DE102013010491B4 - Method and device for determining the topography of a plant - Google Patents

Abstract

Method for determining the topography and/or tomography of roots of at least one asparagus plant (12, 14), which are located within an earth bank (10), electromagnetic radiation being sent in the direction of the plant (12, 14) and electromagnetic radiation being sent from the direction of the plant (12, 14) is received, characterized in that the received electromagnetic radiation is evaluated as a function of the transmitted electromagnetic radiation and a control signal (s) is then generated, the value of which is a measure of the topography of the roots of the asparagus plant (12, 14 ).

Description

The present invention relates to a method that can be used to determine the topography and/or tomography of plants within a soil. The invention also relates to a radar device that can carry out the method according to the invention as well as a harvesting device and a fertilizer or irrigation device that can be controlled using the method according to the invention.

Such a topography or tomography determination preferably includes plant parts, such as roots or crops, such as asparagus spears, potatoes, onions, radishes or the like. Furthermore, it is possible to analyze not only the plants but also the soil surrounding them, such as earth walls or the like. Although the invention is essentially described below using asparagus plants, it is by no means limited to this.

Asparagus plants are usually mostly below the surface of the earth, which can be flat or have the shape of an earth wall - hereinafter also referred to as an asparagus wall. Only shortly before harvest do individual asparagus spears emerge from the ground and can thus be visually noticed.

At the present time, targeted monitoring of the growth process of each asparagus spear in an asparagus wall is not possible, as the repeated exposure of each individual plant for the purpose of inspection does not appear to make economic sense. For this reason, the results of the measures carried out during the growth process (fertilization, irrigation, etc.) can only be determined holistically and without differentiation (“which measure brought which result?”) before or during the harvest. In addition, the use of fertilizers, for example, cannot be controlled selectively, but is carried out uniformly for the entire asparagus wall, which results in unnecessary costs for the producer and unnecessary strain on the soil and the crop - and ultimately for the consumer.

It therefore makes sense to obtain information about how the plant's development is progressing during the growth process in order to then be able to intervene in a targeted manner through appropriate measures - if necessary also locally on the respective asparagus plant - such as fertilization, irrigation, etc.

Furthermore, harvesting asparagus is often a complex process in which each individual stalk of asparagus is manually exposed and, if it has the necessary degree of ripeness, pierced. In addition to the already laborious process, those plants that are not yet ready for harvest must be buried again and checked again at a later date using the procedure described. If, on the other hand, each asparagus plant is not uncovered, the piercing process takes place “blindly”, so that a targeted harvesting process by the harvester cannot be guaranteed. There is then a risk that the asparagus spear in question will either be cut too short and/or neighboring asparagus spears will be affected because they are accidentally caught by the harvesting knife.

The asparagus harvesting machines available on the market make the manual work involved in harvesting partially obsolete, but they bring with them a number of significant disadvantages, which is why they have not yet been able to replace asparagus harvesting by hand.

One option for automated asparagus harvesting is to remove the entire asparagus wall and sieve out the asparagus spears it contains. A corresponding mechanical asparagus harvest is known, for example EP 0922382 A1 . This most radical form of harvesting has the particular disadvantage that the root balls of the asparagus plants are often damaged due to a fixed height at which the asparagus wall is removed, since the expansion of the individual root balls is different and usually changes over time. Such damage can reduce the yield of the plants in question, or even lead to total failure.

Out of DE 10 2010 001 300 A1 A special device for harvesting asparagus and a corresponding method are also known. It is proposed to insert probes into the asparagus wall and to carry out an imaging procedure using ultrasound or X-rays to determine the position of the asparagus spears. Alternatively, it is suggested there to introduce several current conductors into the asparagus wall, if necessary with simultaneous contact with the asparagus, in order to then determine the position of the asparagus by measuring the different current intensities in the individual conductors. Such a solution has the disadvantage that it is difficult to implement and can also damage the asparagus plants.

Next is over DE 602 02 978 T2 a “device for automatically harvesting asparagus” known, in which, by means of sensors that are pulled along the asparagus wall, an asparagus protruding from the asparagus wall deflects it backwards and thus signals the position of the asparagus to the harvesting machine.

The EP 0 770 321 A1 discloses a device mounted on a vehicle for determining the position of harvestable asparagus plants, with sensors being provided for detecting the distance of the asparagus that is still entirely in the ground from the surface of the ground.

The DE 10 2013 019 531 A1 discloses a device for the automatic detection of asparagus shoots which, by combining the automatic, selective harvesting systems with a georadar system, can distinguish the geometry of the almost vertically growing asparagus shoots (asparagus spears) from the root ball and the surrounding earth and thus specifically asparagus shoots, not only in position, but even at depth, can be pierced specifically with a harvesting tool. It is also possible to identify additional asparagus shoots in the vicinity of the asparagus spear to be harvested and to position the harvesting tool in such a way that the asparagus spear to be harvested can be pricked and shoots that are not yet suitable for harvesting are not damaged.

The US 2002/0008167 A1 discloses a ground-based remote sensing system for use in conjunction with agricultural irrigation systems. The ground-based remote sensing system includes a sensor package mounted on a carriage to move along a rail connected to the agricultural irrigation system. The rail is triangular in cross-section and includes springs between the abutting sections so that movement of the carriage along the rail is not affected by misalignment between the abutting sections. The sensor package is attached to the carriage with a bracket that ensures that the sensor package remains in a predetermined orientation with respect to the agricultural crop from which data is being collected. The mount also includes a tilt sensor that allows correction of errors in agricultural data collection due to misalignments of the sensor package with respect to the agricultural crop. The ground-based remote sensing system also includes guardrails to transmit power from a speed control circuit to the sled motor. The output voltage and thus the speed of the slide of the speed control loop is variable. A traversing direction control circuit reverses the direction of the carriage when it arrives at either end of the track, so that the traversing direction control circuit and the speed control circuit together continuously move the carriage back and forth along the track. As the sled-mounted sensor package moves back and forth, it collects data about agricultural crops, which can then be downloaded to a computer for processing and analysis.

The EP 0 053 994 B1 discloses an asparagus picking robot, that is, an autonomous machine capable of identifying asparagus emerging from the ground and picking it automatically without human intervention.

The DE 10 2006 016 740 A1 discloses a device for an agricultural machine for detecting disturbing objects in a plant field consisting of a large number of plants, with a transmitting device for transmitting a radar signal, the wavelength of which is set depending on the parameters of a plant in the plant field, and a receiving device for receiving a signal transmitted through the plant field reflected radar signal and with an evaluation device that evaluates the received radar signal and detects a disturbing object in the plant field when the signal power of the received radar signal is above an adjustable threshold value.

The EP 0 980 009 A2 discloses a radar including a signal source for emitting an RF signal and a detector for detecting the RF signal reflected from a target and for outputting a signal depending on the range of the target and the amplitude of the reflected signal and further comprising a means for generating an audio signal whose frequency and amplitude depend on the range of the target and the amplitude of the reflected signal. The operator therefore hears an audio signal containing information about detected targets.

