Tracking device based on low earth orbit satellite and spread spectrum communication technology

Abstract

The invention discloses a tracking device based on a low earth orbit satellite and a spread spectrum communication technology, which comprises a receiving antenna, a signal amplification circuit, a monopulse angle measurement tracking receiver and a controller, and is characterized in that the signal amplification circuit is respectively connected with the receiving antenna and the monopulse angle measurement tracking receiver; and the monopulse angle measurement tracking receiver is also connected with the controller. The method comprises the following steps: receiving a satellite signal from a low-orbit satellite through a receiving antenna; the satellite signals are amplified through the signal amplification circuit; then, a monopulse angle measurement tracking receiver calculates an angle error according to the amplitude and the phase difference of the satellite signal, and outputs a corresponding angle error signal; and finally, the controller corrects the pointing angle of the receiving antenna according to the angle error signal, so that the controller measures the satellite-to-satellite angle error of the antenna through the monopulse angle measurement tracking receiver to control the receiving antenna to accurately point to the low-orbit satellite, and the tracking precision is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of low-orbit satellite tracking, and in particular to a tracking device based on low-orbit satellite and spread spectrum communication technology. Background Art

[0002] Existing low-orbit satellite tracking antennas need to continuously change their pointing angles to the satellite in order to keep pointing at the satellite, because low-orbit satellites are in low orbits, run at a high speed, and orbit the earth quickly. However, existing low-cost low-orbit satellite ground receiving antennas all use theoretically calculated pointing angles to control the antenna pointing to the satellite in real time, and do not measure the angular error of the antenna to the satellite, resulting in large pointing errors and low tracking accuracy. Summary of the invention

[0003] The purpose of the present invention is to design a tracking device based on low-orbit satellite and spread spectrum communication technology in order to solve the above problems.

[0004] The present invention achieves the above-mentioned purpose through the following technical solutions: Tracking device based on low-orbit satellite and spread spectrum communication technology, including: A receiving antenna for receiving satellite signals; A signal amplifying circuit, the signal amplifying circuit is connected to the receiving antenna, and the signal amplifying circuit is used to amplify the satellite signal and then output it; A single pulse angle measurement and tracking receiver, the single pulse angle measurement and tracking receiver is connected to the signal amplification circuit, the single pulse angle measurement and tracking receiver is used to calculate the angle error according to the amplitude and phase difference of the satellite signal, and output a corresponding angle error signal; A controller, wherein the input end of the controller is connected to the single pulse angle measurement and tracking receiver, the control end of the controller is connected to the receiving antenna, and the controller is used to correct the pointing angle of the receiving antenna according to the angle error signal.

[0005] The beneficial effects of the present invention are: The tracking device based on low-orbit satellite and spread spectrum communication technology first receives the satellite signal from the low-orbit satellite through the receiving antenna; then the satellite signal is amplified and processed by the signal amplification circuit; then, the single-pulse angle measurement and tracking receiver calculates the angle error according to the amplitude and phase difference of the satellite signal, and outputs the corresponding angle error signal; finally, the controller corrects the pointing angle of the receiving antenna according to the angle error signal, so that the controller can measure the angle error of the antenna to the satellite through the single-pulse angle measurement and tracking receiver to control the receiving antenna to accurately point to the low-orbit satellite, thereby improving the tracking accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1It is an overall block diagram of the tracking device based on low-orbit satellite and spread spectrum communication technology of the present invention; In the figure: 10-receiving antenna, 20-signal amplifying circuit, 30-single pulse angle measurement and tracking receiver, 31-down converter, 32-analog-to-digital converter, 33-processor, 34-Doppler frequency shift compensation module, 35-single pulse angle measurement module, 40-controller, 50-pointing module. DETAILED DESCRIPTION

[0007] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions 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. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0008] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. 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.

