AU2019416157A1

AU2019416157A1 - Electromagnetic exploration system based on airship with adjustable depth of investigation

Info

Publication number: AU2019416157A1
Application number: AU2019416157A
Authority: AU
Inventors: Seong Jun Cho
Original assignee: Korea Institute of Geoscience and Mineral Resources KIGAM
Current assignee: Korea Institute of Geoscience and Mineral Resources KIGAM
Priority date: 2018-12-28
Filing date: 2019-11-07
Publication date: 2021-07-29
Anticipated expiration: 2039-11-07
Also published as: AU2019416157B2; WO2020138703A1; KR101993364B1

Abstract

The present invention relates to an electromagnetic exploration system based on an airship with adjustable depth of investigation, in which a transmission coil (transmitter loop) and a reception coil (receiver loop) are arranged in two individual airships for flight, respectively, to enable deep depth of investigation even though the investigation is aerial exploration far from the ground, and the separation distance between the two airships in flight is differently adjusted for each measurement and a flight separation distance set for each measurement can be stably maintained during flight for the corresponding measurement, so that underground exploration data with various depths according to the geography of an exploration area can be obtained. The system comprises: a leading airship which includes a transmitter loop installed therein and flies along a configured flight route while forming a primary magnetic field; a following airship which includes a receiver loop installed therein and flies along a configured flight route while being spaced a configured separation distance apart from the leading airship, to detect a secondary magnetic field; and a measurement control device for analyzing a measurement value of the secondary magnetic field detected from the receiver loop of the following airship, to perform aerial electromagnetic exploration.

Description

[DESCRIPTION]

[Invention Title]

ELECTROMAGNETIC EXPLORATION SYSTEM BASED ON AIRSHIP WITH ADJUSTABLE DEPTH OF INVESTIGATION

[Technical Field]

[1] The present invention relates to an electromagnetic

exploration system based on an airship, which can adjust the

depth of investigation, and more particularly, to an

electromagnetic exploration system based on an airship, which

can adjust the depth of investigation, wherein as two

individual airships having a transmitter coil and a receiver

coil disposed therein, respectively, fly, a deep depth of

investigation can be explored even though the investigation is

an aerial exploration far from the ground and underground

exploration data including various depths according to

geographical features of an exploration area can be obtained

because a flight distance between two airships is differently

adjusted for each measurement count and a flight distance set

in a corresponding measurement is stably maintained while

?0 flying.

[2]

[Background Art]

[3] An electromagnetic exploration is an exploration method

of discovering an underground conductor or luminous body by

?5 measuring, using a receiver coil, a primary magnetic field generated in a secondary current induced when the primary magnetic field generated by an alternating current flowing into a transmitter coil cuts an underground conductor.

[4] Among various electromagnetic exploration methods, a

small loop electromagnetic exploration (EM, loop-loop EM)

method is an electromagnetic exploration method of

investigating an underground structure by receiving, through a

receiver coil, a response from the underground attributable to

an AC magnetic field transmitted by a transmitter coil.

Measurement may be performed in a coil separation type in

which the transmitter coil and the receiver coil are separated

as in (a) of FIG. 1 and a coil integrated type in which the

transmitter coil and the receiver coil are integrated as in (b)

of FIG. 1. Measurement can be performed conveniently and

rapidly while moving along a target area. In general, a method

of increasing the depth of investigation in the EM method is

so-called geometric sounding for performing an exploration by

increasing an isolated distance between the transmitter coil

and the receiver coil.

?0 [5] Such an EM method has an advantage in that an underground

exploration can be easily performed at a low cost because a

person performs measurement while moving with the coil, but is

not so suitable for performing a wide underground exploration.

[6] Accordingly, the applicant of the present invention

?5 proposed an airship-based electromagnetic exploration apparatus (Korean Patent Application No. 2014-0025679), which can easily perform an electromagnetic exploration on a wide area by performing an aerial exploration by using a flying object in which a transmitter coil and a receiver coil are installed. The airship-based electromagnetic exploration apparatus has an advantage in that the depth of investigation can be improved by increasing the size of magnetic moment represented as transmission intensity because a cross section of the transmitter coil can be increased by installing the transmitter coil along the circumference of an airship envelope.

[7] Nevertheless, the conventional airship-based

electromagnetic exploration apparatus has a fundamental limit

in performing an underground exploration at a deeper depth by

further increasing the depth of investigation because the

electromagnetic exploration apparatus has a structure in which

both the transmitter coil and the receiver coil are disposed

in a single airship. A physical supplement, such as lowering a

flight altitude in order to increase the depth of

?0 investigation, may be performed. However, it is difficult to

expect a fundamental solution to the problem with the limited

depth of investigation through a temporary remedy for simply

lowering the flight altitude in a site having various

geographical features and environment variables.