The US 6,657,577 B1 discloses a system for generating information indicative of the depth and orientation of an object located below the earth's surface, is designed to use electromagnetic radiation emitted by and received by an antenna system associated with the system. The system has a transmitter and a receiver for generating the electromagnetic radiation in cooperation with the antenna system mentioned or for receiving the electromagnetic radiation reflected from the object in cooperation with the antenna system. The antenna system includes a plurality of individual antenna elements, such as dipole antennas, with a substantially linear pole rization. The antenna elements are positioned with respect to the geometric center of the antenna system, with the various centers of the antenna element being offset with respect to the geometric center of the antenna system. The system has a mechanism for rotating the antenna system and thereby polarizing the electromagnetic field around or in relation to the geometric center of the antenna system.

JP H08-292 253 A relates to a microwave scatterometer.

Another method for automated asparagus harvesting is an optical method in which the surface of the asparagus wall is monitored optically (e.g. using a laser and/or a camera, etc.). This means that it can be detected at the points where an asparagus spear breaks through the wall. A corresponding signal can then be given to a robot arm or to a person so that the harvesting is then carried out.

It doesn't matter whether the asparagus must first be electrically contacted for detection and/or position determination, or must come into contact with sensors, or must be detected by an optical device. The obvious disadvantage of all of these methods is that only asparagus spears can be detected that have already broken through the wall or are about to do so.

Another disadvantage of the automated selective harvesting methods described is that the exact position and spatial orientation of the asparagus spears in the wall is not known and therefore, for example, a robot arm can only handle them in a comparatively untargeted manner. This poses the risk that at least some of the asparagus spears will be missed during the harvesting process, for example, and/or several attempts to harvest will have to be made before harvesting has been carried out successfully. Or there is a risk that at least some of the asparagus plants will be pricked incorrectly (for example too short) and/or damaged during the harvest attempt. All of this costs either time (and therefore money, for example through extended working hours) and/or money through unharvested asparagus plants and/or a reduced selling price.

It is the object of the present invention to avoid the disadvantages known from the prior art.

This task is solved by a method according to claim 1. Advantageous embodiments are specified in the subclaims.

• - Spargelstangen und -wurzeln enthalten Wasser und gelöste Salze, was eine hohe Leitfähigkeit und damit eine gute Reflexion elektromagnetischer Wellen, beispielsweise im Mikro- bis Millimeterwellenbereich bedingt.
• - Gleichzeitig heben sich Spargelstangen und -wurzeln dielektrisch sehr gut von ihrer künstlich geschaffenen Umgebung (Spargelwall aus Erde/Sand) ab, was zu einer optimalen Ausgangssituation für seine Detektion führt.
• - Die Größe von Spargelstangen (Länge, Durchmesser) und die Ausdehnung der Wurzeln führen zu gut detektierbaren und lokalisierbaren Reflexionen in einem technisch gut handhabbaren Frequenzbereich.
• - Die sandige Umgebung ist recht homogen und vergleichsweise trocken. Somit werden die elektromagnetischen Wellen durch die Umgebung in einer reproduzierbaren Weise beeinflusst, die sich in der nachfolgenden Signalauswertung vergleichsweise einfach berücksichtigen oder heraus rechnen lässt.
• - Der Spargelwall ist im Allgemeinen von drei Seiten zugänglich, was gute Voraussetzungen für Messungen sowohl in Reflexion als auch in Transmission darstellt (auch Tomographie).
• - Die Spargelstangen sind länglich, daher gibt es eine starke Polarisationsabhängigkeit der Reflexion.
• - Die hier notwendigen Signal-Leistungen werfen keine moralisch/ethischen Bedenken auf. Und weder die (Arbeits-) Sicherheit, noch die Gesundheit von Erntehelfern und/oder Verbrauchern wird gefährdet. - Ganz im Gegensatz zu oben beschriebenen Verfahren mittels Röntgenstrahlung.
• - Ein Radar kann Spargelstangen und -wurzeln kontaktlos detektieren und die Spargelwallparameter feststellen. Es ist nicht nötig, umständlich Sonden in den Spargelwall einzuführen und dazu den Spargel selbst womöglich noch kontaktieren zu müssen, wie es das oben erwähnte, nachteilige Verfahren erfordert. Der Spargel muss beim Einsatz eines Radars auch noch nicht durch den Wall gebrochen sein, wie es etwa die oben beschriebene, nachteilige, Methode mit den Fühlern verlangt. Die Antennen brauchen den Spargelwall nicht direkt zu berühren, sondern können sich in einem gewissen Abstand befinden.

The present invention is based in particular on the following findings.

• - Asparagus spears and roots contain water and dissolved salts, which results in high conductivity and therefore good reflection of electromagnetic waves, for example in the micro to millimeter wave range.
• - At the same time, asparagus spears and roots stand out dielectrically very well from their artificially created environment (asparagus wall made of earth/sand), which leads to an optimal starting situation for its detection.
• - The size of asparagus spears (length, diameter) and the extent of the roots lead to easily detectable and localized reflections in a frequency range that is technically easy to handle.
• - The sandy environment is quite homogeneous and comparatively dry. The electromagnetic waves are thus influenced by the environment in a reproducible manner, which can be taken into account or calculated comparatively easily in the subsequent signal evaluation.
• - The asparagus wall is generally accessible from three sides, which provides good conditions for measurements in both reflection and transmission (including tomography).
• - The asparagus spears are elongated, so there is a strong polarization dependence of the reflection.
• - The signal services required here do not raise any moral/ethical concerns. And neither the (occupational) safety nor the health of harvest workers and/or consumers is endangered. - Completely in contrast to the procedures described above using X-rays.
• - A radar can detect asparagus spears and roots without contact and determine the asparagus wall parameters. It is not necessary to laboriously insert probes into the asparagus wall and possibly have to contact the asparagus itself, as the disadvantageous method mentioned above requires. When using a radar, the asparagus does not have to have broken through the wall, as is required with the disadvantageous method with sensors described above. The antennas do not need to touch the asparagus wall directly, but can be at a certain distance.

The method according to the invention sends out electromagnetic radiation in the direction of the plant to be examined and also receives electromagnetic radiation that comes from its direction. By comparing the two radiations with each other, a control signal is generated, the value of which is a measure of the topography of the plant or its parts. When comparing transmitted and received radiation, various parameters can be taken into account, such as, in particular, differences in amplitude, transit time and/or phase.

It is preferred that the received electromagnetic radiation arises from reflection on the plant to be examined or on the earth surrounding it. A radar method is preferably provided for this. A radar system that works according to the principle of modulated continuous wave radar, for example as Stepped Frequency Continuous Wave (SFCW) radar, has proven particularly useful.

