FI127192B - SYSTEM FOR MEASURING THE ELECTRICAL PROPERTIES OF UNDERGROUND MATERIALS - Google Patents

SYSTEM FOR MEASURING THE ELECTRICAL PROPERTIES OF UNDERGROUND MATERIALS Download PDF

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Publication number
FI127192B
FI127192B FI20165928A FI20165928A FI127192B FI 127192 B FI127192 B FI 127192B FI 20165928 A FI20165928 A FI 20165928A FI 20165928 A FI20165928 A FI 20165928A FI 127192 B FI127192 B FI 127192B
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Finland
Prior art keywords
transducer arrangement
arrangement
transducer
distance
data
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FI20165928A
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Finnish (fi)
Swedish (sv)
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FI20165928A (en
Inventor
Markku Pirttijärvi
Ari Saartenoja
Arto Karinen
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Radai Oy
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Priority to FI20165928A priority Critical patent/FI127192B/en
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Publication of FI20165928A publication Critical patent/FI20165928A/en
Publication of FI127192B publication Critical patent/FI127192B/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
    • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
    • G01V3/12—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with electromagnetic waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R29/00—Arrangements for measuring or indicating electric quantities not covered by groups G01R19/00 - G01R27/00
    • G01R29/08—Measuring electromagnetic field characteristics
    • G01R29/0864—Measuring electromagnetic field characteristics characterised by constructional or functional features
    • G01R29/0871—Complete apparatus or systems; circuits, e.g. receivers or amplifiers

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  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Remote Sensing (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Geology (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geophysics (AREA)
  • Traffic Control Systems (AREA)

Abstract

There is provided a system for measuring electrical properties of materials of subsurface, the system comprising: a first transducer arrangementThere is a system provided for measuring electrical properties of materials of subsurface, system comprising: a first transducer arrangement

Description

System For Measuring Electrical Properties of Materials Of
Subsurface
TECHNICAL FIELD
The invention relates to measuring the electrical properties of the materials of subsurface. For example, such materials may be below visible surface of the Earth. More particularly, the invention relates to use of electromagnetic fields to reveal electrical properties of said materials.
BACKGROUND
Using electromagnetic field to discover electrical properties of material below visible surfaces may be known from the field of metal detectors. Such systems seem to generate and detect electromagnetic fields, wherein said detected fields or changes in them may indicate electrical properties or changes in the electrical properties of measured material. However, known systems and devices seem to be quite inflexible for different use cases. Therefore, it may be beneficial to enhance systems and methods for detecting electrical properties of materials of subsurface.
BRIEF DESCRIPTION
According to an aspect, there is provided the subject matter of the independent claim. Some embodiments are defined in the dependent claims.
One or more examples of implementations are set forth in more detail in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.
BRIEF DESCRIPTION OF DRAWINGS
In the following embodiments will be described in greater detail with reference to the attached drawings, in which
Figure 1 illustrates a system according to an embodiment;
Figures 2A and 2B illustrate a first transducer arrangement according to some embodiments;
Figures 3A and 3B illustrate a second transducer arrangement according to some embodiments;
Figures 4A and 4B illustrate some embodiments;
Figure 5 illustrates an embodiment; and Figure 6 illustrates an embodiment.
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DETAILED DESCRIPTION OF SOME EMBODIMENTS
The following embodiments are exemplifying. Although the specification may refer to “an”, “one”, or “some” embodiment(s) in several locations of the text, this does not necessarily mean that each reference is made to the same embodiment's), or that a particular feature only applies to a single embodiment. Single features of different embodiments may also be combined to provide other embodiments.
Figure 1 shows a system according to an embodiment. The system may denote an electromagnetic (EM) measurement system. Particularly, the system may be referred to as an inductive controlled source EM measurement system. Where reference is made to a system in general in the following text, this should be understood as referring to the system of Figure 1 or similar system. Now referring to Figure 1, a system for measuring electrical properties of materials of subsurface is shown. Said properties may include at least electrical conductivity, but may additionally or alternatively include dielectric permittivity and/or magnetic susceptibility. The material of the subsurface may refer to materials that are under visible surface, such as, under visible surface of the Earth. Thus, for example, this may mean that the materials are in the soil and/or under water or in bedrock. For example, the system may be applicable for geological studies, such as mineral exploration (e.g. locating economically valuable mineralisations from the bedrock) and geological mapping and/or for investigating thickness of sediment and peat layers or groundwater reservoirs. These are just few examples for which the described system may be suitable for.
The system of Figure 1 comprises a first transducer arrangement 10 configured to generate a primary electromagnetic field 12. The system further comprises and a second transducer arrangement 20 configured to detect at least one directed component of the total electromagnetic fields, which comprise the primary electromagnetic field 12 and a secondary electromagnetic field 22 induced from the materials 100 of the subsurface due to the generated primary electromagnetic field 12. In some embodiments, however, the second transducer arrangement 20 is configured to determine the primary and/or secondary EM fields 12, 22. This may be based on post-processing at the second transducer arrangement 20. However, the post-processing may be performed at some other device and the second transducer arrangement 20 may simply store data about the detected EM field(s).
In Figure 1 surface 90 may be shown. The surface may refer to visible
20165928 prh 06 -09- 2017 surface of the Earth, for example. In some embodiments, the surface 90 comprise one or more manmade structures (e.g. buildings, roads, and the like). The system may also be applicable for measuring visible or partially visible materials.
Generally, any material may be measured, but the system may be particularly suitable for measuring materials 100 that are at least partially below the surface 90 (e.g. materials of the subsurface.
According to an embodiment, the first transducer arrangement 10 and the second transducer arrangement 20 are comprised in separate physical entities movable in relation to each other. We will discuss this in more detail below.
However, as one example, the transducer arrangements 10, 20 may be comprised in physical entities that are configured to be placed on the surface 90 (e.g. on ground).
In an embodiment, the system comprises means for storing data about the detected primary and secondary electromagnetic fields (or at least magnetic components of said fields). Thus, for example, the second transducer arrangement 20 may be coupled with a memory (e.g. a data logger, more details are discussed with reference to Figure 3B) which may store said data. For example, said data may comprise detections made on a certain sampling frequency (e.g. 1Hz, 10Hz or 100Hz to name a few examples). It needs to be noted that said data may not necessarily separate the primary field and the secondary field. For example, the separation may be performed in a post-analysis. Thus, the stored data may comprise information about the detected electromagnetic fields (or at least the magnetic components of said fields) at the second transducer arrangement 20.
Changes in the conductivity of the ground generate changes in the shape and intensity of the induced currents that in turn create changes in the measured and/or detected, by the second transducer arrangement 20, EM field components. In other words, the EM anomalies measured above the ground surface 90 may give indication on the conductivity anomalies inside the Earth. Such measurement data may be stored as already discussed above and further utilized if needed.
According to an embodiment, the system of Figure 1 further comprises measuring means for measuring at least one metric being indicative of a distance between the first transducer arrangement 10 and the second transducer arrangement 20. The measurement may be continuous. In some embodiments, said measurement is performed periodically or occasionally. For example, the measurement may happen once per second. In a continuous measurement, the interval may be shorter, for example, 10 times per second. In some cases, the
20165928 prh 06 -09- 2017 measurement may be active, meaning that, for example, the distance is determined during the measurement by an apparatus performing the measurement (e.g. the first transducer arrangement 10). In some cases, the measurement may be passive meaning that the measurement results may be stored in a memory, but, for example, the distance is determined in post-analysis.
According to an embodiment, the system of Figure 1 further comprises measuring means for measuring a metric being indicative of an orientation of the first transducer arrangement 10.
According to an embodiment, the system of Figure 1 further comprises measuring means for measuring a metric being indicative of an orientation of the second transducer arrangement 20. Orientation may mean orientation angle measured with respect to x, y, and z -axis, for example (see axis xyz in Figure 5). Orientation angle may alternatively indicate angle degrees around the x, y, and zaxis (e.g. roll, pitch, yaw or Euler-angles). The orientation may be measured using one or more accelerometers and inertial sensors, for example.
According to an embodiment, the system of Figure 1 further comprises measuring means for measuring a metric being indicative of an altitude of the first transducer arrangement 10.