?5 [8]

[Disclosure]

[Technical Problem]

[9] The present invention has been made to solve the above

problems, and an object of the present invention is to provide

an electromagnetic exploration system based on an airship,

which can adjust the depth of investigation, wherein as two

individual airships having a transmitter coil and a receiver

coil disposed therein, respectively, fly, a deep depth of

investigation can be explored even though the investigation is

an aerial exploration far from the ground and underground

exploration data including various depths according to

geographical features of an exploration area can be obtained

because a flight distance between two airships is differently

adjusted for each measurement count and a flight distance set

in a corresponding measurement is stably maintained while

flying.

[1 0]

[Technical Solution]

[1 1] According to the present invention, there is provided an

?0 airship-based electromagnetic exploration system, including a

leading airship in which a transmitter coil is installed and

which forms a primary magnetic field and flies along a set

flight route, a following airship in which a receiver coil is

installed and which detects a secondary magnetic field, is

?5 isolated from the leading airship at a set distance, and flies along a set flight route, and a measurement control apparatus which performs an aerial electromagnetic exploration by analyzing a measured value of the secondary magnetic field detected by the receiver coil of the following airship.

[1 2] Preferably, the transmitter coil is installed along the

circumference of an envelope of the leading airship, and has

two coils disposed as a horizontal coplanar array and a

vertical coplanar array, respectively.

[1 3] Preferably, the receiver coil is installed along the

circumference of an envelope of the following airship, and has

two coils disposed as a horizontal coplanar array and a

vertical coplanar array, respectively.

[1 4] Preferably, the leading airship includes a magnetic field

generation unit which generates the primary magnetic field by

applying an alternating current to the transmitter coil, a

flight route management unit which manages flight route

information for an electromagnetic exploration of the leading

airship, and a propulsion device which enables the leading

airship to fly along the flight route. A flight control unit

?0 extracts a flight route necessary for a flight from the flight

route management unit, enables the leading airship to fly

based on location information and time information of GPSs,

transmits information on a current location of the leading

airship to the measurement control apparatus, and adjusts a

?5 propulsion force of the propulsion device based on a speed correction value received as corresponding results.

[1 5] Preferably, the location information of the GPSs is

generated through a GPS device, and the GPS device provides

reference time information necessary to generate the primary

magnetic field.

[1 6] Preferably, the flight route management unit manages

flight route information and stopover time information for

each stopover, for an electromagnetic exploration of the

leading airship.

[1 7] Preferably, the following airship includes a magnetic

field detection unit which detects the secondary magnetic

field from the receiver coil, a flight route management unit

which manages flight route information for an electromagnetic

exploration of the following airship, and a propulsion device

which enables the following airship to fly along the flight

route. A flight control unit extracts a flight route necessary

for a flight from the flight route management unit, enables

the following airship to fly at a given flight distance from

the leading airship based on location information and time

?0 information of GPSs, transmits information on a current

location of the following airship to the measurement control

apparatus, and adjusts a propulsion force of the propulsion

device based on a speed correction value received as

corresponding results.

?5 [1 8] Preferably, the location information of the GPSs is generated through a GPS device, and the GPS device provides reference time information necessary to detect the secondary magnetic field.

[1 9] Preferably, the flight route management unit manages

flight route information and stopover time information for

each stopover for an electromagnetic exploration of the

following airship, and enables the following airship to fly at

a given flight distance from the leading airship by adjusting

the stopover time information for each stopover.

[2 0] Preferably, the measurement control apparatus includes an

analysis unit which analyzes the secondary magnetic field

received from the following airship, a storage unit which

stores analysis results of the analysis unit, a distance

monitoring unit which monitors a flight distance between the

two airships by analyzing current location information

received from the leading airship and the following airship,

and a distance correction unit which calculates a speed

correction value for a distance correction when the monitored

flight distance is different from a set flight distance as a

?0 result of the monitoring of the distance monitoring unit. The

measurement control unit transmits the speed correction value

to the leading airship and the following airship in real time.

[21]

[Advantageous Effects]

[2 2] According to the present invention, there is an effect in

that as two individual airships having the transmitter coil

and the receiver coil disposed therein, respectively, fly, a

deep depth of investigation can be explored even though the

investigation is an aerial exploration far from the ground.

[2 3] Furthermore, there is an effect in that underground

exploration data including various depths according to

geographical features of an exploration area can be obtained

because a flight distance between the two airships is

differently adjusted for each measurement count and a flight

distance set in a corresponding measurement is stably

maintained while flying.

[2 4]

[Description of Drawings]

[2 5] FIG. 1 is a diagram for describing an EM method according

to a conventional technology.

[2 6] FIG. 2 is a diagram for describing an airship-based

electromagnetic exploration system according to an embodiment

of the present invention.

