CN1282866C - Digitized radar levelmeter - Google Patents
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- CN1282866C CN1282866C CN 200410092449 CN200410092449A CN1282866C CN 1282866 C CN1282866 C CN 1282866C CN 200410092449 CN200410092449 CN 200410092449 CN 200410092449 A CN200410092449 A CN 200410092449A CN 1282866 C CN1282866 C CN 1282866C
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Abstract
The present invention relates to a digitized radar object position meter which belongs to the technical field of the automatic measurement. The present invention uses a linear FM radar distance measuring method to realize the measurement of the material level of a container and a storage bin and the liquid level in the process of the production. A linear modulation microwave signal is emitted by an antenna, and simultaneously, the antenna receives an echo signal reflected by a target object. Moreover, the emitted signal and the echo signal are processed by a frequency mixer to obtain an intermediate frequency signal. The object position information can be obtained by processing the intermediate frequency signal. The present invention is characterized in that a linear FM signal with high linear degree is generated based on the theory that the frequencies of a voltage controlled oscillator is corrected in non-linear and learning way to ensure the measurement precision. The present invention is suitable for the measurement of various object positions.
Description
One, technical field
The invention belongs to the automatic measurement technology field, is a kind of material level of industrial processes container, warehouse and non-contact measuring device of liquid level of being used for specifically.
Two, background technology
Radar level gauge has noncontact, resolution height, the advantage of medium wide adaptability in level gauging.Measuring method commonly used has two kinds, and a kind of is the pulse radar level-sensing device, and another kind is a continuous frequency modulation formula radar level gauge.The pulse radar level-sensing device need carry out frequency counting in the time of nanosecond, and the big resolution of technical difficulty is low, is replaced by the linear FM radar level-sensing device gradually.The theoretical limit range resolution of LINEAR CONTINUOUS ripple FM radar system depends on system signal bandwidth deltaf R=C/2B, and wherein C represents the light velocity, and B is a modulating bandwidth.This is that to be based upon system be under complete linearity, the ideal situation, has various factors in the actual application and causes that range resolution reduces, and wherein topmost factor is that frequency modulation is non-linear.There is bigger nonlinear relationship between voltage controlled oscillator output frequency and the modulation voltage, adopt linear fully voltage to carry out frequency modulation (PFM), owing to there is frequency shift (FS), Beat Signal after the mixing is not the simple signal under the ideal linearity FM signal situation, frequency spectrum is broadened, thereby causes LFMCW radar level gauge resolution to reduce.Non-linear in order to eliminate, generally adopt 2 kinds of methods: open loop correction and closed-loop corrected.Open loop correction is to measure the electric voltage frequency relation of voltage controlled oscillator in advance, is stored in the storer, and the digital quantity by storage in advance during actual the use is carried out the output of sweep voltage by D/A converter.The shortcoming of this method is that the characteristic of each voltage controlled oscillator is all inequality, and workload is very big in the production debug process, is difficult for mass production.Temperature influence is also very big in the actual use, is difficult to guarantee measuring accuracy.Closed-loop corrected method is to adopt independent counting channel that the frequency signal of output is measured in real time, then the digital quantity that produces control voltage is revised, and to obtain the satisfied linearity, this will increase the workload of cost and software.
In order to address this problem, it is synthetic that the method that people adopt the synthetic and digital phase-locked loop of Direct Digital is carried out numeral to needed signal, but can not drop into the application of reality owing to following reason.At first adopt the synthetic method of Direct Digital also not reach the X-band of fill level radar work at present, can only adopt the method for frequency multiplication or up-conversion, this method one is that cost is too high, system complex, the 2nd, the microwave signal that produces through frequency multiplication has a lot of harmonic components, phase noise is big, can produce negative influence to measurement result.In addition, need a transient process when utilizing phaselocked loop to change frequency, so its frequency inverted time is longer, and can not satisfies the requirement of the high speed frequency sweep characteristic of linear frequency modulation ripple radar.
