A method for generating synthetic aperture radar coherent pulse signals

Abstract

This application belongs to the field of radar system design, and particularly relates to a method for generating coherent pulse signals of a synthetic aperture radar. It includes: Step 1, obtaining the waveform parameters of the radar signal in the imaging mode, and sending the waveform parameters of the radar signal to the signal generation unit, which receives and stores the waveform parameters of the radar signal; Step 2, the signal generation unit performs real-time detection on the frame pulse signal of the timer. When the frame pulse signal is detected, the signal generation unit generates a PRF signal according to the waveform parameters of the radar signal and the frame pulse signal; Step 3, the signal generation unit generates a coherent pulse signal according to the PRF signal and the waveform parameters of the radar signal, and sends the coherent pulse signal to the transmitting unit to be amplified and then radiated through the antenna. This application can greatly improve the stability of the radar imaging function. The image obtained after radar imaging has good focus and no ghosting, and can effectively improve the quality of the radar image.

Description

Technical Field

[0001] This application belongs to the field of radar system design, and particularly relates to a method for generating coherent pulse signals of a synthetic aperture radar. Background Art

[0002] Synthetic aperture radars are widely used for terrain mapping. During operation, the radar continuously emits multiple coherent pulse signals and receives echo signals, and a well-focused terrain image is obtained through synthetic processing of the echo signals. During the signal acquisition process of each frame of radar image, a high degree of coherence must be maintained between different pulse signals emitted by the radar so that the radar can perform subsequent imaging processing. The coherence requirement between pulse signals is that different pulses have the same starting phase during one frame of the image. The coherent pulse signals are generated by a signal generation unit based on the PRF signal of a timer. In a synthetic aperture radar, the timer and the signal generation unit are generally two independent parts. When the radar generates each pulse signal, the starting phase of the pulse signal is determined by the signal generation unit sampling and detecting the PRF signal transmitted from the timer at a certain period. When the signal generation unit detects the rising edge of the timing signal, it is considered that this is the start of the timing signal, and based on this, the corresponding coherent pulse signal is generated.

[0003] The traditional method for generating coherent pulse signals has the following disadvantages: Since the PRF signal generated by the timer in practice is an ideal rectangular wave, the rising edge of the rectangular wave has a certain width, and due to its own factors and external interference, the timing signal may have a certain jitter. When the signal generation unit samples and detects it, there may be a deviation of one sampling clock, which will result in a deviation of the sampling time interval between adjacent pulse signals generated. As a result, when the radar samples the echo signals, there will be a certain deviation between adjacent pulses, and the coherence between different pulse signals during one frame of the image becomes poor, and the radar image after imaging processing shows ghosting and defocusing phenomena.

[0004] Therefore, it is desirable to have a technical solution to overcome or at least mitigate at least one of the above defects of the prior art. Summary of the Invention

[0005] The purpose of this application is to provide a method for generating coherent pulse signals of a synthetic aperture radar to solve at least one problem existing in the prior art.

[0006] The technical solution of this application is as follows:

[0007] A method for generating coherent pulse signals of a synthetic aperture radar, comprising:

[0008] Step 1, obtaining waveform parameters of radar signals in an imaging mode, and sending the waveform parameters of the radar signals to a signal generation unit, and the signal generation unit receives and stores the waveform parameters of the radar signals;

[0009] Step 2: The signal generation unit detects the frame pulse signal of the timer in real time. After detecting the frame pulse signal, the signal generation unit generates a PRF signal according to the waveform parameters of the radar signal and the frame pulse signal;

[0010] Step 3: The signal generation unit generates a coherent pulse signal according to the PRF signal and the waveform parameters of the radar signal, and sends the coherent pulse signal to the transmitting unit to be amplified and then radiated through the antenna.

[0011] In at least one embodiment of the present application, the waveform parameters of the radar signal include pulse period, pulse width, frequency modulation slope, and delay.

[0012] In at least one embodiment of the present application, the imaging mode includes a 1m resolution mode.

[0013] The invention has at least the following beneficial technical effects:

[0014] In the method for generating a coherent pulse signal of a synthetic aperture radar according to the present application, the pulse signal generated by the signal generation unit is stably coherent during one frame of image, and there is no jitter between different pulses, which can greatly improve the stability of the radar imaging function. The image obtained after radar imaging has good focus and no ghosting, and can be used for the timing control of generating coherent pulse signals in the synthetic aperture radar imaging function, which can effectively improve the radar image quality. Description of the Drawings

[0015] Figure 1 is a schematic diagram of a coherent pulse signal generated by the prior art;

[0016] Figure 2 is a schematic diagram of a coherent pulse signal of an embodiment of the present application. Detailed Embodiment

[0017] To make the purpose, technical solution, and advantages of the implementation of the present application clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application. In the drawings, the same or similar reference numerals represent the same or similar elements or elements with the same or similar functions from beginning to end. The described embodiments are some, but not all, of the embodiments of the present application. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present application and should not be construed as limiting the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present application. The embodiments of the present application will be described in detail below with reference to the drawings.

