Digital intermediate frequency signal processing apparatus capable of improving polarimetric synthetic aperture radar (Pol-SAR) channel consistency

Abstract

The invention discloses a digital intermediate frequency signal processing apparatus capable of improving polarimetric synthetic aperture radar (Pol-SAR) channel consistency and relates to the Pol-SAR technology. A data acquisition chip is moved forward to a rear end of a band pass filter and intermediate frequency amplifier. The intermediate frequency in a receiving path can be directly sampled. The apparatus of the invention carries out sampling and digitization to a plurality of polarimetric channel signals of the Pol-SAR at the intermediate frequency, performs quadrature demodulation and filtering to intermediate frequency signals in a digital domain so as to obtain digital video signals and simultaneously performs related digital signal processing to the digital video signals. By using the apparatus of the invention, Pol-SAR channel consistency can be substantially improved; remote sensing precision and accuracy of Pol-SAR can be effectively raised; problems existing in Pol-SAR echo receiving treatment by using a traditional method can be avoided; a quantity of collected channels can be reduced. Using the apparatus is good for miniaturization of a Pol-SAR system.

Description

technical field [0001] The invention relates to the technical field of polarimetric synthetic aperture radar, and relates to a digital intermediate frequency technology used in polarimetric synthetic aperture radar (Pol-SAR, Polarimetric Synthetic Aperture Radar), and a digital intermediate frequency signal processing device for Pol-SAR. Background technique [0002] Pol-SAR is a high-resolution synthetic aperture radar that can obtain target polarization information. In the traditional SAR system, the A / D conversion starts from the video signal, that is, the IF signal is quadrature demodulated and filtered by the analog receiver to obtain two analog video quadrature signals, I and Q, and the SAR digital system part receives two analog quadrature signals. The video signal is digitized by A / D sampling, and then related digital processing and storage records are carried out. The block diagram of the SAR analog receiver is usually as follows figure 2 shown. [0003] The prin...

AI Technical Summary

Problems solved by technology

Limited by the inherent mechanical characteristics and performance of analog devices, image 3 The Pol-SAR receiving and processing device shown will inevitably produce problems such as local oscillator frequency drift, phase noise, false signals generated by frequency mixing, intermodulation and harmonics during amplification, and the result is that the amplitude phase of the two polarization channels cannot be guaranteed to be consistent At the same time, the orthogonality index of the I / Q two-way signal of the same receiving channel is not ideal, and the whole debugging process is very difficult, and the performance parameters are also easily affected by temperature, environment, etc.

In Pol-SAR applications, the echo signals between different polarization channels require high consistency (amplitude consistency and phase consistency), so traditional processing methods are difficult to cope with the precise high-resolution quantitative measurement of Pol-SAR requirements

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