Three, summary of the invention
Digitized radar levelmeter purpose of the present invention is: solve because the problem of the non-linear influence that measuring accuracy is brought of frequency modulation solves the difficult problem of present linearity correction, a kind of radar levelmeter of producing and debugging be convenient to is provided.
Digitized radar levelmeter of the present invention is a kind of non-contact measuring device that the thing position is detected that is used for, it is characterized in that: the normal linearity modulation frequency generation unit that this level meter adopts total digitalization to adjust, this unit produces the reference frequency signal of high linearity and the pumping signal that the control voltage controlled oscillator produces linear frequency, and this pumping signal is for signal processing unit study; This level meter adopts a kind of mode based on study to carry out the pressuring controlling oscillator frequency gamma correction, and the pumping signal that produces the normal linearity FM signal by study realizes online and high precision voltage controlled oscillator linearity correction; This level meter employing is a kind of can be by learning directly to obtain representing the digital quantity sequence of linear frequency modulation state, and this digital quantity sequence is used for D/A converter, the data processing of complexity and conversion when avoiding closed-loop corrected through simple linear transformation; This level meter has adopted and has compared different on-line correction methods with other open loop correction, be that equipment is installed to on-the-spot also can the correction later, avoid preserving the correction parameter under the different operating modes like this, and the frequency measurement that need not be complicated and the calculating of correction parameter, specifically, the present invention mainly comprises normal linearity modulation frequency generation unit, pumping signal unit, microwave unit, intermediate-freuqncy signal is handled collecting unit, the linear frequency modulation output control unit, signal processing logic control module and display keyboard communication interface unit 1[structure see Fig. 1 for details], its normal linearity modulation frequency generation unit is by crystal oscillator 3, Direct Digital Frequency Synthesizers 4, digital phase-locked loop 6, active filter 8, aanalogvoltage switch 9, first buffer amplifier 10, second buffer amplifier 12, voltage controlled oscillator 13, pre-divider 18 is formed, the frequency signal of crystal oscillator 3 outputs is as the reference frequency signal of Direct Digital Frequency Synthesizers 4, produce the reference incoming frequency of phase-locked loop by the control word that changes Direct Digital Frequency Synthesizers 4, produce high-frequency signal by digital phase-locked loop 6 frequencys multiplication, when the control word that is input to Direct Digital Frequency Synthesizers 4 remains unchanged, output through voltage controlled oscillator 13 after the stabilization time of phase-locked loop is stabilized on the Frequency point, if control word according to linear increment Direct Digital Frequency Synthesizers 4, then normal linearity modulation frequency generation unit is created in continuous linear FM signal in the swept frequency range, whether voltage controlled oscillator 13 output frequency signals are stabilized on the predetermined Frequency point to export by the locking of digital phase-locked loop 6 is detected, the employing of pre-divider 19 mainly is to consider that the frequency of operation of some digital phase-locked loop does not also reach the frequency range of radar levelmeter work, adopt pre-divider 19 earlier frequency of operation to be reduced, satisfy the frequency input requirement of digital phase-locked loop 6, active filter 8[sees Fig. 3 for details] by the 3rd buffer amplifier 25, the 4th buffer amplifier 26 and Resistor-Capacitor Unit are formed, generally speaking for the consideration of the electronic noise of phase noise and active device, phase-locked loop mostly adopts passive filter, and consider the problem of loop-locking time, the general lower order filter that adopts, as second order or three rank filter circuits, but in order not influence the stability of voltage because before voltage controlled oscillator 13, its voltage sampled, adopt the active filter of high-order, output terminal at active filter increases the one-level voltage buffer, the main resistance matching problem of considering wave filter output and analog switch interface, further strengthen the stability of voltage controlled oscillator input voltage, improve the correction accuracy of system; Pumping signal unit by A/D converter 11 and with the shared aanalogvoltage switch 9 of normal