has a larger data volume facilitates subsequent radar data imaging processing.

[0141] According to an embodiment of the present disclosure, the radar altitude measuring device 400 may further include a second determination module.

[0142] The second determination module is used to determine the target position information and elevation information of the radar's sub-satellite point on the celestial body based on the altitude information and the radar data packet obtained from the radar, wherein the radar data packet includes the initial position information of the radar in the celestial body's inertial coordinate system and multiple attitude angles of the radar.

[0143] According to an embodiment of the present disclosure, the second determining module may include a first determining unit, a second determining unit, and a third determining unit.

[0144] The first determining unit is used to determine the direction information of the radar according to the attitude angle.

[0145] The second determination unit is used to determine the sub-satellite point and the target position information of the sub-satellite point according to the pointing information, the vector length, the initial position information and the latitude and longitude coordinate system of the star body, wherein the vector length represents the altitude information.

[0146] The third determining unit is used to determine the elevation information of the sub-satellite point according to the distance information and height information between the radar and the center of the satellite body obtained from the radar.

[0147] According to an embodiment of the present disclosure, the correction module 410 may include a first obtaining unit and a fourth determining unit.

[0148] The first obtaining unit is used to obtain estimated values ​​of multiple target pulse pressure coefficients according to the initial pulse pressure coefficient and multiple phase estimation error models.

[0149] The fourth determining unit is used to determine the target pulse pressure coefficient corresponding to the detection data according to each target pulse pressure coefficient estimation value and the detection data.

[0150] According to an embodiment of the present disclosure, the selection module 430 may include a fifth determination module.

[0151] The fifth determination module is used to determine the echo position with the largest parameter value as the target echo position based on the parameters of each echo position in the compressed data, wherein the parameters include at least one of the following: amplitude and intensity.

[0152] According to an embodiment of the present disclosure, the compression module 420 may include a transform unit, a second deriving unit, and a conversion unit.

[0153] The transform unit is used to perform Fourier transform on the target pulse pressure coefficient and the detection data respectively to obtain the first frequency domain corresponding to the target pulse pressure coefficient and the detection data respectively.

[0154] The second obtaining unit is used to obtain the second frequency domain according to the first frequency domains corresponding to the target pulse pressure coefficient and the detection data respectively.

[0155] The conversion unit is used to convert the second frequency domain into a time domain to obtain compressed data.

[0156] According to the modules and units of the embodiments of the present disclosure, any multiple or at least part of the functions of any multiple thereof can be implemented in one module. According to any one or more of the modules, units and sub-units of the embodiments of the present disclosure, it can be split into multiple modules for implementation. According to any one or more of the modules and units of the embodiments of the present disclosure, it can be at least partially implemented as a hardware circuit, such as a Field Programmable Gate Array (FPGA), a Programmable Logic Array (PLA), a System on a Chip, a System on a Substrate, a System on a Package, an Application Specific Integrated Circuit (ASIC), or it can be implemented by hardware or firmware of any other reasonable way of integrating or packaging the circuit, or it can be implemented in any one of the three implementation modes of software, hardware and firmware or in any appropriate combination of any of them. Alternatively, according to one or more of the modules and units of the embodiments of the present disclosure, it can be at least partially implemented as a computer program module, and when the computer program module is run, the corresponding function can be executed.

[0157] For example, any multiple of the correction module 410, the compression module 420, the selection module 430 and the determination module 440 can be combined in one module / unit for implementation, or any one of the modules / units can be split into multiple modules / units. Alternatively, at least part of the functions of one or more of these modules / units can be combined with at least part of the functions of other modules / units / sub-units and implemented in one module / unit. According to an embodiment of the present disclosure, at least one of the correction module 410, the compression module 420, the selection module 430 and the determination module 440 can be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on a chip, a system on a substrate, a system on a package, an application specific integrated circuit (ASIC), or can be implemented by hardware or firmware such as any other reasonable way of integrating or packaging the circuit, or implemented in any one of the three implementation methods of software, hardware and firmware or in a suitable combination of any of them. Alternatively, at least one of the correction module 410 , the compression module 420 , the selection module 430 , and the determination module 440 may be at least partially implemented as a computer program module, and when the computer program module is executed, the corresponding function may be performed.

