Antenna system of a radar measuring device for topology detection

Abstract

A radar measuring device with an array antenna for topology detection and a level measuring antenna for level measurement. The array antenna is arranged around the level measuring antenna.

Description

Technical Field

[0001] This invention relates to the measurement of the surface of a filling material. In particular, this invention relates to an antenna system configured for detecting the topology of a radar measuring apparatus on a filling material surface, a radar measuring apparatus having such an antenna system, a method for measuring the topology of a filling material surface, program elements, and a computer-readable medium. Background Technology

[0002] To detect the topology of the filling material surface, a measurement signal can be used to scan the surface. For this purpose, the measuring device or its antenna can be mechanically rotated, or electronic beam control can be performed. A combination of both methods can also be used. For electronic beam control, an array of radiating elements is used in the radar measuring device. In this case, the array is also referred to as an array antenna.

[0003] Then, the level and volume of the filling material can be calculated based on the detected topology.

[0004] The hardware costs for electronic beam control are substantial; the computational workload required for signal evaluation can also be considerable. For this reason, such measurement devices require relatively large amounts of energy. However, depending on the location and connection method of the measurement device, energy is often a scarce resource. Summary of the Invention

[0005] In this context, the object of the present invention is to provide a radar measuring device, particularly a level radar measuring device, which is used with reduced hardware costs and reduced energy consumption.

[0006] A first aspect of the invention relates to an antenna system configured for a radar measurement device for detecting the topology of a filling material surface. Specifically, the radar measurement device can be a level radar measurement device for process automation in an industrial environment. The antenna system includes a first antenna device configured to detect the topology of the filling material surface. Furthermore, the antenna system includes an additional second antenna device configured to detect the level. Therefore, different antenna devices will be used for both level measurement and topology detection.

[0007] The first antenna device is an array antenna, which has an array of radiating elements arranged around the second antenna device.

[0008] For example, the second antenna device is a horn antenna.

[0009] The radiating element of the first antenna assembly can also be a (smaller) horn antenna. The first and second antenna assemblies can also be referred to as horn radiators and can be filled with a dielectric. They can also be in the form of waveguide apertures (filled or unfilled). Patch antennas, rod radiators, or other antennas can also be used.

[0010] According to one embodiment, the diameter or side length of the radiating element of the first antenna device is (significantly) smaller than the diameter or side length of the second antenna device.

[0011] According to another embodiment, the radiating surface of the radiating element of the first antenna device and the radiating surface of the second antenna device are arranged on the same plane. For example, the "radiating surface" of the second antenna device is the opening of the antenna horn. In the case of a horn antenna, the radiating surface of the radiating element of the first antenna device is also the opening plane of each antenna horn. In the case of a planar radiating element (patch antenna), the radiating surface is formed by the surface of the planar radiating element.

[0012] According to another embodiment, the radiating surface of the radiating element of the first antenna device and / or the radiating surface of the second antenna device are holes in a metal plate. These holes may be filled with a dielectric or left unfilled. The holes may have a circular or angular cross-section.

[0013] For example, the metal plate was designed to be circular.

[0014] For example, the radiating elements of the first antenna device are formed into rectangular, hexagonal, or other polygonal shapes with segmented straight line regions.

[0015] According to one embodiment, the radiating elements of the first antenna device include a (first) group of transmitting elements and a (second) group of receiving elements.

[0016] Another aspect of the present invention relates to a radar measuring device, particularly a level radar measuring device, having the antenna system described above and below.

[0017] For example, the radar measuring device is configured to transmit FMCW radar signals using a first antenna device and to transmit pulse signals using a second antenna device.

[0018] For example, a pulse signal can be a radar signal or an ultrasonic signal.

[0019] Another aspect of the invention relates to a method for measuring the topology of a filling material surface, in which the topology of the filling material surface is detected using a first antenna device. Simultaneously, before or after this, the level is detected using a second antenna device. The first antenna device is an array antenna having an array of radiating elements arranged around the second antenna device.

