DE102017123435A1 - Apparatus for calibrating a radar range finder and method for calibrating a radar rangefinder - Google Patents

Abstract

Described and illustrated is a device (1) for the calibration of a radar range finding device (3), in particular for the calibration of a radar level gauge, with at least one measuring section (4) for coupling to at least one transmitting and / or receiving unit (7). of the radar rangefinder device (3) to be calibrated, wherein the measurement path (4) comprises a dielectric waveguide (5) for guiding a measurement signal. The object to provide a device for the calibration of a radar rangefinder, with a particularly simple and efficient way, a calibration is possible, is achieved in that at the dielectric waveguide (5) at least one impedance fault (8) is arranged such that during operation at least the evanescent field (13) of the measurement signal is reflected.

Description

The invention relates to a device for the calibration of a radar rangefinder, in particular for the calibration of a radar level gauge, with at least one measuring section for coupling to at least one transmitting and / or receiving unit to be calibrated radar rangefinder, wherein the measuring section a dielectric waveguide for guiding a measurement signal comprises. In addition, the invention is based on a method for calibrating a radar rangefinder, in particular a radar level gauge with a device comprising at least one measuring section, wherein the measuring section is coupled to a transmitting and / or receiving unit of the radar rangefinder to be calibrated and wherein the measuring section a dielectric waveguide for guiding a measurement signal comprises.

In the field of industrial level measurement technology, the accuracy and reproducibility of the radar devices used are two decisive criteria. Compliance with the specification and the country-specific standards must always be guaranteed. In particular for high-precision radar measurements, so-called calibration measurements are carried out in order to compensate existing distance errors. With known target geometry and arrangement, a calibration can take place, which can significantly increase the accuracy of the radar device used. With this, for example, specified accuracies can be met and their compliance can be proven. For this purpose, typically measuring tracks are used, which consist of a high-precision measuring section in conjunction with a high-precision laser rangefinder. This arrangement allows to measure different targets at different positions. In addition to the high costs and maintenance, the size of the measuring section, which is directly associated with the maximum distance to be measured, represents a decisive disadvantage. Due to the antenna characteristics, absorbers must also be placed against disturbing targets, for example walls, holders, ceiling, floor become.

In addition, digital systems are known that can simulate various radar targets. These can be programmed and changed almost arbitrarily. Here, the focus is on multi-objective simulators, for example for driver assistance systems, which provide a suitable test environment for the complex test scenarios in order, for example, to be able to carry out certification measurements. The advantage of these systems is in particular their compact design. The radar to be tested is aimed at the corresponding calibration device so that the receiving antenna of the digital calibration device receives the radiated signal of the radar to be tested. In the further signal processing chain, this signal is implemented and digital targets and speeds are imposed. Subsequently, the thus modulated signal is mixed up, radiated and received by the radar device to be tested, which now detects and evaluates the impressed targets and speeds. At close targets, in particular at a distance of less than one meter, there is the disadvantage that the processing time is too long to be able to modulate these distances. Especially in the field of industrial level measurement these distances are quite relevant.

In addition, for example, at an operating frequency of 80 GHz radar level gauges have a bandwidth of 5 GHz in a 10 GHz band, which is also a particular challenge for a device for calibrating such a radar device.

From the publication EP 2 026 094 A1 a generic device for the calibration of a radar rangefinder is known, wherein in the waveguide impedance disturbances for reflection of the coupled into the waveguide measurement signal are present. From the transit time of the resulting partial reflections, the radar rangefinder to be calibrated measures the known distance to the impedance disturbance. In this way, the calibration of a radar rangefinder can also be realized with very short distances.

From the publication EP 1 231 480 A2 A method and device for aligning radar devices on vehicles is known. For this purpose, for example, glass fibers or dielectric conductors are used as delay elements for simulating objects of different distances, different lengths being used for different delays.

Based on the above-described prior art, it is an object of the invention to provide a device for the calibration of a radar rangefinder, with a particularly simple and efficient way, a calibration is possible. Moreover, it is an object of the invention to provide a corresponding method for calibrating a radar rangefinder.

