Ionized layer measurement method based on double-star multiband radar system

Abstract

The invention relates to an ionosphere measurement method based on a double-satellite multiband radar system, the double-satellite multiband radar system comprises a satellite A and a satellite B, the satellite A and the satellite B respectively carry different multiband radar systems, the satellite A and the satellite B fly in the same direction, speed and height, and the connecting line direction is perpendicular to the flight direction. Comprising the following steps: controlling a satellite A to alternately transmit a short-wave sweep-frequency signal and an ultra-short-wave sweep-frequency signal to an ionized layer at an incident angle theta; using a satellite A to receive a first echo signal of the ultrashort wave sweep frequency signal scattered by the ionosphere non-uniform body, and using a satellite B to receive a second echo signal of the ultrashort wave sweep frequency signal reflected by the ionosphere; and performing inversion based on the first echo signal to obtain ionosphere non-uniform body information, performing inversion based on the second echo signal to obtain a reflection point position of the reflection region and ionosphere adjacent frequency information, and completing ionosphere measurement. The method has the advantages of being high in measurement information dimension, good in measurement information space-time consistency, wide in space coverage and the like.

Description

Technical Field

[0001] The present invention relates to the field of radar technology in the electronic information industry, and in particular to an ionosphere measurement method based on a dual-satellite multi-band radar system. Background Art

[0002] In the increasingly congested space, the number of targets such as variable-orbit satellites has increased sharply, becoming an important source of threat to the safety of my country's spacecraft, and therefore also the focus of my country's long-term radar monitoring.

[0003] Among the existing methods, radar monitoring using the reflection and refraction of radio waves by the ionosphere has the unique advantage of ultra-long-range detection, so it is of great significance. However, due to the drastic small-scale spatiotemporal changes in the ionosphere, the availability, stability and working mode of this detection method are significantly affected by the ionosphere characteristics at the radar signal puncture point. Therefore, real-time and efficient acquisition of the ionosphere characteristics at the radar signal puncture point can provide important guarantees for radar ultra-long-range detection. The ionosphere critical frequency determines the operating frequency of the ultra-long-range detection radar, while the abnormal structure in the ionosphere, such as the inhomogeneous structure of the E and F regions of the ionosphere, determines the availability and stability of the radar.

[0004] Therefore, designing an ionospheric measurement method based on a dual-satellite multi-band radar system is an urgent problem to be solved. Summary of the invention

[0005] In order to solve the technical problems existing in the above-mentioned prior art, the purpose of the present invention is to provide an ionospheric measurement method based on a dual-satellite multi-band radar system, which can flexibly and efficiently detect the ionospheric near-frequency and inhomogeneous structure information, and realize the integrated detection of ionospheric near-frequency and inhomogeneous body information.

[0006] To achieve the above-mentioned object of the invention, the present invention provides an ionosphere measurement method based on a dual-satellite multi-band radar system, wherein the dual-satellite multi-band radar system comprises a satellite A and a satellite B, wherein the satellite A and the satellite B are respectively equipped with different multi-band radar systems, and the satellite A and the satellite B fly in the same direction, speed and altitude, and the connecting line direction is perpendicular to the flight direction, and the method comprises the following steps:

[0007] Step S1: Control the satellite A at an incident angle θ N Alternately transmitting short-wave sweep frequency signals and ultra-short-wave sweep frequency signals to the ionosphere;

[0008] Step S2, using the satellite A to receive a first echo signal of an ultrashort wave swept frequency signal scattered by an ionospheric inhomogeneity, and using the satellite B to receive a second echo signal of a short wave swept frequency signal reflected by the ionosphere;

[0009] Step S3: obtaining ionospheric inhomogeneity information based on the first echo signal inversion, and obtaining the reflection point position and ionospheric adjacent frequency information of the reflection area based on the second echo signal inversion, thereby completing ionospheric measurement.

