DME Pulsed Interference Suppression Method Based On Wavelet Transformation For GNSS

Global Navigation Satellite System(GNSS) has been widely used in military navigation, civil navigation and many other fields. The development of GNSS reflects the level of science and technology. Many countries have already begun to build their own navigation satellite system and improve it gradually. They add new components to the GNSS, which makes the future GNSS a more complex system. However, the frequencies suitable for transmitting navigation signal are limited, which may cause the problem of electromagnetic compatibility among different navigation signals and radio navigation systems.Distance Measuring Equipment(DME) is one of the radio navigation systems. GPS L5, Galileo E5 and BeiDou B2 are important signals for GNSS. However, the frequencies of these navigation signals overlap with that of DME partially, and strong pulsed signals from the DME stations will degrade the performance of GNSS receiver. Thus, the DME pulsed interference suppression has become a major concern in the GNSS community.Firstly, this paper introduce wavelet packet transformation(WPT) based DME interference suppression. Since the selection of WPT-related parameters pay an important role in the performance of interference suppression, this paper discusses the selections of these parameters including threshold in wavelet-packet-domain, composition level, and wavelet function. Numerical results demonstrate the effectiveness of the selected parameters.Secondly, considering that the traditional DME interference suppression methods are of poor performance when the DME pulse has high density, this paper proposes a hybrid DME interference suppression approach by combining parametric algorithm and wavelet packet algorithm. Furthermore, in order to obtain the approving performance and feasible complexity with any DME pulse density, an integrated method is also proposed which combines the traditional DME pulsed interference suppression method and the proposed hybrid approach.At last, a modified power inversion-based DME suppression method is presented under the condition of array-based airborne antenna receiver through the adaptive array processing technique. In addition, according to the analysis on the measured BeiDou data interferenced by wide-band noise jamming and pulsed interference, this paper introduces an array-based method which can suppress those two kind of interference.