[0020] Another aspect of the invention relates to a program element that, when executed on a processor of a level measuring device, instructs the level measuring device to perform the steps described above and below.

[0021] Another aspect of the present invention relates to a computer-readable medium storing the aforementioned program elements.

[0022] The term "process automation in industrial environments" can be understood as a subfield of technology encompassing all measures for operating machines and equipment without human intervention. One goal of process automation is to automate the interaction of various components within a plant in industries such as chemical, food, pharmaceutical, petroleum, paper, cement, shipping, or mining. To this end, a large number of sensors are used, particularly suited to the specific requirements of process industries, such as mechanical stability, insensitivity to contaminants, extreme temperatures, and extreme pressures. These sensor measurements are typically transmitted to a control room where process parameters such as level, limit levels, flow rate, pressure, or density are monitored, and settings throughout the plant can be changed manually or automatically.

[0023] One subfield of process automation in industrial environments involves logistics automation. In logistics automation, processes inside or outside buildings, or within individual logistics devices, are automated using distance and angle sensors. Typical applications include logistics automation systems for areas such as airport baggage and cargo handling, traffic monitoring (toll collection systems), trade, parcel delivery, and building security (access control). A common thread in the examples listed above is the need to combine presence detection with precise measurements of object size and location. For this purpose, sensors based on optical measurement methods, such as lasers, LEDs, 2D cameras, or 3D cameras, can be used. These sensors detect distance based on the time-of-flight (ToF) principle.

[0024] Another subfield of process automation in industrial environments involves factory / manufacturing automation. Examples of this application can be found in many industries, such as automotive manufacturing, food manufacturing, pharmaceuticals, or general packaging. The goal of factory automation is to automate the production of goods performed by machines, production lines, and / or robots—that is, to operate without human intervention. The sensors used here, and the specific requirements for measurement accuracy in detecting the position and size of the objects, are comparable to those in the aforementioned examples of logistics automation.

[0025] Other embodiments of the invention will now be described with reference to the accompanying drawings. If the same reference numerals are used in the following description of the drawings, they denote the same or similar elements. The illustrations in the drawings are schematic and not drawn to scale. Attached Figure Description

[0026] Figure 1a The level radar measuring device is shown.

[0027] Figure 1b A radar measuring device for detecting the surface topology of a filling material is shown.

[0028] Figure 2a A radar measuring device according to one embodiment is shown.

[0029] Figure 2b It shows Figure 2a A radar measuring device that generates different emission lobes.

[0030] Figure 3a The radiating element is shown.

[0031] Figure 3b The antenna pattern of a single radiating element is shown.

[0032] Figure 4a A one-dimensional array of radiating elements is shown.

[0033] Figure 4b It shows Figure 4a The antenna pattern of the array.

[0034] Figure 4c The antenna pattern, which is altered using electronic beam control, is shown.

[0035] Figure 5a An array consisting of radiating elements with different spacings is shown.

[0036] Figure 5b It shows Figure 5a The antenna pattern of the array.

[0037] Figure 6 An array antenna according to one embodiment is shown.

[0038] Figure 7 A radar measuring device according to one embodiment is shown.

[0039] Figure 8a A top view of an antenna system d according to one embodiment is shown.

[0040] Figure 8b Shown from one side Figure 8a Antenna system.

[0041] Figure 8c It shows Figure 8a A three-dimensional diagram of the antenna system.

[0042] Figure 9Antenna systems with different radiating element arrangements are shown.

[0043] Figure 10 A flowchart of a method according to one embodiment is shown. Detailed Implementation

[0044] Figure 1a A radar measuring device 100 installed in a container 201 is shown. The container contains a filler material 202 with a slightly uneven surface. The radar measuring device 100 includes an antenna device 102 in the form of a horn antenna, which transmits a radar signal in the direction of the filler material surface. This radar signal may be a pulsed radar signal and is represented by an ellipse 203. The radar signal is then reflected off the filler material surface and received by the antenna device 102, and the received radar signal is evaluated in the measuring device 100 to calculate the level.