[0010] According to a technical solution of the present invention, the frequency range of the shortwave signal is 5-25MHz, and the sweep frequency step frequency is 1MHz;

[0011] The frequency range of the ultrashort wave signal is 45-50 MHz, and the sweep step frequency is 1 MHz.

[0012] According to a technical solution of the present invention, the orbital altitudes of the satellites A and B are in the range of 450-600 km;

[0013] The incident angle θ N The value range of is 30°≤θ≤60°.

[0014] According to a technical solution of the present invention, the satellite A is configured with a two-dimensional array antenna, a first radar signal timing controller, and a first radar signal processor;

[0015] The two-dimensional array antenna is used for transmitting radar signals and receiving echo signals;

[0016] The first radar signal timing controller is used for timing control of radar transmission signals and reception signals;

[0017] The first radar signal processor is used to process the radar receiving signal and invert to obtain the ionospheric inhomogeneity information.

[0018] According to a technical solution of the present invention, the satellite B is equipped with a one-dimensional dipole antenna, a second radar signal timing controller, and a second radar signal processor;

[0019] The one-dimensional dipole antenna is used to receive the echo signal;

[0020] The second radar signal timing controller is used for timing control of radar receiving signals;

[0021] The second radar signal processor is used to process the received signal and invert to obtain the reflection point position and ionospheric adjacent frequency information of the reflection area.

[0022] According to a technical solution of the present invention, in step S3, obtaining ionospheric inhomogeneity information based on the first echo signal by inversion specifically includes:

[0023] Based on the plurality of the first echo signals, an ionospheric data matrix is ​​obtained;

[0024] The ionospheric data matrix is ​​input into the convolutional neural network, and the convolutional neural network is used to fuse the scanning results at multiple angles, perform three-dimensional reconstruction of the detection area, complete the ionospheric inhomogeneity recognition, and obtain the ionospheric inhomogeneity information.

[0025] According to a technical solution of the present invention, in step S3, obtaining the reflection point position and ionospheric adjacent frequency information of the reflection area based on the inversion of the second echo signal specifically includes:

[0026] According to the frequency and delay of the second echo signal, the position of the radar signal ionospheric puncture point and the adjacent frequency information fp are calculated. The formula is: fp = fsw × cosθ N , where fsw is the frequency of the incident shortwave signal;

[0027] The satellite A, the satellite B and the signal link between the two satellites are in the same plane. On the plane, the position coordinates of the satellite A are Pa(xa, ya), the position coordinates of the satellite B are Pb(xb, yb), the position coordinates of the ionospheric reflection point are Pr(xr, yr), and the time delay of the signal propagation between the two satellites is t. Then the distance from the satellite A to the ionospheric reflection point is expressed as:

[0028]

[0029] The distance from the satellite B to the ionospheric reflection point is expressed as:

[0030]

[0031] La=Lb and La+Lb=ct;

[0032] Get the position of the ionospheric reflection point.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] The present invention proposes an ionosphere measurement method based on a dual-satellite multi-band radar system. The dual-satellite formation configuration is adopted. Through a combination of one-transmit-one-receive, spontaneous transmission and self-receive, and multi-band frequency sweep detection, the ionosphere near-frequency and inhomogeneous structure information are detected by utilizing the reflection and scattering signals of short waves and ultra-short waves by the ionosphere, thereby realizing the integrated detection of satellite-borne ionosphere near-frequency information and inhomogeneous body information. The method has the advantages of high measurement information dimension, good temporal and spatial consistency of measurement information, wide spatial coverage, high detection flexibility, high detection efficiency, etc., realizes the coordinated detection of multiple key parameters of the ionosphere, and provides the availability of using the ionosphere for target detection.

