WO2019245367A1 - Sonde de détection permettant de détecter un paramètre du sol à une certaine profondeur et procédés de placement et d'utilisation d'une telle sonde - Google Patents

Sonde de détection permettant de détecter un paramètre du sol à une certaine profondeur et procédés de placement et d'utilisation d'une telle sonde Download PDF

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Publication number
WO2019245367A1
WO2019245367A1 PCT/NL2019/050377 NL2019050377W WO2019245367A1 WO 2019245367 A1 WO2019245367 A1 WO 2019245367A1 NL 2019050377 W NL2019050377 W NL 2019050377W WO 2019245367 A1 WO2019245367 A1 WO 2019245367A1
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WO
WIPO (PCT)
Prior art keywords
probe
ground
tip
head
elongate body
Prior art date
Application number
PCT/NL2019/050377
Other languages
English (en)
Inventor
Daan Nicolaas ROETHOF
Mark Jan Pieter RUIJS
Erik Petrus Nicolaas Damen
Original Assignee
Sensoterra B.v.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sensoterra B.v. filed Critical Sensoterra B.v.
Priority to EP19743070.5A priority Critical patent/EP3811077A1/fr
Publication of WO2019245367A1 publication Critical patent/WO2019245367A1/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/24—Earth materials
    • G01N33/246—Earth materials for water content
    • A—HUMAN NECESSITIES
    • A01—AGRICULTURE; FORESTRY; ANIMAL HUSBANDRY; HUNTING; TRAPPING; FISHING
    • A01G—HORTICULTURE; CULTIVATION OF VEGETABLES, FLOWERS, RICE, FRUIT, VINES, HOPS OR SEAWEED; FORESTRY; WATERING
    • A01G25/00—Watering gardens, fields, sports grounds or the like
    • A01G25/16—Control of watering
    • A01G25/167—Control by humidity of the soil itself or of devices simulating soil or of the atmosphere; Soil humidity sensors
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/048—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance for determining moisture content of the material
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/24—Earth materials
    • G01N33/245—Earth materials for agricultural purposes

Definitions

  • Sensing probe for sensing a parameter of the ground at a certain depth methods for placing and using such probes
  • This invention generally relates to the fields of agriculture, horticulture and landscaping, and in particular to that of soil management. More specific, this invention relates to a sensing probe for sensing a parameter of the ground at a certain depth therein, and, although not limited thereto, in an embodiment thereof a probe which can further determine a measured value of a property of the ground, such as humidity, temperature or salinity, from the sensed parameter.
  • a sensing probe for sensing a parameter of the ground at a certain depth therein, and, although not limited thereto, in an embodiment thereof a probe which can further determine a measured value of a property of the ground, such as humidity, temperature or salinity, from the sensed parameter.
  • the invention further relates to methods of placing such probes and using such probes to sense a parameter of the ground.
  • irrigation of land is often carried out in areas where water is a scarce resource. Because of the scarcity of this resource in such areas, ideally, water is only supplied to land in controlled quantities, when and where there is a need for the supply of the water. Even in areas where water is not scarce, control of the quantities of water such that the humidity corresponds to the specific requirements of the species to be grown allows to ameliorate growth conditions and yield.
  • the degree of irrigation required the availability of data which reveals the present amount of moisture in the ground at a meaningful level from the surface is a pre-requisite.
  • the known probes are not capable of withstanding a significant amount of force.
  • the known probes of the type than can be integrally inserted without preforming a hole are thus only suitable for relatively soft types of substrates, e.g. wet soil, and limited depths and limited depths, such as less than 20 cm.
  • a portable soil moisture tester for horticultural applications and home gardening has a soil inserting rod in a casing.
  • the inserting rod may be graduated or marked to indicate the appropriate depth to which the soil moisture is to be tested for a specific plant, or in alternative embodiment provided with a collar that limits the insertion to ensure repeated equal insertion.
  • the mechanical construction of the tester will not resist the forces required to insert the tester deep into the ground and/or in hard layers such as rock or dry clay. The depth at which the moisture can be measure is therefore limited to about 20 cm and the tester is only suitable for soft gardening soil.
  • German utility model DE 20 2005 020951 U1 discloses a device for measuring and displaying the humidity of earth of a pot plant, which comprises a battery and a LED.
  • a device for measuring and displaying the humidity of earth of a pot plant which comprises a battery and a LED.
  • the voltage over the LED will exceed the threshold voltage thereof and the LED lights up. If the moisture content in the soil drops below a threshold value, the light-emitting diode goes out because the voltage over the LED will drop below the threshold voltage.
  • the device can be stuck into the earth in the pot, to a depth where the electrodes are in the area of the roots of the plant.
  • the present invention provides probes, measuring systems and methods for installing and using such probes as described in the accompanying claims.
  • Fig. 1 shows a sectional view of an example of a sensing probe positioned into the ground.
  • Fig. 2 shows a perspective view the example of FIG. 1 during installation thereof.
  • Fig. 3a and 3b shows a sectional views of a part of an elongate body suitable for the example of FIG. 1 , taken along the lines a-a and b-b therein respectively.
  • Fig. 4 shows a circuit diagram of an example of an electronic circuit suitable for the example of FIG.1.
