Application method of chain relation in near-field-to-far-field transformation of near field measurement system
A technology of measurement system and application method, which is applied in the field of near-field to far-field transformation of the chain relation in the near-field measurement system, can solve problems such as complex deconvolution calculations, and achieve easy access to engineering applications, convenience in use, and amount of information. big effect
Active Publication Date: 2018-03-06
BEIHANG UNIV
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Deconvolution calculations are generally more complicated
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[0070] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.
[0071] The current near-field RCS measurement is mainly to perform backward (single station) RCS measurement. For the backward RCS measurement, the transmitting antenna and the receiving antenna are at the same spatial point. If the transmitting and receiving antennas have the same pointing and pattern, the plane wave angle spectra of the two antennas are equal, that is, S T (θ,φ)=S R (θ,φ)=S(θ,φ). The shock response of the system is self-convolution S(θ,φ)*S(θ,φ). For the block diagram of self-convolution, see image 3 . image 3 E in i (x, y) is the complex amplitude on the plane perpendicular to the antenna passing through the center of rotation O of the target.
[0072] Will figure 2 and image 3 combined to get Figure 4 . Will Figure 4 The FFT and IFFT in cancel each other out, Figure 4 Simplified to Figure 5 . Figure 5 ...
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The invention discloses an application method of a chain relation in near-field-to-far-field transformation of a near field measurement system. The method is characterized by changing the NFFFT chainrelation into a new form of expression, and providing relation between F0, FN and field distribution Ei on a plane passing through a target rotation center and vertical to radar exposure line and reflected ray angle bisector. The original relation is completely equivalent to the new relation, and the two relations are different forms of expressions of the chain relation; and however, the new relation solves the problem of inverse convolution in the prior art, and allows the chain relation to enter engineering application much easier. The invention also provides a near field RCS measurement implementation method, which comprises background cancel, FN calibration, NFFFT and NFFFT calibration and the like. Compared with an NFFFT method based on imaging concept and plane-wave synthesis, the near field RCS measurement technique and method are theoretically stricter, have a simple mathematical expression, are clear in physical conception and are convenient to use in engineering.
Description
technical field [0001] The invention belongs to the field of low-observable technology and radar technology, in particular to an application method of a chain relation in the near-field to far-field transformation of a near-field measurement system. A new near-field measurement of scattering properties. Background technique [0002] Traditionally, RCS static measurement methods include external field and compact field. Field measurement occupies a large area, is costly, has many environmental interference sources, is affected by climate, and has low measurement efficiency. The quiet zone of the compact field is small in size and is mostly used for RCS testing of scaled models and components. [0003] In 2008, the Lockheed Martin company of the United States launched an RCS test system based on indoor point source near-field, which is used for the factory performance test of stealth aircraft. [0004] In the case that the far-field condition is not satisfied, the near-fiel...
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IPC IPC(8): G01S7/41
CPCG01S7/411G01S7/418
Inventor 何国瑜李志平王正鹏武建华
Owner BEIHANG UNIV