To carry out the method according to the invention, it has proven useful that the emitted electromagnetic radiation is in the range from 100 MHz to 4 GHz, with the range from 300 MHz to 2 GHz being particularly useful. The main criteria for selecting the frequency ranges mentioned are, on the one hand, the antenna size (for the lower range limit) and, on the other hand, the attenuation in the ground (for the upper range limit).

Carrying out windowing and zero padding (appending zeros) is particularly useful for radar methods that work in the frequency range, so that the data is also generated there. This is the case for SFCW radar systems. For radar methods such as pulse radar, which work entirely in the time domain, these are usually not standard methods that are applied to the data. However, windowing and zero padding can also be applied to data that is available in the time domain (pulse radar) before it is transformed into the frequency domain in order to be processed there. Possible methods of a suitable transformation are Fourier transform, Laplace transform and other methods known to those skilled in the art.

The control signal generated by the method according to the invention can be used to control or regulate harvesting equipment, such as a cutting unit for gently removing an asparagus wall, a piercing and cutting knife or the like. The control signal can also be used to control a machine that can water and/or fertilize the plants.

It is also possible, in addition or instead, for the control signal. is used to generate a graphical representation that can be displayed to a user using a display unit, such as a monitor. This allows the user to be shown the topography and/or growth of the plants being examined. It is also conceivable that, in addition or instead, an optical projection (for example using a laser) onto the ground and/or a display using data glasses takes place, which can support a harvester in his harvesting activity (augmented reality).

The control signal can also be used to control a signaling device that signals to a user using optical and/or acoustic means when the examined plant or the examined area of the earth wall needs to be processed, in particular irrigated and/or fertilized. For this purpose, measured parameters are compared with threshold values and if they are exceeded or fallen below, corresponding signals are output.

It is understood that in the applications mentioned, the control signal can be supplied directly to the downstream devices - such as the harvesting equipment, the machines, the display unit, the signaling device. However, it is also possible for the control signal or its values to be initially stored on a data carrier, which is later read out by the downstream devices mentioned. Suitable data carriers are, for example, corresponding semiconductor components, magnetic memories and/or opto-magnetic memories.

A radar device, which is particularly suitable for carrying out the method according to the invention, can be connected to a transport device, which in turn is able to move the radar device along the ground where the plants to be examined are located. For this purpose, the radar device according to the invention has corresponding connecting means.

In principle, a large number of different types of antennas, which are generally known to those skilled in the art, can be used to implement the invention. In the preferred embodiment, loaded bowtie antennas have proven particularly useful. Such antennas are described, for example, in Amert, T.; Wolf, J.; Albers, L.; Palecek, D.; Thompson, S.; Askildsen, B.; Whites, KW, "Economical resistive tapering of bowtie antennas," Antennas and Propagation Society International Symposium, 2004. IEEE, vol.2, no., pp.1772,1775 Vol.2, 20-25 June 2004; doi: 10. 1 109/APS.2004.1330541

The present invention therefore has the following advantages and possible uses in particular.

By continuously monitoring the growth process of each asparagus plant, it is possible to intervene - if necessary locally for each plant - through targeted irrigation and the use of fertilizers, which, for example, avoids both under-fertilization and over-fertilization, and thus costs and the environment - and product load minimized.

Parameters of the asparagus wall can be determined, such as its moisture, its permittivity and its conductivity. From one or more of these parameters, conclusions can be drawn about necessary actions regarding the management of the asparagus wall, namely irrigation or fertilization.

By continuously determining the size of the asparagus spears, the right time for harvesting can be determined. There is no need to wait for the asparagus to break through the wall, as is required with the disadvantageous optical method described above. The producer can therefore always achieve the full market price for his vegetables, as there is no contact with sunlight and therefore no discoloration.

By determining the asparagus topography (position, size and direction), the arm of a harvesting robot - or other suitable harvesting device - can be controlled.

• 1 eine Radaranordnung zur Bestimmung der Wurzeltopographie (Querschnittsdarstellung)
• 2 die Anordnung gemäß 1 im Längsschnitt
• 3 eine Radaranordnung zur Bestimmung der Permittivität ξ des Spargelwalls
• 4 eine Radaranordnung zur gleichzeitigen Bestimmung von Pflanzen-Topographie und Permittivität ξ des Spargelwalls.

Further advantages and details of the present invention emerge from the following description of preferred exemplary embodiments. Show:

• 1 a radar arrangement for determining the root topography (cross-sectional view)
• 2 according to the order 1 in longitudinal section
• 3 a radar arrangement for determining the permittivity ξ of the asparagus wall
• 4 a radar arrangement for the simultaneous determination of plant topography and permittivity ξ of the asparagus wall.

The preferred embodiments relate to various radar systems that usually work together with an asparagus harvester. The radar systems generate control signals based on radar measurements, which are described in more detail below, which can be used to control an asparagus harvester. The radar systems of the preferred exemplary embodiments are - at least during harvesting operation - firmly connected to one of the asparagus harvesting machines and are moved accordingly in order to carry out an asparagus harvest. Since the asparagus harvesting machines mentioned are known per se, they are not shown in the figures.

1 shows a cross-sectional view of an earth wall 10, in which an asparagus plant can be seen, of which a root ball 12 and a row of asparagus spears 14 are shown here. As is common in asparagus cultivation, the earth wall 10 shown here has a substantially trapezoidal cross-section with a surface 16. The root ball 12 shown here has - based on the cross-sectional view - an upper point 18.

Above the earth wall 10 there is a radar arrangement which includes a transmitting antenna 20, a receiving antenna 22 and a radar device 24. The radar device 24 contains a known transmitting unit 26 for generating and transmitting high-frequency radar signals with usual stages, such as in particular oscillators, modulator, drivers, output stages and filters, as well as a receiving unit 28 for receiving such radar signals with usual stages, such as in particular filters, preliminary stages and the same. Furthermore, the radar device 24 also contains a computing unit 30, which serves in particular to modulate the transmission signals in a suitable manner and to evaluate the received signals.

The two antennas 20, 22 are preferably designed as loaded bowtie antennas with a distance from each other of approximately 0.1 m. Here they are arranged centrally to the earth wall 10, with an almost equal vertical distance DE from the surface 16. DE is preferably approximately 0.1 m. The vertical distance between the antennas 20, 22 and the upper point 18 of the root ball 12 is designated DW. A suitable shield can also be arranged between the two antennas 20, 22 (not shown here) in order to reduce direct antenna crosstalk and thus be able to increase the dynamic range of the radar arrangement. Such shielding can be easily implemented using appropriate absorber material.

2 shows the same arrangement as in a longitudinal view 1 . For reasons of clarity, the internal stages 26, 28, 30 of the radar device 24 are not shown here; In addition, the transmitting antenna 20 is covered by the receiving antenna 22 in this illustration. In 2 It can be seen in particular that within the earth wall There are 10 several asparagus plants. The shape, size and also the height of the corresponding root balls 12 are usually different, so that with the same distance DE between the antennas 20, 22 and the surface 16, different values DW can result depending on the asparagus plants.

