The White Motion Identification System (Aut omat IC Ident ification system, or ALS) is a new type of navigation assistance system used by the international Terrestrial Organization forced rules, which has been widely used in the fields of ship communication and satellite communication. The ship ALS system has been launched into a universal ship automatic identification system, but its communication range is comparable to infinite.On-board AISThe system is a new type of system developed on the root of the ship Ais system, which can accept AIS signal on a larger scale.On-board AISThe secondary function of the system is to stop the analysis and disposal of intercepted AIS signals, which has great significance in both military and civil fields.
In a thriving country,Spaceborne AlSThe study of the system has matured, and some have been successfully used in the practice of satellites. And in the international, on this aspect of the discussion is still in its infancy, many researchers focus on a certain module, at present did not form a good system. On the root of the international study effect, combined with the detailed requirements of scientific research projects, the construction of a good spaceborne Als acceptance system.
The on-board Als acceptance system consists of four modules, which identify the existence detection of sudden signals, blind separation of mixed signals, identification of ALS signal form and recovery of AIS information. Signal existence detection, that is, the intercepted signal detection in which there is a signal. After analyzing the spectrum mode of the signal, a uniform value interception method is proposed, and the detection probability can reach more than 98 when the signal-to-noise ratio is greater than 10dB. Because the Spaceborne platform accepts ALS signal, there is a situation where there is a time slot conflict, that is, the accepted signal can be a mixture of multiple Als signals, for the progressive Spaceborne AIS Admission System Task efficiency, the acceptance signal stopped blind separation. The blind signal separation algorithm is divided into two categories: multi-channel separation and single-channel separation, which are used by ICA (independent weight analysis), and the two algorithms (JADE and FastICA) are completed, and the system matrix is close to the unit array, and the single-channel separation algorithm based on orthogonal sampling is completed on single channel separation. The bit error rate is lower after parting. In the way of removing the disturbance of other communication signals in the AIS signal frequency band, the demand for Als signals to be identified from the communication signal, that is, to stop the ALS signal form identification. A combined recognition algorithm based on high order cumulant and Spectrum is proposed, and the signal sets composed of mountain AM, FM, BPSK, ZFSK, QPSK, 1 6QAM and Als (i.e. GMSK) signals are stopped and identified, and the signal recognition rate is more than 90 per cent at a time when the signal-to-noise ratio is greater than 10dB. 。 AIS information recovery includes AIS signal solution harmonic and Als signal solution frame two parts. With regard to ALS signal demodulation, the differential demodulation method, frequency identification Demodulation method and related Demodulation method are completed, and the function analysis is stopped: AIS signal solution frame, that is, the original meaning of the recovery signal according to HDLC protocol, and the AIS signal is used as an example to stop the analysis of the consequences.
The algorithms of each module of the Spaceborne Als system are completed by MATLAB and C language, and the function of the insulting algorithm is stopped, and the core system is initially completed under the Visua L Studio platform, and finally the discussion of the whole Spaceborne Als acceptance system from the Wood module algorithm is completed.
