Non-contact discharge measurement by means of radar technology for open rivers
The RQ-30+ is a sensor for continuous discharge measurement of rivers, open channels and canals with known cross-section profile. The sensor uses innovative radar technology to measure velocity, water level and discharge. It enables reliable, non-contact measurement without the need for structural work in the water.
Features and advantages
- Contact-free radar method prevents soiling and damage, no sensor maintenance
- Automatic discharge calculation based on hydraulic model with multiple dynamic k-factors
- Sensor self-check with status and error output
- AI-based machine learning for compensation of environmental influences and early detection of errors
- 3-point velocity calibration certificate
- Advanced velocity diagnostics with spectrum display
- Discharge calculation inside the RQ-30+
- Water level and velocity sensor combined in one weather and vandalism proof housing
- Sommer Messtechnik ANR: advanced noise reduction system
Fields of application
The RQ-30+ enables discharge measuerment for rivers, streams, open channels and canals for which continuous monitoring is desired. Thanks to the non-contact radar technology the measuring equipment is not susceptible to contamination, debris or driftwood in the water. Furthermore, the non-contact measurement warrants very low maintenance and fail-safe operation especially during high water or flooding.
Implementation
The sensor can be simply mounted on bridges, on the roofs of closed canals or channel superstructures. The bed of the water should be as stable as possible in order to warrant consistent measurement. A visible swell must be evident on the surface of the water.
Measuring principle
The non-contact radar technology determines the water surface flow velocity using the Doppler frequency shift method and furthermore the water level is established by a travel time measurement. With known cross section profile the discharge Q of the water can then be calculated on basis of the continuity equation: Q = vm · A (h)
Technical details
General
- Dimensions 295 mm x 160 mm x 210,5 mm
- Total weight 5.4 kg
- Protection class IP 67
- Power supply 9... 30 V
- Power consumption at 12V standby approx. 1mA; active operation approx. 140mA
- Operating temperature -40…85 °C (-40…185 °F)
- Lightning protection integrated protection against indirect lightning with a discharge capacity of 0,6kW Ppp over voltage protection
Waterlevel measurement
- Measurement range 0 ... 15 m/ 0 ... 30 m
- Resolution 1 mm
- Radar frequency 80 GHz
- Accuracy ± 2 mm
- Radar opening angle 8° / 4°
Velocity measurement
- Measurement range 0.08 ... 16 m/s (depending on flow conditions)
- Accuracy +/- 0.01 m/s
- Resolution 1 mm/s
- Direction recognition +/-
- Measurement duration 5 ... 240 s
- Measurement interval 8 s ... 5h
- Measurement frequency 24 GHz (K-Band)
- Radar opening angle 12°
- Distance to water surface 0.50 ... 130m
Automatic vertical angle compensation
- Vertical inclination measured internally
- Accuracy +/- 1°
- Resolution +/- 0.1°
Interface
- Output RS-485 ASCII or Modbus RTU, SDI-12, Analog output 4…20 mA (14 bit, max. load 250 Ω), Digital output (low: 0 V, high: Vsupply, max. 1.5 A)
- Digital interface SDI-12; RS 485 or Modbus Protocol: various ASCII-protocols
- Output: water level, velocity and discharge, quality parameters