In the preferred exemplary embodiment, the radar device 24 is designed in such a way that it works as a modulated continuous wave radar, with the Stepped Frequency Continuous Wave (SFCW) radar method having proven particularly useful. The antennas 20, 22 are moved along the earth bank 10 by means of a harvesting vehicle (not shown here), which in 2 is indicated by the arrow P. The radar device 24 carries out measurements of the complex-valued S21 parameter at various measuring points, which indicates the signal attenuation and phase as a result of the transmission. Such measuring points are at a distance of approximately 1 cm from each other along the earth wall 10.

To determine the topography of the root balls 12, in particular their arrangement, shape and size, measurements are preferably carried out at around 100 discrete frequency points in the range from 300 MHz to 2 GHz at each measuring point and corresponding measured values are recorded. These raw data are first subjected to various preprocessing steps by the computing unit 30. In the preferred version, these initially include windowing and then appending with zeros (zero padding). The data is then transferred to the time domain using a discrete Fourier transformation. Data from a so-called background recording is subtracted from the measurement data processed in this way. This is a radar recording carried out in advance, which only contains the static influences, but not changing reflections, such as those from asparagus plants. This means that static influences can be eliminated in all measurements, which arise in particular from direct antenna crosstalk, reflections on the transport vehicle and the like. Such background recordings can be carried out, for example, by carrying out radar measurements on an earth bank 10 without asparagus plants.

During further calculations by the arithmetic unit 30, the direct reflection on the surface 16 is detected after a two-way signal transit time t _E in air. Next, the dominant reflection on the root ball 12 can be determined after the two-way transit time t _W. Taking into account the permittivity ξ of the material of the earth wall 10, the distance DW between

mit

• c₀ Vakuumlichtgeschwindigkeit
• t_E 2-wege Signallaufzeit in Luft
• t_W 2-wege Signallaufzeit zum Wurzelballen 12
• ξ Permittivität des Erdwall-Materials

Root ball surface 18 and the antennas 20, 22 can be determined according to the following equation: $$\text{DW}=0.5*{\text{c}}_0*\left({\text{t}}_{\text{E}}+\left[{\text{t}}_{\text{W}}-{\text{t}}_{\text{E}}\right]/\surd \left(\mathrm{\xi }\right)\right)$$

with

• c ₀ vacuum speed of light
• t _E 2-way signal transit time in air
• t _W 2-way signal transit time to the root ball 12
• ξ Permittivity of the earth embankment material

Such measurements and evaluations are preferably carried out continuously while the radar system is being moved along the earth wall 10. This allows the topography - such as in particular the arrangement, shape and size - of the root ball 12 to be determined.

The permittivity ξ of the earth wall material can be estimated or even measured. A possible measuring method is described below using: 3 described.

The computing unit 30 generates a control signal s, the value of which is a measure of the distance DW. The control signal s is forwarded to an asparagus harvester (for example model KIRPY DE.21 from aisolution), which uses a cutting device to pick up the entire earth wall 10 at a predetermined distance above the root balls 12. The cut asparagus spears 14 are selected, which is usually done manually, and then the earth wall 10 is rebuilt. In such a case, the control signal s serves in particular to control or regulate the height of the cutting unit depending on the topography of the root balls 12 along the earth bank 10.

3 is a cross-sectional view in which the earth wall 10 is symbolically shown with an asparagus plant. A left antenna 120 and a right antenna 122 are connected to the radar device 24 - the inner stages 26, 28, 30 of which are not shown here. These can be designed similarly to the antennas 20, 22 and are also designed as “loaded bowtie” antennas. Here too, the radar device 24 preferably works as a modulated continuous wave radar (for example as an SFCW).

The main difference in the radar arrangement after 3 compared to the radar arrangement according to the 1 , 2 is that in 3 the two antennas 120, 122 are arranged to the side of the earth wall 10, instead of above it. The lateral distance between the left antenna 120 and the earth wall 10 is Dli and the lateral distance between the right antenna 122 and the earth wall 10 is labeled Dre. The point used here as the left and right reference point - based on the cross-sectional representation - is the point that is located halfway up the earth wall 10.

The radar device 24 carries out measurements on its two ports (antenna connections), recording complex-valued data points at approximately 100 discrete frequency points in the range from approximately 300 MHz to 2 GHz, for all configurations, namely that
Antenna 120 for transmitting and antenna 120 for receiving (S11),
Antenna 120 for transmitting and antenna 122 for receiving (S21),
Antenna 122 for transmitting and antenna 120 for receiving (S12), and
Antenna 122 is used for transmitting and antenna 122 is used for receiving (S22).

Analogous to the procedure described above (to 1 and 2 ), the raw data is transferred to the time domain. They are then corrected by the computing unit 30 by subtracting static data from a background measurement once for each S parameter. These static influences include, for example, reflections on the radar system's transport vehicle, as well as the internal antenna reflections for the S11 and S22 measurements.

mit

• tli: 2-wege Signallaufzeit zwischen Antenne 120 und der linken Seite des Erdwalls 10
• tre: 2-wege Signallaufzeit zwischen Antenne 122 und der rechten Seite des Erdwalls 10
• c₀: Vakuumlichtgeschwindigkeit

By evaluating reflection measurements - corresponding to parameters S11, S22 - the distance values Dli and Dre can be determined as follows: $$\begin{array}{l}\text{Dli}=0.5*\text{tli}*{\text{c}}_0\hfill \\ \text{Dr}=0.5*\text{tre}*{\text{c}}_0\hfill \end{array}$$

with

• tli: 2-way signal transit time between antenna 120 and the left side of the earth wall 10
• tre: 2-way signal transit time between antenna 122 and the right side of the earth wall 10
• c ₀ : speed of light in vacuum

For such a measurement, both antennas 120, 122 work as both transmitting and receiving antennas.

mit

• c₀: Vakuumlichtgeschwindigkeit
• tges: 1-wege Gesamtlaufzeit der elektromagnetischen Welle
• Dli: Abstand zwischen linker Antenne 120 und linker Seite des Erdwalls 10
• Dre: Abstand zwischen rechter Antenne 122 und rechter Seite des Erdwalls 10
• Dges: Abstand zwischen den Antennen 120, 122.

By evaluating the S21 measurement, the 1-way signal transit time tges of the electromagnetic wave from the left antenna 120 through the earth wall 10 to the right antenna 122 can be determined (air - earth wall - air). In combination of all three measurements, with a known antenna distance Dges, the permittivity ξ of the earth wall material can be determined as follows: $$\mathrm{\xi }={\left(\left[{\text{c}}_0*\text{tges}-\text{Dli}-\text{Dr}\right]/\left[\text{Dges}-\text{Dli}-\text{Dr}\right]\right)}^2$$

with

• c ₀ : speed of light in vacuum
• tges: 1-way total transit time of the electromagnetic wave
• Dli: Distance between left antenna 120 and left side of earth wall 10
• Dre: Distance between right antenna 122 and right side of earth wall 10
• Dges: Distance between antennas 120, 122.