?0 [2 7] FIG. 3 is a diagram for describing a method of disposing

coils in the airship-based electromagnetic exploration system

according to an embodiment of the present invention.

[2 8] FIG. 4 a diagram for describing a leading airship of the

airship-based electromagnetic exploration system according to

an embodiment of the present invention.

[2 9] FIG. 5 is a diagram for describing a following airship of

the airship-based electromagnetic exploration system according

to an embodiment of the present invention.

[3 0] FIG. 6 is a diagram for describing a measurement control

apparatus of the airship-based electromagnetic exploration

system according to an embodiment of the present invention.

[3 1]

[Best Mode for Invention]

[3 2] Hereinafter, embodiments of the present invention are

described in detail with reference to the accompanying

drawings. First, it is to be noted that the same components or

parts in the drawings denote the same reference numerals as

much as possible. In describing the present invention, a

detailed description of a related known function or

configuration will be omitted in order not to make the gist of

the present invention unnecessarily vague.

[3 3] FIG. 2 is a diagram for describing an airship-based

electromagnetic exploration system according to an embodiment

of the present invention.

?0 [3 4] Referring to FIG. 2, the electromagnetic exploration

system according to an embodiment of the present invention may

be configured to include a leading airship 100 in which a

transmitter coil 110 is installed and which forms a primary

magnetic field and flies along a set flight route, a following

?5 airship 200 in which a receiver coil 210 is installed and which detects a secondary magnetic field, and is isolated from the leading airship 100 at a set distance, and flies along a set flight route, and a measurement control apparatus 300 which performs an aerial electromagnetic exploration by analyzing a measured value of a secondary magnetic field detected by the receiver coil 210 of the following airship 200.

[3 5] In this case, each of the leading airship 100 and the

following airship 200 has a structure in which the airship is

buoyed using gas having specific gravity smaller than that of

the air is contained in a pouch thereof. In the present

invention, each of the leading airship 100 and the following

airship 200 may be a manned airship in which a person is

boarded and directly manipulates the airship or a remote

control unmanned airship controlled by a remote control a (R/C)

apparatus on the ground without a person boarded on the

airship. Preferably, each of the leading airship 100 and the

following airship 200 may have a form of an unmanned airship

in which flight information, such as a flight route or a

flight speed, is set and which flies along a predetermined

?0 route based on the set flight information.

[3 6] The leading airship 100 and the following airship 200

have envelopes 100a and 200a, respectively, which have great

volumes and in which gas (e.g., helium or hydrogen) having

buoyancy is filled, and have structures in which gondolas 100c

?5 and 200c are attached under the envelopes, respectively. In the case of a manned airship, the gondola 100c, 200c is equipped with a cockpit and a boarding room. In the case of an unmanned airship, the gondola includes a propulsion device 150 including a direction control device, a communication unit 122 for receiving a radio wave emitted by the measurement control apparatus 300 on the ground. Detailed configurations of the leading airship 100 and the following airship 200 will be described later more specifically.

[3 7] Each of the leading airship 100 and the following airship

200 will fly in an exploration area while maintaining a

constant altitude and speed. The two airships will maintain a

constant distance while flying.

[3 8] In this case, in general, the envelope 100a, 200a has a

streamlined shape having low air resistance, and may be

divided into a nonrigid type and a rigid type depending on a

configuration. The nonrigid type consists of only a pyramid

shaped pouch not having a frame. The rigid type means that the

envelope is assembled with a light metal frame and an outside

plate and separate many gas pouches or containers are

?0 installed within the envelope. In the case of the rigid type,

the propulsion device, etc. may be directly mounted on the

envelope. Furthermore, in the case of the nonrigid type,

although not illustrated, the inside of the envelope may be

partitioned into multiple air pouches, and each partitioned

?5 air pouch may be filled with a ballooning gas.

[3 9] The leading airship 100 and the following airship 200

have excellent cruising power compared to an aircraft, such as

a fixed-wing aircraft or a rotary-wing aircraft, and are

practical in electromagnetic exploration because the airship

can be operated at a relatively cheaper price than the

aircraft.

[4 0] The envelope 100a, 200a is generally formed to have a

streamlined shape back and forth, and reduces drag.

Manipulation wheels 100b and 200b for adjusting flight

directions may be coupled to the backs of the envelopes 100a

and 200a, respectively. In this case, a vertical stabilization

plate and a horizontal stabilization plate are coupled to each

of the up, down, left and right sides of the manipulation

wheel 100b, 200b, and may have a cross shape. In addition to

the cross shape, the vertical stabilization plate and the

horizontal stabilization plate may have various shapes that

are widely used, such as a "Y" shape.