  • Fig. 5 shows a block diagram of an example of a measurement system which can use the circuit of FIG. 4 and/or the probe of FIG. 1.
  • Fig. 6 shows a flow chart illustrating a method of sensing a parameter of the ground at a certain depth.
  • ground and“soil” are used interchangeably. However, these terms are meant to embrace more than ground established as fit for agriculture. For instance, also very dry ground, or even sandy ground with large particles (stones) in a somewhat rocky area is meant to be covered by the term“ground” as used in this disclosure.
  • the ground may be a naturally occurring substrate, such as the ground of the earth, but may also comprise other, artificial substrates.
  • the substrate can be any suitable substrate, such as rock, stones, gravel, sand, silt, clay, soil, mud, concrete, just to name a few and/or be porous or non-porous.
  • the substrate may have a homogeneous composition or have a composition which varies as a function of depth (over the depth to which the probe is inserted).
  • the substrate may e.g. include one or more layers of different composition, such as a top layer of soil and one or more different underlying layers such as sand or clay, just to name a few examples.
  • the substrate may be one on which a non-animalistic living organism, (such as a plant or a fungus) is grown, although the probes may also be used to as sensors for other substrates e.g. to measure conditions in non-agricultural areas.
  • the example of a sensing probe 1 shown therein is placed in the ground G.
  • the probe 1 has an elongate body B with a tip 2 as the leading end and a head 3 as the trailing end.
  • the term“leading end” refers to the use wherein the tip 2 will be placed onto the ground and leading the way" into the ground.
  • the head 3 is basically trailing behind, i.e., following the probe 1 as a part of the elongate body B that advances into the ground.
  • the head 3 is shaped such that a force can be exerted on the body B in an inserting direction from the head 3 towards the tip 2, to insert the body B into the ground to a desired installation depth.
  • the probe has a subterranean part which extends from the surface of the ground downwards to the installation depth, and an exposed part which extends upwards from the surface.
  • the probe can be used to sense a parameter of a portion of the ground G at a certain depth, between the surface and the installation depth.
  • a large variety of parameters can in principle be sensed, and in this example electrical parameters of the portion, such as resistivity or permittivity are sensed.
  • the elongate body B comprises at least one electrode 7 which is electrically connectable (and in FIG. 1 shown connected to), at a predetermined position of the body, to a portion of ground G which, when the probe is entered into the ground, is adjacent to the body B at the predetermined position.
  • FIG. 1 for example, along the length of the elongate body B several electrodes at a distance from each other are provided.
  • the shown example thus allows the sensed parameter to be sensed at different positions, e.g. different depths. However, more or less electrodes, e.g. a single electrode, may be present, depending on the specific implementation.
  • the body B and more specifically the shaft 1 1 which extends from the head 3, forms a casing 10 inside which the electronic circuit 20 is integrated in the probe.
  • the electronic circuit is provided on a board 8 which extends inside the casing, parallel to longitudinal direction of the body in FIG. 1 and more specific in this example from the head 3 towards the tip 2 up to a lowest electrode.
  • the probe 1 may comprise a separate casing e.g. by attaching and fixating a separate element to the body.
  • the electronic circuit allows a current path through the portion of the ground to be established (as represented by resistances R so n in FIG. 1). Through the current path, a DC current flows during sensing. Because of the DC current, the circuit 20 does not require high frequency components, or frequency converters. Accordingly, the circuit can be implemented as a simple circuit with relatively few and robust components capable of withstanding the forces required to install the probe 1 in hard ground or relatively large depths. This in turn allows a simple installation of the probe 1 , where the entire probe can be installed in a single operation, e.g. by hammering or otherwise exerting a large force, without requiring mounting additional parts of the probe after installation of e.g. a base and with limited risk of damage to the probe.
  • a circuit diagram of an example of a suitable electronic circuit is for instance shown in FIG. 4.
  • the probe is suitable to receive an impact force, such as of a hammer.
  • an impact force such as of a hammer.
  • the probe 1 can thus e.g. be hammered into the ground without the need to separately install the electronics or other parts. This allows to install the entire probe 1 at the desired location in a simple manner into the ground, e.g. by in a single operation where the body B is inserted to a desired depth into the ground. Such an operation can be performed without requiring a highly-trained expert. During tests, it has been shown that the single operation can be be performed in less than 2 minutes, for example less than 1 minute, although this is, of course, not required.
  • the electronic circuit 1 can have relatively small power consumption because the losses stemming from the generation and/or conversion of a high frequency signal can be avoided.
  • the head has a flattened impact surface 31 and an impact force is exerted in a longitudinal direction of the body B.
  • the force is exerted with a tool 4 striking on the impact surface, such as in this example a hammer.
  • the body B is in this example (as more clearly seen in FIG. 1 ) comprises a shaft 1 1 which is attached with an upper end to the head 3 and extends downwards towards the tip 2.
  • the tip is formed by the lower end of the shaft 1 1 but instead a separate tip may be mounted on the lower end.
  • the shaft is a straight shaft 1 1 which extends (between head 3 and tip 2) perpendicular to the impact surface.