4 symbolically shows another preferred embodiment, in which the first radar arrangement ( 1 , 2 ) with the second radar arrangement ( 3 ) is combined. This means that both the pair of antennas 20, 22 and the pair of antennas 120, 122 are connected to the radar device 24, the first pair of antennas 20, 22 being located above the earth wall 10 and the second pair of antennas 120, 122 being arranged to the side of the earth wall 10 .

This makes it possible for a single measurement run for selected positions along the earth wall 10 to first determine its permittivity ξ and then the topography of the root balls 12, with the permittivity determined in this way being used directly to calculate the topography.

An antenna arrangement with several antennas arranged around the earth wall 10 is also particularly suitable for creating tomography images.

In order to be able to evaluate the signals from the two pairs of antennas separately, an electrical antenna switch (not shown) is additionally provided within the radar device 24, by controlling which the two pairs of antennas can be operated separately.

Alternatively, it is of course also possible for the radar device 24 to be designed in such a way that both pairs of antennas can be operated at the same time.

In a further preferred embodiment, the topography of the asparagus spears 14 is determined, which in particular includes their position, location and/or orientation within the earth bank 10. This can be done in addition to or instead of determining the root ball topography. It is in In both cases (asparagus spears and root balls) it is also possible for the polarization dependence of the reflection to be evaluated. For this purpose, the antenna arrangement is preferably 4 used. Based on the determined topography of the asparagus spears 14, a control signal s' is generated. This is used to control piercing and cutting knives, such as those used in the AsparagusPanther model from ai-solutions.

• - Jede der Antennen 20, 22, 120, 122 kann sowohl zum Senden als auch zum Empfangen von elektromagnetischen Wellen verwendet werden.
• - Jede der Antennen 20, 22, 120, 122 kann dabei prinzipiell auch gleichzeitig für beides (Senden und Empfangen) eingesetzt werden.
• - Es ist der Einsatz von einer einzigen Antenne möglich, die sowohl zum Senden der elektromagnetischen Wellen als auch zum Empfangen der gestreuten Wellen dient.
• - Beim Einsatz einer Gruppenantenne / eines Antennenarrays mit mehr als einer Antenne kann etwa auch durch Strahlformung der von den Antennen (parallel und/oder sequenziell) ausgestrahlten Wellen gezielt die gestreute Welle eines bestimmten Bereiches aus dem Observationsvolumen (Erdwall 10 und Umgebung) durch geeignete Fokussierung ermittelt werden. Dadurch ist es weiter möglich, den Bereich, in dem Spargelpflanzen erwartet werden, voxelweise abzurastern, und anhand der Messdaten über das Vorhandensein eines Spargels an der jeweiligen Stelle zu entscheiden, um seine Position, seine Lage und seinen Verlauf im Spargelwall zu ermitteln. Die erwähnte Fokussierung kann dabei erfolgen
  • ◯ mittels analoger und/oder digitaler Phasenschieber im Sende- und/oder Empfangszweig und/oder
  • ◯ mittels mechanischer Mittel, elektrischer Mittel und/oder digital mittels geeigneter (dielektrischer) Linsen und/oder
  • ◯ durch digitale Signalverarbeitung auf Basis der über die einzelnen Sende-Antennen gesendeten Signale und die über die einzelnen Empfangs-Antennen empfangenen (und ggf. in ein Zwischenfrequenz- oder Basisband herab gemischte und/oder mittels eines A/D-Wandlers abgetasteten) Signale.

The preferred exemplary embodiments described can be modified in many ways, such as:

• - Each of the antennas 20, 22, 120, 122 can be used both for transmitting and receiving electromagnetic waves.
• - Each of the antennas 20, 22, 120, 122 can in principle be used for both (transmitting and receiving) at the same time.
• - It is possible to use a single antenna, which is used both to transmit electromagnetic waves and to receive scattered waves.
• - When using a group antenna/an antenna array with more than one antenna, the scattered wave of a specific area from the observation volume (earth wall 10 and surroundings) can be targeted by beam shaping of the waves emitted by the antennas (parallel and/or sequentially) through suitable focusing be determined. This makes it possible to scan the area in which asparagus plants are expected voxel by voxel and to use the measurement data to decide on the presence of asparagus at the respective location in order to determine its position, location and course in the asparagus wall. The aforementioned focusing can take place
  • ◯ by means of analog and/or digital phase shifters in the transmission and/or reception branch and/or
  • ◯ by mechanical means, electrical means and/or digitally by means of suitable (dielectric) lenses and/or
  • ◯ through digital signal processing based on the signals sent via the individual transmitting antennas and the signals received via the individual receiving antennas (and possibly mixed down to an intermediate frequency or baseband and/or sampled using an A/D converter).

• - Die Antennen können bei allen Ausführungsbeispielen so angeordnet bzw. eingesetzt sein, dass Messungen in Reflexion und/oder in Transmission durchgeführt werden. Allgemein gesprochen kann aber jede der eingesetzten Antennen die durch eine anderen Antenne, oder sie selbst, ausgestrahlte und von einem Streukörper (etwa Spargel, Wurzelwerk, Wall-Material, aber auch Störobjekte wie beispielsweise Steine) gestreute elektromagnetische Welle empfangen.
• - Die Wahl der Polarisation kann für jede Antenne im Voraus fest oder auch während des Betriebes veränderlich (diskret und/oder kontinuierlich) einstellbar erfolgen. Dabei kann die jeweilige Polarisation der von jeder eingesetzten Antenne abgestrahlten und empfangenen elektromagnetischen Wellen beispielsweise durch die Wahl und/oder Ausrichtung der Antennen bestimmt werden. Es ist auch denkbar, die Polarisation durch geeignete elektrische (Be-) Schaltung der Antenne einstellen zu können. Ein Ausführungsbeispiel hierfür ist z.B. ein quadratisches Patch-Element, das zwei orthogonale, voneinander entkoppelte Eigenschwingungen aufweist, die mit entsprechend orientierten Polarisationen abstrahlen. Beide Eigenschwingungen können durch jeweils separate Speisestrukturen (z.B. Koaxialspeisung) näherungsweise unabhängig voneinander angeregt werden. Im Empfangsbetrieb verhält sich die Antenne entsprechend reziprok.

When using a group antenna or an antenna array, in addition to the possibility of checking the observation volume for the presence, position, location and course of a sought-after scattering body (here: asparagus), there is another possibility of reconstructing the observation volume through tomography or using a Another possibility of reconstruction is to obtain a representation of the asparagus wall in the local area. Here, a reconstruction can be understood as any such representation that, for example, conveys to a human viewer the representation of an asparagus present in the asparagus wall 10 in a suitable manner, for example on a control monitor on which the “inner workings” of the asparagus wall are shown. At least one antenna for transmitting and receiving should be attached at least on one, but preferably also on two or even three sides of the asparagus wall 10.

