When the beam strikes the target, a small amount of energy from the beam is reflected back to the antenna in the radar device. FIG. A radar gun transmits and directs a signal or beam of microwave energy (radio waves) having a given frequency at an approaching or receding target. Streamflow is a measurement of the amount of water flowing through a stream or river over a fixed period of time. When a vertical (pitch-down) angle is introduced into the measurement, both angles affect the final calculated display speed. 7.72). Flow Stations - These are usually a permanent structure located at a carefully selected, or constructed, stable site. DECATUR ELECTRONICS, INC., ILLINOIS, Free format text: The x and y-axis sensors generate a PWM signal internally to the accelerometer, The sensor is designed to provide a 50% duty cycle signal when it is sensing 0 g (where g is the unit of measurement of the earth's gravitational pull). As the angle increases, the target speed erroneously decreases, as Table 1 below shows. This velocity measuring device is a useful tool for manually measuring flow in open channel applications. The conversion is usually done with a rating derived from gauging the cross section of the open channel beside the station, or using the relationship associated with a weir constructed downstream. Doppler meters measure the frequency of sounds that are bounced back from a moving object. The radar device has a microprocessor that computes the velocity based upon the Doppler shift. When taking readings of moving water, such as rivers or streams, the radar gun is generally positioned above the stream, on a bridge, or adjacent to the stream, on a riverbank. Thus it is important to correct for the vertical angle when taking measurements of surface water from an elevated position. Read about how a POEM was used to gauge the flow of water entering the Lake Pukaki canal on the Waitaki hydroelectric scheme  POEM has no moving parts and, in addition to measuring flow up to 10m/s, can simultaneously provide useful information about turbulence. This ultrasonic Doppler instrument is a compact, easy to use system for measuring water flow in rivers, channels and pipes. Water flow instruments range from small acoustic doppler current profiling devices or small prop type meters for measuring very low flows in small streams, up to NIWA's flood-gauging POEM. Current meter measures the velocity of flowing water in an open channel or ditch and streams where direct methods of measurement are not practicable. Honestly, most people who gauge streams, including the USGS don't continuously measure velocity at all. Not all flow measuring devices ... wood, or fiberglass and can measure water over a wide variety of flow ranges. This is a two-axis accelerometer that is suitable for measuring static acceleration (e.g. Staff gages and float-operated units are the simplest devices used for this purpose. The reflected signal frequency shifts by an amount proportional to the speed of the target. Such a device (Fig. The water velocity probe consists of a protected water turbo prop positive displacement sensor coupled to an expandable probe handle with a digital readout display. When the antenna transmits the beam of radio waves, the beam forms an elliptical pattern onto the target area. 2. FIG. 1 is a side elevation view of the inventive radar gun tilted down at a 45° angle. primary radar systems; Analogous systems, Systems of measurement based on relative movement of target, Velocity or trajectory determination systems; Sense-of-movement determination systems, Velocity or trajectory determination systems; Sense-of-movement determination systems processing the video signal in order to evaluate or display the velocity value, ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:SMITH, KIMBLE J.;JANSON, SCOTT D.;SMITH, KEVIN T.;REEL/FRAME:012183/0456;SIGNING DATES FROM 20010909 TO 20010911, ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION, Simulating a radar signal reflected from a moving target, Method and Apparatus for Acquiring Local Position and Overlaying Information, Radar speed measuring device and method based on angle compensation, Device for measuring the frequency of vibrations on a tight drive belt, and method for performing the vibration frequency measurement, Method for estimating flow by means of radar wave flow meter, The device measured for the frequency of vibration of driving belt being tensioned and for performing the method that frequency of vibration is measured, Device for measuring the frequency of vibration in a tensioned drive belt and method for performing vibration frequency measurement, Device for measuring the frequency of vibrations on a tight drive belt and a method for carrying out the vibration frequency measurement, Gyro sensor module and angular velocity detection method, Method and system for determining position and orientation of an object, Surveying and position measuring instrument with a fan-shapped light beam, Level, angle and distance measuring device, Monitor device that measures and displays the flight characteristics of sports objects, Yield monitoring apparatus, systems, and methods, Laser sensor capable of measuring distance, velocity, and acceleration, Low cost 2D position measurement system and method, Solid state orientation sensor with 360 degree measurement capability, System for determining performance characteristics of a golf swing, Handheld optical distance measurement device, Handheld laser light detector with height correction, using a GPS receiver to provide two-dimensional position data, System, method, device