[4 1] As described above, in the present invention, there is an

advantage in that expenses necessary for exploration are very

?0 low compared to conventional technology composed of an

expensive fixed-wing aircraft or rotary-wing aircraft because

the airship is used in electromagnetic exploration.

Furthermore, a safe aerial exploration can be performed due to

a low degree of danger upon crash.

?5 [4 2]

[4 3] Meanwhile, the transmitter coil 110 and the receiver coil

210 for an electromagnetic exploration are installed in the

envelopes 100a and 200a of the leading airship 100 and the

following airship 200, respectively.

[4 4] In the electromagnetic exploration apparatus according to

an embodiment of the present invention, the transmitter coil

110 is installed along the circumference of the envelope 100a

of the leading airship 100, thus forming a primary magnetic

field. The receiver coil 210 is installed along the

circumference of the envelope 200a of the following airship

200, thus detecting a secondary magnetic field derived by the

primary magnetic field.

[4 5] Each of the transmitter coil 110 and the receiver coil

210 may be installed in a way to be attached to the inside and

outside of the outer cover of each of the envelopes 100a and

200a. In this case, "attachment" may be used as a meaning,

including that the transmitter coil 110 and the receiver coil

210 are firmly mounted on the envelopes 100a and 200a,

respectively, while each having a function of transmitting and

?0 receiving electromagnetic waves. For example, the transmitter

coil 110 and the receiver coil 210 may be attached to the

envelopes 100a and 200a by adhesives, a staple, sewing,

welding, etc.

[4 6] As described above, the present invention can improve the

?5 reliability of measured results because the structure in which the transmitter coil 110 and the receiver coil 210 are directly attached to the envelopes 100a and 200a, respectively, minimize signal interference attributable to metal that constitutes a flight gas or various types of electronic parts in a process of transmitting and receiving electromagnetic waves.

[4 7] Furthermore, since the transmitter coil 110 and the

receiver coil 210 are firmly attached to the envelopes 100a

and 200a, the geometry, a relative location, a tilt angle, etc.

of each of the transmitter coil 110 and the receiver coil 210

can be accurately known upon analysis. Accordingly, data can

be accurately analyzed when the data is analyzed.

[4 8] FIG. 3 is a diagram for describing a method of disposing

coils in the airship-based electromagnetic exploration system

according to an embodiment of the present invention.

[4 9] A method of disposing the transmitter coil 110 and the

receiver coil 210 is called a coil array. A horizontal

coplanar (HCP) array ( (a) in FIG. 3) in which the two coils

are horizontally arranged in parallel, a vertical coplanar

?0 (VCP) array ((b) in FIG. 3) in which the two coils are

vertically arranged in parallel, and a vertical coaxial (VCA)

array ((c) in FIG. 3) are common. The horizontal coplanar

array is chiefly used.

[5 0] In a small loop electromagnetic exploration method to

?5 which the present invention is applied, the depth of investigation of an exploration is commonly 1/2 of the distance between coils. Furthermore, if the area of the transmitter coil 110 is widened, reception sensitivity is increased because the intensity of a transmission primary magnetic field is increased. Furthermore, the depth of investigation is also increased.

[5 1] According to such a principle, in the present invention,

the transmitter coil 110 and the receiver coil 210 are

installed in the two different airships, respectively. That is,

the transmitter coil 210 is installed in the leading airship

100, and forms a primary magnetic field. The receiver coil 210

is installed in the following airship 200, and detects a

secondary magnetic field derived by the primary magnetic field.

The depth of investigation is determined by a distance between

the two airships, more accurately, a distance D between the

transmitter coil 110 and the receiver coil 210 installed in

the two airships.

[5 2] In geographical features that require a deeper depth of

investigation, an exploration may be performed by increasing

?0 the distance D between the leading airship 100 and the

following airship 200. In geographical features that require

only a low depth of investigation, an exploration may be

performed by narrowing the distance D between the leading

airship 100 and the following airship 200. Accordingly, a deep

?5 depth of investigation can be explored despite an aerial exploration far from a surface of the earth. Furthermore, the depth of investigation may be changed by differently adjusting the flight distance between the two airships for each measurement count. Accordingly, underground exploration data including various depths for an exploration area can be obtained.

[5 3] In this case, two transmitter coils 110 playing a role as

a transmitter coil are configured, and may be mounted as a

horizontal coplanar array and a vertical coplanar array.

Furthermore, two receiver coils 210 playing a role as a

receiver coil are also mounted to have the same construction

as the transmitter coils 110. Measurements using the vertical

coplanar array and the horizontal coplanar array can be

performed at the same time because the two orthogonal

transmitter and receiver coils are mounted on each airship.