[0035] The ionospheric near-frequency and inhomogeneous body information measured by the present invention respectively determine the operating frequency and availability of the ultra-long-range radar, can provide operation guarantee for the ultra-long-range radar, and lay the foundation for the realization of space-borne ultra-long-range radar. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] 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. Obviously, the drawings described below are only some embodiments of the present invention, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0037] Figure 1 A diagram schematically showing a detection scene of an ionosphere measurement method based on a dual-satellite multi-band radar system according to an embodiment of the present invention;

[0038] Figure 2 A schematic diagram showing a signal transmission and reception timing diagram of a dual-satellite multi-band radar system according to an embodiment of the present invention;

[0039] Figure 3 The flowchart schematically shows an ionosphere measurement method based on a dual-satellite multi-band radar system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] like Figures 1 to 3 As shown, an ionosphere measurement method based on a dual-satellite multi-band radar system of the present invention, wherein the dual-satellite multi-band radar system comprises a satellite A and a satellite B, wherein the satellite A and the satellite B are respectively equipped with different multi-band radar systems, and the satellite A and the satellite B fly in the same direction, speed and altitude, and the connecting line direction is perpendicular to the flight direction, comprising the following steps:

[0042] Step S1, controlling the satellite A to transmit a shortwave frequency sweep signal and an ultrashortwave frequency sweep signal alternately to the ionosphere at an incident angle θ;

[0043] Step S2, using the satellite A to receive a first echo signal of an ultrashort wave swept frequency signal scattered by an ionospheric inhomogeneity, and using the satellite B to receive a second echo signal of a short wave swept frequency signal reflected by the ionosphere;

[0044] Step S3: obtaining ionospheric inhomogeneity information based on the first echo signal inversion, and obtaining the reflection point position and ionospheric adjacent frequency information of the reflection area based on the second echo signal inversion, thereby completing ionospheric measurement.

[0045] The ionospheric edge frequency information determines the available frequency range and detection distance range for target detection using the ionosphere. The ionospheric inhomogeneity information determines the availability of target detection. The dual-satellite formation configuration is adopted, and through a combination of one-transmit-one-receive, spontaneous transmission and self-receive, and multi-band frequency sweep detection, the ionosphere's reflection and scattering signals of short waves and ultra-short waves are used to detect the ionospheric edge frequency and inhomogeneous structure information, realizing the integrated detection of satellite-borne ionospheric edge frequency information and inhomogeneous body information. It has the advantages of high measurement information dimension, good temporal and spatial consistency of measurement information, wide spatial coverage, high detection flexibility, and high detection efficiency.

[0046] Specifically, refer to Figure 1 , satellite A and satellite B fly in the same direction, speed and altitude, and the connecting line is perpendicular to the flight direction. The orbital altitude of satellite A and satellite B ranges from 450 to 600 km, preferably 500 km. Satellite A is at a certain incident angle θ N Send short-wave and ultra-short-wave sweep signals to the ionosphere, θ N Generally, it is 30°-60°, and the specific value is determined by the distance between the two satellites. The frequency range of shortwave signals is f1-f2, f1 is generally 5MHz, f2 is generally 25MHz, and the sweep step frequency is 1MHz. The shortwave signal is reflected by the ionosphere and received by satellite B. The reflection point position and ionospheric adjacent frequency information in the reflection area can be obtained through inversion. The frequency range of ultrashortwave signals is f3-f4, f3 is generally 45MHz, f4 is generally 50MHz, and the sweep step frequency is 1MHz. When there are abnormal structures in the ionosphere, such as inhomogeneous bodies in the E and F regions, the ultrashortwave signal will be scattered by the inhomogeneous bodies of the ionosphere, and the echo signal is received by satellite A. The information of the inhomogeneous bodies of the ionosphere can be obtained through inversion.

[0047] Reference Figure 2 , satellite A transmits radar signals and receives scattered echo signals from ionospheric inhomogeneities. The radar signal transmission timing and reception timing are arranged alternately. Satellite B receives the radar signal transmitted by satellite A and reflected by the ionosphere. Satellite B only has the reception timing and no transmission timing.

[0048] In some embodiments of the present invention, the satellite A is configured with a two-dimensional array antenna, a first radar signal timing controller, and a first radar signal processor;

[0049] The two-dimensional array antenna is used for transmitting radar signals and receiving echo signals;

[0050] The first radar signal timing controller is used for timing control of radar transmission signals and reception signals;

[0051] The first radar signal processor is used to process the radar receiving signal and invert to obtain the ionospheric inhomogeneity information.

