Transform Domain Interference Suppression in GPS/BD-2 Receiver Based on Fractional Fourier Transform

摘要

Global Navigation Satellite System (GNSS) ,which canprovide accurate PVT (position, velocity, time)information all over the world, has been an importantresource of supporting a wide range of civil scientific,commercial activity and military communication. As theelectro-magnetic environment becoming increasingly complex, though, Global Navigation Satellite System hascertain capability of immunity from interference sinceDirect Sequence Spread Spectrum (DSSS) is utilized, thelow-power received signal is susceptible to intentional orunintentional interferences. Therefore, to ensure itsperformance, the suppression technique is needed toincrease the interference immunity of the GNSS receiver.This paper describes transform domain interferencesuppression in GNSS receiver based on FrFT withadaptive threshold in allusion to the suppression ofcommon interference signals: the narrow-band, multi-toneinterference and the chirp interference. This method, indetecting and localizing the type of interference reservedby pattern recognition module reserves, accomplished theexcision process at corresponding fractional order wherethe energy spectrum have best focused effect in theinterference suppression module. The result that wellinterference suppressing capability of multipleinterferences and chirp interference was rendered in thismethod. In addition, the adaptive threshold algorithm canmake a flexible trade-off between suppression effect andresource consumption in a certain extent.