CN113985357B

CN113985357B - A method for generating coherent pulse signals of synthetic aperture radar

Info

Publication number: CN113985357B
Application number: CN202111306843.0A
Authority: CN
Inventors: 吴赛赛; 陈德民; 牛诚翔
Original assignee: Leihua Electronic Technology Research Institute Aviation Industry Corp of China
Current assignee: Leihua Electronic Technology Research Institute Aviation Industry Corp of China
Priority date: 2021-11-05
Filing date: 2021-11-05
Publication date: 2025-07-04
Anticipated expiration: 2041-11-05
Also published as: CN113985357A

Abstract

The present application belongs to the field of radar system design, and particularly relates to a method for generating a coherent pulse signal of a synthetic aperture radar. It includes: step one, obtaining the waveform parameters of the radar signal in the imaging mode, and sending the waveform parameters of the radar signal to the signal generating unit, which receives and stores the waveform parameters of the radar signal; step two, the signal generating unit performs real-time detection of the frame pulse signal of the timer, and when the frame pulse signal is detected, the signal generating unit generates a PRF signal according to the waveform parameters of the radar signal and the frame pulse signal; step three, the signal generating 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 for amplification and radiation through the antenna. The present application can greatly improve the stability of the radar imaging function, and the image obtained after radar imaging is well focused and has no ghosting, which can effectively improve the quality of radar images.

Description

Method for generating coherent pulse signal of synthetic aperture radar

Technical Field

The 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

Synthetic aperture radar is widely used for topographic mapping, and the radar continuously transmits a plurality of coherent pulse signals and receives echo signals when in operation, and obtains a topographic image with good focusing by synthesizing the echo signals. In the signal acquisition process of each frame of radar image, high coherence is kept between different pulse signals emitted by the radar so that the radar can perform subsequent imaging processing. Coherence between pulse signals requires that different pulses have the same starting phase during a frame of image. The signal generating unit generates the coherent pulse signal based on the PRF signal of the timer, the timer and the signal generating unit are generally two independent parts in the synthetic aperture radar, when the radar generates each pulse signal, the starting phase of the pulse signal is determined by sampling and detecting the PRF signal transmitted by the timer by the signal generating unit in a certain period, when the signal generating unit detects the rising edge of the timing signal, the signal generating unit considers the rising edge of the timing signal as the starting of the timing signal, and the corresponding coherent pulse signal starts to be generated based on the starting phase.

The conventional coherent pulse signal generation method has the following defects that the PRF signal generated by the timer is an undesirable rectangular wave in practice, the rising edge of the rectangular wave has a certain width, the timing signal may have a certain jitter due to self factors and external interference, the signal generation unit sometimes has a sampling clock deviation when sampling and detecting the PRF signal, so that the generated adjacent pulse signals have a sampling time interval deviation, the radar has a certain deviation when sampling echo signals, the coherence between the adjacent pulses in one frame of image is poor, and the imaged radar image has ghost and defocusing phenomena.

It is therefore desirable to have a solution that overcomes or at least alleviates at least one of the above-mentioned drawbacks of the prior art.

Disclosure of Invention

The application aims to provide a synthetic aperture radar coherent pulse signal generation method which aims to solve at least one problem existing in the prior art.

The technical scheme of the application is as follows:

a method of generating a coherent pulse signal for a synthetic aperture radar, comprising:

Step one, acquiring waveform parameters of a radar signal in an imaging mode, and sending the waveform parameters of the radar signal to a signal generation unit, wherein the signal generation unit receives and stores the waveform parameters of the radar signal;

Step two, the signal generating unit detects the frame pulse signal of the timer in real time, and after detecting the frame pulse signal, the signal generating unit generates a PRF signal according to the waveform parameters of the radar signal and the frame pulse signal;

and thirdly, the signal generating 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 for amplification and then radiates the signal through an antenna.

In at least one embodiment of the application, the waveform parameters of the radar signal include pulse period, pulse width, chirp rate, and delay.

In at least one embodiment of the application, the imaging mode comprises a 1m resolution mode.

The invention has at least the following beneficial technical effects:

According to the synthetic aperture radar coherent pulse signal generation method, pulse signals generated by the signal generation unit are stably coherent in one frame of image period, jitter is avoided among different pulses, the stability of a radar imaging function can be greatly improved, images obtained after radar imaging are well focused and have no double images, the method can be used for time sequence control of phase coherent pulse signal generation in the synthetic aperture radar imaging function, and the radar image quality can be effectively improved.