linearity modulation frequency generation unit, first buffer amplifier 10 is formed, when trimming process begins, by aanalogvoltage switch 9 voltage input end of first buffer amplifier 10 is switched to the output terminal of the active filter 8 of normal linearity modulation frequency generation unit earlier, because the frequency of voltage controlled oscillator 13 outputs is decided by the voltage of its input end, therefore under voltage controlled oscillator can the situation of output line resistant frequency, the voltage signal of its input end just has reference value completely, what in fact the input of voltage controlled oscillator 13 was accepted is the pumping signal of active filter 8 outputs, after constant and phase-locked loop reaches lock-out state when the reference frequency signal of Direct Digital Frequency Synthesizers 4 output, this pumping signal is stabilized on certain magnitude of voltage, and the output frequency of this driving voltage signal and voltage controlled oscillator 13 has definite corresponding relation, Direct Digital Frequency Synthesizers 4 each synchronizing frequency increase progressively and phase-locked loop locking after, obtain the digital quantity of the excitation signal voltage value correspondence of a voltage controlled oscillator 13 inputs by A/D converter 11, obtain swept frequency range internal linear FM signal by the control word that changes Direct Digital Frequency Synthesizers 4, the pairing digital quantity sequence of driving voltage signal that applies when obtaining to represent voltage controlled oscillator 13 by the linear frequency modulation output frequency signal, and store in the internal memory, after correction work is finished, by analog switch 9 voltage input end of first buffer amplifier 10 is switched to high-speed d/a converter 5 again, the digital quantity sequence that obtains is exported as normal linear frequency-modulating process high speed D/A converter 5 controlled quentity controlled variables through after the simple linear transformation, produce the FM signal of high linearity at a high speed, the process of this correction is actually the process of a study, and because need not be by the equipment and the instrument of outside, the process of this correction is self-correcting, online carrying out, repeat, even also can carry out after equipment puts into operation; Microwave unit is by circulator 14, emission and receiving antenna 15, coupling mechanism 16, frequency mixer 17 and voltage controlled oscillator 13 compositions shared with normal linearity modulation frequency generation unit, intermediate-freuqncy signal is handled collecting unit by wave filter 18, digital program controlled gain amplifier 20, high-speed a/d converter 22, fifo buffer 23 is formed, because different materials is to the degree of reflection difference of microwave signal, and have under the situation of floating dust or steam electromagnetic wave signal is produced very big decay, in order to improve the scope of application of radar levelmeter, prime amplifier adopts digital program controlled gain amplifier, difference frequency signal after the mixing is carried out processing and amplifying, its gain is controlled by digital signal processing and logic control element, the gain range of choice has enlarged the dynamic range of signal from-12dB to+30dB; The linear frequency modulation output control unit is formed by high-speed d/a converter 5, the 5th buffer amplifier 7 with shared aanalogvoltage switch 9, first buffer amplifier 10, second buffer amplifier 12 of linear frequency modulation output control unit, and signal Processing and logic control element are made up of digital signal processor and corresponding memory circuit 2 and programmable logic chip 21; Adopt programmable logic device (PLD) that the logical signal of input is handled among the present invention, realize logic control and logic output function, accept the control of digital signal processor and carry out logical operation in conjunction with the logical signal of importing, realize high-speed a/d converter 22, fifo buffer 23, Direct Digital Frequency Synthesizers 4, digital phase-locked loop 6,20 control is amplified in analog switch 9 and digital program controlled gain, control and read-write to Direct Digital Frequency Synthesizers 4 adopt the mode of parallel or serial to carry out, generally adopt serial mode to carry out to the control of digital phase-locked loop 6, gather the intermediate-freuqncy signal of returning and carry out data processing by digital signal processor, after calculating real material level signal, utilize the mode that shows via display keyboard communication interface unit 1, or export to outside Displaying Meter by electric current, or communicate the transmission data by communication interface and outside Displaying Meter.