[0009] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0010] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use, or are directions or positional relationships commonly understood by those skilled in the art. These directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0011] Furthermore, the terms “first”, “second”, etc. are merely used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0012] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms such as "setting" and "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0013] In order to solve the problem of low tracking accuracy in low-orbit satellite tracking systems, a tracking device based on low-orbit satellites and spread spectrum communication technology is proposed. Because the signal of the low-orbit satellite is a spread spectrum signal, ordinary angle measurement receivers cannot perform angle measurement calculations, so spread spectrum communication technology is used to measure single-pulse angle measurement signals.

[0014] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings.

[0015] like Figure 1 As shown, the tracking device based on low-orbit satellite and spread spectrum communication technology includes: A receiving antenna 10, for receiving satellite signals; A signal amplifying circuit 20, wherein the signal amplifying circuit 20 is connected to the receiving antenna 10, and the signal amplifying circuit 20 is used to amplify the satellite signal and then output it; A single pulse angle measurement and tracking receiver 30, wherein the single pulse angle measurement and tracking receiver 30 is connected to the signal amplification circuit 20, and the single pulse angle measurement and tracking receiver 30 is used to calculate the angle error according to the amplitude and phase difference of the satellite signal, and output a corresponding angle error signal; A controller 40, wherein the input end of the controller 40 is connected to the single pulse angle measurement and tracking receiver 30, and the control end of the controller 40 is connected to the receiving antenna 10, and the controller 40 is used to correct the pointing angle of the receiving antenna 10 according to the angle error signal.

[0016] In one embodiment, the signal amplifying circuit 20 is a low noise amplifier, and the low noise amplifier is connected to the receiving antenna 10 and the single pulse angle tracking receiver 30 respectively.

[0017] In one embodiment, the monopulse angle tracking receiver 30 comprises: A down converter 31, the down converter 31 is connected to the signal amplifying circuit 20, and the down converter 31 is used to perform down conversion processing on the satellite signal; an analog-to-digital converter 32, the analog-to-digital converter 32 being connected to the down converter 31, and the analog-to-digital converter 32 being used for performing analog-to-digital conversion processing on the satellite signal; A processor 33, one end of the processor 33 is connected to the analog-to-digital converter 32, and the other end of the processor 33 is connected to the controller 40, and the processor 33 is used to perform spread spectrum code capture, carrier tracking, code tracking and data fusion processing on the satellite signal; A single pulse angle measurement module 35, the single pulse angle measurement module 35 is connected to the processor 33, the single pulse angle measurement module 35 is used to measure the amplitude and phase difference of the satellite signal and calculate the angle error of the satellite signal, and output a corresponding angle error signal; The processor 33 is further configured to transmit the angle error signal to the controller 40 .

[0018] In one embodiment, the processor 33 is a DSP processor 33 .

[0019] In this embodiment, the receiving antenna 10 includes multiple antenna units to receive satellite signals from different directions. The signal amplification circuit 20 is implemented by a low-noise amplifier to amplify weak satellite signals and minimize noise to ensure the quality of satellite signals. The controller 40 can be implemented by a controller 40 such as MCU, FPGA (Field Programmable Gate Array), SOC (System On Chip), etc., which is used to exchange data and transmit command control with an external system; specifically, the controller 40 transmits the angle error signal processed by the single-pulse angle measurement tracking receiver 30 to the external system, and provides it for internal use, that is, the controller 40 corrects the pointing angle of the original receiving antenna 10 according to the angle error signal, so that the receiving antenna 10 accurately points to the target satellite to improve the tracking accuracy.