• - In all exemplary embodiments, the antennas can be arranged or used in such a way that measurements are carried out in reflection and/or in transmission. Generally speaking, however, each of the antennas used can receive the electromagnetic wave emitted by another antenna, or itself, and scattered by a scattering body (such as asparagus, roots, wall material, but also disruptive objects such as stones).
• - The choice of polarization can be fixed in advance for each antenna or can be adjusted (discretely and/or continuously) during operation. The respective polarization of the electromagnetic waves emitted and received by each antenna used can be determined, for example, by the choice and/or orientation of the antennas. It is also conceivable to be able to adjust the polarization by suitable electrical (charging) switching of the antenna. An exemplary embodiment of this is, for example, a square patch element that has two orthogonal, mutually decoupled natural oscillations that radiate with correspondingly oriented polarizations. Both natural oscillations can be excited approximately independently of each other by separate feed structures (e.g. coaxial feed). In reception mode, the antenna behaves reciprocally.

• - Es kann eine Sendeeinheit 26 vorgesehen werden, welche das Sendesignal erzeugt (und ggf. über einen D/A-Wandler als Analog-Signal zur Verfügung stellt, das ggf. über eine Mischerstufe mit einem Lokaloszillator in den gewünschten Frequenzbereich umgesetzt wird) und damit die jeweilige Sendeantenne speist, wobei im Zuge der Signal-Auswertung, unabhängig vom tatsächlich gewählten Verfahren, von der gesendeten elektromagnetischen Welle die Kenndaten zu ihrer Frequenz f_s, Phase Φ_s, Polarisation p_s, Amplitude a_s und Antennen-Hauptstrahl-Richtung, ihrerseits definiert durch einen Horizontalwinkel x_s und einen Vertikalwinkel y_s, sowie Antennengewinn g_s und physikalischer Position der Sendeantenne (u_s,v_s,w_s) und physikalischer Orientierung der Sendeantenne (beschrieben durch einen Vektor r_s, \vec{r_s}) im Raum, verwendet werden können. Dabei können alle Parameter ihrerseits von der Zeit t und wiederum allen anderen Parametern abhängen. Die Sendeeinheit 26 kann dabei sowohl im Zeit- wie auch im Frequenzbereich arbeiten.
• - Es kann eine Empfangseinheit 28 vorgesehen werden, die auch mit der Sendeeinheit 26 zusammenfallen kann, welche die an jeder Empfangsantenne empfangene elektromagnetische Welle (welche ggf. über eine Mischerstufe mit einem Lokaloszillator in einen anderen Frequenzbereich, z.B. Basisband, umgesetzt wird und ggf. über einen AD-Wandler als abgetastetes Digitalsignal vorliegt) auswertet und im Zuge der Signal-Auswertung, unabhängig vom tatsächlich gewählten Verfahren, von der empfangenen elektromagnetischen Welle die Kenndaten zu ihrer Frequenz f_e, Phase Φ_e, Polarisation p_e, Amplitude a_e und Antennen-Hauptstrahl-Richtung, ihrerseits definiert durch einen Horizontalwinkel x_e und einen Vertikalwinkel y_e, sowie Antennengewinn g_e und physikalischer Position der Empfangsantenne (u_e,v_e,w_e) und physikalischer Orientierung der Empfangsantenne (beschrieben durch einen Vektor r_e, \vec{r_e}) im Raum, verwendet werden können. Dabei können alle Parameter ihrerseits von der Zeit t und wiederum allen anderen Parametern abhängen. Die Empfangseinheit 28 kann dabei sowohl im Zeit- wie auch im Frequenzbereich arbeiten.
• - Es kann eine Prozessoreinheit bzw. Recheneinheit 30 vorgesehen werden, in welcher die Weiterverarbeitung aller Sende- und Empfangssignale erfolgt. Hierbei können alle bekannten, nämlich entweder aufgrund Vorgabe und/oder durch Messung, Informationen f_s, f_e, Φ_s, Φ_e, p_s, p_e a_s, a_e, x_s, x_e, y_s, y_e und t von sowohl Sende- (Index „s“) als auch Empfangssignalen (Index „e“) und Polarisation p_s, p_e, Gewinn g_s, g_e, Position (u_s,v_s,w_s), (u_e,v_e,w_e) und physikalischer Orientierung der Antennen (beschrieben durch einen Vektor r_s, r_e, \vec{r_s}), \vec{r_e}) im Raum von sowohl Sende- (Index „s“) wie auch Empfangsantennen (Index „e“) dazu herangezogen werden können, die Radardaten von den ungewünschten Störeinflüssen („Noise“, „Clutter“) zu befreien und die gewünschten Information aus den Radardaten zu extrahieren, und/oder um die Radardaten geeignet weiterverarbeiten zu können.
• - Die durch eine geeignete Auswertung und Signalverarbeitung der Daten der Radaraufnahmen gewonnenen Informationen können beispielsweise, aber nicht abschließend, sein: Position, Lage, Orientierung und Größe der Spargelstangen 14, ein- oder mehrdimensional rekonstruierte Bilder der Spargelstangen 14 und ihrer Umgebung (Wurzelwerk, Spargelwall, etc.), Rekonstruiertes Bild, das einen Schnitt durch den Erdwall 10 darstellt, Wassergehalt der Spargelstangen 14, und Spargel-Wall-Parameter wie Wasser- und Feuchtegehalt des Erdwalls 10, Dichte der Spargelstangen 14 zueinander im Erdwall 10, usw.
• - Messungen mit verschiedenen Polarisationen können dabei, ggf. auch unterstützend zu einem der vorstehend erläuterten Verfahren, dazu eingesetzt werden, die Orientierung des Spargels zu ermitteln. Denn beispielsweise wird die Reflexion / Frequenzantwort des Spargels bei einer gewählten Polarisation von seinem tatsächlichen Verlauf abhängen.
• - Wie für Radar typisch lässt sich auch problemlos eine Abstandsmessung durchführen, welche, ggf. auch unterstützend zu einem der vorstehend erläuterten Verfahren, dazu eingesetzt werden kann, den Abstand der Spargelpflanze von einer jeden einzelnen Antenne zu ermitteln und damit seine Positionsbestimmung durchzuführen.
• - Bei allem Vorgenannten kann das konkret zugrundeliegende Radarsystem entweder im Zeit- und/oder im Frequenzbereich arbeiten. Vertreter für ein System im Zeitbereich wären beispielsweise das Puls-, oder auch das PN-Radar („Pseudo Noise Radar“). Im Frequenzbereich wäre der Einsatz von Stepped-Frequency-, oder FMCW-Radare prominente Vertreter. Bei Radarsystemen, die im Frequenzbereich arbeiten, kann direkt durch Wahl der Frequenzen, bei denen Daten aufgezeichnet werden, der Frequenzbereich sowie die Bandbreite der Messung festgelegt werden. Bei Radarsystemen, die im Zeitbereich arbeiten, kann dies prinzipiell nach einer Messung dadurch erfolgen, dass nach einer geeigneten Transformation der Zeitbereichsdaten in den Frequenzbereich dort eine Frequenzselektion stattfindet, ggf. gefolgt von einer geeigneten Rücktransformation in den Zeitbereich. Die Auswertung der Daten im Frequenzbereich kann dabei, ggf. auch unterstützend zu einem der vorstehend erläuterten Verfahren, dazu eingesetzt werden, frequenzspezifische Antwort-Eigenschaften des Spargels auf elektromagnetische Wellen für seine Detektion und Lagebestimmung auszunutzen. Gleiches gilt für denkbare Verfahren zur Messung der genannten Erdwall-Parameter.
• - Grundsätzlich kann die Weiterverarbeitung der Radar-Rohdaten im Frequenz- und/oder im Zeitbereich erfolgen. Wobei eine Transformation der Daten zwischen beiden Räumen etwa mittels der Fourier Transformation möglich ist. Im jeweils geeigneten mathematische Raum können sodann Rekonstruktions-/Migrations-Algorithmen wie etwa Delay-and-Sum, FK-Algorithmus (Frequenz-Wellenzahl-Algorithmus), oder andere Methoden, etwa solche, die der Rekonstruktion ein physikalisches Modell der Wellenausbreitung zugrunde legen, angewendet werden, um aus den Radardaten ein ein- oder mehrdimensionales (Teil-) Bild des, bzw. einen Schnitt durch das Observationsvolumen zu erhalten. Auch eine Mikrowellen-Tomographie des gesamten Volumens, oder eines Teils davon, ist denkbar. Ebenfalls denkbar ist die Anwendung hochauflösender Verfahren auf die Radardaten, wobei als Vertreter der MUSIC-, ESPRIT- und Maximum-Likelihood-Algorithmus, sowie Verfahren aus dem Kontext des space-time adaptive processing zu nennen sind. Mittels statistischer Verfahren können die Radardaten auf bestimmte Merkmale hin untersucht werden und die Ergebnisse entweder eigenständig, oder aber unterstützend zu einem der vorstehenden Verfahren eingesetzt werden.
• - Die Weiterverarbeitung der Radardaten lässt sich jedoch nicht nur per Software durchführen. Es ist auch denkbar, die beschriebenen Signalverarbeitungsprozesse der Radardaten entweder ganz, oder aber wenigstens zum Teil, in Hardware (beispielsweise in einem FPGA oder dezidierten Signalprozessor) zu realisieren, was etwa eine beschleunigte Berechnung ermöglicht.
• - Anstatt das Radarsystem während des Erntebetriebs ständig mit der (nicht dargestellten) Spargelerntemaschine zu verbinden ist es auch möglich, dass das Radarsystem durch eigene Transportmittel im Bereich der Erdwälle 10 bewegt oder nur zeitweise mit der Erntemaschine verbunden ist. In einem solchen Fall wird die Topographie des Spargels (Stangen und/oder Wurzeln) zunächst ermittelt und die zugehörigen Werte des Steuersignals s werden in einem Speichermedium abgespeichert, das beispielsweise als HalbleiterBauelement, als magnetischer und/oder als opto-magnetischer Speicher gestaltet sein kann. Diese abgespeicherten Werte können danach zur Steuerung bzw. Regelung verwendet werden, wie für Vorrichtungen einer Erntemaschine, für Vorrichtungen einer Düngemaschine und/oder zur Anzeige der Topographien auf einer Anzeigeeinheit für einen Nutzer.

