In response to the problem that the conditions of the speed measurement accuracy calibration laboratory for low-frequency ADCP cannot be met，a domestic low-frequency ADCP current velocity measurement accuracy calibration test is conducted in Qiandao Lake using a synchronous comparison method，referring to national and industry standards. Based on preliminary study of the depth of experimental area and the analysis of echo during the trial run stage，parameters such as layer number，layer thickness，and alternating working interval during the comparison process are determined. Multiple-speed turn back comparison tests are conducted in experimental area. The experimental results show that due to factors such as low suspended solids in the water，the echo intensity of the current layer in the Qiandao Lake area is generally weak，and ADCP near bottom layer measurement is affected by strong bottom echo interference. By comparing undisturbed flow layer data，the velocity profile measurement accuracy of domestic DVL II-300 kHz ADCP is equivalent to that of imported ADCP at the same frequency.
[1] PINKEL R.A personal history of Doppler sonar development at the Marine Physical Laboratory,SIO[J].Journal of the Acoustical Society of America,2016,140(4):3284-3285.
[7] HUMMON J M,FIRING E.A direct comparison of two RDI shipboard ADCPs:a 75-kHz ocean surveyor and a 150-kHz narrow band[J].Journal of Atmospheric and Oceanic Technology,2003,20(6):872-888.
[8] HOLLIDAY N P,POLLARD R T,GRIFFITHS G.A comparison of simultaneous measurements from shipboard VM-150 and OS-75 acoustic Doppler current profilers[C]//Proceedings of the IEEE/OES Seventh Working Conference on Current Measurement Technology.San Diego:IEEE,2003.
