US3866231A

US3866231A - Satellite transmitter of ULF electromagnetic waves

Info

Publication number: US3866231A
Application number: US285896A
Authority: US
Inventors: Francis J Kelly
Original assignee: US Department of Navy
Current assignee: US Department of Navy
Priority date: 1972-09-08
Filing date: 1972-09-08
Publication date: 1975-02-11
Anticipated expiration: 1992-02-11

Abstract

A natural gigantic loop antenna is created by the earth''s magnetosphere in combination with a satellite having long insulated conductors ending in a metallic plate. The satellite may be equipped with a transmitter and relay equipment capable of transmitting in the Extra Low and Ultra Low frequency range. These waves are transmitted efficiently by the huge antenna and may be received above, on, or penetrate below the surface of the earth. Such waves may be used to carry communications or for other purposes such as transmission between a satellite and a submarine.

Description

United States Patent [1 1 [111 3,866,231

Kelly Feb. 11, 1975 l l SATELLITE TRANSMITTER OF ULF ELECTROMAGNETIC WAVES [75] Inventor: Francis J. Kelly, Adelphi. Md.

[73] Assignee: The United States of America as represented by the Secretary of the Navy. Washington. DC.

[22 Filed: Sept. 8, 1972 [2]] Appl. No.: 285,896

[52] US. Cl 343/705, 343/DlG. 2, 343/908 [51] Int. Cl. H0lq U28 7 [58] Field of Search 343/DlG. 2, 100 ST, 705, 343/866, 701, 100 ET [561 References Cited UNITED STATES PATENTS 3.188.640 6/1965 Simon et al. 343/100 ST Primary ExaminerMaynard R. Wilbur Assistant Examiner-Richard E. Berger Attorney, Agent, or Firm-Arthur L. Branning; R. S. Sciascia [57] ABSTRACT A natural gigantic loop antenna is created by the earths magnetosphere in combination with a satellite having long insulated conductors ending in a metallic plate. The satellite may be equipped with a transmitter and relay equipment capable of transmitting in the Extra Low and Ultra Low frequency range. These waves are transmitted efficiently by the huge antenna and may be received above, on, or penetrate below the surface of the earth. Such waves may be used to carry communications or for other purposes such as transmission between a satellite and a submarine.

2 Claims, 2 Drawing Figures PATENTED FEB] 1 I975 "Fla,

FIG-2 SATELLITE TRANSMITTER OF ULF- ELECTROMAGNETIC WAVES BACKGROUND OF THE INVENTION Low frequency communication has always been difficult because of the physical size requirements of the antenna structure. The most successful method known to the prior art of generating ELF (below 300 Hz) and ULF (below Hz) waves has been the SANGUINE project, which essentially employs the earth as a radiator. Simply stated, a grounded transmission line is placed over a huge rock deposit. Since the rock deposit usually has a relatively low conductivity, the transmission line forms an effective loop antenna many kilometers deep. Although such loops have been constructed and operated, the disadvantages are many. For example, the system is highly inefficient. Also, it is expensive and requires a great deal of construction. Finally, the most serious disadvantage is the fact that the system is immoveable.

Considering such drawbacks, I have developed an ELF and ULF antenna-satellite system which employs the magnetosphere as a propagating element of a gigantic antenna.

SUMMARY OF THE INVENTION An ELF and ULF communication satellite is subjected to an orbit through the magnetosphere which is typically at least 400 kilometers from the surface of the earth. Two elongated conductors, each having a foil surface attached to the respective end are unreeled from the orbiting communications satellite. Although the length of the conductors are dependent upon a number of parameters, the length of the conductors extend to approximately 25 kilometers each, and usually project 180 disposed from each other.

A signal transmitted from the satellite by way of one conductor flows through the foil, down and along the magnetic field into the ionosphere and back along the magnetic field to the other wire so as to complete a huge loop antenna especially suited for low frequency communication.

OBJECTS DRAWINGS FIG. 1 is a view of the satellite system capable of transmitting ELF and ULF waves as it appears in orbit above the earth; and

FIG. 2 is a diagram of the satellite and the insulated wires and metallic surfaces depending therefrom.

DETAILED DESCRIPTION Referring to FIG. 1, and FIG. 2, there is illustrated a satellite displayed above the ionosphere, in space having the means required to practice this novel method.