Drawings

FIG. 1 is a schematic diagram of a coherent pulse signal generated by the prior art;

Fig. 2 is a schematic diagram of a coherent pulse signal according to one embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application become more apparent, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the accompanying drawings in the embodiments of the present application. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are some, but not all, embodiments of the application. The embodiments described below by referring to the drawings are illustrative and intended to explain the present application and should not be construed as limiting the application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application. Embodiments of the present application will be described in detail below with reference to the accompanying drawings.

In the description of the present application, it should be understood that the terms "center," "longitudinal," "lateral," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, merely to facilitate describing the present application and simplify the description, and do not indicate or imply that the devices or elements being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the scope of the present application.

The application is described in further detail below with reference to fig. 1 to 2.

The application provides a method for generating coherent pulse signals of a synthetic aperture radar, which comprises the following steps:

Step one, acquiring waveform parameters of a radar signal in an imaging mode, and sending the waveform parameters of the radar signal to a signal generating unit, wherein the signal generating unit receives and stores the waveform parameters of the radar signal;

Step two, the signal generating unit detects the frame pulse signal of the timer in real time, and after the frame pulse signal is detected, the signal generating unit generates a PRF signal according to the waveform parameters of the radar signal and the frame pulse signal;

And thirdly, the signal generating unit generates coherent pulse signals according to the PRF signals and waveform parameters of the radar signals, and sends the coherent pulse signals to the transmitting unit for amplification and then radiated through the antenna.

The application relates to a method for generating a coherent pulse signal of a synthetic aperture radar, which comprises the steps that after the radar is converted into a certain imaging mode, system control software sends waveform parameters of the radar signal in the imaging mode to a signal generating unit, the waveform parameters of the radar signal comprise pulse period, pulse width, frequency modulation slope and time delay, the signal generating unit stores the information after receiving the waveform parameters of the radar signal, the signal generating unit detects a frame pulse signal of a timer in real time, when the frame pulse signal of the timer is detected, the signal generating unit combines the stored waveform parameter information to generate a PRF signal, and finally the signal generating unit generates a highly stable coherent pulse signal according to the PRF signal generated by itself and the stored waveform parameter information before, and the highly stable coherent pulse signal is amplified by a transmitting unit and radiated by an antenna.

In a preferred embodiment of the present application, waveform generation of a synthetic aperture radar will be described as an example. In this embodiment, the radar imaging resolution is 1m, and the waveform parameters of the radar signal include a pulse period of 4.096s, a pulse width of 20us, a chirp rate of 1 x 10≡13, and a pulse delay of 40us. Wherein, PRF is 1000Hz, the step of the radar generating coherent pulse signals is as follows, as shown in FIG. 2:

when the radar works in an imaging mode with 1m resolution, the radar system control software sends waveform parameter information of the radar signal to the signal generating unit;

The signal generating unit detects the frame pulse signal of the timer at fs frequency, and when the frame pulse signal of the timer is detected, the signal generating unit generates a PRF signal according to the stored waveform parameter information;

The signal generating unit generates a coherent pulse signal based on the self-generated timing pulse PRF signal and the waveform parameter information stored previously.

According to the synthetic aperture radar coherent pulse signal generation method, the signal generation unit only detects the frame signal in the period of one frame image, and generates the PRF signal according to the frame signal and other waveform parameters, so that the problem that the signal generation unit is sometimes deviated by one sampling clock when sampling the PRF signal transmitted by the timer for many times is avoided, high coherence among different radar pulse signals in the period of one frame image is ensured, and a radar image with good focusing is obtained.

The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any changes or substitutions easily contemplated by those skilled in the art within the scope of the present application should be included in the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A method for generating a coherent pulse signal of a synthetic aperture radar, characterized in that it comprises:

Step 1: Acquire waveform parameters of a radar signal in an imaging mode, and send the waveform parameters of the radar signal to a signal generating unit, which receives and stores the waveform parameters of the radar signal;

Step 2, the signal generating unit performs real-time detection on the frame pulse signal of the timer. After detecting the frame pulse signal, the signal generating unit generates a PRF signal according to the waveform parameters of the radar signal;

Step three: the signal generating 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 for amplification and then 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 a pulse period, a pulse width, a frequency modulation slope and a delay.

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