Measurement using the arrays for minimizing the influence of a

primary magnetic field will also be possible because

operations, such as horizontal coplanar array reception for

vertical coplanar array transmission and vertical coplanar

array reception for horizontal coplanar array transmission,

are possible. In the horizontal coplanar array, the coil may

be installed along the circumference of the envelope in a

horizontal axis direction. In the vertical coplanar array, the

coil may be installed along the circumference of the envelope

?5 in a vertical axis direction. In this case, in the drawing, the coil has been illustrated as being installed along the circumference in the horizontal axis direction or the circumference in the vertical axis direction in the middle portion of the envelope, but the present invention is not limited thereto. The coil may be installed along the circumference of another portion in the horizontal axis or vertical axis direction in addition to the middle portion of the envelope. Furthermore, for the envelope array form of the coil, reference may be made to the patent (Korean Patent

Application No. 2014-0025679) of this applicant.

[5 4]

[5 5] The leading airship 100, the following airship 200, and

the measurement control apparatus 300 are described in detail

below with reference to FIGS. 4 and 5.

[5 6] First, FIG. 4 a diagram for describing the leading

airship of the airship-based electromagnetic exploration

system according to an embodiment of the present invention.

[5 7] The leading airship 100 in which the transmitter coil 110

is disposed in the envelope 100a may be configured to include

a magnetic field generation unit 111 for generating a primary

magnetic field by applying an alternating current to the

transmitter coil 110, a GPS device 121 for receiving time

information for a flight and exploration from global

positioning systems, a communication unit 122 for exchanging

?5 data with the measurement control apparatus 300 on the ground, a flight route management unit 130 for managing flight route information for an electromagnetic exploration of the leading airship 100, a propulsion device 150 for enabling the leading airship 100 to fly along a flight route, and an inertia measurement device 160 for measuring a flight posture of the leading airship 100. The leading airship 100 may include a power unit 140 for supplying power necessary for each operation and a flight control unit 120 for controlling each of the components.

[5 8] The magnetic field generation unit 111 generates a

primary magnetic field by flowing an alternating current into

the transmitter coil 110. In this case, the size of the

primary magnetic field used as a transmission source is

proportional to the number of turns and area of the

transmitter coil 110. Accordingly, in order to enhance output

of the transmission source, the number of turns of the

transmitter coil 110 may be increased. A surface area of the

transmitter coil 110 can be naturally widened because the

transmitter coil 110 is horizontally installed along the

?0 circumference of the envelope 100a, which is filled with gas

having buoyancy and has a great volume.

[5 9] The GPS device 121 receives a signal including time

information from the global positioning systems, calculates a

current location of the leading airship 100, and provides the

?5 time information included in the current location.

[6 0] The communication unit 122 exchanges data with the

measurement control apparatus 300 on the ground. That is, the

communication unit 122 transmits, to the measurement control

apparatus 300 on the ground, information on the current

location of the leading airship 100 calculated by the GPS

device 121 and information on the flight posture of the

airship measured by the inertia measurement device 160.

Furthermore, the communication unit 122 receives a speed

correction value according to the current location from the

measurement control apparatus 300 on the ground.

[6 1] The flight route management unit 130 manages flight route

information and stopover time information for each stopover,

for an electromagnetic exploration of the leading airship 100.

Such a flight route may be set by incorporating geographical

features and characteristics of an area where an exploration

is performed. The leading airship 100 and the following

airship 200 will perform an exploration while flying along the

flight route. The stopover is included in the flight route,

and each transit time is previously designated in each of

?0 multiple stopovers included in the flight route. Accordingly,

the leading airship 100 will fly along a predetermined route

at a predetermined speed.

[6 2] The propulsion device 150 is installed in the gondola

100c, and provides a propulsion force to the main body of the

?5 airship. The propulsion device 150 will enable the leading airship 100 to automatically fly based on the flight route information and stopover time information for each stopover from the flight route management unit 130. The propulsion device 150 may consist of a propeller and an internal combustion engine for providing a rotary power to the propeller. In this case, the propulsion device 150 is preferably made of a non-magnetic material, such as aluminum or an FRP, in order to minimize magnetic interference upon electromagnetic exploration. Parts constituting the internal combustion engine, the propeller, etc. may be fabricated using a non-magnetic material. The propulsion device 150 can significantly reduce the generation of a magnetic field, compared to a method using an electric battery as a power source, using an internal combustion engine method of driving the airship by combusting gasoline, etc., but the present invention is not limited thereto. The power source may be an electric battery.

[6 3] The inertia measurement device 160 includes a gyro sensor

and an acceleration sensor, and outputs posture information of

?0 the leading airship 100. The leading airship 100 experiences a

pitch and a roll due to various factors while flying. As

described above, such a change in the posture of the airship

may distort a position relation between the coils of the

horizontal coplanar array and the vertical coplanar array

?5 mounted on the envelope of the airship. Accordingly, inertia measurement device 160 of the airship measures a flight posture of the leading airship 100 in real time.