Specifically, satellite 10 is in orbit around the earth 8. Depending from the satellite 10 are insulated wires 11 and 13, each approximately 25 kilometers long. The insulated conductors are terminated in large

metallic sheets

12 and 14 respectively.

For an explanation of the system, assume the satellite 10 is employed as a repeater or relay wherein a ground station, operating at microwave frequencies, desires to communicate with a submarine or the like which is below the surface of the ocean. A microwave signal is transmitted from the ground station in the typical well known manner-and received by the satellite.

The satellite converts the microwave energy into a signal having a lower frequency so that the electromagnetic wave may more easily penetrate the water and reach the submarine. Since this type of penetrating energy is usually in the ELF and ULF range, a very large antenna is required to propagate the signal.

The purpose of this invention is to set forth a method which provides an antenna capable of propagating such waves. The ELF wave, for example, goes through wire 11 to plate 14, travels down the natural magnetic line 16 into the lower ionosphere, across the E-layer and follows magnetic line 20 back to plate 12 at the end of insulated wire 13 and returns to satellite 10. This current flow may be explained by the principle that the electrical conductivity in the direction of the naturally occurring magnetic field is very great while the conductivity across the field (i.e. transverse) is much less in a collisionless plasma. Also, the conductivity in the lower ionosphere across the magnetic field is appreciable because collisions with neutral atoms are so frequent as to disrupt the cyclotron motion of the charged particles about the magnetic force lines. This is the restrictive force which keeps the electron movement parallel to the magnetic force lines in the magnetosphere.

This system provides a large current loop which is able to radiate the long ELF and ULF waves very efficiently. In addition, the field immediately below the area 18 where the current turns back toward the satellite, denoted as 22 in FIG. 1, may also be used for communication at that location. That is to say the current in this area is closest to the surface of the earth. Furthermore, the loop as shown in FIG. 1 contains a segment of the ionosphere which is able to trap and support ULF waves in what appears to be a natural waveguide.

Referring to FIG. 2 the satellite 10 may contain a multitude of peripheral equipment including telemetry, radio, and command equipment. The satellite 10 must contain the means to unwind insulated wires 11 and 13. For example, such means are adequately described in US. Pat. No. 3,582,020 issued to Edwin Wrench.

Although the above description has been primarily directed to a satellite having elongated wires and foil plates depending therefrom, it should be noted that a number of alternatives should also be considered. For example, the system could be transported on a one-way or round-trip mission through the magnetosphere. Also, multiple satellites may be used in series or parallel to increase or decrease the loops area or current. Furthermore, in many areas of the magnetosphere very strong fields and currents exist. It may be possible in these areas to generate useful signals by simply making and breaking a connection between the wires in the satellite, thus short-circuiting the natural currents. This would tend to modulate the current flowing in the ionosphere and the radiation from the natural current orbiting asatellite loops. extending long insulated conductors with exposed Finally, although the

foil plates

12 and 14 have been ends h f described as sheets, it should be understood that li an ELF or ULF signal through said long screens, balloons or any other device which will maice conductors to the earths magnetic field; contact with the surrounding magnetosphere 1s suitwhereby the Signal flows through one conductor able down along the earths magnetic field into the iono- Obviously many modifications and variations of the h d b k l h f 1d f the above sp ere an ac aong t e magnetic ie to anpresem mvenuon are possible m light 0 other conductor of said satellite so as to complete 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 and desired to be secured by Letters 5 Patent of th U it d St t i improving the transmission by attaching conductive l. A method of creating a gigantic loop antenna in 15 foil to the exposed ends of said conductors. the earths magnetosphere comprising:

the gigantic loop antenna. 2. The method as claimed in claim 1 further includ'

Claims

1. A method of creating a gigantic loop antenna in the earth''s magnetosphere comprising: orbiting a satellite extending long insulated conductors with exposed ends therefrom; coupling an ELF or ULF signal through said long conductors to the earth''s magnetic field; whereby the signal flows through one conductor down along the earth''s magnetic field into the ionosphere and back along the magnetic field to another conductor of said satellite so as to complete the gigantic loop antenna.

2. The method as claimed in claim 1 further including: improving the transmission by attaching conductive foil to the exposed ends of said conductors.