[0158] It should be noted that the radar altitude measuring device part in the embodiment of the present disclosure corresponds to the radar altitude measuring method part in the embodiment of the present disclosure. The description of the radar altitude measuring device part specifically refers to the radar altitude measuring method part, which will not be repeated here.

[0159] Figure 5 A block diagram of an electronic device suitable for implementing the method described above according to an embodiment of the present disclosure is schematically shown. Figure 5 The electronic device shown is only an example and should not bring any limitation to the functions and scope of use of the embodiments of the present disclosure.

[0160] like Figure 5 As shown, the electronic device 500 according to the embodiment of the present disclosure includes a processor 501, which can perform various appropriate actions and processes according to the program stored in the read-only memory (ROM) 502 or the program loaded from the storage part 508 to the random access memory (RAM) 503. The processor 501 may include, for example, a general-purpose microprocessor (such as a CPU), an instruction set processor and / or a related chipset and / or a special-purpose microprocessor (for example, an application-specific integrated circuit (ASIC)), etc. The processor 501 may also include an onboard memory for caching purposes. The processor 501 may include a single processing unit or multiple processing units for performing different actions of the method flow according to the embodiment of the present disclosure.

[0161] In RAM 503, various programs and data required for the operation of electronic device 500 are stored. Processor 501, ROM 502 and RAM 503 are connected to each other via bus 504. Processor 501 performs various operations of the method flow according to the embodiment of the present disclosure by executing the program in ROM 502 and / or RAM 503. It should be noted that the program can also be stored in one or more memories other than ROM 502 and RAM 503. Processor 501 can also perform various operations of the method flow according to the embodiment of the present disclosure by executing the program stored in the one or more memories.

[0162] According to an embodiment of the present disclosure, the electronic device 500 may further include an input / output (I / O) interface 505, which is also connected to the bus 504. The system 500 may further include one or more of the following components connected to the I / O interface 505: an input section 506 including a keyboard, a mouse, etc.; an output section 507 including a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage section 508 including a hard disk, etc.; and a communication section 509 including a network interface card such as a LAN card, a modem, etc. The communication section 509 performs communication processing via a network such as the Internet. A drive 510 is also connected to the I / O interface 505 as needed. A removable medium 511, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 510 as needed, so that a computer program read therefrom is installed into the storage section 508 as needed.

[0163] According to an embodiment of the present disclosure, the method flow according to an embodiment of the present disclosure can be implemented as a computer software program. For example, an embodiment of the present disclosure includes a computer program product, which includes a computer program carried on a computer-readable storage medium, and the computer program contains a program code for executing the method shown in the flowchart. In such an embodiment, the computer program can be downloaded and installed from the network through the communication part 509, and / or installed from the removable medium 511. When the computer program is executed by the processor 501, the above-mentioned functions defined in the system of the embodiment of the present disclosure are executed. According to an embodiment of the present disclosure, the system, equipment, device, module, unit, etc. described above can be implemented by a computer program module.

[0164] The present disclosure also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments; or may exist independently without being assembled into the device / apparatus / system. The above computer-readable storage medium carries one or more programs, and when the above one or more programs are executed, the method according to the embodiment of the present disclosure is implemented.

[0165] According to an embodiment of the present disclosure, the computer-readable storage medium may be a non-volatile computer-readable storage medium. For example, it may include, but is not limited to: a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM (Erasable Programmable Read Only Memory, EPROM) or flash memory), a portable compact disk read-only memory (Computer Disc Read-Only Memory, CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. In the present disclosure, a computer-readable storage medium may be any tangible medium containing or storing a program, which may be used by or in combination with an instruction execution system, an apparatus or a device.

