For global navigation satellite system(GNSS) signals in Gaussian and Rayleigh fading channel, a novel signal detection algorithm is proposed. Under the low frequency uncertainty case, after performing discrete cosine transform(DCT) to the outputs of the partial matched filter(PMF) for every antenna, the high order components in the transforming domain will be filtered, then the equalgain(EG) combination for the inverse discrete cosine transform(IDCT) reconstructed signal would be done subsequently. Thus,due to the different frequency distribution characteristics between the noise and signals, after EG combination, the energy of signals has almost no loss and the noise energy is greatly reduced. The theoretical analysis and simulation results show that the detection algorithm can effectively improve the signal-to-noise ratio of the captured signal and increase the probability of detection under the same false alarm probability. In addition, it should be pointed out that this method can also be applied to Rayleigh fading channels with moving antenna.
A new iterative algorithm is proposed to reconstruct an unknown sparse signal from a set of projected measurements. Unlike existing greedy pursuit methods which only consider the atoms having the highest correlation with the residual signal, the proposed algorithm not only considers the higher correlation atoms but also reserves the lower correlation atoms with the residual signal. In the lower correlation atoms, only a few are correct which usually impact the reconstructive performance and decide the reconstruction dynamic range of greedy pursuit methods. The others are redundant. In order to avoid redundant atoms impacting the reconstructive accuracy, the Bayesian pursuit algorithm is used to eliminate them. Simulation results show that the proposed algorithm can improve the reconstructive dynamic range and the reconstructive accuracy. Furthermore, better noise immunity compared with the existing greedy pursuit methods can be obtained.
Pulsars are rapidly rotating neutron stars that generate pulsed electromagnetic radiation.A new method for intersatellite relative position determination between a global navigation satellite system(GNSS) and spacecraft using X-ray pulsars is proposed in this paper.The geometric model of this method is formulated,and two different resolution algorithms are introduced and analyzed.The phase cycle ambiguity resolution is investigated,and a new strategy is proposed and formulated.Using the direct vector parameters of the pulsar,geometric dilution of precision(GDOP) is studied.It is shown that this method has advantages of simplicity and efficiency,and is able to eliminate the clock errors.The analytical results are verified numerically via computer simulations.
To bring in a priori information to improve the phase estimation for X-ray pulsar signals, the explicit struct...
Zhang hua 1,2 , Xu Luping 1,2 , Feng Dajun 1,2 1 School of Electronic Engineering, Xidian University, Xi’an 710071, China 2 Institute of Astronautics and Aeronautics, Xidian University, Xi’an 710071, China