According to an embodiment, the system of Figure 1 further comprises measuring means for measuring a metric being indicative of an altitude of the first transducer arrangement 20.
Figures 2A to 2B illustrate some embodiments. Referring to Figure 2A, the first transducer arrangement 10 may generate the primary electromagnetic field 12 (show in Figure 1). The first transducer arrangement 10 may be comprised an entity 200. The entity 200 may be, for example, referred to as an apparatus or device. In an embodiment, the entity 200 is referred to as a transmitter apparatus or transmitter device 200. In an embodiment, the system further comprises signal generation means 210, 220 coupled with the first transducer arrangement 10. The signal generation means 210, 220 may be comprised in the entity 200 or may be situated in a separate physical entity, but still coupled with the first transducer arrangement 10. The signal generation means 210, 220 may be configured to provide an input signal to the first transducer arrangement 10, wherein the first transducer arrangement 10 may be configured to generate the primary electromagnetic field 12 according to said input signal.
The signal generation means 210, 220 may comprise at least a signal generator 210 configured to generate the input signal to the first transducer
20165928 prh 06 -09- 2017 arrangement 10. The signal generation means 210, 220 may further comprise a power source 220, such as a battery or batteries (rechargeable or nonrechargeable), providing power to the signal generator 210.
Still referring to Figure 2A, the first transducer arrangement 10 may comprise at least one induction coil or loop 232. The coil 232 may comprise conductive wired material, such as insulated copper wire. The signal generator 210 may be electrically coupled (e.g. via wire) with the coil 232 so that the input signal may be inputted to the coil 232. In an embodiment, the input signal provided by the signal generation means 210, 220 is alternating current (AC) (i.e. AC signal).
That is, the input signal may vary as a function of time. One example of such input signal may be sinusoidal alternating current (i.e. I=l0cosmt, wherein I denotes the sinusoidal current, Io denotes current amplitude (in amperes), ω denotes angular frequency (i.e. ω = 2πί, wherein f denotes frequeny (in hertzes)) and t denotes time (in seconds)). In an embodiment, the input signal is thus a time-harmonic signal. Thus, the first transducer arrangement 10 may generate a time-harmonic primary electromagnetic field. The AC signal inputted to the coil 232 generates electromagnetic induction (electromotive force or e.m.f.) which further may generate secondary currents into the materials 100 (i.e. conductive materials).
In an embodiment, the first transducer arrangement 10 comprises an electromagnetic coil configured to generate the primary EM field 12.
In an embodiment, the power source 220 comprises one or more batteries. The batteries may be, for example, 12-24 Volt (V) batteries.
In an embodiment, the signal generator 210 is an EM signal generator (e.g. EM sine-wave signal generator).
In an embodiment, the coil 232 is wound N (e.g. N denotes a positive integral number, e.g. 1, 2, 3, 4,100) times around a loop frame 234 (not shown in Figure 2B, but may be present). The loop frame 234 may be rigid so as to keep the coil 232 in proper form. Referring to an embodiment of Figure 2B, a magnetic dipole moment of the coil 232 may be M, M=NIoA, where Io denotes is the amplitude of the current, N is the number of loops in the coil 232, and A (e.g. A = nr2) is the surface area of the loop. At least in some embodiments, the radius of the coil (r) is sufficiently small (e.g. 5-10 times smaller) compared to the distance (e.g. L) between the first transducer arrangement 10 (e.g. the transmitter) and the second transducer arrangement (e.g. the receiver), and thus the arrangement of Figures
2A and/or 2B may be approximated as a magnetic dipole.
In an embodiment, the first transducer arrangement 10 comprises an
20165928 prh 06 -09- 2017 electrically conductive loop. Thus, the coil 232 may not be necessary. The electrically conductive loop may be inputted with said input signal (e.g. sine-wave).
The electrically conductive loop may be electrically insulated, e.g. an electrically insulated metal wire. In another example, the first transducer arrangement 10 comprises an electrically conductive wire. For example, said conductive wire may be configured to be grounded to ground from both of its ends. Thus, the first transducer arrangement 10 may be achieved in many different ways, wherein the first transducer arrangement 10 is configured to receive input signal (e.g. sinusoidal current) and to transduce the received input signal into electromagnetic field (i.e. generate the primary electromagnetic field 12).
The apparatus 200 of Figure 2A may further comprise one or more orientation sensor(s) 240, one or more positioning sensor(s) 250 (sometimes referred to as location sensor(s)), one or more altitude sensor(s) 260, a control circuitry (CTRL) 270, one or more memories 280 (e.g. comprising a computer program code), and/or a communication circuitry (TRX) 290. In an embodiment, the CTRL 270 comprises at least one processor. The at least one memory 280 and the computer program code (i.e. comprised in the memory 280) (software), are configured, with the at least one processor, to cause the respective apparatus 200 to carry out any one of the embodiments or operations thereof. For example, the
CTRL 270 with the one or more memories 280 may be configured to control the apparatus 200. Thus, for example, the CTRL 270 may control the power input and/or the input signal generation by the signal generator 210. For example, the CTRL 270 may be configured to acquire control commands via the TRX 290 and/or via local user interface (e.g. comprised in the apparatus 200). The TRX may utilize, for example, cellular communication (e.g. 2G, 3G, 4G, 5G, Long Term Evolution (LTE), and/or LTE-Advanced (LTE-A)), Bluetooth communication, and/or some other radio frequency technique suitable for conveying user and/or control data over air-interface between two physically separated entities.
The memory 280 may be implemented using any suitable data storage technology, such as semiconductor based memory devices, flash memory, magnetic memory devices and systems, optical memory devices and systems, fixed memory and removable memory. The memory 280 may comprise a database for storing data. The TRX may provide the apparatus 200 with communication capabilities to access the radio access network, for example. The TRX may comprise standard well-known components such as an amplifier, filter, frequency-converter, (de)modulator, and encoder/decoder circuitries and one or more antennas. The
20165928 prh 06 -09- 2017 apparatus 200 may further comprise a user interface comprising, for example, at least one keypad, a microphone, a touch display, a display, a speaker, etc. The user interface may be used to control the apparatus 200 by a user of the apparatus 200.
For example, the user interface may enable distance control (e.g. utilizing the TRX
290) of the apparatus 200.
The one or more orientation sensors 240 may comprise, for example, one or more accelerometers and/or gyroscopes. The orientation sensor(s) 240 may perform measurements indicating the orientation of the first transducer arrangement 10. In particular, the orientation sensor(s) 240 may perform measurements indicating the orientation of the coil 232 such that the orientation of the coil 232 may be determined by the CTRL 270 and/or in post-analysis. The orientation may be measured with respect to the surface 90 (e.g. with respect to ground) and some fixed horizontal direction such as the direction of geographical north. The orientation may also be defined with respect to rotation angles (e.g. roll, pitch and yaw) around three orthogonal coordinate axes (e.g. north, east and up, or x, y, and z (see Fig. 5 for an example)).
The one or more positioning sensors 250 may comprise, for example, a satellite positioning circuitry (e.g. a Global Positioning System (GPS) and/or GLObal NAvigation Satellite System (GLONASS). The satellite positioning circuitry may be configured to perform measurements indicating position of the first transducer arrangement 10, or more particularly the coil 232. Inherently, the position of the apparatus 200 may be measured if the first transducer arrangement 10 is comprised in the apparatus 200. However, the interest may be the position of the first transducer arrangement 10. Further, the satellite positioning circuitry may be used to acquire current time (i.e. GPS or GLONASS may indicate time in the satellite signal). Thus, the positioning sensor(s) 250 may be used to measure time and/or position of the first transducer arrangement 10 (and also the apparatus 200).
In an embodiment, the satellite positioning circuitry may utilize Real
Time Kinematic (RTK) GPS. RTK-GPS may provide accurate location measurements. Accordingly, in an embodiment, the apparatus 200 and/or 300 comprises RTK-GPS. The RTK-GPS may measure location of the respective apparatus. Measured location may be stored into the memory 280, 380 of the respective apparatus. The RTK-GPS may require one or more fixed base stations.
Thus, the described system may comprise one or more base stations in communication with the RTK-GPS at the apparatus 200, 300.