[0045] In level radar technology, different types of antennas have proven reliable and useful depending on their location and usage. For example, parabolic mirrors are used for applications requiring very high directivity. These antennas can achieve very high antenna gain at relatively small installation depths.

[0046] Another well-established antenna structure is the horn antenna. Besides its high gain, this widely used antenna can also be constructed very robustly at low cost. Typically, horn antennas also incorporate lenses with various advantages in the front region. On one hand, the construction of horn antennas can be more compact due to the shortening effect of electromagnetic waves in plastic. Furthermore, lenses can be used to create process seals relative to the process measuring device (radar measuring device 100). Horn antennas are typically supplied with waveguides.

[0047] Horn antennas are typically designed to be circular or rotationally symmetrical. Since container openings in process industries are often circular, rotationally symmetrical antennas fit well into the containers. Container openings often have threads that allow the antenna to be screwed into them. Circular antennas are also advantageous in this regard. Horn antennas can also be manufactured at low cost as machined parts.

[0048] Figure 1b A radar level measuring device 105 for detecting the topology of the filler material surface 204 is shown. This radar level measuring device is configured to detect the topology of the filler material surface 204 of the loose material pile 202, or to identify deposits 205 on the container wall (see [link]). Figure 2a ).

[0049] Figure 1bThe radar level measuring device 105 shown has an antenna device 101 (which is in the form of an array antenna with an array of radiating elements), and electronic beam control can be performed by means of this antenna device to scan the surface of the filling material, thereby detecting the topology of the filling material surface. Reference numeral 203 indicates different beam directions.

[0050] In addition to systems that mechanically rotate the antenna, systems capable of electronically rotating the antenna's main radiation direction can also be used. A semi-mechanical system can also be used, which mechanically rotates one direction of the antenna's main lobe and electronically rotates the other. Antenna systems capable of electronically rotating antenna lobes will be described below.

[0051] An electronically rotating antenna is an antenna whose main radiation direction and main receiving direction (main lobe) can be rotated electronically or digitally. These antennas have a large number of transmit and / or receive channels. These radar measurement devices are often referred to as multiple-input multiple-output (MIMO) radar devices. The various possibilities for changing the main radiation and main receiving directions on the transmit and receive sides will not be described below.

[0052] The position of the antenna element plays a crucial role here. Antenna element 103 (see, for example, see...) Figure 6 () Spanning the antenna array. Here, antenna elements 103 are generally of the same type and are oriented and polarized in the same way in their main radiation direction.

[0053] In cases involving multiple antenna elements, including more than two antenna elements, it has been shown that having the same distance d1 between these antenna elements is advantageous (see [link to relevant documentation]). Figure 4a If all radiating elements 103 now emit the same signal simultaneously, then the result is the same as... Figure 3a Directional characteristics of the individual radiator 103 in (see) Figure 3b Different overall directional characteristics (see) Figure 4b ).

[0054] When the dimensions are correct, the overall directional characteristics not only result in higher antenna gain but also a smaller aperture angle. If these transmitted signals are now assigned a specified phase shift, the direction of the main radiation direction can be altered (see...). Figure 4c These characteristics typically exhibit the same behavior in both transmitting and receiving scenarios.

[0055] The antenna spacing between each radiator affects the main radiation direction. If the antenna spacing d2 (see...) Figure 5aIf the antenna gain is greater than half the wavelength of the transmitted signal, so-called grating lobes will appear. These grating lobes have almost the same antenna gain as the main lobe, but in a different direction. Depending on the application, it is important to avoid these grating lobes because they can create false targets in radar images.

[0056] Figure 5b This type of grating lobe 501 is shown.