  • the body B transfers the impact force from the impact surface 31 to the tip 2 to drive the body B into the ground to the desired depth.
  • the probe 1 (with its tip 2 put on the surface of the ground and the elongate body B aligned with the direction of gravity) remains straight, and does not permanently deform or noticeably bend elastically. This facilitates installing the probe with simple and widely available means such as a hammer into relatively hard layers and/or deep into the ground, and by any labourer who is fit enough to use that hammer.
  • the probe 1 can thus be installed in a simple manner to sense at a significant depth.
  • the head 3 may remain exposed at the surface, and either be flush therewith or project from the ground.
  • This allows a wireless data communication connection between a transmitter in the head of the probe and e.g. a remote data station, via which data collected by the probe can be transmitted.
  • the electronic circuit 2 is provided on a board 8 in the body B and more specifically embedded in the material thereof, with direct contact between the board and the material of the body.
  • the electronic circuit in this example lies between the head and the tip and is fixated relative to the body and unmovable with respect to the body.
  • the electronic circuit 2 is not shielded from the impact forces and e.g. vibrations or shocks induced thereby in the body will transfer to the board.
  • the board 8 cannot move relative to the body B and accordingly mechanical wear due to repetitive flexing thereof can be prevented.
  • circuitry sensitive to mechanical forces such as communication circuitry like e.g. transmitter, a receiver or a transceiver can be provided, with an antenna for wireless transmission of data and/or receiving GPS data to determine a location of the probe 1 may be provided, and/or a battery.
  • the communication circuitry may be embedded in a shock absorbing material 12, such as a silicon gel based material. This material absorbs the vibrations generated by the impact force and thus shields the (typically high frequency and thus relatively sensitive) electronics from impact forces exerted on the head 3 when inserting the probe into the ground.
  • this allows separately shielding the sensitive circuitry from the impact force, while enabling to mount the robust circuitry without additional protection for the robust circuitry.
  • a suitable connection may be present, such as an l z C bus connection.
  • the body B may have any shape and dimensions suitable for the specific implementation. It has been found that due to the robustness of the electronic circuit, even probes with an elongate body with a length of at least 0.9 meter, such as at least 1 meter can still be inserted with a limited risk of damage to the electronics. It is further found that a length of less than 1 .7 meter, such as less than 1.5 meter can be sufficient for accurate measurements of parameters of interest deep into the ground. The length can for example be in the range of 1 to 1.5 meter. In particular a length in the range of 1.1 to 1.3 meter has found to be suitable to sense the parameters of interest while still being capable of being inserted into the ground in a single operation, e.g.
  • the probe protrudes from the ground after installing, and for examples senses to a depth of between 70% and 90% of its length, such as about 75%. Particularly good results have been obtained with a probe having a body of 1.2 m, senses to a depth of 0.9 m.
  • a relatively thin elongate body can be construed with sufficient strength, without requiring e.g. reinforcing ribs or other reinforcing elements at the outside thereof.
  • this can be an elongate body without reinforcing elements over at least the lower half of the body, between the tip and the middle of the body and preferably without such elements over the entire length of the body, from the tip up to the bottom of the head.
  • the body can for example have a needle like shape or other slender cylindrical pointed or tapered shape.
  • a body for example with the above specified lengths
  • a body with a maximum diameter of less than 5 cm, such at less than 3 cm, for example 1 inch (about 2.54 cm), less than 2 inch, or even smaller such as 0.5 inch or less and even not more than 1 cm can be inserted without breaking.
  • an elongate body with a diameter of at least 0.7, such as 1 cm, for example 2 cm already is sufficiently strong to withstand the forces.
  • the elongate body B can e.g. have a needle or stick-like shape, like a cylindrical pointed or (slightly) tapered shape.
  • the elongate body B is preferably long and thin. This allows the friction to be reduced when the probe is advanced into the ground, and allows relatively deep levels in the ground with a limited amount of force being required.
  • the body may have a lengtlrdiameter (I/d) ratio of at least 30, such as for example at least 40, and even at least 80 for instance. Tests with a ratio between 50 and 70 and in particular about 55 to 65 have yielded satisfactory results. Such ratios can advantageously be applied in elongate bodies with a length and/or diameter within the ranges specified in the preceding paragraphs.
  • the probe has a mechanical construction which strengthens the elongate body while retaining a smooth outer shape thereof and without requiring e.g. reinforcing ribs or other elements at the outside of the elongate body.
  • a probe can be obtained which exhibits relatively little friction between the probe and ground when inserting, and the amount of force required to insert the probe be reduced accordingly.
  • the elongate body is formed in FIG. 1 as a straight shaft, which reduces the friction between body and ground when inserting.
  • the straight shaft has a diameter or thickness which, from the head towards the tip does not increase, but is either constant or reduces. Said differently, at any given location along the length of the straight shaft, the diameter or thickness is not larger than the diameter or thickness at all the other locations between the head and the given location.
  • the body B comprises a rod 5 and a tube 6 extending along the length of the rod 7 from the head up to the tip.
  • the tube 6 encloses the rod 5 and is of a different material.
  • the tube 6 and rod 5 are preferably made of different materials. This allows electing a material for one of them that compensates for weaknesses of the other, and vice versa.
