Target set processing in a fluid flow velocity instrument to reduce noise

Patent metadata

Field	Value
Publication number	US-9453853-B2
Application number	US-201213571328-A
Country	US
Kind code	B2
Filing date	Aug 9, 2012
Priority date	Aug 9, 2011
Publication date	Sep 27, 2016
Grant date	Sep 27, 2016

Abstract

One aspect provides a fluid flow measurement instrument, comprising: a sensor producing a signal representative of reflections of an emitted signal; and a meter being coupled to the sensor and configured to: produce two or more sub-measurements from said signal representative of reflections of an emitted signal; and compute a fluid flow velocity estimate using the two or more sub-measurement signals. Other aspects are described and claimed.

First claim

What is claimed is:

1. A fluid flow measurement instrument, comprising:
an emitter that emits a signal that interacts with a fluid flow;
a sensor that detects reflections of the emitted signal and produces a signal representative of the reflections of the emitted signal;
the emitter being programmed to operate in a plurality of modes and according to a spacing policy, the plurality of modes comprising;
an operating mode in which a series of signals are emitted during a measurement logging interval; and
an idle mode in which the emitter does not emit a signal for a period during the measurement logging interval;
and

a meter being coupled to the sensor and configured to:
produce two or more sub-measurements within a single measurement logging interval, wherein the two or more sub-measurements are separated in time according to a spacing policy of the measurement logging interval to produce substantially independent velocity estimates; and
combine the sub-measurements of a measurement logging interval to produce a fluid flow velocity estimate;
wherein the spacing policy reduces bright target bias; and
wherein the spacing policy is determined according to a bright target velocity.

2. The fluid flow measurement instrument of claim 1 , wherein the two or more sub-measurements are chosen from a continuous stream of sub-measurements.

3. The fluid flow measurement instrument of claim 1 , wherein the two or more sub-measurement are chosen from a discontinuous set of sub-measurements.

4. The fluid flow measurement instrument of claim 1 , wherein the spacing policy is determined according to a lowest expected bright target velocity.

5. The fluid flow measurement instrument of claim 1 , wherein the spacing policy is determined from a previous velocity estimate.

6. The fluid flow measurement instrument of claim 1 , wherein the two or more sub-measurements are selected from among a plurality of sub-measurements through sorting by value.

7. The fluid flow measurement instrument of claim 6 , wherein sorting by value is a sorting process selected from the group consisting of:
excluding sub-measurements having absolute values larger than a threshold;
excluding sub-measurements having absolute values smaller than a threshold; and
including sub-measurements having signed values between a first threshold and a second threshold.

8. The fluid flow measurement instrument of claim 1 , wherein the two or more sub-measurements are selected from among a plurality of sub-measurements based on one or more thresholds, the thresholds being determined based on a plurality of sub-measurement values.

9. A fluid flow estimating method, comprising:
emitting, with an emitter, a signal that interacts with a fluid flow;
the emitter emitting a signal in a plurality of modes and according to a spacing policy, the plurality of modes comprising:
an operating mode in which a series of signals are emitted during a measurement logging interval; and
an idle mode in which the emitter does not emit a signal for a period during the measurement logging interval;

producing with a sensor a signal representative of reflections of the emitted signal;
producing, with a meter coupled to the sensor, two or more sub-measurements within a single measurement logging interval, wherein the two or more sub-measurements are separated in time according to a spacing policy of the measurement logging interval to produce independent substantially velocity estimates; and
combining the sub-measurements of a measurement logging interval to produce a fluid flow velocity estimate,
wherein the spacing policy reduces bright target bias; and
wherein the spacing policy is determined according to a bright velocity.

10. The fluid flow estimating method of claim 9 , wherein the two or more sub-measurements are chosen from the group consisting of:
a continuous stream of sub-measurements; and
a discontinuous set of sub-measurements.

11. The fluid flow estimating method of claim 9 , wherein the spacing policy is determined according to a value selected from the group consisting of:
a lowest expected bright target velocity; and
a previous velocity estimate.

12. The fluid flow estimating method of claim 9 , wherein the two or more sub-measurements are selected from among a plurality of sub-measurements through sorting by value.

13. The fluid flow estimating method of claim 12 , wherein sorting by value is a sorting process selected from the group consisting of:
excluding sub-measurements having absolute values larger than a threshold;
excluding sub-measurements having absolute values smaller than a threshold; and
including sub-measurements having signed values within a range;
wherein one or more of the threshold and the range is determined based on a plurality of sub-measurement values.

14. A fluid flow estimating program product, comprising:
a non-transitory device readable storage medium storing program code executable by a processor of a measurement instrument, the program code comprising:
program code for emitting, with an emitter, a signal that interacts with a fluid flow;
the emitter emitting a signal in a plurality of modes and according to a spacing policy, the plurality of modes comprising:
an operating mode in which a series of signals are emitted daring a measurement logging interval; and
an idle mode in which the emitter does not emit a signal for a period during the measurement logging interval;

program code for producing with a sensor a signal representative of reflections of the emitted signal;
program code for producing two or more sub-measurements within a single measurement logging interval, wherein the two or more sub-measurements are separated in time according to a spacing policy of the measurement logging interval to produce substantially independent velocity estimates; and
program code for combining the sub-measurements of a measurement logging interval to produce a fluid flow velocity estimate,
wherein the spacing policy reduces bright target bias; and
wherein the spacing policy is determined according to a bright velocity.

Assignees

• Rick David Langley
• Hach Co

Inventors

• Rick David Langley

Classifications

• G01F1/667

  Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters · CPC title

• G01P5/241 Primary

  by using reflection of acoustical waves, i.e. Doppler-effect · CPC title

• G01F1/663

  by measuring Doppler frequency shift · CPC title

• G01F1/002

  wherein the flow is in an open channel · CPC title