Multimode GNSS (global navigation satellite system) testing receiver with precise phase center

Abstract

The invention provides a multimode GNSS (global navigation satellite system) testing receiver with a precise phase center. The testing receiver is divided into a GNSS receiving antenna and an active receiver, wherein the GNSS receiving antenna adopts a four-feed-point broadband circular polarization design method, standing wave bandwidth and axial ratio bandwidth cover frequencies of four major GNSS navigation signals, and the GNSS receiving antenna is simple in design and manufacturing structure and high in system stability and has a few spare parts; and the active receiver adopts a broadbandelectric bridge, a low-noise amplifier and a switch filter network to achieve received signal preprocessing.

Description

technical field [0001] The invention relates to the field of GNSS testing, in particular to a multi-mode GNSS testing receiver with an accurate phase center. Background technique [0002] At present, four major GNSS (Global Navigation Satellite System) satellite navigation systems have been established in the world, namely the GPS of the United States, the second generation of Beidou of China, the Galileo system of Europe and the GLONASS system of Russia, which provide positioning, measurement and timing services for ground users. It has been widely used in civil and military fields, and plays a pivotal role in engineering construction, scientific research, resource exploration and military deployment. GNSS receivers are divided into the following types according to specific uses: (1) navigation receivers, used to determine the position and speed of moving carriers and other information, the accuracy of single-point testing is low, the receiver structure is simple, and the c...

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Problems solved by technology

[0016] The measurement antenna with four feed points uses a complex feed network to combine the signals into one and send them to the active receiver. The feed network is complex, and its loss will increase the noise figure of the receiver and deteriorate the receiver sensitivity.

[0017] The zenith gain of the circularly polarized antenna is too high, resulting in the antenna's radiation ability concentrated near the zenith, and the radiation ability to the airspace at low elevation angles is insufficient, and the cross polarization at low elevation angles is severely deteriorated, resulting in the deterioration of the ability of the receiving system to resist multipath transmission

[0018] The existing choke coils have insufficient ability to suppress back-lobe creeping waves. Since the choke ring is made of a metal structure, it suppresses electromagnetic waves through a 1 / 4 wavelength short-circuit surface, but its ability to suppress surface creeping wave transmission is limited.

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