Method and device for generating reference frequency signal of double-base satellite-borne SAR system

Abstract

The embodiment of the invention provides a method for generating a reference frequency signal of a double-base satellite-borne SAR system. The method comprises the steps of receiving a control instruction, and determining a working mode based on the control instruction; when the working mode is a double-star interference imaging mode, taking an external taming crystal oscillator as a vibration source, wherein the frequency of the external taming crystal oscillator is synchronous with a preset vibration source; amplifying the crystal oscillator signal sent by the vibration source to obtain an amplified crystal oscillator signal; carrying out frequency multiplication on the amplified crystal oscillator signal to obtain a frequency-multiplied signal; performing power distribution on the frequency-doubled signal, and outputting the frequency-doubled signal conforming to preset power; and filtering and amplifying the frequency-doubled signal conforming to the preset power, and outputting the reference frequency signal. The embodiment of the invention also provides a device for generating the reference frequency signal of the double-base satellite-borne SAR system and a computer storagemedium.

Description

Technical field [0001] The invention relates to the technical field of synthetic aperture radar reference frequency signal generation, in particular to a method, device and computer storage medium for generating a reference frequency signal of a dual-base spaceborne SAR system. Background technique [0002] For the dual-based satellite-borne synthetic aperture radar (Synthetic Aperture Radar, SAR) system, because two satellites are required for interferometric imaging, the frequency and phase consistency of the clock signal and the local oscillator signal between the two satellites are consistent during imaging. Very high requirements, the consistency of the reference signal can determine the quality of binary satellite imaging to a certain extent. The current SAR system reference signal generation mainly has the following two methods: one is that the reference signal generated by the crystal oscillator is multiplied and divided by the phase-locked loop to generate the various re...

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Problems solved by technology

The advantage of the first method is that the phase-locked loop can minimize the harmonic clutter generated in the process of frequency multiplication, and the link of the circuit in the process of frequency multiplication is relatively short. It is usually recommended to use this scheme for reference signal generation, but this The scheme also has its disadvantages. One is that there are generally more than one power supply voltages required in the phase-locked loop frequency multiplication link, and an additional power supply voltage is required. Second, the initial phase of the signal output by the phase-locked loop frequency multiplication is not a fixed value and has a certain randomness. sex

The advantage of the second method is that the structure is simple, and the initial phase of the output signal is consistent with the crystal oscillator. The disadvantage is that the frequency multiplication link is long, and the harmonic clutter is not easy to filter out, and the volume is large.

[0003] Since the dual-base spaceborne SAR system has both a single-satellite imaging mode and the most important dual-satellite interference imaging mode, the main technical defect of the two schemes mentioned above is that the reference frequency sources in the two satellites are each equipped with a crystal oscillator The reference frequency signal is provided. The frequency and phase relationship between the two crystal oscillators is uncertain each time the power is turned on. Therefore, the reference signal provided by the crystal oscillator is not synchronized on the two satellites. The asynchronous signal will cause double-star interference imaging. Can not work normally

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