Surface mapping by virtual array processing via separate transmissions

• US 9,217,660 B2
• Filed: 03/18/2013
• Issued: 12/22/2015
• Est. Priority Date: 01/30/2013
• Status: Active Grant

• Current Assignee: Rosemount Tank Radar AB (Emerson Electric Company)
• Original Assignee: APM Automation Solutions Ltd. (Emerson Electric Company)
• Inventors: Zlotnick, Yossi, Bartov, Avishai
• Primary Examiner(s): ALLEN, ANDRE J
• Application Number:
  US13/845,169
• Publication Number:
  US 20140208845A1
• Time in Patent Office: 1,009 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G01F 22/00 Methods or apparatus for measuring volume of fluids or fluent solid material, not otherwise provided for
• CPC Class Codes: G01F 23/284 Electromagnetic waves
• CPC Class Codes: G01F 23/296 Acoustic waves
• CPC Class Codes: G01F 23/2962 Measuring transit time of reflected waves
• CPC Class Codes: G01F 23/802 Particular electronic circuits for digital processing equipment
• CPC Class Codes: G01S 13/003 Bistatic radar systems; Multistatic radar systems
• CPC Class Codes: G01S 13/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S13/46
• CPC Class Codes: G01S 13/88 Radar or analogous systems specially adapted for specific applications electromagnetic prospecting or detecting of objects, e.g. near-field detection, G01V3/00
• CPC Class Codes: G01S 15/003 Bistatic sonar systems; Multistatic sonar systems
• CPC Class Codes: G01S 15/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S15/46
• CPC Class Codes: G01S 15/88 Sonar systems specially adapted for specific applications seismic or acoustic prospecting or detecting G01V1/00
• CPC Class Codes: G01S 3/46 using antennas spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
• CPC Class Codes: G01S 3/808 using transducers spaced apart and measuring phase or time difference between signals therefrom, i.e. path-difference systems
• CPC Class Codes: G01S 7/52006 with provision for compensating the effects of temperature

Abstract

A system for measuring the height of bin contents includes transmitters for transmitting pulses of wave energy towards the upper surface of the contents and receivers for receiving echoes of the pulses and producing corresponding signals. The transmitters and receivers are distributed aerially above the contents. The system also includes a processing apparatus, for using the received signals to map the upper surface, that includes correlators that correlate pulse waveforms with the signals, and a beamformer. In one embodiment, the beamformer computes, from the signals considered as corresponding to echoes, of pulses from fewer synthetic transmitters, received at a synthetic receiver array, respective directions of arrival of the signals. In another embodiment, the beamformer computes respective directions of transmission and arrival of the signals, and the processing apparatus also includes a processor that selects, according to the computed transmission and arrival directions, which signals to use for the mapping.

Claims

1. A system for measuring a height of a content of a bin, comprising:

(a) a plurality of transmitters for transmitting respective pulses of wave energy towards an upper surface of the content; and

(b) a plurality of receivers for receiving an echo of each said pulse, each said receiver producing a respective signal in response to said echo;

wherein said transmitters and receivers are distributed aerially above the content, the system further comprising

(c) a processing apparatus, for jointly transforming said signals into a plurality of measured distances from said receivers to said upper surface, that includes;

(i) for each said receiver, a correlator for correlating a waveform of each said pulse with said respective signal, thereby producing a correlated signal, and

(ii) a beamformer for computing, from said correlated signals considered as corresponding to echoes, of pulses transmitted by synthetic transmitters corresponding to said plurality of transmitters, said synthetic transmitters being fewer in number than said plurality of transmitters, that are received by an array of synthetic receivers, said synthetic receivers corresponding to said plurality of receivers, a respective direction of arrival of each said correlated signal from said upper surface to said receiver of said correlated signal.

2. The system of claim 1, wherein said wave energy is acoustic energy.

3. The system of claim 2, further comprising:

(d) a thermometer for measuring an interior temperature of the bin, said processing apparatus basing said transforming, of said signals into said measured distances, on said measured interior temperature.

4. The system of claim 1, wherein said wave energy is electromagnetic energy.

5. The system of claim 1, wherein said processing apparatus is operative to compute, for each said direction of arrival, a corresponding said measured distance.

6. The system of claim 1, wherein at least a portion of said receivers are transducers that also function as at least a portion of said transmitters.

7. The system of claim 1, wherein said transmitters transmit said pulses sequentially.

8. The system of claim 7, wherein, subsequent to said transmission of one of said respective pulses by one of said transmitters, said transmission of a next said pulse by another one of said transmitters is delayed until said echo of said one pulse has been received by all said receivers.