[0057] Such grating lobes can be avoided by designing the antenna array such that the antenna spacing is ≤ half a wavelength, thus preventing the generation of grating lobes, or by logically shielding false targets generated by grating lobes.

[0058] Another aspect of antenna array design is the total coverage area, also known as the antenna aperture, and hereinafter referred to as the radiating area. Generally, the larger the aperture, the smaller the antenna aperture angle.

[0059] One goal is to achieve an antenna aperture with a small aperture angle but with as few grating lobes and sidelobes as possible. This can be achieved with a large number of radar channels, but this in turn increases cost and power consumption. At this point, it is important to find an optimal solution.

[0060] Figure 4b , Figure 4c and Figure 5b The antenna patterns in the text refer to linear antenna arrays, that is, antenna groups composed of radiating elements arranged in rows (such as...). Figure 5a (As shown). Therefore, when the directivity characteristics are plotted along the longitudinal range of the array, the corresponding antenna pattern can be obtained. The main lobe can now be rotated in this direction.

[0061] If the main radiation direction is now to rotate in two spatial directions (dimensions), then the array must also be as follows. Figure 6 The array 102 extends in two spatial directions. It now consists of four subarrays, each with five antenna elements 103, each having a linear range. Here, the antenna elements 103 can be transmitters and / or receivers.

[0062] By allocating antenna elements accordingly as transmitters and / or receivers and by controlling them and associated signal processing accordingly, beamforming on both the transmitting and receiving sides can be operated using this array. In this case, one possible allocation scheme for antenna elements 103 is to configure and operate horizontal antenna elements as transmitters and vertical elements as receivers.

[0063] An important aspect of energy consumption is the subsequent calculations, particularly those in digital beamforming. Digital beamforming is a method used to change the primary receiving direction of a receiver array or to measure the received energy from any direction. This can be done using a Fast Fourier Transform (FFT). This digital beamforming can be calculated in a particularly energy-efficient manner within the digital processing unit of a microcontroller or FPGA (Field Programmable Gate Array).

[0064] It has proven advantageous that the array to be computed is linear (see...). Figure 4a , Figure 5a ) or rectangular (see Figure 6 Furthermore, the antennas have a constant spacing in their respective spatial directions. In one embodiment, the antenna spacing in the spatial direction x may, for example, have a different spacing than that in the spatial direction y. Therefore, these spacings should only be constant in their respective spatial directions.

[0065] To calculate the spatial dimension, only one FFT is needed. In other antenna devices (e.g., hexagonal arrays), more than one FFT is required to calculate the spatial dimension, which is detrimental to the overall energy balance of the device because the computation time is longer when evaluating measurement data.

[0066] Energy balance plays a crucial role, especially for two-wire interfaces widely used in process automation in industrial environments. Here, the measuring device has only a very limited amount of power available for data detection and evaluation. This predetermined energy can be used for level and topology measurements through a correspondingly slower measurement cycle.

[0067] Because the topology of the filling material typically changes slowly and the formation of adhesions is also a slow process, slow measurement cycles are acceptable. However, in principle, level measurement is important for some areas in process industries with high measurement cycles (such as in relatively fast sequences). To combine these two measurement techniques into a single device, a combination of a conventional level measurement device and a topology detection measurement device has been proposed, taking into account the limited available energy.

[0068] Figure 7 A radar measuring device 100 according to an embodiment of the present invention is shown. The radar measuring device 100 may be a level radar measuring device and includes an antenna system 105. The antenna system 105 has an antenna device 705 for level measurement and a transmitting and receiving antenna array 706a, 706b, 706c, 706d, 706e, 706f for topology detection.

[0069] The antenna device 705 for level measurement can be designed as a horn antenna with a lens and positioned at the center of the process-facing side of the antenna system. The antenna gain of the level antenna 705 is greater than the antenna gain of a single radiator in the topology detection arrays 706a to 706f.

