Chaos Theory Based Ultrasonic Doppler for Velocity Measurement of Fluid in the Petroleum Channel

In the ultrasonic Doppler flow measure method, Flow measurement is achieved by detecting the Doppler frequency shift of ultrasound during transmission in the fluid. However, the received acoustic signals are weak ones submerged in strong noise; for the extremely low signal-to-noise ratio or in the background of strong noise, frequency of the signals can not be precisely measured, or even the signal can not be detected at all with the traditional method of frequency measurement dependent on the signal-to-noise ratio. It is the main trend of development of chaos theory at the present stage that it is applied in information processing; the above deficiencies can be overcome by the chaotic oscillator with sensitivity to weak signals and immunity to the noise, which can detect useful signal in the strong noise, and precisely determine its frequency. In this paper, sensitivity of chaotic oscillator to weak signal and its strong immunity to noise is applied to detect useful signal in strong noise, and precisely determine its frequency and the signal-to-noise ratio is calculated as -28.6dB.Compared with traditional methods of measuring frequency, the signal-to-noise ratio has been greatly improved, thereby enhancing measurement accuracy of the pipeline flow rate.