The variation of the polarization is in principle also conceivable using a mechanically adjustable and/or rotatable antenna holder. The receiving and transmitting antennas do not have to have the same polarization, but they can.

• - A transmission unit 26 can be provided, which generates the transmission signal (and possibly via a D/A converter as an analog signal which, if necessary, is converted into the desired frequency range via a mixer stage with a local oscillator) and thus feeds the respective transmitting antenna, whereby in the course of the signal evaluation, regardless of the method actually selected, the characteristics of the transmitted electromagnetic wave are obtained Frequency f_s, phase Φ_s, polarization p_s, amplitude a_s and antenna main beam direction, in turn defined by a horizontal angle x_s and a vertical angle y_s, as well as antenna gain g_s and physical position of the transmitting antenna (u_s,v_s,w_s) and physical orientation of the transmitting antenna ( described by a vector r_s, \vec{r_s}) in space, can be used. All parameters can in turn depend on time t and all other parameters. The transmitting unit 26 can work in both the time and frequency domains.
• - A receiving unit 28 can be provided, which can also coincide with the transmitting unit 26, which converts the electromagnetic wave received at each receiving antenna (which may be converted into another frequency range, e.g. baseband, via a mixer stage with a local oscillator) and, if necessary, via an AD converter is present as a sampled digital signal) and in the course of the signal evaluation, regardless of the method actually selected, the characteristics of the received electromagnetic wave for its frequency f_e, phase Φ_e, polarization p_e, amplitude a_e and antenna main beam direction , in turn defined by a horizontal angle x_e and a vertical angle y_e, as well as antenna gain g_e and physical position of the receiving antenna (u_e,v_e,w_e) and physical orientation of the receiving antenna (described by a vector r_e, \vec{r_e}) in space can. All parameters can in turn depend on time t and all other parameters. The receiving unit 28 can work in both the time and frequency domains.
• - A processor unit or computing unit 30 can be provided, in which the further processing of all transmission and reception signals takes place. Here, all known information f_s, f_e, Φ_s, Φ_e, p_s, p_e a_s, a_e, x_s, x_e, y_s, y_e and t from both transmission (index "s") can be used, either based on specification and/or through measurement. as well as received signals (index "e") and polarization p_s, p_e, gain g_s, g_e, position (u_s,v_s,w_s), (u_e,v_e,w_e) and physical orientation of the antennas (described by a vector r_s, r_e, \vec{r_s}), \vec{r_e}) in the space of both transmitting (index "s") and receiving antennas (index "e") can be used to separate the radar data from unwanted interference ("noise", “Clutter”) and to extract the desired information from the radar data, and/or to be able to further process the radar data appropriately.
• - The information obtained through suitable evaluation and signal processing of the data from the radar recordings can be, for example, but not exhaustive: position, position, orientation and size of the asparagus spears 14, one- or multi-dimensionally reconstructed images of the asparagus spears 14 and their surroundings (root system, asparagus wall , etc.), reconstructed image that shows a section through the earth bank 10, water content of the asparagus spears 14, and asparagus wall parameters such as water and moisture content of the earth bank 10, density of the asparagus spears 14 relative to one another in the earth bank 10, etc.
• - Measurements with different polarizations can be used, possibly also in support of one of the methods explained above, to determine the orientation of the asparagus. For example, the reflection / frequency response of asparagus will depend on its actual course with a selected polarization.
• - As is typical for radar, a distance measurement can also be carried out without any problems, which, if necessary in support of one of the methods explained above, can be used to determine the distance of the asparagus plant from each individual antenna and thus determine its position.
• - With all of the above, the specific underlying radar system can work either in the time and/or frequency domain. Representatives of a system in the time domain would be, for example, the pulse or PN radar (“pseudo noise radar”). In the frequency range, the use of stepped frequency or FMCW radars would be prominent representatives. For radar systems that work in the frequency range, the frequency range and the bandwidth of the measurement can be determined directly by selecting the frequencies at which data is recorded. In the case of radar systems that work in the time domain, this can in principle be done after a measurement in that, after a suitable transformation of the time domain data into the frequency domain, a frequency selection takes place there, possibly followed by a suitable inverse transformation into the Time range. The evaluation of the data in the frequency range can be used, if necessary in support of one of the methods explained above, to exploit frequency-specific response properties of the asparagus to electromagnetic waves for its detection and position determination. The same applies to conceivable methods for measuring the earth wall parameters mentioned.
• - In principle, the raw radar data can be further processed in the frequency and/or time domain. A transformation of the data between the two spaces is possible, for example using the Fourier transformation. Reconstruction/migration algorithms such as delay-and-sum, FK algorithm (frequency-wavenumber algorithm), or other methods, such as those that base the reconstruction on a physical model of wave propagation, can then be used in the appropriate mathematical space. can be used to obtain a one- or multi-dimensional (partial) image of, or a section through, the observation volume from the radar data. Microwave tomography of the entire volume, or part of it, is also conceivable. It is also conceivable to apply high-resolution methods to the radar data, examples of which include the MUSIC, ESPRIT and maximum likelihood algorithms, as well as methods from the context of space-time adaptive processing. Using statistical methods, the radar data can be examined for specific characteristics and the results can be used either independently or to support one of the above methods.
• - However, further processing of the radar data cannot only be carried out using software. It is also conceivable to implement the described signal processing processes of the radar data either entirely or at least in part in hardware (for example in an FPGA or dedicated signal processor), which enables accelerated calculation.
• - Instead of constantly connecting the radar system to the asparagus harvester (not shown) during harvesting, it is also possible for the radar system to be moved in the area of the earthworks 10 using its own means of transport or to be only temporarily connected to the harvester. In such a case, the topography of the asparagus (stalks and/or roots) is first determined and the associated values of the control signal s are stored in a storage medium, which can be designed, for example, as a semiconductor component, as a magnetic and/or as an opto-magnetic memory. These stored values can then be used for control or regulation, such as for devices of a harvesting machine, for devices of a fertilizer machine and/or for displaying the topographies on a display unit for a user.