  • the compressive deformability in the longitudinal direction and the bending stiffness of the rod can be higher than of the tube.
  • the tube enhances the longitudinal transfer of the impact force because the tube shields the rod from the impact, whereas the rod prevents bending of the tube upon impact.
  • the compressive deformability in the longitudinal direction and the bending stiffness of the tube can be higher than of the rod.
  • the tube as a containment sleeve or kind of“straight jacket” for the rod, which constrains a freedom of movement of the rod and/or the impact force induced expansion of the rod transverse to the longitudinal direction.
  • a body with good “hammerable” properties can be obtained, such as resistance to plastic deformation upon impact forces.
  • the tube completely or partially inhibits bending of the rod induced by the impact force and hence dispersion of this force in other directions than the longitudinal direction of the body B.
  • This allows to a particularly slender (i.e. high length/diameter ratio) body which can be inserted with relatively little effort.
  • a suitable material for a constraining sleeve can for example be a fibre-reinforced composite material, like glass or carbon fibre-reinforced, whereas a suitable material for the rod can e.g. be a hard material like an epoxy based resin.
  • the probe can then e.g. be manufactured by placing the board 8 in a tube 6 and filling the void(s) between the tube and board with a liquid precursor of the rod material which is subsequently hardened. This allows to obtain a strong body B in a very simple manner.
  • the electronic circuit 20 is implemented on a board, such as a printed circuit board (PCB)).
  • the components of the circuit 20 are mounted on the board and in this example connected via tracks in the board, as generally known in the field of PCBs.
  • the components of the electronic circuit 20 may alternatively be placed on another carrier e.g. a part of the rod and/or be connected in a different manner such as through a suitable wiring.
  • the board 8 is located inside the rod 5, more specifically embedded in the material of the rod 5.
  • the rod 5 may for instance form a potting of the board 8.
  • the rod 5 fills the complete inside of the tube 6 and accordingly there is no empty space between the board 8 and the tube 6. This allows to seal off the electronic circuit from e.g. moisture penetrating the body while, due to the robustness of the circuit, it will withstand the mechanical forces transferred via the rod.
  • the inside of the tube 6 may be filled after the electronic circuit 20 and electrodes 7 are placed in the tube 6. This allows seal-off any openings between the electrodes 7 and the tube 6 and thus hermetically sealing the inside of the tube, for example against moisture or soiling.
  • the electrode 7 may be implemented in any manner suitable for the specific implementation, for example such as to make resistive and conductive contact with the portion of the ground.
  • the contact may e.g. have a capacitive component.
  • the current path through the portion of the ground may be connected to the DC current source or sink in any suitable manner.
  • the electrode 7 may be used to provide the current path to any suitable type of electronic circuit, and may be connected to other types of electronic circuits, e.g. more complex and less robust instead of one sensing with a DC current through the ground.
  • the body may comprise electrical connections 9 which connect the electrodes 7 to the electronic circuit 20.
  • both the electrodes and the electronic circuit 20 are mounted on the board 8 and electrical connections 9 are provided as tracks on the board 8.
  • the board 8 is embedded in the rod, without gaps between the board 8 and rod 6. The board can thus not move relative to the rod 6 and probe 1 has a very robust elongate body B. Moreover, in this robust body this risk of loosening of the connection between electrodes 7 and circuit 20 when the probe is inserted into the ground is very low.
  • the electrode 7 can be provided on the outside of the elongate body B.
  • the electrodes are preferably flush with the outer surface of the elongate body B, so that the electrodes do not provide additional friction when the measuring probe is advanced into the ground.
  • the electrode 7 extends, in radial direction of the body B, from the board up to the outer wall of the tube 6.
  • the electrode 7 lays exposed to touch and may physical contact with the portion of the ground, and thus make conductive contact therewith.
  • the body B (and in this specific example the tube 6 thereof) is provided with a window at the location of the electrode, which is closed off by the exposed surface of the electrode, and preferably sealed in a liquid tight manner.
  • a window with a width w, as illustrated in FIG. 3b of less than 20% of the circumference, for example less than 16% does not noticeably affect the strength of the body B.
  • the window has a height h which is less than 1 .5 times the width, such as a square window.
  • the hammerability can be further improved
  • the probe 1 may have one or more than one electrode 7.
  • the probe 1 can for instance comprise at least one pair of two electrodes which are spaced apart in the longitudinal direction of the body, for establishing a resistive current path (as illustrated with the impedances Rsoil in FIG. 1) between the electrodes of the pair through the portion of the ground.
  • a resistive current path as illustrated with the impedances Rsoil in FIG. 1
  • This not only allows to sense the parameter at different depths into the ground but also allows to avoid cross-over currents and ensures that the currents through the different portions remains separated from each other. Accordingly, the accuracy can be improved.
  • the electrodes are arranged in pairs, with the side of the tube at which the electrodes are exposed, and thus make contact with the ground, alternating.
  • the side of the ground that is sensed by a pair alternates and for example a first pair can sense at a first side of the tube 6 whereas the next, lower pair can sense at the opposite side of the tube 6.
  • This allows for example to reduce the risk that at one side, for example, the contact between electrode 7 and ground is insufficient, such as due to an airgap between those for example.