[0070] The level antenna 705 can also be designed for a different frequency range than the topology measurement antenna array. For example, the antenna array can be designed for a frequency of 80 GHz, while the level antenna can be designed for a frequency of 180 GHz.

[0071] For example, the antenna elements 706a to 706f of the array antenna can be designed as waveguide apertures or horn radiators, or as waveguide apertures or horn radiators filled with a dielectric. Patch antennas, rod radiators, or other antennas are also possible.

[0072] In one embodiment, the openings of the horn array antenna and the openings of the level horn antenna are recessedly formed on a layer of the metal plate 802 (see [link]). Figure 8a , Figure 8b and Figure 8c The metal plate 802 is designed, for example, to be circular and suitable for passing through a DN 100 or DN 80 process connector. Therefore, the antenna system has a smaller diameter than the opening of the processing container. Thus, the entire antenna can be inserted into the container through the process connector.

[0073] Furthermore, the arrangement of antennas 706a to 706f in the array is related to the level antenna 705. For example, both the transmitting and receiving arrays of the topology detection antenna device have a linear design. Here, the transmitting antenna device may include one or more rows. Similarly, the receiving antenna device may include one or more rows. In this exemplary embodiment, the transmitting row and the receiving row are orthogonal to each other.

[0074] In one embodiment, the level horn antenna 102 is located at the center of the antenna system 105 and is surrounded by the transmit and receive row antennas of the topology detection antenna device 101. Due to the rectangular antenna array arrangement of the topology detection array antenna, energy-efficient beamforming algorithms can be used. Furthermore, the level antenna can also be designed to be as large as possible.

[0075] According to another embodiment, the antennas 103 of the array are arranged in a hexagonal shape (see [reference]). Figure 9 This allows the array to make better use of available space. It also allows for the design of larger level antennas.

[0076] According to another embodiment, the number of transmitting antenna elements is not equal to the number of receiving antenna elements.

[0077] According to another embodiment, the antenna system 105 has one or more anti-adhesion devices. Examples include radomes, air purging devices, or bags or caps made of flexible PTFE material.

[0078] According to another embodiment, level measurement and topology detection measurement use different measurement principles, particularly different radar measurement principles. For example, level measurement can be performed using a pulse radar method, while topology detection measurement can be performed using an FMCW method.

[0079] Furthermore, the polarization of the level antenna can be different from that of the array antenna to suppress interference reflections.

[0080] These measurements can also be performed in parallel or sequentially. In the case of simultaneous measurements, it is advantageous to choose the radar method or radar frequency so that the two measurements do not interfere with each other.

[0081] Level measurement can also be based on different measurement principles, such as ultrasonic level measurement or optical level measurement.

[0082] According to another embodiment, the level antenna is designed as a rectangular horn antenna. Therefore, when combined with a rectangular antenna array, the rectangular horn antenna can optimally utilize the spanned area within the antenna array and achieve maximum gain.

[0083] The antenna system comprises a single level antenna and separate antenna arrays for topology detection. The diameter of the antenna system is typically smaller than the container opening. The level antenna is surrounded by the antenna arrays. Different subarrays can be aligned with each other in the same manner. For example, as... Figure 6 As shown, the linear subarrays can have the same orientation. The Tx transmitting antennas are aligned in the x-direction, while the Rx receiving antennas are aligned in the y-direction.

[0084] The subarray can also be aligned with the level antenna in the same way. The level antenna and the array antenna can use different frequency ranges. A common anti-adhesion device can be provided. In particular, different radar methods can be used for level measurement and topology measurement. Different polarizations of the level antenna and the array antenna can also be applied.

[0085] Figure 10A flowchart of a method according to one embodiment is shown. In step 1001, the topology of the filling material surface is detected using a first antenna device. In step 1002, the level is detected using a second antenna device. In step 1003, both measurements are used to calculate the volume of the filling material, and in step 1004, the level or volume is output. It should be noted that these two measurement methods can also be performed independently of each other. Level detection can be performed independently of topology. Level measurement can have a higher measurement rate than topology measurement. Topology measurement can be performed independently of level measurement. Measurement data from level measurement can be used to improve measurement reliability and check the reasonableness of measurement data from topology detection, but this is by no means necessary.

