Satellite-borne AIS signal serial separation method based on parameter estimation

Abstract

The invention discloses a satellite-borne AIS signal serial separation method based on parameter estimation. The method comprises the steps that a cross-correlation algorithm is used for conducting time delay and frequency offset combined estimation on mixed satellite-borne AIS baseband signals, and the signals are corrected according to an estimation result; incoherent detection and CRC verification are conducted on the corrected signals to obtain a correct sequence, parameter estimation under data assistance is conducted by using the sequence to obtain amplitude information and phase information of the mixed signals; number re-modulation is conducted on the detected code element sequence by using delay, frequency offset, phase and amplitude which are obtained through estimation to construct one route of modulation signal, the route of constructed signal is subtracted from the mixed signals, and then separation of one route of signal is realized; repeated separation is conducted on the rest of the mixed signals, and then serial separation of the mixed signals is realized. The satellite-borne AIS signal serial separation method based on parameter estimation solves the problem that in a satellite-borne AIS system, correct detection is hard to realize due to aliasing caused by slot collision which is generated when the receiving end of a satellite receives signals.

Description

(1) Technical field: [0001] The invention belongs to the field of communication technology, and relates to a ship automatic identification system (Automatic Identification System, AIS), in particular to a serial separation method of space-borne AIS signals under parameter estimation and its realization system. (two) background technology: [0002] In the original shore-based AIS system, the ship-borne AIS equipment forms a subnet with a radius of about 20nmile. In this subnet, different slipways work together with the SOTDMA protocol, and the data exchanged between slipways will not have time slot conflicts. In spaceborne AIS, the arc radius of the satellite's field of view exceeds 1500nmile, and there will be multiple subnets in the same field of view, and the signals transmitted by the ship stations in different subnets will inevitably have time slot conflicts, resulting in the received signal being weak. mixed signals. At the same time, the operating frequency of the spa...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problem that the signal received by the existing space-borne AIS mixed signal separation method has time delay and large frequency offset and is difficult to separate, and cannot be directly applied to the space-borne AIS system, and provides a method based on synchronization parameter estimation. Spaceborne AIS Mixed Signal Serial Separation Method

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