[0020] In this embodiment, the single pulse angle measurement and tracking receiver 30 includes a down converter 31, an analog-to-digital converter 32, a processor 33 and a single pulse angle measurement module 35; wherein the processor 33 can be implemented using a DSP (Digital Signal Process) processor 33 to perform spread spectrum code capture, carrier tracking, code tracking and data fusion processing, etc. It can be understood that the down-converter 31 performs down-conversion processing on the satellite signal amplified by the signal processing circuit, that is, down-converts the high-frequency satellite signal to an intermediate frequency or a low-frequency satellite signal; the analog-to-digital converter 32 performs analog-to-digital conversion processing on the satellite signal after the down-conversion, that is, converts the analog satellite signal into a digital satellite signal and then transmits it to the processor 33; the processor 33 performs spread spectrum code capture, carrier tracking, code tracking and data fusion processing on the satellite signal after the analog-to-digital conversion, wherein the processor 33 adopts a parallel capture algorithm based on fast Fourier transform to perform spread spectrum code capture and tracking to improve the spread spectrum code capture speed; the single pulse angle measurement module 35 measures the amplitude and phase difference of the satellite signals received by multiple antenna units and compares them to calculate the angle error of the satellite signal, and the angle error signal is transmitted to the controller 40 through the processor 33 to control the pointing angle of the receiving antenna 10. Compared with the existing method of using a theoretically calculated pointing angle to control the receiving antenna 10 to point to the satellite, the amplitude and phase difference of the satellite signal are measured by the single pulse angle measurement module 35 to calculate the angle error to reduce the pointing error, thereby achieving high-precision tracking.

[0021] The tracking device based on low-orbit satellite and spread spectrum communication technology of the present invention first receives the satellite signal from the low-orbit satellite through the receiving antenna 10; then amplifies the satellite signal through the signal amplification circuit 20; then, the single-pulse angle measurement and tracking receiver 30 calculates the angle error according to the amplitude and phase difference of the satellite signal, and outputs the corresponding angle error signal; finally, the controller 40 corrects the pointing angle of the receiving antenna 10 according to the angle error signal, so that the controller 40 measures the angle error of the antenna to the satellite through the single-pulse angle measurement and tracking receiver 30 to control the receiving antenna 10 to accurately point to the low-orbit satellite, thereby improving the tracking accuracy.

[0022] Since low-orbit satellites run at a high speed, the Doppler frequency shift of satellite signals is relatively large. Ordinary tracking receivers cannot adapt to the rapid changes in Doppler frequency when receiving satellite signals. Therefore, the single-pulse angle measurement tracking receiver 30 adopts a Doppler frequency shift compensation method to solve this problem.

[0023] In one embodiment, the single pulse angle measurement and tracking receiver 30 also includes a Doppler frequency shift compensation module 34, which is connected to the processor 33, and is used to perform frequency compensation on the satellite signal according to the satellite orbit parameters and the Doppler frequency shift of the satellite signal.

[0024] In this embodiment, the Doppler frequency shift compensation module 34 uses the Kalman filtering algorithm for filtering, X(k + 1) = AX (k) + Wω(k), y(k) = HX (k) + vω(k), where X(k) is the state vector, Wω(k) is the state noise, y(k) is the measurement value, vω(k) is the measurement noise, A is the state transfer matrix, H is the measurement matrix, and vω(k) cannot be simply regarded as Gaussian white noise. The reasons for its formation include the instability of the frequency synthesizer and various external factors. In the Doppler frequency offset tracking stage, as the tracking time increases, the estimated value of the Doppler frequency offset gradually converges to the theoretical value. The Kalman algorithm ensures the steady-state convergence of the frequency offset estimation value in the tracking stage, thereby realizing that the Doppler frequency shift compensation module 34 performs frequency compensation according to the satellite orbit parameters and the Doppler frequency shift of the satellite signal to ensure stable tracking of the satellite signal.

[0025] In one embodiment, the tracking device based on low-orbit satellite and spread spectrum communication technology further includes a pointing module 50, the input end of the pointing module 50 is connected to the controller 40, and the control end of the pointing module 50 is connected to the receiving antenna 10; The controller 40 is further configured to output a corresponding pointing angle signal according to the angle error signal, and control the pointing module 50 to adjust the receiving antenna 10 to a preset pointing angle.

