Bistatic system and method for ocean bottom mapping and surveying
First Claim
1. A system for mapping the ocean bottom through the transmission and reception of underwater sonic pulses which comprises two ships, traveling some distance apart, wherein each of said ships is equipped with means for transmitting sonic pulses to be scattered off the ocean floor in such a direction so that portions of said scattered pulses will be intercepted by its companion ship, means on each ship for receiving said sonic pulses and determining the angles of arrival of said intercepted pulses, means on each ship for determining the time of transmission and the time of reception of said sonic pulses, positioning means on each ship for determining its global location, the system having a relative positioning means for determining the relative position of said ships with respect to each other, communication means on each ship for transmitting and receiving data from its companion ship, the system having means for recording, processing and analyzing said intercepted pulses to determine the depth of the ocean bottom at the locations of the pulse reflections, and the system having a means for recording said analyzed data;
0 Assignments
0 Petitions
Accused Products
Abstract
A bistatic system and method is disclosed for mapping a large swath of the ocean bottom on a single sweep using two survey ships traveling approximately side-by-side some distance apart on parallel courses. Each ship transmits a fan shaped sonic pulse or ping symmetrically downward about the vertical and transverse to the ship'"'"'s longitudinal axis and processes the backscattered echo for depth. The forward scattered portion of this pulse or a second sonic pulse transmitted downward at an angle between the ships toward the other ship is received by the other ship and is analyzed to determine ocean bottom depths of the swath between the ships. The analyzed width of an insonified swath portion is sufficiently wide so as to overlap, at an edge, with an edge of each adjacent insonified swath portion analyzed. This partial redundancy provides a means for continuous calibration by comparing depth determinations for consistency and accuracy. Precise global navigational fixes and relative intership positional fixes are to be provided by the satellite Global Positioning System (GPS) as well as other navigational systems.
52 Citations
17 Claims
- 1. A system for mapping the ocean bottom through the transmission and reception of underwater sonic pulses which comprises two ships, traveling some distance apart, wherein each of said ships is equipped with means for transmitting sonic pulses to be scattered off the ocean floor in such a direction so that portions of said scattered pulses will be intercepted by its companion ship, means on each ship for receiving said sonic pulses and determining the angles of arrival of said intercepted pulses, means on each ship for determining the time of transmission and the time of reception of said sonic pulses, positioning means on each ship for determining its global location, the system having a relative positioning means for determining the relative position of said ships with respect to each other, communication means on each ship for transmitting and receiving data from its companion ship, the system having means for recording, processing and analyzing said intercepted pulses to determine the depth of the ocean bottom at the locations of the pulse reflections, and the system having a means for recording said analyzed data;
- 8. A method for mapping the ocean bottom comprising the steps of having two sonar survey ships, each equipped with means for transmitting and intercepting underwater sonic pulses off the ocean floor, travel some distance apart along approximately parallel course, having each of said ships transmit, at specified time intervals, sonic pulses to be scattered off the ocean floor in such a direction that portions of said scattered pulses are intercepted by its companion ship, having said ships kept to courses sufficiently close to each other to be able to intercept portions of said scattered sonic pulses, providing each of said ships with a data transmission and reception communication system, providing positioning data to said ships allowing each of said ships to determine its global location and its relative position with respect to its companion ship, providing each of said ships with the times of transmission of said pulses, having each of said ships determine the times it intercepts portions of said pulses, having each of said ships determine the angles of arrival of portions of said scattered sonic pulses it intercepts, having at least one of said ships record the angles of arrival, position and time data of the received portions of said pulses, having at least one of said ships process and analyze the intercepted pulses to determine the depths of the ocean at the locations of the pulse reflections, and having at least one of said ships record this analyzed data.
Specification