Advantage of the present invention: be mainly used in industrial and mining enterprises various things position measurement and be used for some range observation occasions.The correction of the linear frequency modulation linearity can be implemented in that line is proofreaied and correct and proofreaies and correct at any time, need not external measurement devices; Adopt digitized mode to proofread and correct, correcting mode and algorithm are simple, proofread and correct back linearity height; The cost of instrument is low, produces and debugs simply, enhances productivity; The measuring accuracy height, error is little, antijamming capability is strong, adapt to abominable industrial environment, and is reliable and stable.
Four, description of drawings
Fig. 1 is the structural drawing of way of realization 1 of the present invention
Fig. 2 is the structural drawing of way of realization 2 of the present invention
Fig. 3 is the active filter structural drawing
Fig. 4 is the structural drawing of way of realization 3 of the present invention
Number in the figure
1, display keyboard communication interface 2, digital signal processor and corresponding memory circuit
3, crystal oscillator 4, Direct Digital Frequency Synthesizers
5, high-speed d/a converter 6, digital phase-locked loop
7, the 5th buffer amplifier 8, active filter
9, aanalogvoltage switch 10, first buffer amplifier
11, high-precision a/d converter 12, second buffer amplifier
13, voltage controlled oscillator 14, circulator
15, antenna 16, coupling mechanism
17, frequency mixer 18, wave filter
19, pre-divider 20, digital program controlled gain amplifier
21, programmable logic device (PLD) 22, high-speed a/d converter
23, fifo buffer 24, aanalogvoltage switch
25, the 3rd buffer amplifier 26, the 4th buffer amplifier
27, aanalogvoltage switch
Five, embodiment
Embodiment 1: as shown in Figure 1, among Fig. 1 except that antenna 15 other parts can be assembled in a metal shell inside, antenna 15 can adopt electromagnetic horn or bar antenna, also can adopt waveguide, when correcting state, make voltage controlled oscillator 13 accept the control in phaselocked loop loop by switching analoging switch 9, in tuning range, progressively produce linear FM signal by the frequency control word that changes Direct Digital Frequency Synthesizers 4, gather the driving voltage signal of voltage controlled oscillator 13 by high-precision A/D converter 11, memory is changed and stored to digital signal processor 2, after correction is finished, switching analoging switch 9 makes voltage controlled oscillator 13 accept the control of high-speed d/a converter 5, carries out real-time linear frequency modulation.This moment, digital signal processor 2 utilized 22 pairs of intermediate-freuqncy signals of high-speed a/d converter to gather, Serial No. to collection carries out the FFT computing, spectrum analysis obtains monitored order subject matter position, the thing position can show on the display of radar levelmeter itself, also can utilize the mode of digital communication, supervisory instrument, pen recorder or the host computer that the analog current signal teletransmission is arrived other.A/D converter 11 should adopt high-precision A/D converter among Fig. 1, and for example 16 A/D converter can obtain 1/65536 resolution, and obviously precision can satisfy requirement of actual application fully.Because frequency can be stabilized on the interior any point of linear frequency modulation scope, not too high requirement of speed to the A/D conversion, therefore can also adopt more high-precision ∑-Δ type A/D converter, resolution can reach 20 or higher, and the selection of A/D interface mode can be walk abreast or serial because be used for the sampling of correction signal, speed less demanding, so can paying the utmost attention to of serial, interface is simple, and saves the area that can effectively reduce circuit board.