  • gaps can e.g. occur when the ground dried after placing the probe.
  • the electrodes 7 can, as in the example, be separated in the longitudinal direction of the elongate body B.
  • the electrodes 7 can be distributed over several positions over a certain length of the elongate body B, in order to sense at different depths and e.g. determine a variation of a property of the ground as a function of depth, e.g. nutrient concentration or humidity.
  • the predetermined positions may all be equally distributed along the elongate body of the sensing probe 1 .
  • at least one electrode 7 is located closer to the tip 2 than to the head 3 and for example an electrode 7 is provided at or close by the tip 2.
  • the tip 2 can be electrically conductive.
  • Fig. 4 shows a schematic diagram illustrating an electronic circuit 20 which can be used in the example of a sensing probe 1 of FIG. 1 . Because the illustrated example may for the most part be implemented using electronic components and circuitry known to those skilled in the art, details thereof will not be explained in any greater extent than that considered necessary for the understanding and appreciation of the underlying concepts.
  • the electronic circuit 20 may be provided inside the sensing probe 1 .
  • the shown example of an electronic circuit 20 is connected to a power source 21 which is internal to the probe 1 and part of the circuit prior to the probe being placed, but it will be apparent that the electronic circuit 20 may alternatively or additionally be connected to an internal power source which e.g. is placed inside the probe only after installing the probe in the ground, or be connected to an external power source.
  • the power source 21 is a DC power source, such as a commercially available battery having a voltage of, for example, 3.6 V. However, also other kinds of (rechargeable) batteries with other voltages may be used.
  • the circuit 20 comprises a DC current source 23, in this exampled implemented as a capacitor, which is connected to the electrode 7, for establishing a current path through the portion of the ground (as represented in the FIG. by the resistive component Rsoil oi the impedance of this portion), through which a DC current flows which monotonically changes the charge in the DC current source.
  • the current path can e.g. provide a conductive connection between two electrodes 7 or between an electrode and an external mass, external to the probe, which forms an electrical ground.
  • the DC current flowing can for example monotonically charge the source 23 or, alternatively, monotonically discharge the source 23.
  • a DC current source is present and charge stored therein can be discharged through the current path, but it will be apparent that alternatively a DC current sink may be present in which charge is stored through the current path.
  • the DC current may for example be a constant current or a monotonically changing current, such as one exhibiting an exponential decay.
  • a DC current can travel unaided over a relatively long distance without loss of information about the monotonic change. Consequently, the location of the electrodes can be relatively remote from the electronic circuit 20, and for example the electronic circuit 20 be located at a head-side end of the board. Therefore, the need to have in the body itself already bulky processing circuitry or complex and sensitive elements like transmission lines is obviated.
  • This enables allows a long and thin probe, which in turn allows for measuring at a deep level in the ground, and a robust design of the probe.
  • the robust design in turn allows for an installation process of the probes, in which the probes may be hammered into the ground using a hammer or the like.
  • the circuit 20 further comprises a signal generator which generates a signal representing the sensed parameter.
  • the signal generator determines the sensed parameter from an aspect of the monotonic change. Since in the shown electronic circuit 20, when in operation, the DC current flows through the portion of the ground, and the sensed parameter is determined from an aspect of the monotonic change, the circuit does not require high frequency components, or frequency converters.
  • the signal generator may use any aspect of the monotonic change suitable for the specific implementation and the sensed parameter may likewise be any suitable parameter which can be derived therefrom.
  • the parameter can for example be the impedance of the portion(s) of the ground, or components of the impedance.
  • the signal generator comprises a timer 28 which can measure a period of time it takes to monotonically change the charge from a predetermined initial level L1 to a predetermined second level L2.
  • a signal representing the measured period of time t can be outputted.
  • the timing circuitry may comprise a clock generator and a clock counter which is triggered by the voltage over the capacitor to start counting the clock pulses of the clock generator.
  • the timing circuitry may e.g. measure the time, and additionally be arranged to generate an error signal when the period of time exceeds a predetermined maximum, such as for example less than 0.1 second for example less than 0.05 seconds, such as 0.02 seconds or less.
  • the timer can, additionally or alternatively, be arranged to generate a value of zero when the period of time is below a predetermined minimum, such as not more than 1 millisecond, such as 0.5 milliseconds or less, for example 400 ps.
  • measuring the time allows to obtain a digital value without requiring e.g. analog to digital converters or other complex circuitry to convert an analog sensor signal.
  • the circuit 20 directly generates a signal which can be processed by a suitable digital processor.
  • the capacitance C of the DC current source is known and constant, and accordingly the variation in impedance of the ground determines the differences in time required to monotonically discharge the capacitor, e.g. the voltage changing from a predetermined initial level L1 to a predetermined second level L2. This impedance can thus be sensed by measuring the time.
  • the signal generator may use another aspect of the monotonic change, such as the voltage over opposite sides of the portion of ground or the amount of current through the path to determine the sensed parameter.
  • the electronic circuit may e.g. comprise a current multiplier circuit, like a current mirror with non-unity mirroring which measures the amount of current flowing through the current path, e.g. over a predetermined period of time and generate a signal which represents the sensed parameter, e.g. determined therefrom.
