US3089117A

US3089117A - Navigation system with electroacoustic leader cables

Info

Publication number: US3089117A
Application number: US7954A
Authority: US
Inventors: Batchelder Laurence
Original assignee: Individual
Current assignee: Individual
Priority date: 1960-02-10
Filing date: 1960-02-10
Publication date: 1963-05-07
Anticipated expiration: 1980-05-07

Description

7, 1963 1... BATCHELDER 3,089,117

NAVIGATION SYSTEM WITH ELECTROACOUSTIC LEADER CABLES Filed Feb. 10, 1960 INVENTOR. Jaw! ame fia/e/ar A/fforne/ United States Patent 3,089,117 NAVIGATION SYSTEM WITH ELECTROACOUSTIC LEADER CABLES Laurence Batchelder, Cambridge, Mass., assiguor, by

mesne assignments, to the United States of America as represented by the Secretary of the Navy Filed Feb. 10, 1960, Ser. No. 7,954 8 Claims. (Cl. 340-4) The present invention relates to a novel and improved ship navigation system and more particularly to novel and improved apparatus for facilitating navigation of a ship through a predetermined navigable area during a mine sweeping operation and for fixing the position of mine devices detected therewithin.

In a mine sweeping operation, it is ordinarily necessary to tow a sweep over a series of parallel courses. Each course must be accurately located and followed so that the swept paths overlap sufliciently to avoid the possibility of a hiatus therebetween. Adjacent swept paths, however, should not overlap so much as to destroy efliciency unduly. When a mine is detected, its exact position must oftentimes be recorded so that disposal can subsequently be effected.

Although various types of navigational aides for ship guidance during a mine sweeping operation or for guidance through a narrow channel havebeen devised heretofore, considerable ditficulty has been experienced in the past in providing a system which is relatively simple in construction and yet provides a high degree of navigational precision and accuracy.

Accordingly, it is a principal object of the present invention to provide a novel and improved guidance system for a ship whereby a defined course or channel may be accurately and precisely navigated.

It is a further object of the present invention to provide a novel and improved ship guidance system which is characterized by a pair of continuous conductors disposed along opposite sides of a predetermined channel whereby the position of the ship within the channel may be continuously and precisely defined.

A still further object of the present invention is to provide a novel and improved ship navigational system for use during a mine sweeping operation.

Still another object of the present invention is to provide novel and improved apparatus for detecting and recording the exact position of the mines in a predetermined area during a mine sweeping operation.

Another object of the present invention is to provide novel and improved channel guidance and/or mine sweeper navigational and detection equipment which is suitable for rapid installation aboard any vessel, which may be easily removed therefrom, and which continuously provides the navigator or pilot with the exact position of the vessel and/ or mines disposed within the channel.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing wherein:

FIG. 1 is a perspective view showing the manner in which the channel defining cables of the present invention are positioned along the bed of the channel annd energized by suitable sonic or ultrasonic energy sources.v

FIG. 2 is a geometric diagram which illustrates the manner in which the position of the ship within the channel may be computed. I

Referring first to FIG. 1 of the drawing, the width of the channel or general area 3 which is to be navigated or swept of mine devices or the like 4 is delineated by the continuous coaxial cables 5 and 6 which are anchored at the bottom of the channel in any suitable manner along opposite sides thereof. The length of the channel is preferably subdivided into a plurality of subsections. One such channel subsection is shown in the drawing at 7. Each subsection of the channel isdefined by the cross channel coaxial cables 8 and 9.

The central conductor of cable 5 iselectrically connected by means of conductor 10 in series With the secondary winding of transformer 11, the battery or other suitable source of direct current potential 12, and the external conductor of cable 6. The primary winding of transformer 11 is energized in any suitable manner such as by means of the conventional sonic or ultrasonic frequency generator source or the like 13. The central conductor of cable 6 is electrically connected by means of conductor 14 in series with the secondary winding of transformer 15, the battery or other suitable source of direct current potential 16, and the external conductor of cable 5. The primary winding of transformer 15 is energized in any suitable manner such as by means of the conventional sonic or ultrasonic frequency generator source or the like 17. The operating frequencies of the generator sources 13 and 17 are individually selected such that the signals generated thereby can easily be isolated in the ship carried hydrophone equipment 18 which detects the electrostrictively produced sound waves, and in the receiver or the like 18a which detects the electromagnetic waves and provides the zero time reference signals for the system.

The cables 8 and 9 which define the channel subsection 7 are similarly energized respectively by the sonic or ultrasonic frequency generator sources or the like 20 and 21. Thus, the central conductor of cable 8 is electrically connected by means of conductor 22 in series with the secondary winding of transformer 23, the DC. source 24, and the external conductor of cable 9. The primary winding of transformer 23 is energized by generator 20. The central conductor of cable 9 is electrically connected by means of conductor 25 in series with the secondary winding of transformer 26, the DC. source 27, and the external conductor of cable 8. The primary winding of transformer 26 is energized by means of generator 21. The operating frequencies of generators 20 and 21 are selected so that they can easily be isolated in the hydrophone equipment 18 and in the receiver 18a on the ship 19 one from another and also from the signals of generators 13 and 17.