[0018] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation on the protection scope of the present application.

[0019] The following will further describe the present application in conjunction with the attached Figures 1 to 2 drawings.

[0020] The present application provides a method for generating a synthetic aperture radar coherent pulse signal, including the following steps:

[0021] Step 1: Obtain the waveform parameters of the radar signal in the imaging mode, and send the waveform parameters of the radar signal to the signal generation unit. The signal generation unit receives and stores the waveform parameters of the radar signal.

[0022] Step 2: The signal generation unit detects the frame pulse signal of the timer in real time. When the frame pulse signal is detected, the signal generation unit generates a PRF signal according to the waveform parameters of the radar signal and the frame pulse signal.

[0023] Step 3: The signal generation unit generates a coherent pulse signal according to the PRF signal and the waveform parameters of the radar signal, and sends the coherent pulse signal to the transmitting unit to be amplified and radiated through the antenna.

[0024] For the method for generating a synthetic aperture radar coherent pulse signal of the present application, after the radar switches to a certain imaging mode, the system control software sends the waveform parameters of the radar signal in this imaging mode to the signal generation unit. The waveform parameters of the radar signal include pulse period, pulse width, frequency modulation slope, and delay. After receiving the waveform parameters of the radar signal, the signal generation unit stores this information; the signal generation unit detects the frame pulse signal of the timer in real time. When the frame pulse signal of the timer is detected, the signal generation unit generates a PRF signal by combining the previously stored waveform parameter information; finally, the signal generation unit generates a highly stable coherent pulse signal according to the self-generated PRF signal and the previously stored waveform parameter information, and sends it to the transmitting unit to be amplified and radiated through the antenna.

[0025] In a preferred embodiment of the present application, the waveform generation of a certain synthetic aperture radar is taken as an example for illustration. In this embodiment, the radar imaging resolution is 1 m, and the waveform parameters of the radar signal include: the pulse period is 4.096 s, the pulse width is 20 μs, the frequency modulation slope is 1×10^13, and the pulse delay is 40 μs. Among them, PRF is 1000 Hz. The steps for the radar to generate coherent pulse signals are as follows, as Figure 2 shown:

[0026] When the radar switches to the imaging mode with a resolution of 1 m, the radar system control software sends the above-mentioned waveform parameter information of the radar signal to the signal generation unit;

[0027] The signal generation unit detects the frame pulse signal of the timer at a frequency of fs. When the frame pulse signal of the timer is detected, the signal generation unit itself generates a PRF signal according to the waveform parameter information stored previously;

[0028] The signal generation unit generates coherent pulse signals according to the timing pulse PRF signal generated by itself and the waveform parameter information stored previously.

[0029] For the method for generating coherent pulse signals of the synthetic aperture radar of the present application, during one frame of image, the signal generation unit only detects the frame signal and generates a PRF signal by itself according to the frame signal and other waveform parameters, avoiding the problem that the signal generation unit sometimes deviates by one sampling clock when sampling the PRF signal transmitted by the timer multiple times, ensuring that during one frame of image, different radar pulse signals are highly coherent and a well-focused radar image is obtained.

[0030] The above is only the specific implementation manner of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present application should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A method for generating a synthetic aperture radar coherent pulse signal, characterized in that, Including: Step 1: Obtain the waveform parameters of the radar signal in the imaging mode, and send the waveform parameters of the radar signal to the signal generation unit, and the signal generation unit receives and stores the waveform parameters of the radar signal; Step 2: The signal generation unit performs real-time detection on the frame pulse signal of the timer. When the frame pulse signal is detected, the signal generation unit generates a PRF signal according to the waveform parameters of the radar signal; Step 3: The signal generation unit generates a coherent pulse signal according to the PRF signal and the waveform parameters of the radar signal, and sends the coherent pulse signal to the transmitting unit to be amplified and radiated through the antenna.

2. The method for generating a synthetic aperture radar coherent pulse signal according to claim 1, wherein The waveform parameters of the radar signal include pulse period, pulse width, frequency modulation slope, and delay.

3. The method for generating a synthetic aperture radar coherent pulse signal according to claim 1, wherein The imaging mode includes a 1m resolution mode.

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