GNSS Synthetic Aperture Beamforming Technology Research

With the use of satellite navigation and positioning system is more and more widespread in the military field,more and more important role,it is bound to face a variety of strong interference against the environment,there is no anti-jamming capability of military satellite navigation receiver is no viability.Antenna array technology is currently the most effective anti-jamming interference suppression measures,it has become a mainstream means of navigation receiver interference.Conventional antenna array receiver need to use multiple array elements,multiple RF channels,the device hardware complexity,size and power consumption is much larger than the traditional single-antenna receiver,these drawbacks limiting its scope of application.This article on how to use a single antenna synthetic aperture beamforming and interference were studied,the main contents of the following three parts:(1)To establish a GNSS signal model of synthetic aperture.Compared with traditional physical real aperture,the basic principles of GNSS synthetic aperture is motion characteristics using a single antenna or antenna array,rotating through the signal sampling at different times to achieve equivalent results virtual element space samples.The core process is moving along with the antenna received samples from the time domain into a spatial sampling conversion.A typical combination of formation,gives a single antenna GNSS uniform and non-uniform motion synthetic aperture array signal model.(2)GNSS algorithm based on the formation of the synthetic aperture beam stationary signal simulation analysis,based on the comparison of the model under the influence of the antenna uniform linear motion and non-uniform motion of the beam formation.Simulation results show that: Under certain conditions,synthetic aperture array antenna for GNSS and physical real aperture array uniform motion can be considered equivalent;when increasing the number of synthetic array element,forming nulls narrowed compared to the direction of change poor large interference signal suppression effect,it is not an infinite number of array elements is increased,the beam pattern should be combined with the actual requirements to select an appropriate number of array elements;limited impact velocity errors on the beam pattern,but the antenna movement faster,picket interval shorter mean higher sampling rate,the hardware requirements are higher,we need to consider the sampling rate and phase compensation factors such hardware to choose a suitable antenna velocity;In summary,when other factors are ignored carrier phase When synthetic aperture array uniform motion can be equivalent to a physical real aperture array;and compared to the physical real aperture arrays,the number of array elements can be flexibly designed,mutual coupling can be eliminated,affecting channel mismatch;and also reduce the size and power consumption.(3)Since GNSS synthetic aperture array uniform motion approximation is equivalent to the physical real aperture array,the weighting factor based on the computational complexity of proposed synthetic aperture beam forming FFT algorithm that the weighting factor of 1.Simulation algorithm performance comparison with the conventional form of physical entities based on synthetic aperture array beam aperture FFT,the analysis and comparison of performance that the two are basically the same,to verify the feasibility of forming a beam through FFT-based synthetic aperture.