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The one or more altitude sensors 260 may be configured to perform measurements indicating an altitude of the first transducer arrangement 10. The reference level may be the surface 90 (e.g. ground). Thus, the altitude may denote the altitude of the first transducer arrangement 10 with respect to the surface 90.
In another example, the altitude may denote altitude with respect to sea level. In post-analysis or by utilizing the CTRL 270, it may be possible to determine the distance between the surface 90 and the first transducer arrangement 10 utilizing the exact distance (e.g. laser measurement) or by knowing altitude of the surface 90 and of the first transducer arrangement 10 with respect to sea level. The altitude sensor(s) 260 may comprise laser measurement (e.g. laser distance) sensor(s) and/or barometer(s). Different measurements and/or comparisons may be performed to determine said altitude. Further, whether altitude is measured with respect to sea level or with respect to ground level may not be important if the altitude reference point is known. That is, the altitude data measured using the altitude sensor(s) 260, 360 may be used to determine altitude difference between the first and second transducer arrangements 10, 20.
It further needs to be noted that the measurements and/or results of the measurements performed by the entities 240, 250, and/or 260 may be stored in to the memory 280 (e.g. database). Thus, the data gathered may be utilized, for example, in a post-analysis. Thus, for example, altitude data, positioning data, time data, and/or orientation data maybe stored into the memory 280. The altitude data may denote altitude data of the first transducer arrangement 10. The positioning data may denote positioning data of the first transducer arrangement 10. The orientation data may denote orientation data of the first transducer arrangement
10. Said data may be gathered for a certain time period, e.g. for a measurement time period. Positioning or position data may sometimes be referred to as location data.
According to an embodiment, the apparatus 200 or the first transducer arrangement 10 may store data about the generated primary EM field 12 to the memory 280. The said data may include the intensity of the current (I) in the coil or loop 232 (Fig. 2A), for example. Alternatively, the intensity of the primary field may be measured directly by a reference coil attached in a fixed point in the first transducer arrangement 10. Thus, in post-analysis for example, characteristics (.e.g intensity) of the generated primary EM field 12 may be determined. This may be compared with the data about the measured EM fields (measured by the second transducer arrangement 20).
A further notice is made with respect to the altitude sensor(s) 260. Such
20165928 prh 06 -09- 2017 sensor(s) 260 may be particularly beneficial to be used in an aerial vehicle (AV).
Thus, for example, if the apparatus 200 is an Unmanned Aerial Vehicle (UAV), it may be beneficial to measure the altitude of the UAV 200.
Let us then consider the second transducer arrangement 20 in more detail with reference to embodiments of Figures 3A to 3B. The second transducer arrangement 20 may comprise one or more coils or loops of insulated metal wire. Preferably, coils are used where insulated metallic wire is wound around magnetically permeable (e.g. ferromagnetic) material. Thus, according to an embodiment, the second transducer arrangement 20 comprises at least one (e.g.
three) coil (maybe, for example, induction coils) 302,304,306. In case of a plurality of coils 302, 304, 306, the axes of the coils may be arranged orthogonally in relation to each other (e.g. three-component coil). This may be shown in Figure 3A. Using three orthogonal coils or loops in the second transducer arrangement 20 (i.e. the receiver) may enhance the detection of the total EM field (e.g. the sum of primary and secondary EM fields) by the second transducer arrangement 20. The voltage (e.m.f. in volts) induced in the coil is related to the time derivative of the magnetic flux density (dB/dt in teslas per second or volts per square-meter) according to Faraday’s law of induction, which may be simplified as e.m.f = -NA dB/dt, where N is the number of wire turns and A is the surface area of the coil or loop (in square20 meters). The induced voltage can then be used to determine the intensity of magnetic field, H= Β/μ, (in amperes per meter), where μ is the magnetic permeability (in volt-second per ampere-meter) of the material inside the coil. For an air-filled loop the magnetic permeability is equal to that of the free-space μ=μο= 4π107 Vs/(Am).
According to an embodiment, the second transducer arrangement 20 comprises at least one magnetometer. The magnetometer may be a scalar magnetometer measuring the total intensity of magnetic field, B, (in teslas or voltsecond per square-meter) or a vector magnetometer measuring directed components of the magnetic field (e.g. Bx, By, Bz). In some embodiments, the magnetometer(s) may be used instead of the coils 302, 304, 306 or loop(s). However, in some embodiment, the second transducer arrangement 20 may comprise magnetometer(s), coils and/or loops. The different detectors can be used simultaneously or non-simultaneously (e.g. CTRL 370 can be used to select which of the detectors are used at which time).
Now referring to Figure 3B, an entity 300 (e.g. an apparatus or a device) is shown. The apparatus 300 may comprise the second transducer arrangement 20.
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In an embodiment, the entity 300 is referred to as a receiver apparatus or receiver device 300. According to an embodiment, the second transducer arrangement 20 comprises at least one coil 302-306, wherein each coil 302-306 is coupled with a pre-amplifier 312-316. Thus, the electromagnetic component (e.g. magnetic components of the electromagnetic field) detected by the coil(s) 302-306 may be amplified and further the amplified signals may be inputted to a controller (CTRL) 370 of the apparatus 300.
The CTRL 370 may comprise at least one lock-in-amplifier (LIA). For example, if there are three coils 302-306, the CTR1 370 may comprise three LIAs.
An LIA may comprise, for example, a low-pass filter, dual-phase detection, and an amplifier. Thus, the detected magnetic components may be processed (e.g. analog processing) and separated into in-phase and quadrature (out-of-phase) components by the apparatus 300. The in-phase (a.k.a. real) component is the amplitude of the measured field component that is in the same phase as the input signal and the quadrature (a.k.a. out-of-phase or imaginary) component is the amplitude of the measured field component that is 90 degrees out of phase with the input signal (i.e., the current in the transmitter loop). The true phase may be determined from the frequency of the input signal and time synchronization between the LIA(s) and input signal. Further, the values of in-phase and quadrature components of each measured electromagnetic field component may be stored in a memory 380 of the apparatus 300 for later processing.
Alternatively, the determination of in-phase and quadrature components may be performed without lock-in-amplifiers in data post-analysis by digital signal processing based on Fourier transformation provided that the measured electromagnetic field data is accurately synchronized in time with the input signal (i.e., the current in the transmitter loop). In this case, the data stored in memory 380 comprises values of raw (unprocessed) electromagnetic field components measured by the induction coils or magnetometers. The sampling frequency of the electromagnetic data must be sufficiently high (e.g. 5-10 times higher than the frequency of the input signal) to enable determining in-phase and quadrature components in data post-analysis.
In an embodiment, the system further comprises synchronization means for synchronizing time of the data measured by the second transducer arrangement 20 (e.g. data comprising EM field data, distance data, altitude data, and/or orientation data and/or location data) with the primary electromagnetic field 12 generated by the first transducer arrangement 10. This can be achieved,
20165928 prh 06 -09- 2017 for example, by transmitting synchronization signal(s) between the apparatus 200 and 300. Thus, the time at the apparatus 200 and apparatus 300 may be synchronized (e.g. essentially the same). In some other embodiments, the synchronization means comprise a synchronization circuitry (e.g. crystal oscillator, atomic clock) at the apparatus 200 and at the apparatus 300. Synchronization means may also utilize satellite positioning circuitry (such as GPS) for syncing the apparatus 200 and the apparatus 300. Thus, the apparatuses 200, 300 may be synced by using satellite positioning circuitry at both apparatuses 200, 300. Purpose of the synchronization may be that the data stored by the apparatus 200 and data stored by the apparatus 300 are in sync with each other. Hence, the data stored by the apparatus 300 (e.g. the measured data by the second transducer arrangement) may be in sync with the data stored by the apparatus 200 (e.g. log data about the generated primary EM field 12). This may improve the comparability of the data of the apparatus 200 and the data of the apparatus 300.