[6 4] The flight control unit 120 controls the leading airship

100 to generate a primary magnetic field through the

transmitter coil 110 while the leading airship 100 flies along

a predetermined route. That is, the flight control unit 120

extracts a flight route necessary for a flight from the flight

route management unit 130, and enables the leading airship 100

to autonomously fly based on location information and time

information from the GPS device 121. Furthermore, the flight

control unit 120 may transmit information on a current

location of the leading airship 100 to the measurement control

apparatus 300 on the ground through the communication unit 122

while the leading airship 100 flies, may receive a speed

correction value from the measurement control apparatus 300 on

the ground, and may adjust a propulsion force of the

propulsion device 150.

[6 5]

[6 6] Next, FIG. 5 is a diagram for describing the following

?0 airship of the airship-based electromagnetic exploration

system according to an embodiment of the present invention.

[6 7] The following airship 200 in which the receiver coil 210

is disposed in the envelope 200a may be configured to include

a magnetic field detection unit 211 for detecting a secondary

?5 magnetic field from the receiver coil 210, a GPS device 221 for receiving time information for a flight and exploration from global positioning systems, a communication unit 222 for exchanging data with the measurement control apparatus 300 on the ground, a flight route management unit 230 for managing flight route information for an electromagnetic exploration of the following airship 200, a propulsion device 250 for enabling the following airship 200 to fly along a flight route, and an inertia measurement device 260 for measuring a flight posture of the following airship 200. The following airship

200 may include a power unit 240 for supplying power necessary

for an operation and a flight control unit 220 for controlling

each of the components.

[6 8] The magnetic field detection unit 211 detects a secondary

magnetic field in the receiver coil 210. The secondary

magnetic field is formed by an eddy current generated in the

underground in response to a primary magnetic field generated

by the transmitter coil 110 of the leading airship 100. The

receiver coil 210 and the magnetic field detection unit 211

detect the secondary magnetic field.

?0 [6 9] The GPS device 221 receives a signal, including time

information, from global positioning systems, calculates a

current location of the following airship 200, and provides

the time information included in the current location.

[7 0] The communication unit 222 exchanges data with the

?5 measurement control apparatus 300 on the ground. That is, the communication unit 222 transmits, to the measurement control apparatus 300 on the ground, information on the current location of the following airship 200 calculated by the GPS device 221 and information on a flight posture of the airship measured by the inertia measurement device 260. Furthermore, the communication unit 222 receives a speed correction value according to the current location from the measurement control apparatus 300 on the ground. Furthermore, the communication unit 222 transmits, to the measurement control apparatus 300 on the ground, a secondary magnetic field detected by the magnetic field detection unit 211.

[7 1] The flight route management unit 230 manages flight route

information and stopover time information for each stopover,

for an electromagnetic exploration of the following airship

200.

[7 2] In this case, the flight route of the following airship

200 is the same as the flight route of the leading airship 100.

However, the following airship 200 flies along the same route

as the leading airship 100 in the state in which the following

?0 airship 200 has been isolated from the leading airship 100 by

the flight distance D because stopover time information for

each stopover included in the flight route is more delayed

than stopover time information of the leading airship 100.

That is, the flight distance D may be produced by giving a

?5 time difference to a transit time for each stopover of the leading airship 100 and the following airship 200. The lengthy of the flight distance D may be adjusted by adjusting the time difference.

[7 3] As a result, the flight distance D is a distance between

the transmitter coil 110 and the receiver coil 210 disposed in

the two airships. The depth of investigation is determined by

the distance. In geographical features that require a deeper

depth of investigation, an exploration may be performed by

increasing the distance D between the leading airship 100 and

the following airship 200. In geographical features that

require only a low depth of investigation, an exploration may

be performed by narrowing the distance D between the leading

airship 100 and the following airship 200. Accordingly, a deep

depth of investigation can be explored despite an aerial

exploration far from a surface of the earth. Furthermore, the

depth of investigation may be changed by differently adjusting

the flight distance between the two airships for each

measurement count. Accordingly, underground exploration data

including various depths for an exploration area can be

?0 obtained.

[7 4] The propulsion device 250 is installed in the gondola

200c, and provides a propulsion force to the main body of the

airship. The propulsion device 250 will enable the following

airship 200 to automatically fly based on flight route

?5 information and stopover time information for each stopover from the flight route management unit 230.

[7 5] The inertia measurement device 260 includes a gyro sensor

and an acceleration sensor, and outputs information on a

posture of the following airship 200. The following airship

200 experiences a pitch and a roll due to various factors

while flying. As described above, such a change in the posture

of the airship distorts a position relation between the coils

of the horizontal coplanar array and the vertical coplanar

array mounted on the envelope of the airship. Accordingly, the

inertia measurement device 260 of the airship measures a

flight posture of the following airship 200 in real time, and

corrects a measured value based on the measured flight posture

upon processing of data.

