Horn shaped radar water level gauge for river water level monitoring. Click to view details

Description :

　　Measurement principle of radar level gauge

　　Radar level gauge is a radar level gauge based on the principle of time domain reflection (TDR). The electromagnetic pulse of the radar level gauge propagates along the steel cable or probe at the speed of light. When it encounters the surface of the measured medium, some of the pulses of the radar level gauge are reflected to form echoes and return to the pulse emitting device along the same path. The distance between the emitting device and the surface of the measured medium is proportional to the propagation time of the pulse between them, and the liquid level height is calculated.

　　Precautions for radar level gauge

　　1. The measurement range starts from the point where the beam touches the bottom of the tank, but in special cases, if the tank bottom is concave or conical, measurement cannot be carried out when the level is below this point.

　　If the medium has a low dielectric constant and the bottom of the tank is visible when it is at a low liquid level, it is recommended to set the zero point at a low height of C to ensure measurement accuracy.

　　In theory, it is possible to measure the position of the antenna, but considering the effects of corrosion and adhesion, the final value of the measurement range should be at least 100mm away from the antenna.

　　4. For overflow protection, a safe distance can be defined to be added to the blind spot.

　　5. The small measurement range is related to the antenna.

　　Distance measurement principle of radar level gauge

　　The radar level gauge emits modulated electromagnetic waves to the liquid surface, and the reflected echo signal from the liquid surface is received by the radar and mixed with the transmitted signal. The frequency of the resulting difference frequency signal is proportional to the distance from the liquid surface. A high-precision signal processing algorithm combining Zoom FFT and energy center of gravity correction algorithm is proposed for the application of millimeter wave radar level gauges. Zoom FFT is used for spectral refinement with a small refinement factor, and the energy center of gravity correction algorithm is used to accurately estimate the frequency of the difference frequency signal. This algorithm eliminates the influence of FFT fence effect on ranging accuracy, and the computational complexity and storage space are relatively reasonable The simulation results show that when the signal-to-noise ratio of the difference frequency signal is 12dB, the algorithm controls the root mean square error of the distance measurement to the millimeter level.

　　With the improvement of industrial automation level, radar level gauges have been widely used in fields such as petroleum, metallurgy, and chemical engineering In the industrial production process, even small measurement errors of level gauges can cause huge economic losses, and improving the measurement accuracy of level gauges has become an urgent need.

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• Horn shaped radar water level gauge