The apparatus 300 of Figure 3B may further comprise one or more orientation sensor(s) 340, one or more positioning sensor(s) 350, one or more altitude sensor(s) 360, a control circuitry (CTRL) 370, one or more memories 380 (e.g. comprising a computer program code) and/or a communication circuitry (TRX) 390. In an embodiment, the CTRL 370 comprises at least one processor. In some embodiments, the at least one memory 380 and the computer program code (i.e. comprised in the memory 380) (software), are configured, with the at least one processor, to cause the respective apparatus 300 to carry out any one of the embodiments or operations thereof. To efficiency reasons the entities 340-390 are not discussed in a greater detail. However, it needs to be noted that the one or more orientation sensor(s) 340 may be or comprise same or similar sensors and/or functionalities as the one or more orientation sensor(s) 240. Similarly, the one or more positioning sensor(s) 350 may be or comprise same or similar sensors and/or functionalities as the one or more positioning sensor(s) 250. Similarly, the one or more altitude sensor(s) 360 may be or comprise same or similar sensors and/or functionalities as the one or more altitude sensor(s) 260. Similarly, the one or more memories (s) 380 may be similar as the one or more memories 280. Similarly, the TRX 390 may be similar or the same as the TRX 290. Essentially, the entities 340-360 may be configured to measure orientation, position/location, time, and/or altitude of the second transducer arrangement 20. The measurements and/or results may be stored into the memory 380.
The second transducer arrangement 20 may be configured to store the
20165928 prh 06 -09- 2017 detected electromagnetic field measurements into the memory 380. The storing may be performed by the apparatus 300 in some embodiments (e.g. the CTRL 370).
The data stored into the memories 280, 380 may be used to calculate the secondary magnetic field 22 that is indicative of materials 100 in the subsurface. Just as one example, knowing the input current (I) in coil 232 and the distance between the first transducer arrangement 10 and the second transducer arrangement 20, the primary magnetic field 12 at the second transducer arrangement 20 may be determined from the detected EM field measurements. Thus, the input current and distance data and the measured or detected electromagnetic field data, may be used, by the CTRL 370 or by an external entity performing post-analysis, to determine the secondary electromagnetic field 22. The secondary electromagnetic field 22 may be influenced by the conductivity of the materials 100. Thus, for example, a conductivity map may be composed on the basis of the described determination. It needs to be noted that the measured or detected EM field data comprises data about the primary electromagnetic field 12 and about the secondary electromagnetic field 22. The measured current and distance may be used to estimate the primary electromagnetic field 12 at the second transducer arrangement 20, and thus the secondary EM field 22 may be calculated based on the estimated the primary electromagnetic field 12 and on the detected total EM field at the second transducer arrangement, for example. Further, orientation data and/or altitude data, which are described below in more detail, may further be used in calculating/determining the secondary electromagnetic field 22. Using said additional data may make the calculating/determining even more accurate considering situations discussed later where the first and second transducer arrangements are situated in or physically attached to two separate aerial vehicles, for example. Thus, in an embodiment, also the orientation data, location data and/or the altitude data for the second transducer arrangement 20 and/or the apparatus 300 are stored into the memory 380. The stored data may be used in post-analysis to estimate the secondary EM field 22.
According to an embodiment, the apparatus 200 and/or apparatus 300 further comprise a timing circuitry. The timing circuitry may be configured to synchronize time at both apparatuses 200, 300. Thus, both apparatuses 200, 300 may perform actions in sync. The timing circuitry may comprise, for example, clock (e.g. crystal oscillator, atomic) that is able to provide exact timing.
According to an embodiment, the apparatus 200 and/or apparatus 300 further comprise a distance circuitry. The distance circuitry may be configured to
20165928 prh 06 -09- 2017 measure and/or maintain a distance between the first and second transducer arrangements 10, 20. For example, if the apparatuses 200, 300 are UAVs or are comprised in UAVs, the distance circuitry may control the distance between the first and second transducer arrangements 10, 20 during flight. The distance controlling may be based on, for example, on radio frequency measurement. That is, for example, one of the UAVs may transmit a radio frequency signal (e.g. TRX 290, 390) that may be received by the other UAV (e.g. TRX 290, 390). Thus, the distance between the two may be measured. The timing circuitry may be utilized to synchronize the distance measurement so that the receiver may know exactly at what instant the signal is transmitted. Thus, the distance between the two may be measured even more accurately. In some embodiments, both apparatuses 200, 300 are configured to transmit and/or receive signals from each other, wherein the distance circuitries are configured to determine and/or maintain distance between the two.
In an embodiment, the distance data comprising at least one metric being indicative of a distance between the first and second transducer arrangements 10, 20 is stored into the memory 280 and/or 380 by the apparatus 200 and/or by the apparatus 300. The at least one metric may comprise location data indicating location of the first and/or second transducer arrangements 10, 20.
The at least one metric may comprise distance measurements based on laser measurement, ultra-sound and/or radio measurement (e.g. transmitting ultrasound and/or radio signal(s) between the apparatuses 200, 300). In an embodiment, the apparatus 200 and/or 300 comprises a distance measurement circuitry configured to measure distance between the first transducer arrangement
10 and the second transducer arrangement 20. For example, utilization of the distance measurement circuitry may be based on high frequency technique that utilizes propagation speed or phase-difference of high-frequency EM-pulse(s). For example, an apparatus may transmit an EM pulse to the other apparatus, wherein a distance measurement circuitry determines, based on phase-difference or propagation speed, the distance between the two.
So, for example, both apparatuses 200, 300 may store the distance data comprising location data and/or distance measurements. In some embodiments, only one of the apparatuses 200, 300 stores the distance data. For example, this may suffice if one of the apparatuses is not mobile (i.e. is stationary). For example, in the case that the only one of the apparatuses 200, 300 is mobile (e.g. only one AV and the other is a ground station), the mobile apparatus may store its location data.
20165928 prh 06 -09- 2017
Thus, the recorded location data can be used to determine distance when the location of the immobile apparatus is also known.
It needs to be noted that the location of the first transducer arrangement 10 with respect to the apparatus 200 may need to be taken into account. Similarly, the location of the second transducer arrangement 20 with respect to the apparatus 300 may need to be taken into account. Actually, the distance between the radio frequency antenna(s) and the first and/or the second transducer arrangements 10, 20 may be beneficial to know.
Let us then look at some embodiments which relate to use of one or more AVs in the system. Referring to an embodiment of Figure 4A, the system of Figure 1 may further comprise at least one aerial vehicle (AV) 400, 500. In some embodiments, the apparatus 200 is or is comprised in the AV 400. However, in some embodiments, the apparatus 200 is attached to the AV 400. In some embodiments, the apparatus 300 is or is comprised in the AV 500. However, in some embodiments, the apparatus 300 is attached to the AV 500. The following examples and embodiments are described such that the apparatus 200, 300 is the AV 400, 500. However, this is not always the case as said above, and thus said examples and/or embodiments may be applicable to other use cases (e.g. apparatus 200, 300 is attached to the AV 400, 500). In an embodiment, the at least one AV 400, 500 is a UAV.
For example, the arrangement 10 may be hangably attached to the AV 400. In another example, the apparatus 200 may be hangably attached to the AV 400. The hangable attachment may mean that the arrangement 10 hangs substantially freely under the AV 400 during flight. In another example, the attachment(s) may be rigid such that the arrangement 10 may not substantially move with respect to the AV 400 (e.g. a rigid attachment element). However, when the AV 400 tilts, the orientation of the arrangement 10 may substantially change (i.e. swaying). Similar attachment(s) may be utilized for the arrangement 20 to the AV 500.
In an embodiment, the arrangement 10 may be attached to the AV 400 using a gimbal or similar attachment means. In an embodiment, the arrangement 20 may be attached to the AV 400 using a gimbal or similar attachment means. Thus, both or at least one of the AVs 400, 500 may utilize gimbal. It is also noted that the arrangements 10, 20 may be part of the apparatuses 200, 300 respectively, and thus the gimbal may be used to attach both or at least one of the apparatuses 200, 300 to the AVs 400, 500. In an embodiment, the gimbal comprises a stabilizer
20165928 prh 06 -09- 2017 configured to maintain a predetermined orientation of the arrangement 10, 20 with respect to the AV 400, 500.
In an embodiment, the first transducer arrangement 10 and/or the second transducer arrangement 20 is coupled with the at least one AV 400, 500. In an embodiment, both the first transducer arrangement 10 and the second transducer arrangement 20 are coupled with the AVs 400, 500 respectively (i.e. the first transducer arrangement 10 is coupled with the first AV 400 and the second transducer arrangement 20 is coupled with the second AV 400). In an embodiment, the second transducer arrangement 20 is coupled with the second AV 500, wherein the system comprises only one AV. For example, the first transducer arrangement 10 or the apparatus 200 is configured to be placed on the surface 90.