In operation the manner in which the ship can be con tinuously located within the channel between cables 5 and 6 is geometrically illustrated in FIG. 2. As shown therein, the bed of the channel or other body of water to be navigated and/or demined is represented by the X-axis of the coordinate system. The cables on either side of the channel are located at f; and f the foci of the ellipse E. The position of the shipwithin the channel is shown at S. Using the Pythagorean theorem Inasmuch as c, the distance of one of the cables from the center of the channel, is a constant, x the position of the ship with respect to the center of the channel can easily be computed by developing D.C. voltages proportional to dB and d and applying these voltages difierentially to a suitable indicating or recording device.

Voltages proportional to d and d for the computation of d and d are developed from the time intervals required for the waves produced by the phenomenon of electrostriction in the cables to reach the ship-carried hydrophone.

Inasmuch as the details of the circuitry on the ship used to detect, square, and combine the signals from the cables differentially form no part of the present invention, and since many suitable conventional circuits are well known and available, the same are not provided herein for the sake of simplicity.

The apparatus herein described provides not only a convenient and reliable means for navigating the ship through the prearranged channel, but also provides a unique navigational aid for the accurate guidance of the ship in a mine sweeping operation when it is necessary to tow a sweep over a series of parallelcourses. Each course must be located such that the swept paths overlap sufiiciently to avoid the possibility of a hiatus therebetween, and at the same time not overlap so much as to be unduly inefficient. With the navigational aid of the present invention, the exact position of the ship can be continuously plotted so that the sweeping operation can be performed with accuracy and dispatch.

Where suitable mine disposal means are not carried on the ship 19, the exact position of the ship and the mine detecting equipment thereon must be recorded during the sweeping operation. and their associated circuits, which function in the same manner as the above described circuits of cables 5 and 6 provide the desired accurate record of the longitudinal position of the ship when a mine is detected. By thus plotting the exact position of each mine detected within the channel, the disposal operation can be carried out at any suitable later time.

Although the principle of electrostriction is employed to energize cables 5, 6, 8, and 9 and to transmit signals theerfrom, it is to be understood that similar circuitry employing the principle of magnetstriction or utilizing the similar piezoelectric effect could be used without departing from the spirit or scope of the present invention.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

The cross channel cables 8 and 9.

1. Apparatus for continuously indicating the position of a ship within a channel said apparatus comprising a pair of coaxial cables positioned on the bed of the channel, said cables being disposed along opposite longitudinal sides of the channel; a high frequency energy source for each cable; a first circuit which includes in series the central conductor of one cable, one high frequency source, and the peripheral conductor of the other cable; and a second circuit which includes in series the central conductor of the other cable, the other high frequency source, and the peripheral conductor of the one cable.

2. The apparatus of claim 1 wherein the material from which the coaxial cables are constructed exhibits electrostrictive properties.

3, The apparatus of claim 2 wherein means are provided for individually polarizing the said first and said second circuits.

4. The apparatus of claim 3 wherein the polarizing means include sources of direct current potential.

5. The apparatus of claim 1 further including a third and a fourth coaxial cable, said third and fourth coaxial cables being spaced one from the other and disposed across the width of the channel; third and fourth high frequency sources; a third circuit which includes in series the central conductor of the third cable, the third high frequency source and the peripheral conductor of the fourth cable; and a fourth circuit which includes in series the central conductor of the fourth cable, the fourth high frequency source, and the peripheral conductor of the third cable.

6. The apparatus of claim 5 wherein the material from which all the cables are constructed exhibits electrostrictive properties.

7. The apparatus of claim 6 wherein means are provided for individually polarizing the said circuits.

8. The apparatus of claim 7 wherein the polarizing means include sources of direct current potential.

References Cited in the file of this patent UNITED STATES PATENTS 1,388,949 Hanson Aug. 30, 1921 2,391,079 Van Dyck Dec. 18, 1945 2,956,278 Branchu Oct. 11, 1960

Claims

1. APPARATUS FOR CONTINUOUSLY INDCATING THE POSITION OF A SHIP WITHIN A CHANNEL SAID APPARATUS COMPRISING A PAIR OF COAXIAL CABLES POSITIONED ON THE BED OF THE CHANNEL, SAID CABLES BEING DISPOSED ALONG OPPOSITE LONGITUDINAL SIDES OF THE CHANNEL; A HIGH FREQUENCY ENERGY SOURCE FOR EACH CABLE; A FIRST CIRCUIT WHICH INCLUDES IN SERIES THE CENTRAL CONDUCTOR OF ONE CABLE, ONE HIGH FREQUENCY SOURCE, AND THE PERIPHERAL CONDUCTOR OF THE OTHER CABLE; AND A SECOND CIRCUIT WHICH INCLUDES IN SERIES THE CENTRAL CON-