[0052] In some embodiments of the present invention, the satellite B is configured with a one-dimensional dipole antenna, a second radar signal timing controller, and a second radar signal processor;

[0053] The one-dimensional dipole antenna is used to receive the echo signal;

[0054] The second radar signal timing controller is used for timing control of radar receiving signals;

[0055] The second radar signal processor is used to process the received signal and invert to obtain the reflection point position and ionospheric adjacent frequency information of the reflection area.

[0056] In some embodiments of the present invention, in step S3, obtaining ionospheric inhomogeneity information based on the first echo signal by inversion specifically includes:

[0057] Based on the plurality of the first echo signals, an ionospheric data matrix is ​​obtained;

[0058] The ionospheric data matrix is ​​input into the convolutional neural network, and the convolutional neural network is used to fuse the scanning results at multiple angles, perform three-dimensional reconstruction of the detection area, complete the ionospheric inhomogeneity recognition, and obtain the ionospheric inhomogeneity information.

[0059] In some embodiments of the present invention, in step S3, obtaining the reflection point position and ionospheric adjacent frequency information of the reflection area based on the second echo signal inversion specifically includes:

[0060] The shortwave signal sweeps between 5MHz and 25MHz with a step width of 1MHz and is incident on the ionosphere at an angle of θ. Some frequencies of the shortwave signal will be reflected by the ionosphere and received by satellite B, while the other part will be transmitted through the ionosphere. Based on the propagation law of radio waves in the ionosphere, the position of the radar signal ionosphere penetration point and the adjacent frequency information fp are calculated according to the frequency and delay of the second echo signal. The formula is: fp = fsw × cosθ N , where fsw is the frequency of the incident shortwave signal;

[0061] The satellite A, the satellite B and the signal link between the two satellites are in the same plane. On the plane, the position coordinates of the satellite A are Pa(xa, ya), the position coordinates of the satellite B are Pb(xb, yb), the position coordinates of the ionospheric reflection point are Pr(xr, yr), and the time delay of the signal propagation between the two satellites is t. Then the distance from the satellite A to the ionospheric reflection point is expressed as:

[0062]

[0063] The distance from the satellite B to the ionospheric reflection point is expressed as:

[0064]

[0065] La=Lb and La+Lb=ct;

[0066] Get the position of the ionospheric reflection point.

[0067] The invention discloses an ionosphere measurement method based on a dual-satellite multi-band radar system. The dual-satellite formation configuration is adopted. Through a one-transmit-one-receive, self-transmit and self-receive, multi-band frequency sweep detection combination mode, the ionosphere reflection and scattering signals of short waves and ultra-short waves are utilized to detect the ionosphere near-frequency and inhomogeneous structure information. The method realizes the integrated detection of satellite-borne ionosphere near-frequency information and inhomogeneous body information. The method has the advantages of high measurement information dimension, good measurement information temporal and spatial consistency, wide spatial coverage, high detection flexibility, high detection efficiency, etc., realizes the coordinated detection of multiple key parameters of the ionosphere, and provides the availability of using the ionosphere for target detection.

[0068] The ionospheric near-frequency and inhomogeneous body information measured by the present invention respectively determine the operating frequency and availability of the ultra-long-range radar, can provide operation guarantee for the ultra-long-range radar, and lay the foundation for the realization of space-borne ultra-long-range radar.

[0069] Parts of the present invention that are not described in detail belong to the well-known technology in the art.

[0070] It should be noted that although the embodiments of the present invention described above are illustrative, they are not intended to limit the present invention, and therefore the present invention is not limited to the above specific embodiments. Without departing from the principles of the present invention, any other embodiments obtained by those skilled in the art under the guidance of the present invention are deemed to be within the protection of the present invention.

