The infrared detection technology of ballistic missile based on near space platform can effectively make up the shortcomings of high-cost of traditional early warning satellites and the limited earth curvature of ground-based early warning radar. To estimate the detection range of near space-based infrared system for boost-phase ballistic missile, the background infrared radiation as well as ballistic missiles is analyzed in detail. As for the lack of applicability and accuracy of the role distance algorithm which based on the performance contrast, the wave number to the radiation flux formula is introduced. The detection ranges of skin, plume and tail nozzle for boost-phase ballistic missile at 4.25 to 4.55μm are simulated under various conditions. The results show that the improved algorithm can provide the certain engineering application value for the design of near space-based infrared system.
The infrared detection technology of ballistic missile based on near space platform can effectively make up the shortcomings of high-cost of traditional early warning satellites and the limited earth curvature of ground-based early warning radar. In terms of target detection capability, aiming at the problem that the formula of the action distance based on contrast performance ignores the background emissivity in the calculation process and the formula is only valid for the monochromatic light, an improved formula of the detecting range based on contrast performance is proposed. The near space infrared imaging system parameters are introduced, the expression of the contrastive action distance formula based on the target detection of the near space platform is deduced. The detection range of the near space infrared system for the booster stage ballistic missile skin, the tail nozzle and the tail flame is calculated. The simulation results show that the near-space infrared system has the best effect on the detection of tail-flame radiation.
The propagation characteristics of the orbital angular momentum in vortex waves have been studied. The representation of electric multipole radiation filed is derived from the Laugerre-Gaussian beams to electromagnetic vortex. Simulation results show the capability of using the orbital angular momentum for remote imaging.
The ballistic missile hyperspectral data of imaging spectrometer from the near-space platform are generated by
numerical method. The characteristic of the ballistic missile hyperspectral data is extracted and matched based on two
different kinds of algorithms, which called transverse counting and quantization coding, respectively. The simulation
results show that two algorithms extract the characteristic of ballistic missile adequately and accurately. The algorithm
based on the transverse counting has the low complexity and can be implemented easily compared to the algorithm based
on the quantization coding does. The transverse counting algorithm also shows the good immunity to the disturbance
signals and speed up the matching and recognition of subsequent targets.
An improved anomaly detection and classification algorithm based on high-order statistics is presented. In order to solve some challenging problems, such as initializing projection, quantifying of anomaly classes and evaluating the performances. Firstly, initialize the projection vectors used by the idea of global RX algorithm. It gives priority to the detection of the anomalies with powerful energy. Secondly, analyze the current data whether have anomaly information or not so that it determines the terminal conditions and the quantities of anomaly classes. Thirdly, use two methods to evaluate the classification performance quantitatively. One is to match the results in the condition of reference images to evaluate the effects of anomaly detection and background suppression, the other is to segment the resultant images to calculate some features such as the classification rate, the number of detected anomalies and the number of false alarms. Simulated and Experimental results show that the improved algorithm has the capability of robustness and better anomaly detection performances under complex unknown background than traditional algorithm does.
In this paper, we propose an effective possibility density functions method of channel estimation with Viterbi algorithm
based on transitions. We also investigate the performance of the electronic dispersion compensation schemes via this
new channel estimation method. The schemes Simulation results show that it exhibits the similar performance with the
sophisticated MLSE scheme.
The applications of Electronic Dispersion Compensation (EDC) have recently attracted attention for high speed long
haul transmission. Moreover, recent progress in signal formats has gained interest in recent years such as Differential
Quadrature Phase Modulation (DQPSK). This format has higher spectral efficiency and reduced symbol rate compared
to binary modulation compared to binary modulation formats. In this paper, we investigate the application of different
EDC schemes with DQPSK format against chromatic dispersion (CD). The schemes are nonlinear feed-forward
equalizer (FFE) and Decision-Feedback equalizer (DFE) and butterfly FFE-DFE. We demonstrate that butterfly structure
can mitigates nonlinearity of cross-coupling because of processing two DPQSK tributaries independently. A 40 Gb/s
simulated transmission system over 160km length is established. Simulation results show that butterfly FFE-DFE has
better performance than separate FFE-DFE.
This paper discusses electronics dispersion compensation (EDC) by decision feedback equalizer (DFE) in high speed
optical communication system using the LMS and the RLS algorithms, respectively. The theory of the decomposed DFE
derived from basic concept of DFE in EDC is studied. Compared with the traditional DFE, the system complexity of new
one has been reduced while it still keeps the high performance of DFE. Simulation results prove the validity of
practicability and indicate that the decomposed DFE using RLS algorithm can more effectively eliminate intersymbol
interference (ISI) after being transmitted long distance.
Walsh-Haar function system that was first intruoduced by us is a new kind of function systems, and has a good global/local property. This function system is called Walsh ordering function system since its generation kernel functions belong to Walsh ordering Walsh function system. We worked out a recursive property of the matrix corresponding to the first Walsh-Haar functions in Walsh-Haar function system, and we also proved that Walsh-Haar function system is perfect and orthogonal similar to Walsh function system and Haar function system. Thus, discrete Walsh-Haar transformation (DW-HT) is an orthogonal transformation that can be widely used in signal processing. In this paper, using the recursive property of the matrix and the fast algorithm of discrete Walsh transformation (DWT) in Walsh ordering, we have designed a fast algorithm of Walsh ordering DW-HT based on the bisection technique. The idea and method used in this paper can be used for designing fast algorithms of other ordering DW-HTs and other discrete orthogonal transformations.