[0086] It should also be noted that "comprising" or "having" does not exclude other elements and steps, and "a" or "an" does not exclude multiple. Furthermore, it should be noted that features or steps described with reference to one of the above exemplary embodiments may also be used in combination with other features or steps of the other above exemplary embodiments. Reference numerals in the claims should not be construed as limiting.

Claims

1. An antenna system (105) configured for use in a radar measuring device (100) for detecting the topology of a filling material surface (204), the antenna system comprising: A first antenna device (101) is configured to detect the topology of the surface of the filling material; as well as A second antenna device (102) is configured to detect the level; The first antenna device is an array antenna, which has an array of radiating elements (103) arranged around the second antenna device; The radiating surface of the radiating element (103) of the first antenna device (101) and the radiating surface of the second antenna device (102) are arranged on the same plane. The radiating element (103) of the first antenna device (101) includes a group of transmitting elements arranged in one or more rows and a group of receiving elements arranged in one or more columns perpendicular to the one or more rows.

2. The antenna system (105) according to claim 1, in, The second antenna device (102) is a horn antenna.

3. The antenna system (105) according to claim 1 or 2, in, The radiating element (103) of the first antenna device (101) is a horn antenna or waveguide aperture that can be filled with dielectric material.

4. The antenna system (105) according to claim 1 or 2, in, The diameter or side length of the radiating element (103) of the first antenna device (101) is smaller than the diameter or side length of the second antenna device (102).

5. The antenna system (105) according to claim 1 or 2, in, The radiating surface of the radiating element (103) of the first antenna device (101) and the radiating surface of the second antenna device (102) are arranged in the form of filled or unfilled holes in a metal plate (802).

6. The antenna system (105) according to claim 5, in, The metal plate (802) is designed to be circular.

7. The antenna system (105) according to claim 1 or 2, in, The radiating element (103) of the first antenna device (101) is rectangular.

8. A radar measuring device (100) having an antenna system (105) according to any one of the preceding claims.

9. The radar measuring device (100) according to claim 8, configured to transmit FMCW radar signals using the first antenna device (101) and to transmit pulse signals using the second antenna device (102).

10. The radar measuring device (100) according to claim 9, in, The pulse signal is a radar signal or an ultrasonic signal.

11. The radar measuring device (100) according to claim 8 or 9, in, The overall diameter of the antenna system is smaller than the diameter of the container opening, the radar measuring device is inserted through the container opening, and / or the radar measuring device is fastened to the container opening.

12. A method for measuring the topology of a surface (204) of a filling material, comprising the following steps: The topology of the surface of the filling material is detected using the first antenna device (101); The level is detected using the second antenna device (102); The first antenna device is an array antenna, which has an array of radiating elements (103) arranged around the second antenna device; The radiating surface of the radiating element (103) of the first antenna device (101) and the radiating surface of the second antenna device (102) are arranged on the same plane. The radiating element (103) of the first antenna device (101) includes a group of transmitting elements arranged in one or more rows and a group of receiving elements arranged in one or more columns perpendicular to the one or more rows.

13. A computer-readable medium storing program elements that, when executed on a processor of a level measuring device, instruct the level measuring device to perform the following steps: The topology of the filling material surface is detected using the first antenna device (101); The level is detected using the second antenna device (102); in, The first antenna device is an array antenna having an array of radiating elements (103) arranged around the second antenna device; The radiating surface of the radiating element (103) of the first antenna device (101) and the radiating surface of the second antenna device (102) are arranged on the same plane. The radiating element (103) of the first antenna device (101) includes a group of transmitting elements arranged in one or more rows and a group of receiving elements arranged in one or more columns perpendicular to the one or more rows.

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