In an embodiment, the first transducer arrangement 10 is coupled with the first aerial vehicle 400 and the second transducer arrangement 20 is coupled with the second aerial vehicle 500. As the transducer arrangements may be comprised in the apparatuses 200 and 300 respectively, it is noted that the apparatuses may be the AV 400 and AV 500 respectively, or the apparatuses 200 and 300 may be coupled with the AVs 400, 500 respectively as explained above.
Referring to Figure 4A, the at least one AV 400, 500 (so, for example, one or two AVs depending on the configuration of the system) may be configured to fly during the measurement operation. This may mean that the at least one AV 400, 500 may be configured to fly at least for a certain time during the measurement operation. Thus, in some embodiments, the measurement operation may last longer than said certain time. However, in some embodiments, the AV(s) 400, 500 are configured to fly such that the AV(s) 400, 500 are in the air when the measurement operation starts and stops, or in the air at least a main part of the measurement operation. The measurement operation may refer to generating the primary electromagnetic field and detecting the primary and secondary electromagnetic fields 12, 22 (or at least the magnetic components of said fields).
As discussed, there may be a distance (R in Figure 4A) between the first and second transducer arrangements 10, 20 during the measurement operation. If the first and second transducer arrangements 10, 20 are stationary, the distance may need to be measured only once. However, if the first and second transducer arrangements 10, 20 are movable with respect to each other (or at least one is movable with respect to the other), the distance may need to measured continuously or at least regularly. The distance data may be stored to the memory 280 and/or to the memory 390 by the apparatus 200 and/or 300, as discussed
20165928 prh 06 -09- 2017 above. Distance measurement may be based on, for example, radio frequency signaling as discussed above. The distance data may be used, for example, in postanalysis when determining the secondary electromagnetic field data from the detected electromagnetic field data.
Further, if the system comprises the at least one AV 400, 500, the first and second transducer arrangements 10, 20 may be at an altitude (Hl, H2) during the measurement operation. The altitude may vary during the measurement, and thus it may be beneficial to be stored into the memory 290 and/or into the memory 390. For example, if only one AV is used, the altitude data concerning transducer arrangement coupled with said only one AV may need to be stored. However, if both the first and second transducer arrangements 10, 20 are airborne, the altitude data may be stored for both. It needs to be noted that, according to an embodiment, the AV(s) 400, 500 is configured to fly at a certain altitude. However, due to wind and air pressure changes, for example, the altitude may change. Thus, the altitude data may be beneficial to be measured and stored. The altitude data concerning the first and/or second transducer arrangements 10, 20 may be used in the postanalysis, for example. For example, the altitude may have an effect on the strength of the electromagnetic fields and their magnetic components. Thus, this may have an effect on the detected electromagnetic fields (or at least their magnetic components). In other words, the lower the first and/or second transducer arrangements 10, 20 are, the stronger the detected electromagnetic fields may be. E.g. as the first transducer arrangements 10 is closer to the surface 90 (and inherently to the materials 100), the induced current into the materials 100 may be higher. Thus, the generated secondary electromagnetic field may also be stronger.
Figure 4B illustrates an embodiment. Referring to Figure 4B, the at least one AV 400, 500 is configured to fly a predetermined route 404. In an embodiment, the predetermined route comprises a plurality of waypoints. Thus, said waypoints may be configured and the predetermined route may be calculated between the waypoints.
In an embodiment, the at least one AV 400, 500 is configured to fly a route 404 between a plurality of waypoints. Thus, for example, two waypoints may be given, wherein the route may be directly or indirectly between the two waypoints.
In an embodiment, both AVs 400, 500 are configured to fly said route
404. For example, in such case, the AVs 400, 500 may be configured to fly in tandem
20165928 prh 06 -09- 2017 or side by side. In both options, there may be a distance between the two, and thus a distance between the first and second transducer arrangements 10, 20. The distance may be preconfigured or predetermined, but may still be measured and stored as discussed above. If the AVs 400, 500 are configured to fly in tandem, in an embodiment the first AV 400 is configured to fly the predetermined route 404, wherein the second AV 500 is configured to follow the first AV 400. In an embodiment, the AV 500 is configured to follow the first AV 400 at a predetermined distance. In some embodiments, however, the second AV 500, comprising the secondary transducer arrangement 20, is configured to lead, and the first AV 400 is configured to follow at a predetermined distance. As discussed above, at least in some embodiments, the first transducer arrangement 10 may be coupled with the first AV 400 whereas the second transducer arrangement 20 may be coupled with the second AV 500.
In an embodiment, at least one of the first and second aerial vehicles
400,500 is configured to substantially maintain a predetermined distance between the first and second transducer arrangements 10, 20 during flight of the first and second aerial vehicles 400, 500 (i.e. relative position between the arrangements 10, 20 is tried to maintain substantially the same). Thus, for example, both may fly the predetermined route 404. In an embodiment, one of the first and second aerial vehicles 400, 500 is configured to follow the other aerial vehicle 400, 500 (i.e. fly in tandem). Example of this may be shown in Figure 4B, wherein the second AV 500 may follow the first AV 400 trying to maintain the predetermined distance between the two on the predetermined route 404.
Still referring to Figure 4B, the route 404 may comprise a starting point
402 and an ending point. Between the starting point 402 and the ending point, the at least one AV 400, 500 may be configured to fly. The predetermined route 404 may further be limited to an area 401 (e.g. map area). For example, in an embodiment, the system may be configured to fly a route 404 to measure a predetermined area 401. That is, for example, if a user selects the area 401, the system may be configured to generate the route 404 to measure said area 401. For example, the apparatuses 200, 300 and/or the AVs 400, 500 may comprise control logic (e.g. CTRL 270, 370) that may be configured to generate the route 404 on the basis of the inputted area 401. As a further notice, the route 404 indicated with dashed line may be the not yet flown route, whereas the continuous line may indicate already flown route. In an alternative embodiment, the respective AV 400, 500 may comprise a controller comprising an autopilot configured to control flight
20165928 prh 06 -09- 2017 of the respective AV 400, 500.
Let us then again refer to Figure 2A, wherein the signal generation means 210, 220, or more particularly, the signal generator 210 may be configured to generate the input signal to the first transducer arrangement 10 (e.g. to the coil
232). In an embodiment, the signal generator is configured to generate the input signal such that the input signal comprises only one frequency. The frequency may be the resonant frequency of the first transducer arrangement 10. In an embodiment, the frequency is the resonant frequency of the second transducer arrangement 20. Thus, in an embodiment, the first transducer arrangement 10 and/or second transducer arrangement 20 are configured to a same resonant frequency. Further, the signal generator 210 may be configured to produce the input signal on said resonant frequency. Such arrangement may reduce power loss (i.e. parasitic effects, e.g. unwanted capacitive and/or inductive reactance) in the first transducer arrangement 10 and/or in the second transducer arrangement 20.
In an embodiment, the input signal may be a composition of a plurality of signals each having a different frequency. Thus, the first transducer arrangement 10 may generate (i.e. output) the primary electromagnetic field according to a multi-frequency input signal. For example, the input signal may be a composition or a sum of three frequencies. Thus, for example, the input signal may be a multi20 frequency sine-wave signal.
In an embodiment, the first transducer arrangement 10 or the signal generation means 210, 220 comprises a switch. The switch may be configured to change frequency of the input signal. For example, the switch may change the frequency at a predetermined rate (e.g. every 1 second or after every 100 full wave cycles). For example, three frequencies may be used, wherein each is inputted at a time. However, it may be possible to input multi-frequency signals and still change the input signal (e.g. a plurality of different multi-frequency signals).