Reference character list

10

earth wall

12

root ball

14

Asparagus spears

16

Surface of the earth wall

18

Top point of the root ball

20

transmitting antenna

22

receiving antenna

24

Radar device

26

Transmitting unit

28

Receiving unit

30

Computing unit

120

left antenna

122

right antenna

EN

vertical distance between antennas and earth wall

DW

vertical distance between antennae and root ball

Dges

horizontal distance between antennas ( 3 )

Dli

horizontal distance between left antenna and earth wall

Dr

horizontal distance between right antenna and earth wall

P

Arrow

Claims (15)

Method for determining the topography and/or tomography of roots of at least one asparagus plant (12, 14), which are located within an earth bank (10), electromagnetic radiation being sent in the direction of the plant (12, 14) and electromagnetic radiation being sent from the direction of the plant (12, 14) is received, characterized in that the received electromagnetic radiation is evaluated as a function of the transmitted electromagnetic radiation and then a control signal (s) is produced, the value of which is a measure of the topography of the roots of the asparagus plant (12, 14). Procedure according to Claim 1 , characterized in that the received electromagnetic radiation is created by reflection and scattering of the transmitted electromagnetic radiation on the earth wall (10) and / or the plant (12, 14) and / or other objects that are located in the area being examined. Method according to one of the preceding claims, characterized in that the transmitted electromagnetic radiation is modulated according to a radar method and the received electromagnetic radiation is evaluated accordingly. Method according to one of the preceding claims, characterized in that the transmitted electromagnetic radiation is in the frequency range from 100 MHz to 4 GHz, preferably within 300 MHz to 2 GHz. Method according to one of the preceding claims, characterized in that the values of the received electromagnetic radiation are processed by means of windowing and/or zero padding and/or subjected to a suitable transformation. Method according to one of the preceding claims, characterized in that the values of the received electromagnetic radiation are corrected by static values from a previous background recording. Method according to one of the preceding claims, characterized in that the polarization dependence of the scattered electromagnetic radiation is evaluated. Procedure according to one of the previous ones Claims 1 until 7 , characterized in that - at least one antenna (20, 22) is provided for sending and receiving the radiation, - the at least one antenna (20, 22) is moved along the earth wall (10) and the distance (DW) at predetermined measuring points between the at least one antenna (20, 22) and a root ball (12), - the topography essentially results from the positions of the measuring points and the associated distances (DW). Method according to one of the preceding claims, characterized in that the received electromagnetic radiation arises from transmission of the transmitted electromagnetic radiation through the earth wall (10). Procedure according to one of the previous ones Claims 1 until 9 , characterized in that (a) the control signal (s) is used to control a harvesting device and / or to control a fertilizer or irrigation device and / or (b) the control signal (s) is used to control a display unit, whereby a Users can see the topography, tomography and/or the progress of the growth process of the plants being examined. Method according to one of the preceding claims, characterized in that the control signal (s) is used to control a signaling device, whereby a user can be signaled optically and/or acoustically when the examined plant or the examined area of the earth bank (10) is being irrigated or needs to be fertilized. Radar device for carrying out the method according to one of the preceding method claims with an antenna (20) for transmitting electromagnetic radiation and an antenna (22) for receiving electromagnetic radiation and a radar device (24) for generating, receiving and evaluating the electromagnetic radiation, characterized in that the radar device has connecting means by which it can be connected to a transport device, which in turn is suitable for moving the radar device along an earth bank (10). Radar device according to the first device claim, characterized in that at least one of the antennas (20, 22) are designed as loaded bowtie antennas. Device for harvesting a plant (12, 14) or its parts (14), which are located within an earth bank (10), characterized in that harvesting means are present, the position and / or operating state of which depends on the value of the according to a The control signal (s) determined in accordance with the previous method claims can be controlled and/or regulated. Device for fertilizing and/or irrigating a plant (12, 14) or parts thereof, which are located within an earth bank (10), characterized in that fertilizers or irrigation agents are present which are arranged and designed in such a way that they Depending on the value of the control signal (s) determined according to one of the previous method claims, the plant (12, 14) or the earth wall (10) can be supplied with fertilizer or water.

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