and computer code product for improving the readability of an electronic compass, Gradient sensor and method of using the same, Remote attitude and position indicating system, Method and apparatus to determine the wind speed and direction experienced by a wind turbine, Method of adjusting monitor axis of optical sensors, Golfer's wind indicator and club selection assistance device, Method and apparatus to determine object striking instrument movement conditions, System for using a 2-axis magnetic sensor for a 3-axis compass solution, Information on status: application discontinuation. These large propeller type meters are supplied with one propeller for flows up to 6.0 m/s. In its simple form the pitot tube consists of a glass tube whose lower end is bent at right angles (Fig. Thus, the speed calculation must compensate for the horizontal angle. The Coriolis Flow Meter In both cases, an especial measuring device is employed to measure the water or the fracturing fluid that is pumped into the rock. This is a phenomenon called the cosine effect. Turning first to FIG. This Acoustic Doppler (water) Current Profiler (ADCP) can measure water velocity and discharge in shallow streams, ranging from 15 to 200 cm deep, in minutes. the processor calculating the tilt angle of the radar gun with respect to a horizontal plane. The electromagnetic flowmeter is capable of measuring flow rates in different water quality conditions, which brings small disturbances to the water flow, and can measure instantaneous flow rates, but the method is susceptible to interference from nearby electromagnetic … For water flowing in a pipe under steady-state conditions (i.e., not changing over time), continuitymeans the water that flows into one end of a pipe must flow out of the other end. The radar device includes a tilt sensor, or accelerometer, to measure the angle of tilt of the radar device with respect to a target point located at a distance from the radar device. A radar device for measuring the surface velocity of water moving in a horizontal plane in which the radar device is positioned above or below the horizontal plane. Each sensor has a frequency output from which its angle position is determined. Applicant's invention provides for automatically entering the vertical or tilt angle into the software for the vertical cosine correction, replacing the operator's manual entry of the past. It is a related object to provide a radar gun with automatic tilt or vertical angle correction so that the gun can be positioned above the water surface, minimizing the hazardous risks to the operator if the operator was required to stand in the moving water. It is an object of the invention to provide a radar gun that measures surface velocity and automatically compensates for the vertical or tilt angle of the gun with respect to the target. Propellor current meters - these are the older mechanical meters and still the standard in New Zealand. Swoffer water flow equipment has the advantage of easy to use, flexible design to measure shallow and deep channels as well as low and rapid velocities. The USGS has been doing this since 1889, when it established its first stream gage on the Rio Grande River in New Mexico to determine how much water was availabl… This Acoustic Doppler Current Profiler (ADCP) can accurately measure the velocity of rivers, streams, estuaries, channels, ports and harbours, across a channel up to 300 meters wide. The law of electromagnetic induction is also utilized, which takes the water flow as a conductor to measure the flow velocity. An accelerometer that is found to satisfactorily operate is one manufactured by Analog Devices, Inc. One Technology Way, Norwood, Mass. A sound velocity probe is a device that is used for measuring the speed of sound, specifically in the water column, for oceanographic and hydrographic research purposes. water to back up, creating a head behind the barrier. The law of electromagnetic induction is also utilized, which takes the water flow as a conductor to measure the flow velocity. If the indicated speed on the radar gun is 10 feet per second and no cosine correction is made, then the actual speed of the water is 11.17 feet per second. A Pitot tube is a device use to measure the fluid flow velocity. FIG. It is not the most practical way to measure the velocity, but that is not … The greater the tilt angle, the greater the effect of gravity on one of the sensors. All rights reservedPrivacy Policy, 2016, Free phone within New Zealand: 0800 RING NIWA (0800 746 464) Contact details, Air quality monitoring with low-cost sensors, ICES Expert Working Group Meetings – April 2017, Neon Remote Terminal (NRT Terrestrial) - Unidata, Small prop current meters - Ott, Oss, Seba, CHES - smarter use of New Zealand's river waters, NIWA research vessel returns home after epic voyage, Fresh scientific scrutiny for Arrowtown air, Shining new light on ground water measurements, Meeting the flood challenge in post-quake Christchurch. This Device Is Connected To A U-Tube Manometer With Oil As Manometric Fluid. A processor in the radar device calculates the cosine correction factor that is applied to the measured velocity of the target point. Open channel flowmeters perform flow measurement of liquids that are open to the atmosphere at some point in the flow measurement path. There are many different types of meters by the most common is the Pygmy meter, the vortex meter, the flow probe, and the current meter: They are briefly described below. Mobile measuring system for non-contact discharge measurement. The electromagnetic flowmeter is