An anti-image interference quadrature IF architecture for satellite receivers

• Published in: Chinese journal of aeronautics Vol. 27; no. 4; pp. 955 - 963
• Main Authors: He, Weidong, Lu, Xiaochun, He, Chengyan, James, Torley
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2014
• Subjects: Algorithms; Aliasing; Architecture; Circuit design; Complex LMS; I/Q mismatches; Image reject; Interferences; Intermediate frequency; Quadratures; Receiver architecture; Receivers; 全球导航卫星系统; 前端电路设计; 卫星接收器; 图像失真; 无线信号; 架构; 正交; 防干扰; Receiver architecture; Image reject; Complex LMS; I/Q mismatches; Interferences
• ISSN: 1000-9361
• DOI: 10.1016/j.cja.2014.06.005

Since Global Navigation Satellite System（GNSS） signals span a wide range of frequency, wireless signals coming from other communication systems may be aliased and appear as image interference. In quadrature intermediate frequency（IF） receivers, image aliasing due to in-phase and quadrature（I/Q） channel mismatches is always a big problem. I/Q mismatches occur because of gain and phase imbalances between quadrature mixers and capacitor mismatches in analog-to-digital converters（ADC）. As a result, the dynamic range and performance of a receiver are severely degraded. In this paper, several popular receiver architectures are summarized and the image aliasing problem is investigated in detail. Based on this analysis, a low-IF architecture is proposed for a single-chip solution and a novel and feasible anti-image algorithm is investigated. With this anti-image digital processing, the image reject ratio（IRR） can reach approximately above50 dB, which relaxes image rejection specific in front-end circuit designs and allows cheap and highly flexible analog front-end solutions. Simulation and experimental data show that the antiimage algorithm can work effectively, robustly, and steadily.