According to a first teaching of the present invention, the above-mentioned object is achieved by a device mentioned at the outset in that at least one impedance disturbance is arranged on the dielectric waveguide such that in the Operation at least the evanescent field of the measuring signal is reflected. According to the invention, it has been recognized that, when a measurement signal is conducted through a dielectric waveguide, the reflection of the evanescent field forming on the edge of the waveguide can be measured, so that the field actually to be transmitted can continue to propagate unhindered through the waveguide. This has the particular advantage that the arrangement of the impedance interference at and not in the dielectric waveguide, the arrangement can be designed to be particularly flexible and, for example, is changeable. Moreover, it can also be realized in a particularly simple manner by arranging a plurality of impedance disturbances of different distances to be measured. In addition, particularly short distances for the calibration of a radar rangefinder can be realized.

According to one embodiment, the at least one impedance fault is designed as an impedance fault element, in particular as a separate impedance fault element.

According to a further embodiment, the at least one impedance interference is arranged on the dielectric waveguide such that in operation only the evanescent field of the measurement signal is reflected.

When it is said that the at least one impedance noise is "on" the dielectric waveguide, it is meant that the impedance noise is located outside the waveguide. In detail, the at least one impedance perturbation on the waveguide is either arranged such that the impedance perturbation makes contact with the waveguide or that the impedance perturbation on the waveguide is spaced from the waveguide.

Preferably, the at least one impedance disturbance is not located at the end of the waveguide.

As a result of the arrangement according to the invention, short distances as well as long distances for the calibration of a radar rangefinder can be realized, in particular simultaneously, whereby the device can be used particularly flexibly.

According to a preferred embodiment, the device has a coupling element which is arranged at one end of the dielectric waveguide. During operation, this coupling element serves to couple the measurement signal emitted by the radar range finding device to be calibrated into the dielectric waveguide.

According to a further advantageous embodiment, the at least one impedance disturbance is designed such that it at least partially surrounds the waveguide. For example, the at least one impedance disturbance in the form of a cylinder or a ring can completely surround the waveguide. Alternatively, the at least one impedance disturbance may also partially enclose the waveguide.

Furthermore, it is advantageous if the at least one impedance disturbance is detachably, preferably positively or non-positively, connected to the dielectric waveguide. This embodiment has the advantage that the impedance disturbance on the dielectric waveguide can be offset so that different distances to be measured can be realized, depending on the application. According to a further embodiment, the at least one impedance disturbance is inextricably connected to the waveguide, preferably the at least one impedance disturbance is designed in one piece with the waveguide.

According to a further advantageous embodiment, the at least one impedance fault is designed as a static reflector or as a dynamic reflector.

According to one embodiment, the dynamic reflector is arranged at a fixed position of the dielectric waveguide. According to another embodiment, the dynamic reflector moves along the dielectric waveguide. According to a particularly preferred embodiment, the dynamic reflector is designed as a rotating body, preferably as a rotating cylinder. The presence of such a dynamic reflector has the advantage that the detection of moving objects can also be taken into account in the calibration of a radar rangefinder. By varying the direction of rotation and / or the rotational speed of a rotating body, various test scenarios can be realized.

According to a further embodiment, the static reflector is designed as a metallic or dielectric body.

It is particularly preferred if a plurality of impedance perturbations are arranged along the dielectric waveguide, so that different distances can be taken into account simultaneously for a calibration process. The different impedance perturbations can be configured identically or have differences, for example with respect to their reflectivity. In addition, it is also advantageous to combine static and dynamic reflectors.

It is particularly advantageous if at least two impedance disturbances are arranged in the course of the measurement path, which reflect different degrees.

According to a further embodiment, the at least one impedance disturbance is designed as a dispersive reflector or as a polarizing reflector.

According to a further embodiment, the dielectric waveguide is at least partially made of a flexible dielectric solid, in particular of plastic, such as PE, PP, PTFE, etc. exists.

According to a further embodiment, the dielectric waveguide is at least partially designed as a thermoplastic. This embodiment is advantageous since, for example, impedance structures can be thermoformed in a particularly simple manner.

According to a further embodiment, the dielectric waveguide is designed as a dielectric fiber, which transports the measurement signal by means of total reflection.

According to a further embodiment, the device has a carrier element, wherein the dielectric waveguide, preferably spirally, is arranged around the carrier element. Such a carrier element preferably consists of plastic, preferably of polystyrene, particularly preferably of foamed polystyrene. For example, the support element is designed as a cylinder. This embodiment has the advantage that even the determination of large distances can be realized to save space.

