Design Of Muti-mode Muti-band GNSS Receiver RF Front-end

The full name of GNSS systems is the global navigation satellite system,It includes all of the satellite navigation system at present,Such as GPS?America?,Galileo?Europe?,glonass?Russia?,and China's independent research and development of BD satellite navigation system.With the advent of these navigation systems,the traditional single-frequency receiver more and more can not meet people's positioning accuracy requirements,so how to combine GPS with other GNSS systems to achieve more reliable and stable navigation and positioning system will become a hot issue in today's research,The important thing is that the dual-model receiver can receive GPS satellite signals and Compass satellite signals.Aiming to the development trend of GNSS satellite navigation system at present,this paper summarizes and analyzes the satellite navigation receivers at various patterns,and describes the architecture of all kinds of receivers.Thus a kind of multi-mode multi-frequency GNSS receiver is designed which can receive BDS/GPS satellite navigation signals at the same time.It can receive L1 and L2 frequency bands of GPS,B1and B2 frequency bands of BDS at the same time.Firstly,this paper introduces the correlative background and present situation at home and abroad of navigation receivers,and shows the application background clearly in domestic design of receivers at present stage.Then,the paper introduces system architectures and technical indicators of the navigation receivers.To compare the system structure and technical indicators of receivers commonly used,and to combine with the power consumption and cost etc factors,the navigation receiver with superheterodyne structure is adopted.Device selectionis based on the system scheme and specific indexes to complete index distribution of each module.Finally,the link simulation,validation and improvement design are achieved in rf simulation software ADS.The drawing of the whole system is completed in Hardware design software Altium Designer,and by testing the corresponding test results are given finally.The GNSS navigation receiver designed in this paper uses single input multiple output overall train of thought.To combine with the simulation tool,the noise coefficient of the multimode receiver is 2 db through the test,and channel standing wave ratio is less than1.8.The machine has more than 100 db gain,with 70 db gain control range at the same time;OP_1dB for 10.5 dBm,frequency of module power output for 6 dBm,stray inhibit the fabric-65 dBc,phase noise of-101dBc/Hz@100 KHz.The results show that the system indicators meet the design requirements.