J. Korean GNSS Society 1(1), 29-34 (2012) http://dx.doi.org/10.11003/JKGS.2012.1.1.029 published irst issue Autumn 2012 Copyright © The Korean GNSS Society http://www.gnss.or.kr plSSN: 2287-7398 J KGS Journal of the Korean GNSS Society 1. INTRODUCTION Recently, many advanced countries show a great interest in Global Navigation Satellite System (GNSS). GPS of USA, Galileo of Europe and GLONASS of Russia are its representative systems (Kim et al. 2004). If various GNSS signals are provided by these modernization plans, the users can receive multi-band signals and perform better navigations. However, processing newly added signal is accompanied by the development of new algorithm. In addition, an algorithm to ensure the interoperability between diferent systems is, also, required. To develop and validate these algorithms, the signals to satisfy GNSS signal standard are required. However, since Radio Frequency (RF) signals without Full Operational Capability (FOC) cannot be collected, the studies are restricted. Even though RF signals are collected, a signal generator must be developed to satisfy the GNSS signal standard because the signal cannot be collected from diverse user environment. Design of Component-Based GNSS Multi-Band IF Signal Generator Sung Lyong Cho 1 , Deok Won Lim 2 , Sang-Rae Yeo 1 , Chansik Park 3 , Dong-Hwan Hwang 1 , Sang Jeong Lee 1† 1 Department of Electronics Engineering, Chungnam National University, Daejeon 305-764, Korea 2 Satellite Navigation Department, Korea Aerospace Research Institute, Daejeon 305-806, Korea 3 Department of Electronics Engineering, Chungbuk National University, Cheongju 361-763, Korea ABSTRACT A software GNSS signal generator for the GPS L1/L2/L5 and Galileo E1/E5 signals is proposed in this paper. And this signal generator is designed and implemented with several components by considering the reuse and expansion of components for similar GNSS signals. The characteristics of the reusability of the components are confirmed with the carrier generation and the band-pass filter components. And the functionality of the GNSS multi-band IF signal generator is validated by using the commercial software GPS L1 receiver, and the performance of signal acquisition, tracking and accuracy of horizontal position error are analyzed for this validation. As a result, the GPS L1 signal generator operates successfully and it could be expected that other signal generators also operate well because most of components are the same as those of the GPS L1 signal generator. Keywords: GPS, Galileo, IF signal generator, component The GNSS multi-band signal generator can be divided into hardware-based simulator and software-based simulator depending on its implementation method. The signal generated by a hardware-based simulator has high similarity to satellite signal and a signal property similar to actual RF signal. However, it is hard to use the hardware- based simulator in small sized study groups due to high production cost resulted from the requirement of heavy expenses in development process. In addition, it is diicult to change its hardware when a new RF signal is added. On the other hand, the software-based simulator can generate a signal in desired user environment and satellite RF signal under development based on Interface Control Document (ICD). However, it has disadvantages that it cannot reflect hardware-based properties, and it is diicult to generate RF band signal. he software-based signal generators have been studied in GNSS related companies and universities around the world. VEGA Inc. in Germany developed Galileo System Simulation Facility (GSSF) which is a Galileo system simulator and is being used for the verification of Galileo Test Environment (GATE), which is the ground test environment of the Galileo system (http://www.gssf.eu/ GSSF%20subpage%20What%20is%20GSSF.htm). However, Received Aug 30, 2012 Revised Oct 10, 2012 Accepted Oct 23, 2012 † Corresponding Author E-mail: eesjl@cnu.ac.kr Tel: +82-42-821-6582 Fax: +82-42-823-4494