[7 6] The flight control unit 220 controls the following

airship 200 to detect a secondary magnetic field through the

receiver coil 210, while fling along a predetermined route, in

the state in which the following airship 200 has been isolated

from the leading airship 100 by a given distance. That is, the

flight control unit 220 extracts a flight route necessary for

a flight from the flight route management unit 230, and

enables the following airship 200 to autonomously fly based on

location information and time information of the GPS device

221. Furthermore, the flight control unit 220 may transmit

information on a current location of the following airship 200

?5 to the measurement control apparatus 300 on the ground through the communication unit 222 while the following airship 200 flies, may receive a speed correction value from the measurement control apparatus 300 on the ground, and may adjust a propulsion force of the propulsion device 250.

Furthermore, the flight control unit 220 may transmit the

secondary magnetic field, detected by the magnetic field

detection unit 211 through the receiver coil 210, to the

measurement control apparatus 300 on the ground through the

communication unit 222 so that an exploration can be analyzed.

[7 7] In this case, the generation of the primary magnetic

field by the transmitter coil 110 of the leading airship 100

and the detection of the secondary magnetic field by the

receiver coil 210 of the following airship 200 may be

accurately synchronized using, as a triggering signal, time

data provided by the GPS devices 121 and 221.

[7 8]

[7 9] Next, FIG. 6 is a diagram for describing the measurement

control apparatus of the airship-based electromagnetic

exploration system according to an embodiment of the present

?0 invention.

[8 0] The measurement control apparatus 300 operating on the

ground may be configured to include a communication unit 320

for exchanging data with the leading airship 100 and the

following airship 200, an analysis unit 330 for analyzing a

?5 secondary magnetic field of the following airship 200 received through the communication unit 320, a storage unit 340 for storing the analysis results of the analysis unit 330, a distance monitoring unit 350 for monitoring a flight distance between the two airships by analyzing information on current locations of the leading airship 100 and the following airship

200 received through the communication unit 320, and a

distance correction unit 360 for calculating a speed

correction value for a distance correction when the monitored

flight distance is different from a set flight distance as a

result of the monitoring of the distance monitoring unit 350.

The measurement control apparatus 300 may include a

measurement control unit 310 for controlling each of the

components.

[8 1] The communication unit 320 exchanges data with the

leading airship 100 and the following airship 200. More

specifically, the communication unit 320 receives information

on a current location and flight posture of the leading

airship 100 from the leading airship 100, and transmits a

speed correction value according to the current location, if

necessary. Furthermore, the communication unit 320 receives

information on a current location and flight posture of the

following airship 200 and a measured secondary magnetic field

from the following airship 200, and transmits a speed

correction value according to the current location, if

necessary.

[8 2] Accordingly, the two airships can constantly fly along

the same route in the state in which the two airships have

been isolated from each other by the flight distance D because

the distance between the two airships is controlled in real

time while the two airships fly.

[8 3] The distance monitoring unit 350 calculates a flight

distance between the two airships by analyzing information on

current locations of the leading airship 100 and the following

airship 200 received through the communication unit 320, and

recognizes whether the calculated flight distance is smaller

than or greater than a set flight distance D.

[8 4] The distance correction unit 360 calculates a speed

correction value for adjusting a current flight distance to

the set flight distance D when the distance monitoring unit

350 detects the set flight distance or more. The speed

correction value may have a form in which the speed of the

airship is raised or lowered, and may also include a period in

which the speed is raised or lowered. Furthermore, such a

speed correction value is preferably transmitted to the

?0 following airship 200, but may be transmitted to the leading

airship 100 or may be transmitted to the two airships.

[8 5] In the aforementioned description and drawings, the

measurement control apparatus 300 has been described and

illustrated as being installed and operated on the ground, but

?5 the measurement control apparatus 300 may be installed and operated in the leading airship 100 or the following airship

200.

[8 6]

[8 7] In an electromagnetic exploration, the leading airship

100 and the following airship 200 fly along a predetermined

route at a constant distance. Furthermore, in order to change

the depth of investigation, the flight distance D is changed

and measured several times in the same measurement line. For

example, this is a method of measuring the flight distance D

by setting the flight distance to 20 m in the first flight and

then measuring the flight distance D by increasing the flight

distance D to 40 m, 60 m, 80 m, and 100 m in the same

measurement line. Accordingly, underground exploration data

including various depths for the same exploration area can be

obtained.

[8 8] Furthermore, if the depth of investigation needs to be

changed depending on geographical features during one flight,

the measurement control apparatus 300 on the ground may set a

new flight distance D through the distance correction unit 360.