  • the sensed parameter may be the dielectric constant of the portion of ground.
  • the signal generator may e.g. use the capacitance of the electrodes 7 to determine the sensed parameter.
  • the monotonic change may be for a predetermined period, and the signal generator determine both at the start and end of the period e.g. the voltage over the electrodes 7 at opposite sides of the portion prior and determine the dielectric constant therefrom.
  • the electrodes 7 will act as a capacitor and accordingly the voltage there over be a function of the capacitance, which in turn is linearly proportional to the dielectric constant.
  • the variations in voltages can be related to the changes in the dielectric constant. It will be apparent that this may e.g. be combined with measuring the resistance and given that the voltage over a capacitor is a function both resistivity and dielectric constant be determined from several measurements.
  • FIG. 4 may be operated as follows. Initially, a loop between the power source 21 and the DC current source 23 may be enabled, e.g. with switch 27 closing the loop. This allows the DC current source to be charged to a predetermined initial level L1 , with current flowing from the source 21 through charging resistor 24. For example, the DC current source 23 may be charged for a predetermined period of time, e.g. 10 milliseconds. Assuming that the resistance 24 is known, this results in a predetermined charge to the initial level L1. Worded mathematically, when charging the capacitor:
  • V bmten I (t) R 0 + q (t) C 0
  • 0 represents the resistance of the resistor 24 and L 0 represents the capacitance of the capacitor. This can be rewritten as:
  • the second term in this equation can be neglected and the charge q(t) becomes simply V battery C 0 .
  • the duration of setting the charge to the predetermined level can be relatively short and for example a charging of less than 50 milliseconds, such as less than 20 milliseconds, e.g. 10 milliseconds be sufficient to apply this approximation. It has been found that even if a sufficiently small capacitance is used that renders the time constant R 0 C 0 a fraction of this period of time, still such a capacitance can provide sufficient current to accurately determine the sensed parameter.
  • the loop may then be interrupted and another loop be closed of which the current path through the portion of ground is part and accordingly the capacitor be discharged.
  • the anode or cathode of the DC current source or sink 23 the portion of ground and the electrodes 7 at the beginning and end of the current path through the portion are connected in series. Accordingly, when discharging a DC current will pass through the portion of the ground.
  • the impedance thereof determines the current flow, and thus the manner in and rate at which the charge of the DC current source or sink is changed.
  • the anode and cathode are connected to each other (through a serial loop), but it will be apparent that instead e.g.
  • the cathode only one thereof, such as the cathode, can be connected in series with the electrodes via the current path, e.g. to an electrical ground connected to a negative electrode.
  • the serial connection is without parallel branches and accordingly all current will pass through the portion.
  • the circuit may contain branches parallel to the serial connection, like for example a current mirror which copies the current flowing through the portion to allow to measure this current, for example.
  • the current path connects two electrodes 7 at opposite sides of the portion and the cathode of the capacitor is connected through the, resistive, current path with the anode thereof.
  • the resistive component determines the rate at which the charge changes, i.e. the capacitor discharges and accordingly the time required to discharge the capacitor 23 from the initial predetermined level L1 to another second predetermined level L2 is a measure for the impedance of the portion of the ground.
  • the power source when discharging the capacitor, the power source is no longer present and so:
  • Rsoii represents the resistive component of the impedance of the ground, as represented in the circuit diagram of FIG. 2 with resistor R s0 n .
  • the capacitor or other DC current source may be charged to the predetermined initial level L1 .
  • the DC current source may then be discharged and upon starting to discharge, a timer 28 may be started.
  • the change in charge can for example be measured by measuring the voltage over the capacitor and to that end the circuit 20 comprises a voltage meter 25 which provides input to a comparator 26.
  • the comparator receives as a reference a voltage corresponding to the second predetermined level L2 and outputs a signal when the measured voltage drops below the second level L2.
  • This signal is transmitted to stop a timer (elk) 28 which when stops outputs a signal representing the value of the time when stopped.
  • the voltage meter and comparator may be implemented with relatively simple and robust circuitry.
  • the circuit 20 may e.g. be provided on a board, like a printed circuit board with connections to the respective electrodes.
  • the circuit may be connected to transmission circuitry 30, such as a transmitter with an antenna.
  • the transmission circuitry 30 may for example be off— board.
  • Such off-board circuitry can e.g. be present in a shielded space where the circuitry is shielded from the impact forces and vibrations, whereas the circuit 20 is unshielded, such as embedded in the body B.
  • the signal from the signal generator can for example be output to a remote calculator 29 outside the probe, such as a remote data centre, which calculates therefrom a measured value of a measured property of the ground.
  • a signal representing the measured period of time t can be output by the transmission circuitry 30 via a wireless connection, and from the period of time a measured value of the measured property be determined, such as a humidity percentage.
  • the probe may be connected via a wired connection to a data collecting node, for example a collecting node placed in a field where several probes are present, all connected via wires to the node.
  • the collecting node may then be connected, e.g. via a wired or wireless data communication network, to a remote data centre or other data processing node.
  • the calculator 29 can be integrated in the probe and connect the circuit 20 to the transmission circuitry 30.
