THE CHOICE OF SIGNALS FOR HYDROACOUSTIC NAVIGATION SYSTEM OF TRANSFORMATION UNDERWATER APPARATUS TO DOCKING MODULE

Abstract

The proposed work is the first part of the overall work on the development of the structure of the hydroacoustic navigation system (HNST) for bringing the autonomous underwater vehicle (AUV) to the docking module (DM). The second (final) part will be published in the next issue of the journal. The purpose of this work is to select signals for building HNST providing reduction in a near zone at the distances not exceeding 300 m, an AUV and its docking with the carrier is considered. Mutual definition of a distance and angular position DM of the carrier and AUV relative to each other is carried out for this purpose. Determination of mutual angular coordinates can be carried out with use of HNST with short and ultra-short base. HNST with short base is preferable for realization from the point of view of simplicity. However, its installation on the AUV can be impossible because of rather small sizes of the device, and on AUV should be installed HNST with ultra-short base. HNST with short base can be established on the docking module. Since there are no reasons to assume the high speed of change of the phase characteristic of the developed high-frequency channel of transformation therefore the interval of stationarity of the phase characteristic should be significantly more than duration of a symbol at a speed of transfer of 4 kBit/s. Therefore, it is advisable to exchange measurement data between AUV and DM in the composition of HNST by relative phase modulation (DPSM). Reception of signals is performed by a suboptimal incoherent receiver on which entrance deep restriction of an entrance signal is carried out. The use of deep signal limitation at the receiver input allows to exclude operation of automatic control of strengthening at a stage of entry into communication, as a result, it is possible to reduce the duration of communication sessions. In the combined information navigation system, it is expedient: to apply as navigation signals of data exchanged between AUV and DM based on the results of mutual measurement of navigation parameters; to carry out data exchange between AUV and DM by method DPSM with a speed V = 4 kBit/s; to carry out transfer of the block of data with application of the correcting block cyclic code ; to apply to reception of a block of data diversity reception in combination with majority decoding characters, and then correct errors in the data block with the help of code, and to accompany the issuance of data to the user sign detection code errors in the block.