[0166] For example, according to an embodiment of the present disclosure, the computer-readable storage medium may include the ROM 502 and / or the RAM 503 described above and / or one or more memories other than the ROM 502 and the RAM 503 .

[0167] An embodiment of the present disclosure also includes a computer program product, which includes a computer program, and the computer program contains a program code for executing the method provided by the embodiment of the present disclosure. When the computer program product runs on an electronic device, the program code is used to enable the electronic device to implement the radar altitude measurement method provided by the embodiment of the present disclosure.

[0168] When the computer program is executed by the processor 501, the above functions defined in the system / device of the embodiment of the present disclosure are executed. According to the embodiment of the present disclosure, the system, device, module, unit, etc. described above can be implemented by a computer program module.

[0169] In one embodiment, the computer program may rely on tangible storage media such as optical storage devices, magnetic storage devices, etc. In another embodiment, the computer program may also be transmitted and distributed in the form of signals on a network medium, and downloaded and installed through the communication part 509, and / or installed from the removable medium 511. The program code contained in the computer program may be transmitted using any appropriate network medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0170] According to an embodiment of the present disclosure, the program code for executing the computer program provided by the embodiment of the present disclosure can be written in any combination of one or more programming languages. Specifically, these computing programs can be implemented using high-level process and / or object-oriented programming languages, and / or assembly / machine languages. Programming languages ​​include, but are not limited to, Java, C++, python, "C" language or similar programming languages. The program code can be executed entirely on the user computing device, partially on the user device, partially on the remote computing device, or entirely on the remote computing device or server. In the case of a remote computing device, the remote computing device can be connected to the user computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or can be connected to an external computing device (for example, using an Internet service provider to connect through the Internet).

[0171] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the systems, methods and computer program products according to various embodiments of the present disclosure. In this regard, each box in the flowchart or block diagram may represent a module, a program segment, or a part of a code, and the above-mentioned module, program segment, or a part of the code contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the box may also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the block diagram or flowchart, and the combination of boxes in the block diagram or flowchart, can be implemented with a dedicated hardware-based system that performs the specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions. It can be understood by those skilled in the art that the features recorded in the various embodiments and / or claims of the present disclosure can be combined and / or combined in a variety of ways, even if such a combination or combination is not explicitly recorded in the present disclosure. In particular, without departing from the spirit and teaching of the present disclosure, the features described in the various embodiments and / or claims of the present disclosure may be combined and / or combined in a variety of ways. All of these combinations and / or combinations fall within the scope of the present disclosure.

[0172] The embodiments of the present disclosure are described above. However, these embodiments are only for illustrative purposes and are not intended to limit the scope of the present disclosure. Although the embodiments are described above separately, this does not mean that the measures in the various embodiments cannot be used in combination to advantage. The scope of the present disclosure is defined by the attached claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art may make a variety of substitutions and modifications, which should all fall within the scope of the present disclosure.

Claims

1. A method for measuring radar altitude, comprising: Performing ionospheric correction on detection data acquired from the radar to obtain a correction coefficient and a target pulse pressure coefficient corresponding to the correction coefficient, wherein the detection data is obtained by the radar detecting the surface of a celestial body; According to the target pulse pressure coefficient, pulse compressing the detection data to obtain compressed data, wherein the resolution of the compressed data meets a preset resolution requirement; Based on a preset selection rule, finding the target echo position in the compressed data from the compressed data; The height information of the radar is determined according to the time delay corresponding to the target echo position, the sampling rate of the detection data and the window height of the radar receiving the detection data, wherein the height information The calculation of is shown in formula (8) and formula (9): （8） （9） in, The window height for radar to receive target compression data. is the sampling rate of the target compressed data, c is the speed of light, is the sampling point number corresponding to the maximum value in the target compressed data, is the target echo delay, is the pulse width emitted by the radar.

