FPGA-based software defined radio technologies for GNSS receiver design

约克大学和COMDEV团队此前曾就NSERC Engage赠款进行合作，以开发软件定义无线电(SDR)星载全球导航卫星系统(GNSS)接收器。目前的应用是提议开发一种原型SDR全球导航卫星系统接收器，该接收器能够跟踪从地球表面反射的全球导航卫星系统信号并区分土壤水分的变化。全球可持续发展计划认为，未来的纳微卫星/微卫星飞行任务具有巨大的潜力，可以低成本、近实时、区域性或全球性地确定近地表土壤水分含量，并为包括气候科学家、农民和政策制定者在内的众多用户带来好处。主要的科学问题是利用反射的全球导航卫星系统信号遥感近地表土壤水分变化的能力。考虑到这一问题的复杂性，目标将是只区分不同土壤水分的信号返回差异，而不是进行校准估计。具体研究问题包括：1)确定这样的GNSS反射仪系统的规格和组件，包括天线、RD前端、GNSS接收机组件和测量处理算法；2)设计基于FPGA的SDR GNSS反射仪接收机；3)测试和调试所开发的系统。约克大学与COM DEV的合作伙伴关系提供了开发一系列新的星载卫星导航产品和服务的潜力。

The York University and COM DEV team has previously worked together on an NSERC Engage grant to develop a software defined radio (SDR) spaceborne Global Navigation Satellite System (GNSS) receiver. The current application follows-on by proposing the development of a prototype SDR GNSS receiver capable of tracking GNSS signals reflected from the Earth's surface and to distinguish variations in soil moisture content. COM DEV sees the significant potential of a future nanosatellite / microsatellite mission carrying such a commercialized payload for low-cost, near-real-time, regional or global near-surface soil moisture content determination, and the benefits for a host of users, including climate scientist, farmers, and policy-makers.The primary scientific issue is the ability to remotely sense near-surface soil moisture variations with reflected GNSS signals. Given the complexity of this problem, the goal will be to only distinguish differences in signal returns for different soil moisture content, rather than to make calibrated estimates.The specific research problems are 1) identiying the specifications and components for such a GNSS reflectometry system, including: antennas, RD front-end, GNSS receiver components, and measurement processing algorithms; 2) designing the FPGA-based SDR GNSS reflectometry receiver; and 3) testing and tuning the developed system.The potential value of the resulting prototype GNSS reflectometry receiver for soil moisture content could be a commercializable space product for COM DEV to sell domestically and for the export market. The York University partnership with COM DEV offers the potential to develop a family of new spaceborne satellite navigation products, as well as services.