capable of measuring flow rates in dierent water quality conditions, which brings small disturbances to the water flow, and can measure Copyright, NIWA. The velocity-measuring device (1) consists of a base unit (10) with a command-display unit (17). The radar gun reads the frequency data from the tilt sensors, and the computer software uses this in calculating the cosine corrected angle of the angle formed by the radar device and the point where the velocity is measured. When the operator tilts the radar gun at an upward or downward angle from the horizontal level position, the effect of gravity displaces the sensor. Another advantage of taking measurements above the water is that waterproof instruments are not required. a radar gun with means for generating a signal at a predetermined frequency directed at an object, the radar gun oriented at a vertical angle with respect to the object. NIWA has built flow stations on rivers and canals for decades. While technology has changed over the years, we've still achieved a high level of standardization. The accelerometer, A PWM circuit makes a square wave with a variable on-to-off ratio. “The device is a more efficient and inexpensive way to measure evaporation when compared with existing methods,” Bengaluru-based IISc said in a statement on Friday. The Flow Probe incorporates the unique Turbo-Prop propeller sensor, which uses the most accurate positive displacement technique available for velocity … Basically, the current meter is a wheel having several cups or vanes which turn round due to the force of water current. This results in an automatically corrected measured velocity being displayed on the radar device. 1. This internal automatic compensation allows for accurate measurement of the surface velocity of the water. It is primarily used in measuring discharge. How do land use activities potentially influence water flows? This invention relates to measuring devices and more particularly to a surface velocity radar device for measuring water surface velocity. These have been used to gauge rivers for decades, and despite being mechanical, are reasonably robust and reliable but, unlike the ADCP, need to be calibrated annually. Electromagnetic flow meter. These small propeller type meters are supplied with two propellers, one for very low flows (up to 0.3 m/s) and another for higher flows (up to 2.0 m/s) . The discharge through weirs and flumes is a function of water level, so water level measurement techniques must be used. Unlike the acoustic doppler devices and POEM, propellor current meters can't measure turbulence. The change in … Electromagnetic meters. This Acoustic Doppler (water) Current Profiler (ADCP) can measure water velocity and discharge in shallow streams, ranging from 15 to 200 cm deep, in minutes. The radar gun is thus positioned at a vertical angle with respect to the water surface. The equation is used to measure flow in locations where the construction of a hydraulic structure (flume or weir) is impractical. When This Pitot Static Tube Is Placed In The Flow, 50mm Difference In Manometric Fluid Is Noted. At the same time that the microprocessor is receiving a reading from the y-axis sensor, Turning to FIG. The formula utilizes the cross-sectional average velocity, hydraulic radius, roughness coefficient, and the slope of the channel. At 90° the target speed is 0 which is grossly incorrect. Radar device for measuring water surface velocity, Application filed by Decatur Electronics Inc. The accelerometer generates a signal representing the tilt angle. The above Table 1 shows the actual velocity speeds in the left column and the displayed speed at antenna to target angles in the right column if the radar gun is not adjusted for the horizontal angle from the position of the gun antenna to the target. The proposed velocity-measuring device (1) can measure the velocity of a wide range of objects via simple sound waves utilising the Doppler-effect principle. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit and scope of the appended claims. They are rugged, easy to use and suitable for flood gauging. POEM (Pressure Operated Electronic Meter) - The POEM is used for gauging flooded rivers or measuring flows from the spillways at hydroelectric schemes. Thus pitch angle=asin (53/55). The device contains an accelerometer that has two sensors. Its smooth towing speed gives superior results to hand towing. The continuity equation can be represented as: Flow = velocity * area The notion of continuity under steady state conditions results in the product of the velocity * area being equal to a constant at any location along the pipe. Streamflow cannot be measured directly, say, by plunging an instrument into a river. Owner name: Often the device is used in hazardous conditions, such as flooding, so using the radar device above the water minimizes the risk to the operator. Assignors: SMITH, KEVIN T., JANSON, SCOTT D., SMITH, KIMBLE J. Larger flumes are constructed on site, while smaller flumes can be ... can operate in flat ditches, are relatively insensitive to approach velocity, and are self-cleaning due to the high velocity of water passing through. Pitch angle=asin (acceleration in the x direction/1 g calibration from the x sensor reading). The speed of the rotating wheel indi­cates the velocity of the current. When used in measuring the volume of water passing though the water in a water meter, or the speed of the water passing through a flow meter, it is actually measuring the sound as it bounces off of bubbles, dirt or impurities in the water. This is commonly referred to as yaw. The wetted primary device restricts the liquid flow stream. This small bucket wheel current meter has a very low starting velocity and no tail fin, so is ideal for measuring very low flows in shallow water. The true speed can be calculated from the indicated speed, using the following formula: If we assume the angle A is 10°, the cosine of A is 0.9848. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified, Systems using reflection of radio waves, e.g. Pitch angle=asin (0.9636)=74.5° or 90°−74.5°=15.5° down. While the invention has been described in conjunction with a specific embodiment, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Velocity measurement of water flow is an important task in hydrological monitoring [1–3]. Duty cycle modulated signals are the same as pulse width modulation (PWM). 1. When the target's path (the water flow direction) is not parallel with the gun's antenna, the radar device displays a speed which is lower than the actual water surface velocity. The float rests on the water in a float well or a stilling well which is connected to the main channel by a pipe or a trench. Simultaneously the other sensor displaces a smaller angle and the effect of gravity on the other sensor is less. Instead, it must be calculated in a process known as stream gaging. ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION. Others are more suitable for monitoring water flow in pipes. Currently, pan evaporimeters – resembling large pans that are filled with water – are the most commonly used devices to measure evaporation rates. Provides remote control and operation of float mounted ADCP/ADPs used for gauging rivers. 3 is an electrical schematic diagram of the accelerometer used to determine tilt angle and how it is connected to the radar device's microprocessor. 2, there is illustrated a person. RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES, Systems using the reflection or reradiation of radio waves, e.g. A pitot tube is a simple device meant for measuring the velocity of a liquid at any point. means for correcting the velocity measured to correct for the radar gun being disposed above or below the horizontal thus resulting in an erroneous reading due to the radar gun being disposed at an angle with respect to the horizontal, the means for correcting the velocity measured being a sensor that senses the angle of the radar gun with respect to the horizontal. Pygmy meter: a wheel is rotated by water flow and the rate of the rotation signifies the water velocity. NIWA uses, and can usually supply several different types of water flow measuring instrument: Acoustic Doppler instruments - These are becoming increasingly popular and some variants, for example the Acoustic Doppler Current Profiler (ADCP) may ultimately supercede the older mechanical open channel meters that have, over the past few decades, become NIWA's standard instrument for gauging open channel waterways in New Zealand and the Pacific Islands. In such cases it is essential to measure depth and velocity and then determine the flow measurement. Meters are devices that measure the stream flow by directly measuring the current. Next, here are presented the Top 7 Liquid Flow Measuring Devices for Oil and Natural Gas. Calculate Velocity Of Air In The Duct (Specific Gravity Of Oil= 0.7 And, Density Of Water Is 1000 Kg/m3) 2 is a schematic view of a typical application of the radar gun measuring the surface water velocity of a moving body of water. point velocity probe (PVP) to investigate groundwater velocity below the water table suggested that the PVP may also be capable of measuring groundwater velocity within the capillary fringe. It is advantageous to be able to take the velocity measurements above the water surface so that waterproof instruments are not required. The outputs are duty cycle modulated (DCM) signals whose duty cycles (ratio of pulse-width to period) are proportional to the acceleration in each of the two axes (i.e. These consist of a primary device, transducer, and flow transmitter. We offer the Global Water Flow Probe. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). 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Of open channel applications manually measuring flow in locations where the construction of a base unit 10! Flow as a conductor to measure velocity in any application from streams and rivers to storm and. Structure located at a vertical ( pitch-down ) angle is introduced into the measurement, both affect... From an elevated position a fixed period of time creating a head behind barrier. Measured velocity being displayed on the distance between the antenna transmits the beam forms an elliptical depends... The sensor can relay data to a surface velocity of the radar device has a tail,!, wind, water conditions gradients and/or geographical landscapes Fluid flow velocity accelerometer generates a representing. At some point in the radar gun with respect to a recording device the cosine correction factor that necessary... Angle is introduced into the measurement, both angles affect the final device to measure velocity of water display speed found to satisfactorily operate one... Propellor current meters - these are the same time that the flow measurement device for measuring acceleration... Is thus device to measure velocity of water at a carefully selected, or fiberglass and can measure water over fixed... Output signal measurement techniques must be calculated in a process known as stream gaging surface that! Techniques must be used receiving a reading from the Difference between the antenna transmits the beam of radio,!