Embodiment 2: as shown in Figure 2, cancelled A/D converter 11, the output of first buffer amplifier 10 among Fig. 1 is connected to another analog switch 24[sees Fig. 2 for details], can utilize a slice A/D converter to finish like this and proofread and correct and measure, in order to represent conveniently, drawn among the figure two aanalogvoltage switches 9 and 24, when the correction learning duty, what aanalogvoltage switch 9 was accepted is the pumping signal of active filter 8 outputs, and what analog switch 24 was accepted is the pumping signal of first buffer amplifier, 10 outputs; What aanalogvoltage switch 9 was accepted when normal operating conditions is the swept-frequency signal of high-speed d/a converter 5 through 7 outputs of the 5th buffer amplifier, and what analog switch 24 was accepted is through digital program controlled gain amplifier 20 amplified IF signal.Therefore, these two aanalogvoltage switches 9 and 24 are two independently chips.
Embodiment 3: other is with embodiment 2, and only two aanalogvoltage switches 9 and 24 are chips that comprise two covers or overlap same assembly more, and for example the aanalogvoltage switch 27[of dpdt double-pole double-throw (DPDT) sees Fig. 4 for details].The function of aanalogvoltage switch also can be replaced by relay.
Claims (1)
1. digitized radar levelmeter, it is a kind of non-contact measuring device that the thing position is detected that is used for, it is characterized in that: the normal linearity modulation frequency generation unit that this level meter adopts total digitalization to adjust, this unit produces the reference frequency signal of high linearity and the pumping signal that the control voltage controlled oscillator produces linear frequency, and this pumping signal is for signal processing unit study; This level meter adopts a kind of mode based on study to carry out the pressuring controlling oscillator frequency gamma correction, and the pumping signal that produces the normal linearity FM signal by study realizes online and high precision voltage controlled oscillator linearity correction; This level meter employing is a kind of can be by learning directly to obtain representing the digital quantity sequence of linear frequency modulation state, and this digital quantity sequence is used for D/A converter, the data processing of complexity and conversion when avoiding closed-loop corrected through simple linear transformation; This level meter has adopted and has compared different on-line correction methods with other open loop correction, be that equipment is installed to on-the-spot also can the correction later, avoid preserving the correction parameter under the different operating modes like this, and the frequency measurement that need not be complicated and the calculating of correction parameter; This level meter mainly comprises normal linearity modulation frequency generation unit, pumping signal unit, microwave unit, intermediate-freuqncy signal is handled collecting unit, the linear frequency modulation output control unit, signal processing logic control module and display keyboard communication interface unit (1), normal linearity modulation frequency generation unit is by crystal oscillator (3), Direct Digital Frequency Synthesizers (4), digital phase-locked loop (6), active filter (8), aanalogvoltage switch (9), first buffer amplifier (10), second buffer amplifier (12), voltage controlled oscillator (13), pre-divider (19) is formed, the frequency signal of crystal oscillator (3) output is as the reference frequency signal of Direct Digital Frequency Synthesizers (4), produce the reference incoming frequency of phase-locked loop by the control word that changes Direct Digital Frequency Synthesizers (4), produce high-frequency signal by digital phase-locked loop (6) frequency multiplication, when the control word that is input to Direct Digital Frequency Synthesizers (4) remains unchanged, output through voltage controlled oscillator (13) after the stabilization time of phase-locked loop is stabilized on the Frequency point, control word according to linear increment Direct Digital Frequency Synthesizers (4), then normal linearity modulation frequency generation unit is created in continuous linear FM signal in the swept frequency range, whether voltage controlled oscillator (13) output frequency signal is stabilized on the predetermined Frequency point to export by the locking of digital phase-locked loop (6) is detected, the employing of pre-divider (19) mainly is to consider that the frequency of operation of some digital phase-locked loop does not also reach the frequency range of radar levelmeter work, adopt pre-divider (19) earlier frequency of operation to be reduced, satisfy the frequency input requirement of digital phase-locked loop (6), active filter (8) is by the 3rd buffer amplifier (25), the 4th buffer amplifier (26) and Resistor-Capacitor Unit are formed, before control voltage of voltage-controlled oscillator is sampled at second buffer amplifier (12), do not influence the stability of voltage controlled oscillator (13) input control voltage, adopt the active filter of high-order, output