9. The system of claim 1, wherein said measured distances are to a plurality of locations on said upper surface.

10. The system of claim 1, wherein said processing apparatus is operative to form a Cartesian product of said plurality of transmitters and said plurality of receivers, thereby forming a synthetic array including said synthetic transmitters and said synthetic receivers, said synthetic array for which said beamformer computes said directions of arrival.

11. The system of claim 10, wherein said respective directions of arrival are computed from said correlated signals considered as corresponding to echoes of pulses transmitted by a single said synthetic transmitter.

12. A method of measuring a height of a content of a bin, comprising:

(a) positioning a plurality of transmitters and a plurality of receivers aerially above the contents;

(b) transmitting, from each said transmitter, a respective pulse of wave energy towards an upper surface of the content;

(c) receiving an echo of each said pulse, using said receivers, each said receiver producing a respective signal in response to said echo; and

(d) jointly transforming said signals into a plurality of measured distances from said receivers to said upper surface by steps including;

(i) for each said receiver and each said pulse, correlating a waveform of said each pulse with said signal, thereby producing a correlated signal,

(ii) computing, from said correlated signals, considered as corresponding to echoes, of pulses transmitted by synthetic transmitters corresponding to said plurality of transmitters, said synthetic transmitters being fewer in number than said plurality of transmitters, that are received by an array of synthetic receivers, said synthetic receivers corresponding to said plurality of receivers, a respective direction of arrival of each said correlated signal from said upper surface to said array, and

(iii) for each said direction of arrival, computing a respective said measured distance.

22. The system of claim 12, wherein the correspondence of:

i) said synthetic transmitters to said plurality of transmitters, and, ii) said synthetic receivers to said plurality of receivers, is based on a Cartesian product of said plurality of transmitters and said plurality of receivers.

13. A system for measuring a height of a content of a bin, comprising:

(a) a plurality of transmitters for transmitting respective pulses of wave energy towards an upper surface of the content; and

(b) a plurality of receivers for receiving at least one echo of each said pulse, each said receiver producing, in response to each said echo, a respective signal;

wherein said transmitters and receivers are distributed aerially above the content, the system further comprising;

(c) a processing apparatus, for transforming said signals into a plurality of locations on said upper surface, that includes;

(i) for each said receiver, a correlator for correlating a waveform of each said pulse with each said respective at least one signal, thereby producing at least one respective correlated signal,

(ii) a beamformer for computing, from said correlated signals, a respective direction of transmission and a respective direction of arrival of each said correlated signal, and

(iii) a processor for;

(A) selecting, from among said correlated signals, according to said directions of transmission and said directions of arrival, only said correlated signals that represent direct echoes from said upper surface, and

(B) computing said locations from said selected correlated signals.

14. The system of claim 13, wherein said wave energy is acoustic energy.

15. The system of claim 14, further comprising:

(d) a thermometer for measuring an interior temperature of the bin, said processing apparatus basing said transforming, of said signals into said locations, on said measured interior temperature.

16. The system of claim 13, wherein said wave energy is electromagnetic energy.

17. The system of claim 13, wherein at least a portion of said receivers are transducers that also function as at least a portion of said transmitters.

18. The system of claim 13, wherein said transmitters transmit said pulses sequentially.

19. The system of claim 18, wherein, subsequent to said transmission of one of said respective pulses by one of said transmitters, said transmission of a next said pulse by another one of said transmitters is delayed until said at least one echo of said one pulse has been received by all said receivers.

20. The system of claim 13, wherein said transmitters transmit at least a portion of said pulses simultaneously.

21. A method of measuring a height of a content of a bin, comprising:

(a) positioning a plurality of transmitters and a plurality of receivers aerially above the contents;

(b) transmitting, from each said transmitter, a respective pulse of wave energy towards an upper surface of the content;

(c) receiving at least one echo of each said pulse, using said receivers, each said receiver producing a respective signal in response to each said echo; and

(d) transforming said signals into a plurality of locations on said upper surface by steps including;

(i) for each said receiver and each said pulse, correlating a waveform of said each pulse with each said respective at least one signal, thereby producing at least one respective correlated signal,

(ii) computing, from said correlated signals, a respective direction of transmission and a respective direction of arrival of each said correlated signal,

(iii) selecting, from among said correlated signals, according to said directions of transmission and arrival, only said correlated signals that represent direct echoes from said upper surface, and

(iv) computing said locations from said selected correlated signals.