In an embodiment, the first transducer arrangement 10 or the signal generation means 210, 220 comprises a filter circuitry. Said switch maybe coupled with the filter circuitry, wherein the filter circuitry is configured to change the resonant frequency of the first transducer arrangement 10. Thus, when the frequency is changed, the filter circuitry may be caused to adjust the resonant frequency of the first transducer arrangement 10 such that it is substantially the same as the new input signal. For example, the filter circuitry may denote one or more RLC-circuitries (Resistor (R), Inductor (L), and Capacitor (C)), wherein each RLC circuitry is configured for a specific frequency. For example, this is
20165928 prh 06 -09- 2017 accomplished by changing the capacitor in the RLC circuit. Thus, for example, if a first frequency is selected, the filter circuitry may apply a first RLC configuration causing the first transducer arrangement 10 to have said first frequency as the resonant frequency. Similarly, for example, if a second frequency is selected, the filter circuitry may apply a second RLC configuration causing the first transducer arrangement 10 to have said second frequency as the resonant frequency. This may apply to more than two frequencies, RLC configurations and resonant frequencies.
Similarly, in an embodiment, the second transducer arrangement 20 may comprise a switch and a filter circuitry configured to change the resonant frequency of the second transducer arrangement 20 (e.g. according to the predetermined rate).
In an embodiment, the signal generation means 210,220 are configured to change frequency of the input signal (e.g. 100Hz, 1000Hz, 10000Hz, to name a few examples) according to a frequency change rate (e.g. every second, two times per second or ten times per second, to name a few examples). One example of this may be the use of said switch. In another example, the CTRL 270 may be configured to control the signal generator to change the frequency according to the frequency change rate. In an embodiment, the second transducer arrangement 20 is configured to change the resonant frequency according to the frequency change rate. For example, the apparatus 200 may request the apparatus 300 to cause changing of the resonant frequency according to the frequency change rate (e.g. utilizing the switch and/or filter circuitry).
In an embodiment, the frequency change rate is at least partially based on the frequency of the input signal in the first transducer arrangement. The lower the frequency is the longer is the time needed to measure the electromagnetic field at the second transducer arrangement accurately. Thus, the frequency change rate of the signal generator 210 may be adjusted according to the frequency of input signal.
So, to enhance measuring of multiple frequencies (e.g. each frequency at a time) the signal generation means 210, 220 may require a switch that changes the frequency of the signal generator 210 and changes the capacitor (e.g. filter circuitry) accordingly to adjust the resonant frequency. Similar means may be comprised in or coupled with the second transducer arrangement 20. For example, the frequency is changed either a) based on time (e.g. every n seconds, wherein n denotes a positive real number) or b) based on a triggering information coming from the apparatus 200 to apparatus 300 causing the second transducer
20165928 prh 06 -09- 2017 arrangement to start measuring the next frequency. Alternatively, in case b), the apparatus 300 may transmit a triggering information to the apparatus 200 causing the first transducer arrangement to transmit the next frequency (i.e. the apparatus
300 asks for new frequency after the measurement has been made successfully).
Accordingly, the device transmitting the request may also change the transmitted frequency/measured frequency. This may enable the system to ensure that the transmitter and receiver apparatuses are in-sync, i.e. transmit and receive at same frequency or frequencies.
Thus, in an embodiment, the apparatus 200 changes frequency of the input signal according to the frequency change rate. The apparatus 200 may transmit a control message to the apparatus 300 indicating a frequency change event (e.g. the frequency is changed or will be changed). The apparatus 300 may cause the second transducer arrangement 20 to start measurements or detection on the indicated frequency. The control message may not necessarily comprise the new frequency. It may simply indicate that the frequency is changed from one to another (e.g. frequency number 1, 2, or 3).
In an embodiment, the signal generation means 210, 220 are configured to input a first input signal to the first transducer arrangement 10. The apparatus 200 may receive a control message from the apparatus 300 requesting a frequency change. For example, if the second transducer arrangement 20 has successfully performed detections on the primary and secondary electromagnetic fields, the frequency change may be requested. The apparatus 200 may cause the signal generation means to change the inputted signal into a second input signal having a different frequency compared with the first input signal. Thus, in an embodiment, the apparatus 300 requests frequency change by transmitting a control message to the apparatus 200. The control message(s) discussed above may be transferred utilizing the TRXs 290, 390, for example.
In an embodiment, frequency of the input signal is between 100-20000 Hz.
In an embodiment, the AVs 400, 500 are configured to fly the predetermined route 404 a plurality of times. For example, a different frequency or a set of different frequencies may be used for each time.
In an embodiment, the AVs 400 are configured to fly at a predetermined distance from each other as also described above. For example, the distance may be under 100 meters, such as 85 meters.
In an embodiment, the at least one AV 400, 500 is configured to fly
20165928 prh 06 -09- 2017 above tree-top-level (e.g. just above trees). For example, the distance from the surface 90 may be up to 35 meters. However, in some embodiments it may be higher or lower.
Let us then refer to Figure 5 illustrating an embodiment. The first transducer arrangement 10 and the second transducer arrangement 20 may be shown having a horizontal distance L between the two. R may denote direct (i.e. one-sight) distance between the two. Using trigonometric calculations, any of the R, L, dz may be calculated if two of them are known. It needs to be noted that the arrangements 10, 20 may be situated in the apparatuses 200, 300 and/or in the
UAVs 400, 500. As indicated in the Figure 5, the location of the first transducer arrangement 10 and the location of the second transducer arrangement 20 may be measured three-dimensionally. In some embodiments, the location may be twodimensional. Three-dimensional location may mean that the entity in question has a location on X, Y, and Z axis (e.g. easting, northing and upward). Thus, the location of the first transducer arrangement 10 may be measured and indicated as z1( ylt xlt and the location of the second transducer arrangement 20 may be measured and indicated as z2,y2-x2· Measuring of the locations may be performed by the positioning or location sensor(s) 250, 350. Further, altitude measurement may be utilized in some embodiments. However, for example, GPS, or GLONASS signals may be used to measure three-dimensional location. Additionally or alternatively, Galieo that is expected to be ready in the future years, may be utilized when it’s operation.
It also needs to be noted that the orientation of the first transducer arrangement 10 and/or second transducer arrangement 20 may play role in the measurement. As described, also the orientation data may be stored into the memories 280, 380. According to an embodiment, the orientation sensor(s) 240 are configured to measure orientation of the first transducer arrangement 10 (e.g. sensor(s) 240 are comprised or attached to the arrangement 10). According to an embodiment, the orientation sensor(s) 340 are configured to measure orientation of the second transducer arrangement 20 (e.g. sensor(s) 340 are comprised or attached to the arrangement 20). The orientation parameters may comprise roll, pitch and/or yaw angles rr,pr,yr. These may be measured by the orientation sensors 240 and/or 340, and stored into the memories 280 and/or 380.
So as described, the transmitter apparatus 200 may comprise a loop of insulated metal wire (e.g. coil 232, alternatively some other conductive material may be used). The primary EM field may be generated by a time-harmonic current
20165928 prh 06 -09- 2017 in said loop (e.g. generated by the signal generator 210). The receiver apparatus
300 may comprise three orthogonal induction coils 302-306 that measure three orthogonal components (e.g. Hz, Hy, Hx) of the total EM field, which is the sum of the primary EM field 12 (generated by the transmitter apparatus 200) and the secondary EM field 22 generated due to currents induced into the conductive materials 100 of the subsurface.
The post-analysis may be utilized to deduct the secondary EM field (or at least the magnetic field (H) of the secondary EM field) from the detected total EM field. Thus, for example, vertical component 510 and/or radial component 520 of the total EM field may be calculated by rotating the measured magnetic field components Hx, Hy and Hz by the amount of roll, pitch and yaw angles of the receiver. Thus, for example, the three coils and the measured orientation may be further used to enhance the post-analysis results.
