JPS57172274A - Multi-channel acoustic wave geological survey device - Google Patents

Abstract

PURPOSE:To execute a geological survey by oscillating an acoustive wave at equal distance intervals without being influenced by a tidal current, by deriving an average speed of a ship, which is required for sailing by an expected distance, in accordance with a moving distance of the ship in every short time, and deciding the oscillation time interval. CONSTITUTION:For instance, one oscillator and a lot of receivers are installed at invervals of 10m to a streamer cable, and it is towed by a ship. Radio waves from ground stations R1, R2 are received by a main station R of the ship, and distances r1, r2 are derived and are sent out as a binary code signal. An operating circuit A operates position coordinates X, Y of the ship in accordance with position signals X1, Y1, X2 and Y2, height signals Z1, Z2 and the distance signals r1, r2 from a position coordinate signal generating circuit B of the ground stations R1, R2. Said coordinates are sent to a coordinate converting circuit C, and are converted to coordinats X', Y' based on a survey line by use of an output of an inclined angle (theta) signal generating circuit D. This operation is repeated at intervals of 0.5sec, an average ship speed V1 is derived by a moving distance operating circuit E and a ship speed operating circuit F, and the oscillation time is operated G so that an oscillation distance interval T becomes constant, and is oscillated from an oscillator (c).