According to a further embodiment, the device has at least one holder, preferably of rigid dielectric foam, which are designed and arranged such that it guides the dielectric waveguide. The use of hard foam has the advantage that due to the low reflection, a largely undisturbed transmission of the measurement signal can be ensured.

In order not to disturb the signal transmission, according to a next embodiment, the waveguide is also guided in air.

According to a next embodiment, the at least one impedance fault and / or the at least one holder is or are arranged on the carrier element. According to this embodiment, the dielectric waveguide is guided at a distance from the carrier element, so that the carrier element does not influence the signal propagation during operation.

• - Aussenden eines Messsignals durch die Sendeeinheit des zu kalibrierenden Radar-Entfernungsmessgeräts und Einkopplung des Messsignals in den dielektrischen Wellenleiter,
• - Empfangen wenigstens eines Reflexionssignals durch die Empfangseinheit wobei das Reflexionssignal wenigstens die Reflexion des evaneszenten Feldes des Messsignals an der wenigstens einen Impedanzstörung umfasst,
• - Auswerten des wenigstens einen Reflexionssignals durch das zu kalibrierende Radarentfernungsmessgerät, insbesondere durch die Bestimmung der gemessenen Entfernung der wenigstens einen Impedanzstörung aus der Laufzeit des Reflexionssignals und/oder durch die Bestimmung einer Frequenzverschiebung des Reflexionssignals in Bezug auf das ursprüngliche Messignal,
• - Vergleich der gemessenen Entfernung mit dem vorgegebenen Abstand und/oder der zu erwartenden Frequenzverschiebung,
• - Justierung der Radarentfernungsmesseinrichtung, wenn die Abweichung der gemessenen Entfernung und des vorgegebenen Abstandes und/oder der gemessenen Frequenzverschiebung und der zu erwartenden Frequenzverschiebung einen zuvor festgelegten Toleranzbereich überschreitet.

According to a second teaching of the present invention, the object stated at the outset is achieved by a method mentioned at the outset in that at least one impedance disturbance is arranged at a predetermined distance from the radar rangefinder on the dielectric waveguide, and in that the method comprises the following steps:

• Sending out a measuring signal by the transmitting unit of the radar rangefinder to be calibrated and coupling the measuring signal into the dielectric waveguide,
• Receiving at least one reflection signal by the receiving unit, wherein the reflection signal comprises at least the reflection of the evanescent field of the measurement signal at the at least one impedance interference,
• Evaluating the at least one reflection signal by the radar range measurement device to be calibrated, in particular by determining the measured distance of the at least one impedance interference from the transit time of the reflection signal and / or by determining a frequency shift of the reflection signal with respect to the original measurement signal,
• Comparison of the measured distance with the predetermined distance and / or the expected frequency shift,
• - Adjustment of the radar range measuring device when the deviation of the measured distance and the predetermined distance and / or the measured frequency shift and the expected frequency shift exceeds a predetermined tolerance range.

In this case, the at least one impedance fault can be arranged before each calibration of the radar rangefinder device, or, for example, when the device is put into operation by the arrangement of the at least one impedance fault, the at least one distance to be measured can be determined.

According to a particularly preferred embodiment of the method, the device for calibrating a radar range measuring device is designed according to one of the previously described embodiments.

If there are several impedance disturbances, the reflection signal of each impedance disturbance is evaluated separately.

• 1 ein erstes Ausführungsbeispiel einer erfindungsgemäßen Vorrichtung für die Kalibration eines Radarentfernungsmessgerätes im Betrieb,
• 2 eine schematische Darstellung eines zweiten Ausführungsbeispiels einer erfindungsgemäßen Vorrichtung,
• 3 eine schematische Darstellung eines dritten Ausführungsbeispiels einer erfindungsgemäßen Vorrichtung und
• 4 ein erstes Ausführungsbeispiel eines erfindungsgemäßen Verfahrens.

In particular, there are a multitude of possibilities, the devices according to the invention and the method according to the invention to design and develop. Reference is made to both the independent claims subordinate claims as well as to the following description of preferred embodiments in conjunction with the drawings. In the drawing show:

• 1 a first embodiment of a device according to the invention for the calibration of a radar range measuring device in operation,
• 2 a schematic representation of a second embodiment of a device according to the invention,
• 3 a schematic representation of a third embodiment of a device according to the invention and
• 4 a first embodiment of a method according to the invention.