Information regarding the electrical conductivity of the subsurface may be obtained by numerical modelling and inversion. Numerical modelling may be used to compute synthetic EM field component(s) at the receiver device 300 due to fields generated by the transmitter device 200. The numerical model may be onedimensional (i.e. conductive layered half-space) or three-dimensional (i.e. a mesh of conductive rectangular elements). The parameters of the model (e.g.
conductivity and thickness of the layers or conductivity of the mesh elements) may optimized to minimize the misfit between measured data and modelled EM fields. The EM response used in numerical computations may be defined as ratio between measured total field (Ht) and numerically computed primary (free-space) magnetic field (Ho) or more specifically as the normalized field of different directed components (e.g. (Hzt-Hzo)/Ho and/or (Hxt-Hxo)/Ho)). The EM response may also be defined as Hz/Hr ratio between the vertical (Hz) component 510 and radial Hr (i.e. away from the EM transmitter) component 520 of the measured EM field. The said primary EM field and EM response at the receiver apparatus (i.e. the second transducer arrangement 20) may be computed using the measured orientations of the transmitter (i.e. the arrangement 10) and receiver (i.e. arrangement 20), and either 1) the on-sight distance (R) between the transmitter and receiver, measured using a dedicated device(s) (e.g. radio frequency measurement between apparatuses 200, 300) and the altitudes of the transmitter and the receiver (altitude sensor(s) 260, 360 providing the horizontal loop separation L and the altitude difference dz shown in Figure 5); or 2) X, Y and Z coordinates measured using the positioning sensor(s) 250, 350 on the transmitter and the receiver (as
20165928 prh 06 -09- 2017 knowing the three-dimensional positions may be used to calculate the distances R and L and altitude difference dz).
In general, the apparatus 300 may store orientation data indicating orientation of the second transducer arrangement 20, position data indicating position (i.e. meaning here same as location) of the second transducer arrangement
20, altitude data indicating altitude of the second transducer arrangement 20 and/or data concerning the detected EM field(s) 12, 22. In general, the apparatus 200 may store orientation data indicating orientation of the first transducer arrangement 10, position data indicating position of the first transducer arrangement 10, and/or altitude data indicating altitude of the first transducer arrangement 10. Further, one or both apparatuses 200, 300 may store distance data comprising position data and/or distance measurements, wherein the distance data is indicative of a distance between the first and second transducer arrangements 10, 20. The data may be stored to the memories 280, 380 respectively.
Figure 6 illustrates an embodiment. Referring to Figure 6, a method for measuring electrical properties of materials of subsurface is shown. The method comprises: generating, by a first transducer arrangement 10, a primary electromagnetic field 12 (block 610); measuring, by a second transducer arrangement 20, electromagnetic fields (e.g. comprising primary EM field 12 and secondary EM field 22), the first and second transducer arrangements 10, 20 being comprised in separate physical entities movable in relation to each other (block 620); and measuring at least one metric being indicative of a distance between the first transducer arrangement 10 and the second transducer arrangement 20 (block
630). Some other method steps are disclosed with respect to Figures 1 to 5.
It is further noted that although in some instances term detected is used when describing EM field measurements by the second transducer arrangement 20, this may need to be essentially understood as measurement. Thus, the second transducer arrangement 20 may be configured to measure EM fields. Measuring, at least in some instances, may comprise storing the measurements in a memory of the apparatus 300, for example.
A yet further notice is that, in an embodiment, the data stored by the apparatus 200 and the data stored by the apparatus 300 comprises time stamps associated with the stored metrics. Thus, it may be verified that the data stored by the apparatus 200 and the data stored by the apparatus 300 is comparable.
As used in this application, the term ‘circuitry’ refers to all of the
20165928 prh 06 -09- 2017 following: (a) hardware-only circuit implementations, such as implementations in only analog and/or digital circuitry, and (b) combinations of circuits and software (and/or firmware), such as (as applicable): (i) a combination of processor(s) or (ii) portions of processor(s)/software including digital signal processor(s), software, and memory(ies) that work together to cause an apparatus to perform various functions, and (c) circuits, such as a microprocessor(s) or a portion of a microprocessor(s), that require software or firmware for operation, even if the software or firmware is not physically present. This definition of 'circuitry' applies to all uses of this term in this application. As a further example, as used in this application, the term ‘circuitry’ would also cover an implementation of merely a processor (or multiple processors) or a portion of a processor and its (or their) accompanying software and/or firmware.
In an embodiment, at least some of the processes described in connection with Figures 1 to 6 may be carried out by an apparatus comprising corresponding means for carrying out at least some of the described processes. Some example means for carrying out the processes may include at least one of the following: detector, processor (including dual-core and multiple-core processors), digital signal processor, controller, receiver, transmitter, encoder, decoder, memory, RAM, ROM, software, firmware, display, user interface, display circuitry, user interface circuitry, user interface software, display software, circuit, antenna, antenna circuitry, and circuitry. In an embodiment, the at least one processor, the memory, and the computer program code form processing means or comprises one or more computer program code portions for carrying out one or more operations according to any one of the embodiments of Figures 1 to 6 or operations thereof.
According to yet another embodiment, the apparatus carrying out the embodiments comprises a circuitry including at least one processor and at least one memory including computer program code. When activated, the circuitry causes the apparatus to perform at least some of the functionalities according to any one of the embodiments of Figures 1 to 6, or operations thereof.
At least some of the techniques and methods described herein may be implemented by various means. For example, these techniques may be implemented in hardware (one or more devices), firmware (one or more devices), software (one or more modules), or combinations thereof. For a hardware implementation, the apparatus(es) of embodiments may be implemented within one or more application-specific integrated circuits (ASICs), digital signal
20165928 prh 06 -09- 2017 processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field programmable gate arrays (FPGAs), processors, controllers, micro-controllers, microprocessors, other electronic units designed to perform the functions described herein, or a combination thereof. For firmware or software, the implementation can be carried out through modules of at least one chip set (e.g. procedures, functions, and so on) that perform the functions described herein. The software codes may be stored in a memory unit and executed by processors. The memory unit may be implemented within the processor or externally to the processor. In the latter case, it can be communicatively coupled to the processor via various means, as is known in the art. Additionally, the components of the systems described herein may be rearranged and/or complemented by additional components in order to facilitate the achievements of the various aspects, etc., described with regard thereto, and they are not limited to the precise configurations set forth in the given figures, as will be appreciated by one skilled in the art.
At least some embodiments as described may also be carried out in the form of a computer process defined by a computer program or portions thereof. Embodiments of the methods described in connection with Figures 1 to 6 may be carried out by executing at least one portion of a computer program comprising corresponding instructions. The computer program may be in source code form, object code form, or in some intermediate form, and it may be stored in some sort of carrier, which may be any entity or device capable of carrying the program. For example, the computer program may be stored on a computer program distribution medium readable by a computer or a processor. The computer program medium may be, for example but not limited to, a record medium, computer memory, read-only memory, electrical carrier signal, telecommunications signal, and software distribution package, for example. The computer program medium may be a non-transitory medium, for example. Coding of software for carrying out the embodiments as shown and described is well within the scope of a person of ordinary skill in the art. In an embodiment, a computer-readable medium comprises said computer program.
Even though the invention has been described above with reference to an example according to the accompanying drawings, it is clear that the invention is not restricted thereto but can be modified in several ways within the scope of the appended claims. Therefore, all words and expressions should be interpreted broadly and they are intended to illustrate, not to restrict, the embodiment. It will be obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways. Further, it is clear to a person skilled in the art that the described embodiments may, but are not required to, be combined with other embodiments in various ways.