?0 A new distance correction value generated as corresponding

results may be transmitted to the leading airship 100 or the

following airship 200. Accordingly, the number of flights can

be minimized and an exploration result suitable for

geographical features can be obtained because measurement is

?5 performed at a different depth of investigation depending on an area and geographical features without performing measurement at a single depth of investigation in a one exploration flight.

[8 9]

[9 0] The best embodiments have been disclosed in the drawings

and specification. Specific terms have been used herein, but

the terms are used to only describe the present invention, but

are not used to limit the meaning of the terms or the scope of

the present invention written in the claims. Accordingly,

those skilled in the art will understand that various

modifications and other equivalent embodiments are possible

from the embodiments. Accordingly, the true technical range of

protection of the present invention should be determined by

the technical spirit of the following claims.

Claims

[CLAIMS]

[Claim 1]

An airship-based electromagnetic exploration system,

comprising:

a leading airship in which a transmitter coil is

installed and which forms a primary magnetic field and flies

along a set flight route;

a following airship in which a receiver coil is installed

and which detects a secondary magnetic field, is isolated from

the leading airship at a set distance, and flies along a set

flight route; and

a measurement control apparatus which performs an aerial

electromagnetic exploration by analyzing a measured value of

the secondary magnetic field detected by the receiver coil of

the following airship.
[Claim 21

The airship-based electromagnetic exploration system of

claim 1, wherein the transmitter coil is installed along a

circumference of an envelope of the leading airship, and has

?0 two coils disposed as a horizontal coplanar array and a

vertical coplanar array, respectively.
[Claim 31

The airship-based electromagnetic exploration system of

claim 1, wherein the receiver coil is installed along a

?5 circumference of an envelope of the following airship, and has two coils disposed as a horizontal coplanar array and a vertical coplanar array, respectively.
[Claim 4]

The airship-based electromagnetic exploration system of

claim 1, wherein the leading airship comprises:

a magnetic field generation unit which generates the

primary magnetic field by applying an alternating current to

the transmitter coil;

a flight route management unit which manages flight route

information for an electromagnetic exploration of the leading

airship; and

a propulsion device which enables the leading airship to

fly along the flight route,

wherein a flight control unit extracts a flight route

necessary for a flight from the flight route management unit,

enables the leading airship to fly based on location

information and time information of GPSs, transmits

information on a current location of the leading airship to

the measurement control apparatus, and adjusts a propulsion

?0 force of the propulsion device based on a speed correction

value received as corresponding results.
[Claim 5]

The airship-based electromagnetic exploration system of

claim 4, wherein:

the location information of the GPSs is generated through a GPS device, and the GPS device provides reference time information necessary to generate the primary magnetic field.
[Claim 6]

The airship-based electromagnetic exploration system of

claim 4, wherein the flight route management unit manages

flight route information and stopover time information for

each stopover, for an electromagnetic exploration of the

leading airship.
[Claim 7]

The airship-based electromagnetic exploration system of

claim 1, wherein the following airship comprises:

a magnetic field detection unit which detects the

secondary magnetic field from the receiver coil;

a flight route management unit which manages flight route

information for an electromagnetic exploration of the

following airship; and

a propulsion device which enables the following airship

to fly along the flight route,

wherein a flight control unit extracts a flight route

necessary for a flight from the flight route management unit,

enables the following airship to fly at a given flight

distance from the leading airship based on location

information and time information of GPSs, transmits

?5 information on a current location of the following airship to the measurement control apparatus, and adjusts a propulsion force of the propulsion device based on a speed correction value received as corresponding results.
[Claim 8]

The airship-based electromagnetic exploration system of

claim 7, wherein:

the location information of the GPSs is generated through

a GPS device, and

the GPS device provides reference time information

necessary to detect the secondary magnetic field.
[Claim 9]

The airship-based electromagnetic exploration system of

claim 7, wherein the flight route management unit manages

flight route information and stopover time information for

each stopover for an electromagnetic exploration of the

following airship, and enables the following airship to fly at

a given flight distance from the leading airship by adjusting

the stopover time information for each stopover.
[Claim 10]

The airship-based electromagnetic exploration system of

claim 1, wherein the measurement control apparatus comprises:

an analysis unit which analyzes the secondary magnetic

field received from the following airship;

a storage unit which stores analysis results of the

?5 analysis unit; a distance monitoring unit which monitors a flight distance between the two airships by analyzing current location information received from the leading airship and the following airship; and a distance correction unit which calculates a speed correction value for a distance correction when the monitored flight distance is different from a set flight distance as a result of the monitoring of the distance monitoring unit, wherein the measurement control unit transmits the speed correction value to the leading airship and the following airship in real time.

[FIGURE TRANSLATION]

FIG. 1

FIG. 2

FIG. 3

FIG. 4

FIG. 5

FIG. 6