  • the calculator may then, for example, calculate measured values from the signal received from the circuit 20 and send those via the transmission circuitry to a receiver outside the probe via a wired or wireless connection.
  • the measured time correlates to the impedance and can be used by the calculator 29 to calculate a measured property of the ground, such as humidity.
  • a measured property of the ground such as humidity.
  • the sensed parameter is the dielectric constant of the ground
  • the humidity thereof can be calculated based on the known dielectric constants of water and dry ground.
  • the model may for example be a known model and accordingly this is not described in further detail. It should be apparent that in this respect the resistive and/or capacitive components of the impedance can be determined in absolute terms or in relative terms (e.g. changes therein).
  • the probe can be arranged to obtain a sensing result, or measurement derived therefrom, on the basis of a single charge and/or single discharge of the capacitor through a portion of ground. Accordingly, obtaining data will cost very little energy.
  • the probe can for example be arranged to sense by performing a single monotonic change, e.g. just of a single charge or of a single discharge. Accordingly, only a small amount of energy is required to obtain relatively accurate measurement data.
  • the probe may e.g. comprise a memory connected to the calculating circuitry for storing multiple sensing results or measurements.
  • the probe may be provided with a transmitter 30, via which a wired or wireless connection can be established to a receiving node, and the measurement system transmit via the connection in a single batch of data, data representing the stored results. This allows to reduce the energy required to transmit the data and hence the overall power consumption of the probe.
  • FIG. 6 this flow chart illustrates a method of sensing with a probe a parameter of ground at a depth in a portion of ground adjacent to the probe. The method can e.g. be performed in a probe with a circuit as shown in FIG. 4 or another suitable electronic circuit.
  • Such a method may comprise the use, with the probe inserted into ground to a desired depth, of the portion as a current path for a DC current which monotonically changes the charge of a DC current source or current sink from a predetermined initial level to a predetermined second level.
  • a period of time elapsing between changing the charge from the predetermined initial level to the predetermined second level or from another aspect of the monotonic change the sensed parameter may be determined.
  • a signal representing the elapsed period of time may be outputted.
  • a capacitor 23 is charged by the power source 21 to level L2. As illustrated with block S2, the charged capacitor 23 may be discharged through the current path to the level L1.
  • the probe 1 the time needed to discharge the capacitor 23 to the level L1 is measured.
  • the probe 1 may be provided with a stopwatch or a timer, or the like, which is able to measure the time.
  • the probe 1 is configured to measure the time with accuracy in the order of micro-seconds.
  • the sensed parameter such as the resistivity
  • the sensed parameter may be determined from the measured period of time, as explained above and illustrated with block S3. This may e.g. be outputted to outside the probe, e.g. to a remote data processing station, or to other circuitry inside the probe. Subsequently, as illustrated with block S4, from the determined period of time a measured value of a measured property, such as salinity, temperature or humidity may be calculated, as illustrated with block S5. Data may then be outputted which represents the measured value, as illustrated with block S6.
  • This data may for example be outputted in a for human perceptible form, in order to e.g. allow a farmer to manage the growing of crop, or for instance to a soil management system which controls the condition of the soil and compares the measured value with a present criterion to e.g. add or reduced the concentration of nutrients, water or otherwise in the ground.
  • the probe 1 may be arranged to carry out a single measurement. Accordingly, it may not be necessary to perform the charging and or discharging more than once to obtain a measurement result. This may allow for qualitative results of the properties of the portion of ground. However, if desired, the changing of the charge may be performed several times and for example an average value be determined therefrom or data representing a batch of measurement values be sent.
  • the DC current source may be a battery
  • the electronic circuit comprise circuit that measures or calculates e.g. the charge or current delivered by the battery during a certain period of time and which outputs the measured or calculated value to the signal generator.
  • a circuit can be e.g. a commercially available integrated circuit battery management system or BMS, such as sold by NXP Semiconductors of Eindhoven, the Netherlands under serial number MC33771 B.
  • BMS integrated circuit battery management system
  • the DC current source and the power source may be the same.
  • connections between electronic components as discussed herein may be any type of connection suitable to transfer signals from or to the respective nodes, units or devices, for example via intermediate devices. Accordingly, unless implied or stated otherwise, the connections may for example be direct connections or indirect connections.
  • the connections may be illustrated or described in reference to being a single connection, a plurality of connections, unidirectional connections, or bidirectional connections. However, different embodiments may vary the implementation of the connections. For example, separate unidirectional connections may be used rather than bidirectional connections and vice versa.
  • plurality of connections may be replaced with a single connection that transfers multiple signals serially or in a time multiplexed manner. Likewise, single connections carrying multiple signals may be separated out into various different connections carrying subsets of these signals. Therefore, many options exist for transferring signals.
  • the probe can, alternatively, or additionally, be dedicated to measuring other parameters of the ground, such as salinity, temperature etc. which can be determined from the sensed parameter.
  • the probe may also be used in other applications, such as for example surveillance like monitoring the risk of desertification or forest fires, for example.
  • the probe has a single elongate body with a single tip.