Claims (12)

1. Järjestelmä pinnanalaisten materiaalien sähköisten ominaisuuksien mittaamiseksi, joka järjestelmä käsittää:1. A system for measuring the electrical properties of subsurface materials, comprising: ensimmäisen muunninjärjestelyn (10), joka on konfiguroitua first converter arrangement (10) configured 5 generoimaan primaarinen sähkömagneettinen kenttä (12);5 generate a primary electromagnetic field (12); toisen muunninjärjestelyn (20), joka on konfiguroitu mittaamaan sähkömagneettisia kenttiä (12, 22), jotka ensimmäinen ja toinen muunninjärjestely (10, 20) muodostavat erilliset fyysiset kokonaisuudet, jotka ovat liikutettavissa suhteessa toisiinsa;a second transducer arrangement (20) configured to measure electromagnetic fields (12, 22), the first and second transducer arrangements (10, 20) forming separate physical entities movable relative to one another; 10 mittausvälineet ainakin yhden metriikan mittaamiseksi, joka ilmaisee ensimmäisen muunninjärjestelyn (10) ja toisen muunninjärjestelyn (20) välisen etäisyyden; ja signaalin generointivälineet (210, 220), jotka on kytketty ensimmäiseen muunninjärjestelyyn (10),10 measuring means for measuring at least one metric indicating the distance between the first converter assembly (10) and the second converter assembly (20); and signal generating means (210, 220) coupled to the first converter arrangement (10), 15 tunnettu siitä, että järjestelmä käsittää lisäksi:15 characterized in that the system further comprises: tallennusvälineet (280, 290) ainakin etäisyystiedon tallentamiseksi, joka käsittää kyseisen ainakin yhden metriikan, joka ilmaisee ensimmäisen muunninjärjestelyn (10) ja toisen muunninjärjestelyn (20) välisen etäisyyden, ja tiedon tallentamiseksi, joka ilmaisee toisen muunninjärjestelyn (20) mittaamatstoring means (280, 290) for storing at least distance information comprising said at least one metric indicating the distance between the first converter arrangement (10) and the second converter arrangement (20), and storing information indicating the measurements of the second converter arrangement (20); 20 sähkömagneettiset kentät (12, 22), ja siitä, että tallennusvälineet (280, 290) ovat lisäksi ensimmäisen muunninjärjestelyn (10) generoiman primaarisen sähkömagneettisen kentän (12) tietojen tallentamista varten, jotka mainitut tiedot ilmaisevat sinimuotoisen vaihtovirtatulosignaalin voimakkuuden ensimmäisen muunninjärjestelyn (10)And electromagnetic fields (12, 22), and the recording means (280, 290) for further storing information of a primary electromagnetic field (12) generated by the first transducer arrangement (10), said data indicating a first transducer arrangement (10) of a sinusoidal AC input signal. 25 kelassa tai silmukassa (232), joka ensimmäinen muunninjärjestely on konfiguroitu generoimaan primaarinen sähkömagneettikenttä (12) mainitun sinimuotoisen vaihtovirtatulosignaalin mukaan.25 in a coil or loop (232) configured to generate a primary electromagnetic field (12) according to said sinusoidal AC input signal. 2. Patenttivaatimuksen 1 mukainen järjestelmä, missä sähkömagneettiset kentät (12, 22) käsittävät mainitun primaarisenThe system of claim 1, wherein the electromagnetic fields (12, 22) comprise said primary 30 sähkömagneettisen kentän (12) ja sekundaarisen sähkömagneettisen kentän (22), joka on indusoitunut mainituissa materiaaleissa primaarisen sähkömagneettisen kentän (12) takia generoituneista virroista.30 electromagnetic fields (12) and secondary electromagnetic fields (22) induced in said materials by currents generated by the primary electromagnetic field (12). 20165928 prh 04-12-201720165928 prh 04-12-2017 3. Patenttivaatimuksen 1 tai 2 mukainen järjestelmä, missä toinen muunninjärjestely (20) on konfiguroitu mittaamaan ainakin yksi sähkömagneettisten kenttien (12, 22) suunnattu komponentti.The system of claim 1 or 2, wherein the second transducer arrangement (20) is configured to measure at least one directional component of the electromagnetic fields (12, 22). 5 4. Minkä tahansa edeltävän patenttivaatimuksen mukainen järjestelmä, missä toinen muunninjärjestely (20) käsittää kolme induktiokelaa (302, 304, 306) ja/tai magnetometria, jotka on järjestetty kohtisuoraan suhteessa toisiinsa ja konfiguroitu mittaamaan mainittujen sähkömagneettisten kenttien (12, 22) kolmea ortogonaalista komponenttia.The system of any preceding claim, wherein the second transducer assembly (20) comprises three induction coils (302, 304, 306) and / or magnetometers arranged perpendicular to one another and configured to measure the three orthogonal fields of said electromagnetic fields (12, 22). component. 5. Minkä tahansa edeltävän patenttivaatimuksen mukainen järjestelmä, joka lisäksi käsittää:The system according to any one of the preceding claims, further comprising: mittausvälineet (250, 350) ainakin joko ensimmäisen muunninjärjestelyn (10) sijainnin tai toisen muunninjärjestelyn (20) sijainnin.measuring means (250, 350) for at least the location of either the first converter assembly (10) or the second converter assembly (20). 6. Minkä tahansa edeltävän patenttivaatimuksen mukainen järjestelmä, joka lisäksi käsittää:The system according to any one of the preceding claims, further comprising: mittausvälineet (240, 340) ainakin joko ensimmäisen muunninjärjestelyn (10) asennon tai toisen muunninjärjestelyn (20) asennonmeasuring means (240, 340) at least either the position of the first converter assembly (10) or the position of the second converter assembly (20) 20 mittaamiseksi.20 to measure. 7. Minkä tahansa edeltävän patenttivaatimuksen mukainen järjestelmä, missä mittausvälineet käsittävät etäisyysmittauspiiristön, joka on konfiguroitu mittaamaan ensimmäisen muunninjärjestelyn (10) ja toisen muunninjärjestelynThe system of any preceding claim, wherein the measuring means comprise a distance measuring circuit configured to measure the first converter assembly (10) and the second converter assembly. 25 (20) välinen etäisyys.25 (20). 8. Minkä tahansa edeltävän patenttivaatimuksen mukainen järjestelmä, joka käsittää lisäksi: synkronointivälineet toisen muunninjärjestelyn (20) mittaamien tietojen ajan synkronoimiseksi ensimmäisen muunninjärjestelyn (10)The system of any preceding claim, further comprising: synchronizing means for synchronizing the time measured by the second converter assembly (20) with the first converter assembly (10). 30 generoiman primaarisen sähkömagneettisen kentän kanssa.30 generated by a primary electromagnetic field. 9. Minkä tahansa edeltävän patenttivaatimuksen mukainen järjestelmä, missä signaalin generointivälineet (210, 220) on konfiguroitu muuttamaan sinimuotoisen vaihtovirtatulosignaalin taajuutta taajuusmuutostahdin mukaan.The system of any of the preceding claims, wherein the signal generating means (210, 220) is configured to vary the frequency of the sinusoidal AC input signal according to the frequency change rate. 10. Minkä tahansa edeltävän patenttivaatimuksen mukainen järjestelmä, joka lisäksi käsittää:The system of any preceding claim, further comprising: ainakin yhden ilma-aluksen (400, 500), missä ainakin joko ensimmäinen muunninjärjestely (10) tai toinen muunninjärjestely (20) onat least one aircraft (400, 500), wherein at least one of the first converter arrangement (10) or the second converter arrangement (20) is 5 kytketty mainittuun ainakin yhteen ilma-alukseen (400, 500).5 coupled to said at least one aircraft (400, 500). 11. Patenttivaatimuksen 10 mukainen järjestelmä, missä ensimmäinen muunninjärjestely (10) on kytketty ensimmäiseen ilma-alukseen (400) ja toinen muunninjärjestely (20) on kytketty toiseen ilma-alukseen (500).The system of claim 10, wherein the first transducer arrangement (10) is coupled to the first aircraft (400) and the second transducer arrangement (20) is coupled to the second aircraft (500). 12. Patenttivaatimuksen 10 tai 11 mukainen järjestelmä, missä kyseinen ainakin yksi ilma-alus (400, 500) on konfiguroitu lentämään ennalta määrätty reitti (404) tietyllä korkeudella maasta.The system of claim 10 or 11, wherein said at least one aircraft (400, 500) is configured to fly a predetermined route (404) at a certain altitude. 15 13. Patenttivaatimuksen 11 tai 12 mukainen järjestelmä, missä ainakin joko ensimmäinen tai toinen ilma-alus (400, 500) käsittää ohjaimen, joka käsittää autopilotin, joka on konfiguroitu ylläpitämään oleellisesti ennalta määrätty etäisyys ensimmäisen ja toisen muunninjärjestelyn (10, 20) välillä ensimmäisen ja toisen ilma-aluksen (400, 500) lennon aikana.The system of claim 11 or 12, wherein at least one of the first or second aircraft (400, 500) comprises a controller comprising an autopilot configured to maintain a substantially predetermined distance between the first and second transducer arrangements (10, 20) of the first and another aircraft (400, 500) in flight.
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Publication number Priority date Publication date Assignee Title
US20210140307A1 (en) * 2019-11-12 2021-05-13 Saudi Arabian Oil Company Removing the Effect of Near-Surface Inhomogeneities in Surface-to-Borehole Measurements

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210140307A1 (en) * 2019-11-12 2021-05-13 Saudi Arabian Oil Company Removing the Effect of Near-Surface Inhomogeneities in Surface-to-Borehole Measurements

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