terminal at active filter increases the one-level voltage buffer, mainly considers the resistance matching problem of wave filter output and analog switch interface; Pumping signal unit by A/D converter (11) and with the shared aanalogvoltage switch (9) of normal linearity modulation frequency generation unit, first buffer amplifier (10) is formed, when trimming process begins, by aanalogvoltage switch (9) voltage input end of first buffer amplifier (10) is switched to the output terminal of the active filter (8) of normal linearity modulation frequency generation unit earlier, because the frequency of voltage controlled oscillator (13) output is decided by the voltage of its input end, therefore under voltage controlled oscillator (13) can the situation of output line resistant frequency, the voltage signal of its input end just has reference value completely, after constant and phase-locked loop reaches lock-out state when the reference frequency signal of Direct Digital Frequency Synthesizers (4) output, the pumping signal of active filter (8) output is accepted in the input of voltage controlled oscillator (13), this pumping signal is stabilized on certain magnitude of voltage, and the output frequency of this driving voltage signal and voltage controlled oscillator (13) has definite corresponding relation, each synchronizing frequency of Direct Digital Frequency Synthesizers (4) increase progressively and phase-locked loop locking after, obtain the digital quantity of the excitation signal voltage value correspondence of a voltage controlled oscillator (13) input by A/D converter (11), obtain swept frequency range internal linear FM signal by the control word that changes Direct Digital Frequency Synthesizers (4), the pairing digital quantity sequence of driving voltage signal that applies when obtaining to represent voltage controlled oscillator (13) by the linear frequency modulation output frequency signal, and store in the internal memory, after correction work is finished, by analog switch (9) voltage input end of first buffer amplifier (10) is switched to high-speed d/a converter (5) again, the digital quantity sequence that obtains is exported as normal linear frequency-modulating process high speed D/A converter (5) controlled quentity controlled variable through after the simple linear transformation, produce the FM signal of high linearity at a high speed, the process of this correction is actually the process of a study, and need be by the equipment and the instrument of outside, the process of this correction is self-correcting, online, repeat, even also can carry out after equipment puts into operation; Microwave unit is by circulator (14), emission and receiving antenna (15), coupling mechanism (16), frequency mixer (17) and voltage controlled oscillator (13) composition shared with normal linearity modulation frequency generation unit, intermediate-freuqncy signal is handled collecting unit by wave filter (18), digital program controlled gain amplifier (20), high-speed a/d converter (22), fifo buffer (23) is formed, because different materials is to the degree of reflection difference of microwave signal, and have under the situation of floating dust or steam electromagnetic wave signal is produced very big decay, in order to improve the scope of application of radar levelmeter, prime amplifier adopts digital program controlled gain amplifier, difference frequency signal after the mixing is carried out processing and amplifying, its gain is controlled by digital signal processing and logic control element, the gain range of choice has enlarged the dynamic range of signal from-12dB to+30dB; The linear frequency modulation output control unit is formed by high-speed d/a converter (5), the 5th buffer amplifier (7) with shared aanalogvoltage switch (9), first buffer amplifier (10), second buffer amplifier (12) of linear frequency modulation output control unit, and signal Processing and logic control element are made up of digital signal processor and corresponding memory circuit (2) and programmable logic chip (21); Adopt programmable logic device (PLD) that the logical signal of input is handled, realize logic control and logic output function, accept the control of digital signal processor and carry out logical operation in conjunction with the logical signal of importing, realize high-speed a/d converter (22), fifo buffer (23), Direct Digital Frequency Synthesizers (4), digital phase-locked loop (6), the control of analog switch (9) and digital program controlled gain amplifier (20), control and read-write to Direct Digital Frequency Synthesizers (4) adopt the mode of parallel or serial to carry out, generally adopt serial mode to carry out to the control of digital phase-locked loop (6), gather the intermediate-freuqncy signal of returning and carry out data processing by digital signal processor, after calculating real material level signal, utilize the mode of demonstration via display keyboard communication interface unit (1), or export to outside Displaying Meter by electric current, or communicate the transmission data by communication interface and outside Displaying Meter.