  • the bodies may extend in parallel with their respective tips at the same side and the probe further comprise a transversal connection between the bodies which fixates the transversal distance, transversal to the longitudinal direction of the elongate bodies, for maintaining the bodies into position relative to each other when simultaneously inserting the elongate bodies into the ground.
  • any reference signs placed between parentheses shall not be construed as limiting the claim.
  • the word‘comprising’ does not exclude the presence of other elements or steps then those listed in a claim.
  • the terms“a” or“an,” as used herein, are defined as at least one or more than one.

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Abstract

La présente invention concerne une sonde de détection qui détecte un paramètre du sol à une certaine profondeur. La sonde comprend un corps allongé ayant une pointe comme extrémité avant pour entrer dans le sol et une tête comme extrémité arrière. La tête est formée de telle sorte qu'une force puisse être exercée sur le corps dans une direction d'insertion de la tête vers la pointe afin d'insérer le corps dans le sol à une profondeur souhaitée. Le corps allongé comprend une ou plusieurs électrodes pouvant être reliées électriquement, au niveau d'une position prédéfinie sur le corps, à une partie de sol qui, lorsque la sonde est insérée dans le sol, est adjacente à la position prédéfinie sur le corps. Un circuit électronique est intégré à l'intérieur de la sonde, ledit circuit pouvant être connecté à une source d'alimentation. Le circuit comprend une source ou un puits de courant continu connecté à l'électrode de manière à établir un trajet de courant à travers la partie de sol à travers lequel circule un courant continu qui change de manière monotone la charge dans la source ou le puits de courant continu. Un générateur de signal génère un signal représentant le paramètre détecté. Le générateur de signal est connecté au trajet de courant afin de déterminer, sur la base d'un aspect du changement monotone, le paramètre détecté. Le signal peut être délivré par l'intermédiaire d'une sortie du circuit.
PCT/NL2019/050377 2018-06-22 2019-06-18 Sonde de détection permettant de détecter un paramètre du sol à une certaine profondeur et procédés de placement et d'utilisation d'une telle sonde WO2019245367A1 (fr)

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NL2021169A NL2021169B1 (en) 2018-06-22 2018-06-22 Sensing probe for sensing a parameter of the ground at a certain depth, methods for placing and using such probes
NL2021169 2018-06-22

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CN111189878A (zh) * 2020-01-23 2020-05-22 福建省恒鼎建筑工程有限公司 土壤含水量检测系统及土壤肥瘦预警方法
CN112162082A (zh) * 2020-09-10 2021-01-01 安徽科技学院 一种基于fds100的便携式土壤水分测量仪
CN112710338A (zh) * 2021-01-22 2021-04-27 安徽农道智能科技有限公司 便携式农业小气候梯度观测杆及其控制方法
EP3916384A1 (fr) * 2020-05-25 2021-12-01 KUI Technologies Oy Dispositif de mesure pour mesurer la température et l'humidité dans un élément structurel
KR102350571B1 (ko) * 2021-01-21 2022-01-11 정승백 화분 배양토의 함수율 측정장치
WO2022060640A1 (fr) * 2020-09-15 2022-03-24 GRAVITY TECHNOLOGIES, LLC d/b/a/ GROUNDWORX Procédé et système d'installation de dispositifs de détection de conditions de sol sans fil et de surveillance et d'utilisation de signaux transmis à partir de ces derniers
US11445275B2 (en) * 2020-02-15 2022-09-13 Michael Murray Soil and environment sensor and method of use
WO2024107568A1 (fr) * 2022-11-14 2024-05-23 Stationkeep Llc Pénétromètre hélicoïdal géotechnique pour mesurer des propriétés d'ingénierie de sédiments

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Publication number Priority date Publication date Assignee Title
CN111189878A (zh) * 2020-01-23 2020-05-22 福建省恒鼎建筑工程有限公司 土壤含水量检测系统及土壤肥瘦预警方法
CN111189878B (zh) * 2020-01-23 2022-08-16 福建省恒鼎建筑工程有限公司 土壤含水量检测系统及土壤肥瘦预警方法
US11445275B2 (en) * 2020-02-15 2022-09-13 Michael Murray Soil and environment sensor and method of use
EP3916384A1 (fr) * 2020-05-25 2021-12-01 KUI Technologies Oy Dispositif de mesure pour mesurer la température et l'humidité dans un élément structurel
CN112162082A (zh) * 2020-09-10 2021-01-01 安徽科技学院 一种基于fds100的便携式土壤水分测量仪
WO2022060640A1 (fr) * 2020-09-15 2022-03-24 GRAVITY TECHNOLOGIES, LLC d/b/a/ GROUNDWORX Procédé et système d'installation de dispositifs de détection de conditions de sol sans fil et de surveillance et d'utilisation de signaux transmis à partir de ces derniers
KR102350571B1 (ko) * 2021-01-21 2022-01-11 정승백 화분 배양토의 함수율 측정장치
CN112710338A (zh) * 2021-01-22 2021-04-27 安徽农道智能科技有限公司 便携式农业小气候梯度观测杆及其控制方法
WO2024107568A1 (fr) * 2022-11-14 2024-05-23 Stationkeep Llc Pénétromètre hélicoïdal géotechnique pour mesurer des propriétés d'ingénierie de sédiments

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