Design of calibration body used for simultaneously performing multi-calibration and background extraction measurement and processing method thereof

Abstract

The invention discloses the design of a calibration body used for simultaneously performing multi-calibration and background extraction measurement and a processing method thereof. The shape design ofthe calibration body is proposed. The calibration body ECAM is an important improvement to the shape of the existing SCAM calibration body. A circular arc surface in the SCAM shape structure is modified into an elliptical arc surface, wherein the minor axis length of the elliptical arc surface can be adjusted according to actual needs. The RCS ratio of a number of equivalent standard scatterers,which can be used for calibration of a target radar cross section (RCS), of the ECAM can be changed, which is beneficial to meet the requirements of multi-calibration. Based on the calibration body ECAM design, a new method of background auxiliary measurement and extraction processing is proposed. The ECAM is used as an auxiliary measurement body for 360-degree omnidirectional rotation measurement. Measurement data within the azimuth range of equivalent large and small ellipsoidal columns of the ECAM are selected. Concentric circle fitting optimization is carried out to acquire accurate estimation of background signals BI(f) and BQ(f). The accuracy of subsequent background vector subtraction and RCS multi-calibration processing is improved.

Description

technical field [0001] The invention relates to the technical fields of communication and radar, in particular to a novel calibration body shape design and a signal processing method for simultaneously completing multiple calibration processing and background extraction measurement in radar cross section (RCS) measurement of a target. Background technique [0002] Radar Cross Section (RCS), as an important parameter reflecting the electromagnetic characteristics of targets, plays an important role in the research of radar detection and identification, target stealth and anti-stealth. Calibration processing and background offset are important links in target RCS measurement, which largely affect the measurement uncertainty and the effectiveness of subsequent data processing. In microwave anechoic chamber and RCS static measurement in the field, the target to be measured is generally placed on the rotating top of the low-scattering support, the measuring radar is fixed, the ta...

AI Technical Summary

Problems solved by technology

[0054] Disadvantages of prior art 1: First, in the test field using low-scattering metal brackets, the coupling scattering between the calibration ball and the metal bracket is very serious, so metal calibration balls generally cannot be used in the RCS test field using metal brackets The second is that the background measurement problem of the target bracket is not solved by using the metal calibration ball

[0057] The disadvantages of prior art 2: first, the auxiliary device cannot be used for RCS calibration; second, it is necessary to design a special mechanism to drive the auxiliary measurement carrier to translate back and forth. It is necessary to hide the rotating top in the carrier, so it is required that the designed auxiliary measurement carrier must have a large size

[0060] Disadvantages of prior art 3: the technology of using eccentric cylinders for auxiliary measurement and background extraction avoids the requirement of translation of the carrier, but this technology also has the following obvious disadvantages:

At this time, if the eccentric cylinder is used to assist in extracting the background level of the bracket, it is equivalent to accurately extracting a weak signal 1000 times smaller than the main echo from the measurement echo, and the extraction accuracy is difficult to guarantee

[0065] It can be seen that according to formula (18), the theoretical RCS value of this calibration body increases with the increase of frequency, which is not conducive to the auxiliary measurement and processing of background extraction

[0066] (2) The metal cylinder RCS placed vertically does not change with the orientation, so it cannot be used for dual calibration measurement and processing (reference W.D.Wood, P.J.Collins, T.Conn, "The CAM RCS Dual-Cal Standard," Proc.of the25th Antenna Measurement Techniques Association Symposium, Irvine, CA, 2003.);

[0071] The main disadvantage of prior art 4: the CAM calibration body can be equivalent to three standard scatterers of small cylinder, large cylinder and flat plate, so it can be used for multiple calibration measurement and processing

[0078] The main disadvantage of prior art 5: the SCAM calibration body can be equivalent to three standard scatterers: a large sphere, a small sphere and a cylindrical surface, which are used for multiple calibration measurements and processing

However, because the arc surface is obtained by using the height of the calibration body as the diameter, when the dimensions of the large and small spheres and the height are determined, the RCS ratio of the SCAM equivalent large sphere to the small sphere is fixed and cannot satisfy The need for multiple calibration volume ratios in multiple calibration measurement processing

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