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| CN 200410092449 CN1282866C (en) | 2004-12-23 | 2004-12-23 | Digitized radar levelmeter |
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|---|---|---|---|
| CN 200410092449 CN1282866C (en) | 2004-12-23 | 2004-12-23 | Digitized radar levelmeter |
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| CN1282866C true CN1282866C (en) | 2006-11-01 |
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Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102005036872B4 (en) * | 2005-08-02 | 2016-03-24 | Vega Grieshaber Kg | Vibration-level level detection device and method for vibration-level level detection |
| CN101110565B (en) * | 2007-06-28 | 2010-04-14 | 安徽蓝盾光电子股份有限公司 | Linearity correcting device for radar voltage controlled oscillator collecting vehicle information |
| CN100590450C (en) * | 2007-11-21 | 2010-02-17 | 厦门大学 | Microwave geodimeter |
| EP2161551A1 (en) | 2008-09-04 | 2010-03-10 | VEGA Grieshaber KG | Variable transmission output for fill state measurement |
| DE102011007372B4 (en) * | 2011-04-14 | 2023-05-04 | Endress+Hauser SE+Co. KG | Calibration and/or monitoring method for FMCW radar level gauges |
| US8730093B2 (en) * | 2011-09-27 | 2014-05-20 | Rosemount Tank Radar Ab | MFPW radar level gauging with distance approximation |
| DE102012111839B4 (en) * | 2012-12-05 | 2021-08-05 | Endress+Hauser SE+Co. KG | Radar-based level measuring device with a synthesizer circuit |
| DE102015109463A1 (en) * | 2015-06-15 | 2016-12-15 | Endress + Hauser Gmbh + Co. Kg | Method for checking the functionality of a radar-based level gauge |
| HUE060006T2 (en) * | 2017-05-09 | 2023-01-28 | Grieshaber Vega Kg | Fill level measurement, pressure measurement or flow rate measurement with short measurement time |
| DE102017123185A1 (en) * | 2017-10-05 | 2019-04-11 | Krohne S. A. S. | Method and level measuring device for determining the level of a medium by means of continuous wave radar measurement |
| DE102018200763A1 (en) * | 2018-01-18 | 2019-07-18 | Robert Bosch Gmbh | Apparatus and method for processing an input signal and radar apparatus |
| EP3804148A4 (en) | 2018-06-01 | 2021-10-27 | Culvert-Iot Corporation | An intelligent tracking system and methods and systems therefor |
| WO2020243557A1 (en) * | 2019-05-31 | 2020-12-03 | Culvert-Iot Corporation | An intelligent tracking system and methods and systems therefor |
| US11715060B2 (en) | 2019-05-31 | 2023-08-01 | X Development Llc | Intelligent tracking system and methods and systems therefor |
| CN113390899B (en) * | 2021-06-01 | 2022-08-23 | 中国科学院合肥物质科学研究院 | Microwave reflectometer with online automatic calibration function |
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Assignee: Guangdong Chungchak Heavy Industry Co., Ltd. Assignor: Taiyuan University of Technology Contract fulfillment period: 2007.9.23 to 2012.9.23 contract change Contract record no.: 2009440001741 Denomination of invention: Digitized radar levelmeter Granted publication date: 20061101 License type: Exclusive license Record date: 20091026 |
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Free format text: EXCLUSIVE LICENSE; TIME LIMIT OF IMPLEMENTING CONTACT: 2007.9.23 TO 2012.9.23; CHANGE OF CONTRACT Name of requester: GUANGDONG CHUNGCHAK HEAVY INDUSTRY CO., LTD. Effective date: 20091026 |
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