2. The method according to claim 1, further comprising: The target position information and elevation information of the sub-satellite point of the radar on the celestial body are determined according to the altitude information and a radar data packet obtained from the radar, wherein the radar data packet includes the initial position information of the radar in the celestial body inertial coordinate system and multiple attitude angles of the radar.

3. The method according to claim 2, wherein: Determining the position information and elevation information of the sub-satellite point of the radar on the star body according to the altitude information and the radar data packet obtained from the radar includes: Determining the direction information of the radar according to the attitude angle; Determine the sub-satellite point and the target position information of the sub-satellite point according to the pointing information, the vector length, the initial position information and the latitude and longitude coordinate system of the star body, wherein the vector length represents the altitude information; The elevation information of the sub-satellite point is determined according to the distance information between the radar and the center of the star and the height information obtained from the radar.

4. The method according to claim 1, wherein: The step of performing ionospheric correction on the detection data acquired from the radar to obtain a correction coefficient and a target pulse pressure coefficient corresponding to the correction coefficient includes: Obtaining a plurality of estimated values ​​of the target pulse pressure coefficients according to an initial pulse pressure coefficient and a plurality of phase estimation error models; The target pulse pressure coefficient corresponding to the detection data is determined according to each of the target pulse pressure coefficient estimation values ​​and the detection data.

5. The method according to claim 4, wherein: The phase estimation error model includes the following formulas (1) to (6): Wherein, formula (2) is the Taylor expansion expression of formula (1); are coefficients of different levels after Taylor expansion, i is a positive integer; k is an integer, n is a preset value, and when the value of k changes, multiple phase error estimation values ​​are obtained according to the estimation error model and the detection data Pulse pressure coefficient estimate; is the frequency of the detection data, and its range is the radar’s operating frequency band. is the center frequency of the radar; z is the height of the radar in the ionosphere; n(z) is the ionosphere reflection coefficient, f p (z) is the ionospheric plasma frequency, c is the speed of light, and H1 is the estimated altitude of the radar; for ; B is the bandwidth of electromagnetic waves emitted by the radar.

6. The method according to claim 5, wherein: The target pulse pressure coefficient It is expressed by formula (7): （7） in, is the initial pulse pressure coefficient; is a plural unit; and They are Fourier transform and inverse Fourier transform respectively.

7. The method according to claim 1, wherein: The pulse compressing the detection data according to the target pulse pressure coefficient to obtain compressed data includes: Performing Fourier transform on the target pulse pressure coefficient and the detection data respectively to obtain first frequency domains corresponding to the target pulse pressure coefficient and the detection data respectively; Obtaining a second frequency domain according to the first frequency domains respectively corresponding to the target pulse pressure coefficient and the correction data; and The second frequency domain is converted into the time domain to obtain the compressed data.

8. The method according to claim 1, wherein: The step of finding the target echo position in the compressed data based on a preset selection rule includes: Based on the parameters of each echo position in the compressed data, the echo position with the largest parameter value is determined as the target echo position, wherein the parameters include at least one of the following: amplitude and intensity.

9. A radar altitude measuring device, comprising: A correction module, used for performing ionospheric correction on the detection data obtained from the radar to obtain a correction coefficient and a target pulse pressure coefficient corresponding to the correction coefficient, wherein the detection data is obtained by the radar detecting the surface of a celestial body; A compression module, configured to perform pulse compression on the detection data according to the target pulse pressure coefficient to obtain compressed data, wherein the resolution of the compressed data meets a preset resolution requirement; A selection module, used for finding the target echo position in the compressed data from each channel of the compressed data based on a preset selection rule; and A determination module is used to determine the height information of the radar according to the time delay corresponding to the target echo position, the sampling rate of the detection data and the window height of the radar receiving the detection data, wherein the height information The calculation of is as follows: in, The window height for radar to receive target compression data. is the sampling rate of the target compressed data, c is the speed of light, is the sampling point number corresponding to the maximum value in the target compressed data, is the target echo delay, is the pulse width emitted by the radar.

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