Claims

1. An ionosphere measurement method based on a dual-satellite multi-band radar system, characterized in that: The dual-satellite multi-band radar system comprises a satellite A and a satellite B, wherein the satellite A and the satellite B are respectively equipped with different multi-band radar systems, and the satellite A and the satellite B fly in the same direction, speed and altitude, and the connecting line direction is perpendicular to the flight direction, and comprises the following steps: Step S1: Control the satellite A at an incident angle θ N Alternately transmitting short-wave sweep frequency signals and ultra-short-wave sweep frequency signals to the ionosphere; Step S2, using the satellite A to receive a first echo signal of an ultrashort wave swept frequency signal scattered by an ionospheric inhomogeneity, and using the satellite B to receive a second echo signal of a short wave swept frequency signal reflected by the ionosphere; Step S3: obtaining ionospheric inhomogeneity information based on the first echo signal inversion, and obtaining the reflection point position and ionospheric adjacent frequency information of the reflection area based on the second echo signal inversion, thereby completing ionospheric measurement.

2. The ionosphere measurement method based on a dual-satellite multi-band radar system according to claim 1, characterized in that: The shortwave signal frequency range is 5-25MHz, and the sweep frequency step frequency is 1MHz; The frequency range of the ultrashort wave signal is 45-50 MHz, and the sweep step frequency is 1 MHz.

3. The ionosphere measurement method based on a dual-satellite multi-band radar system according to claim 2, characterized in that: The orbital altitudes of the satellite A and the satellite B range from 450 to 600 km; The incident angle θ N The value range of is 30°≤θ≤60°.

4. The ionosphere measurement method based on a dual-satellite multi-band radar system according to claim 3 is characterized in that: The satellite A is equipped with a two-dimensional array antenna, a first radar signal timing controller, and a first radar signal processor; The two-dimensional array antenna is used for transmitting radar signals and receiving echo signals; The first radar signal timing controller is used for timing control of radar transmission signals and reception signals; The first radar signal processor is used to process the radar receiving signal and invert to obtain the ionospheric inhomogeneity information.

5. The ionosphere measurement method based on a dual-satellite multi-band radar system according to claim 4 is characterized in that: The satellite B is equipped with a one-dimensional dipole antenna, a second radar signal timing controller, and a second radar signal processor; The one-dimensional dipole antenna is used to receive the echo signal; The second radar signal timing controller is used for timing control of radar receiving signals; The second radar signal processor is used to process the received signal and invert to obtain the reflection point position and ionospheric adjacent frequency information of the reflection area.

6. The ionosphere measurement method based on a dual-satellite multi-band radar system according to claim 5, characterized in that: In the step S3, obtaining the ionospheric inhomogeneity information based on the first echo signal by inversion specifically includes: An ionospheric data matrix is ​​obtained based on the plurality of first echo signals; The ionospheric data matrix is ​​input into the convolutional neural network, and the convolutional neural network is used to fuse the scanning results at multiple angles, perform three-dimensional reconstruction of the detection area, identify ionospheric inhomogeneities, and obtain ionospheric inhomogeneity information.

7. The ionosphere measurement method based on a dual-satellite multi-band radar system according to claim 6, characterized in that: In the step S3, obtaining the reflection point position and ionospheric adjacent frequency information of the reflection area based on the second echo signal inversion specifically includes: According to the frequency and delay of the second echo signal, the position of the radar signal ionospheric puncture point and the adjacent frequency information fp are calculated. The formula is: fp = fsw × cosθ N , where fsw is the frequency of the incident shortwave signal; The satellite A, the satellite B and the signal link between the two satellites are in the same plane. On the plane, the position coordinates of the satellite A are Pa(xa, ya), the position coordinates of the satellite B are Pb(xb, yb), the position coordinates of the ionospheric reflection point are Pr(xr, yr), and the time delay of the signal propagation between the two satellites is t. Then the distance from the satellite A to the ionospheric reflection point is expressed as: The distance from the satellite B to the ionospheric reflection point is expressed as: La=Lb and La+Lb=ct; Get the position of the ionospheric reflection point.

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