1 shows a device 1 for the calibration of a radar rangefinder 3 and a radar rangefinder to be calibrated 3 , The device 1 has a measuring section 4 on that a dielectric waveguide 5 includes, as well as a coupling element 6 for coupling a measuring signal into the dielectric waveguide 5 , The radar rangefinder 3 has a transmitting and receiving unit 7 on, wherein for calibration, the transmitting unit is a measuring signal in the direction of the coupling element 6 emits and the receiving unit at least one reflection signal from the direction of the coupling element 6 receives.

At a given distance is at the dielectric waveguide 5 a first impedance fault 8th arranged, the first impedance interference 8th as a static reflector 9 is designed. At a second predetermined distance from the coupling element 6 or to the radar rangefinder 3 is on the dielectric waveguide 5 a second impedance fault 8th arranged, wherein the second impedance error 8th as a dynamic reflector 10 is designed. The dynamic reflector 10 is presently designed as a rotating cylinder, which on a support element 12 is arranged.

In addition, the dielectric waveguide 5 by means of holders 11 around the carrier element 12 wound at a distance, wherein the carrier element 12 in the illustrated embodiment is designed as a plastic cylinder, in this case made of foamed polystyrene. This allows both long measuring distances as well as a flexible arrangement of impedance interferences 8th Different distances can be realized to save space. Basically, the dimensions of the device, in detail the diameter D of the cylinder, the height H of the cylinder, the distance w of the brackets 11 to the cylinder or the distance h of the brackets with each other depending on the particular application of the radar rangefinder 3 ,

2 schematically shows a combination of a dielectric waveguide 5 and three impedance perturbations 8th in the form of static reflectors 9 on the dielectric waveguide 5 are arranged and have contact with this. There is also another impedance fault 8th in the form of a dynamic reflector 10 available. The dynamic reflector 10 is designed as a rotating cylinder, which is spaced from the waveguide 5 is arranged. Also shown is the exponentially decaying evanescent field 13 one through the dielectric waveguide 5 moving measuring signal. In the illustrated embodiment, this evanescent field 13 at least partially on the dynamic reflector 10 reflected.

In 3 schematically another embodiment of a device according to the invention is shown, wherein on the dielectric waveguide 5 both impedance disturbances 8th in the form of static reflectors 9 as well as a dynamic reflector 10 are arranged. The first static reflector 9 is annular around the dielectric waveguide 5 arranged, but has no contact with this. The second static reflector 9 encloses the dielectric waveguide 5 only partially and is also spaced to this arranged. The third static reflector 9 encloses the dielectric waveguide 5 also only partially and also has contact with this.

In 4 is a first embodiment of a method according to the invention 2 for calibrating a radar rangefinder 3 shown, wherein the device 1 for calibrating the radar rangefinder 3 as in 1 is shown configured, and wherein the radar rangefinder to be calibrated 3 at a predetermined distance R to the device 1 is arranged (see 1 ).

In a first step 14 sends the transmitting unit of the radar rangefinder to be calibrated 3 a measurement signal, via the coupling element 6 in the dielectric waveguide 5 is coupled.

In a next step 15 receives the receiving unit of the radar rangefinder 3 a first reflection signal, wherein the reflection signal at least the reflection of the evanescent field 13 of the measurement signal at the first impedance fault 8th includes.

In a next step 16 determines the radar rangefinder to be calibrated 3 the measured distance to the first impedance fault 8th from the duration of the reflection signal.

In a further step 17 becomes the measured distance at the predetermined distance to the impedance disturbance 8th compared.

If the deviation of the measured distance and the predetermined distance exceeds a predetermined tolerance range, the radar rangefinder is in a next step 18 adjusted.

Subsequently, the steps become 15 to 18 go through again, the reflection of the measurement signal at the second impedance error 8th , in the form of a dynamic reflector 10 takes place and wherein instead of or in addition to the measured distance, the frequency shift of the reflection signal is evaluated.