[0026] In this embodiment, the controller 40 adjusts the pointing angle of the receiving antenna 10 according to the angle error information and outputs a corresponding pointing angle signal, and controls the pointing module 50 to adjust the receiving antenna 10 to a preset pointing angle to correct the angle of the receiving antenna 10 toward the low-orbit satellite, thereby improving the tracking accuracy.

[0027] The tracking device based on low-orbit satellite and spread spectrum communication technology in the present invention solves the problem of poor tracking accuracy caused by low-orbit satellite tracking relying on theoretical angle calculation to point to the satellite, and also solves the problem of Doppler frequency shift when tracking satellite signals, thereby achieving rapid synchronization and stable tracking and reception of low-orbit satellite signals, and improving the tracking accuracy of the low-orbit satellite communication system, thereby facilitating the ground application of low-orbit satellites.

[0028] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A tracking device based on low-orbit satellite and spread spectrum communication technology, characterized in that: The tracking device based on low-orbit satellite and spread spectrum communication technology includes: A receiving antenna for receiving satellite signals; A signal amplifying circuit, the signal amplifying circuit is connected to the receiving antenna, and the signal amplifying circuit is used to amplify the satellite signal and then output it; A single pulse angle measurement and tracking receiver, the single pulse angle measurement and tracking receiver is connected to the signal amplification circuit, the single pulse angle measurement and tracking receiver is used to calculate the angle error according to the amplitude and phase difference of the satellite signal, and output a corresponding angle error signal; A controller, wherein the input end of the controller is connected to the single pulse angle measurement and tracking receiver, the control end of the controller is connected to the receiving antenna, and the controller is used to correct the pointing angle of the receiving antenna according to the angle error signal.

2. The tracking device based on low-orbit satellite and spread spectrum communication technology according to claim 1, characterized in that: The monopulse angle measurement and tracking receiver comprises: A down converter, the down converter is connected to the signal amplifying circuit, and the down converter is used to perform down conversion processing on the satellite signal; an analog-to-digital converter, the analog-to-digital converter being connected to the down-converter, and the analog-to-digital converter being used to perform analog-to-digital conversion processing on the satellite signal; a processor, one end of which is connected to the analog-to-digital converter, and the other end of which is connected to the controller, and the processor is used to perform spread spectrum code capture, carrier tracking, code tracking and data fusion processing on the satellite signal; A single pulse angle measurement module, the single pulse angle measurement module is connected to the processor, the single pulse angle measurement module is used to measure the amplitude and phase difference of the satellite signal and calculate the angle error of the satellite signal, and output a corresponding angle error signal to the processor; The processor is also used to transmit the angle error signal to the controller.

3. The tracking device based on low-orbit satellite and spread spectrum communication technology according to claim 2, characterized in that: The single pulse angle measurement and tracking receiver also includes a Doppler frequency shift compensation module, which is connected to the processor and is used to perform frequency compensation on the satellite signal according to satellite orbit parameters and the Doppler frequency shift of the satellite signal.

4. The tracking device based on low-orbit satellite and spread spectrum communication technology according to claim 2, characterized in that: The processor is a DSP processor.

5. The tracking device based on low-orbit satellite and spread spectrum communication technology according to claim 1, characterized in that: The tracking device based on low-orbit satellite and spread spectrum communication technology also includes a pointing module, an input end of the pointing module is connected to the controller, and a control end of the pointing module is connected to the receiving antenna; The controller is further configured to output a corresponding pointing angle signal according to the angle error signal, and control the pointing module to adjust the receiving antenna to a preset pointing angle.

6. The tracking device based on low-orbit satellite and spread spectrum communication technology according to claim 1, characterized in that: The signal amplifying circuit is a low noise amplifier, and the low noise amplifier is connected to the receiving antenna and the single pulse angle measurement and tracking receiver respectively.

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