An Experimental Multi Band Receiver for the GermanGalileo Test Environment (GATE)

摘要

For the purpose of pre Galileo system verification andtesting, the Galileo Test Environment (GATE) is setup inthe German Alps to reproduce a realistic test bed for theGalileo satellite navigation system. In fact, a completeminiature navigation system is built up consisting of a control,ground and pseudo-space segment.For system monitoring and testing a receiver is required,which is capable of processing all signals specified in theGalileo system specification. To prove interoperability andfor reference purposes the receiver will also process Galileoand GPS signals on L1 in a common processing chain.This paper describes a modular receiver design, developedfor the use as a user receiver as well as a system monitor receiver.The receiver is based on a PXI computer frameworkwhere the slot zero controller serves as the navigation processorand user interface. Up to three single band receiverswith radiofrequency front end and base band processor occupyup to nine slots of the PXI framework to serve anyof the Galileo radiofrequency bands E5, E6 and L1. Asthe base band units are FPGA based, all units are equallydesigned.To reduce cost the three receiver front-ends have an identicalPCB-layout. LO-frequencies and filter characteristicsdistinguish individual front-end boards. As the whole E5-band including the first side slopes of both E5a and E5bis to be received with one of the three front-ends (AltBOCmode) the requirements on amplitude and group delay flatnessin the passband are challenging. The very high bandwidthrequires high performance components and a carefuldesign. For the other two bands the bandwidth is more relaxed.All three front-ends have a low-IF architecture witha single analog mixer stage and filter stages that differ foreach frequency band in the RF- and IF-domain, respectively.For the subsequent A/D-converter jitter is a major