LIST OF REFERENCE NUMBERS

1

Device for the calibration of a radar rangefinder

2

Method for calibrating a radar rangefinder

3

Radar rangefinder

4

measuring distance

5

dielectric waveguide

6

coupling element

7

Transmitting and receiving unit

8th

impedance fault

9

static reflector

10

dynamic reflector

11

bracket

12

support element

13

evanescent field

14

Emitting a measuring signal

15

Receiving at least one reflection signal

16

Evaluation of the reflection signal

17

comparison

18

adjustment

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 2026094 A1 [0005]
• EP 1231480 A2 [0006]

Claims (16)

Device (1) for the calibration of a radar rangefinder (3), in particular for the calibration of a radar level gauge, with at least one measuring section (4) for coupling to at least one transmitting and / or receiving unit (7) of the radar to be calibrated Distance measuring device (3), wherein the measuring section (4) comprises a dielectric waveguide (5) for guiding a measuring signal, characterized in that at least one impedance interference (8) is arranged on the dielectric waveguide (5) such that at least the evanescent Field (13) of the measurement signal is reflected. Device (1) according to Claim 1 , characterized in that the at least one impedance perturbation (8) at least partially surrounds the dielectric waveguide (5). Device (1) according to one of Claims 1 or 2 characterized in that the at least one impedance perturbation (8) is detachably connected to the dielectric waveguide (5). Device (1) according to one of Claims 1 to 3 , characterized in that the at least one impedance fault (8) is a static reflector (9) or a dynamic reflector (10). Device (1) according to Claim 4 , characterized in that the dynamic reflector (10) as a rotating body, preferably as a rotating cylinder, is configured. Device (1) according to one of Claims 4 or 5 , characterized in that the static reflector (9) is designed as a metallic or dielectric body. Device (1) according to one of Claims 1 to 6 , characterized in that in the course of the measuring path (4) at least two impedance interference (8), which reflect different degrees, are arranged. Device (1) according to one of Claims 1 to 7 , characterized in that the at least one impedance interference (8) is designed as a dispersive reflector or as a polarizing reflector. Device (1) according to one of Claims 1 to 8th , characterized in that the dielectric waveguide (5) consists at least partially of a flexible dielectric solid, in particular of plastic, such as PE, PP, PTFE, etc. Device (1) according to one of Claims 1 to 9 , characterized in that the dielectric waveguide (5) is at least partially designed as a thermoplastic. Device (1) according to one of Claims 1 to 10 , characterized in that the dielectric waveguide (5) is designed as a dielectric fiber. Device (1) according to one of Claims 1 to 11 , characterized in that a carrier element (12) is present and that the dielectric waveguide (5), preferably spirally, is arranged around the carrier element (12). Device (1) according to one of Claims 1 to 12 , characterized in that at least one holder (11), preferably made of rigid dielectric foam, is present and that the dielectric waveguide (5) by means of at least one holder (11) is guided. Device (1) according to Claim 12 or 13 , characterized in that the at least one impedance interference (8) and / or the at least one holder (11) is or are arranged on the carrier element (12). Method (2) for calibrating a radar range finding device (3), in particular a radar level gauge with a device (1) comprising at least one measuring section (4), wherein the measuring section (4) is connected to a transmitting and / or receiving unit (7) the radar distance measuring device (3) to be calibrated is coupled, wherein the measuring path (4) comprises a dielectric waveguide (5) for guiding the measuring signal, wherein at least one impedance fault (8) at a predetermined distance from the dielectric waveguide (5) Radar distance measuring device (3) is arranged, and wherein the method (2) comprises the following steps: - emitting (14) a measuring signal by the transmitting unit of the radar rangefinder (3) to be calibrated and coupling the measuring signal in the dielectric waveguide (5 ), - receiving (15) at least one reflection signal by the receiving unit, wherein the reflection signal at least the reflection of the evanescent field (13) evaluation of the at least one reflection signal by the radar range finding device (3) to be calibrated, in particular by determining the measured distance of the at least one impedance disturbance (8) from the transit time of the at least one impedance disturbance (8) Reflection signal and / or by determining a frequency shift of the reflection signal with respect to the original measurement signal, Comparison (17) of the measured distance with the predetermined distance and / or the expected frequency shift, - adjustment (18) of the radar rangefinder (3), if the deviation of the measured distance and the predetermined distance and / or the measured frequency shift and the expected frequency shift exceeds a predetermined tolerance range. Method (2) according to Claim 15 , characterized in that the device (1) for calibrating the radar rangefinder (3) according to one of Claims 1 to 14 is designed.

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