Objectives  The airborne laser bathymetry system transmitted laser pulse through the complex channel which consisted of atmosphere, air-sea interface and water channel. The signal power decreased exponential with the increment of the water depth, and the pulse waveform was stretched and distorted at the same time. These two types of transmission characteristics would limit the maximum detection depth and the measurement accuracy of depth, respectively.

  Methods  The purpose of the proposed algorithm is to improve the measurement accuracy of laser bathymetry system on the premise of ensuring the maximum detection depth performance. First, the water quality and Monte Carlo simulation method are used to study the different depth of echo signal characteristics. It reveals the propagation properties of laser signal and establishes a new parameter design method for laser bathymetry system, which can meet the requirment of international airborne laser depth bathymetry system. Then, the waveform distortion of echo signals at different depths are simulated under the specific system parameters. The adaptive matching filter algorithm is designed to improve the measurement precision.

  Results  The simulation results revealed that the designed system parameters and the adaptive matched filtering algorithm can achieve the performance with the maximum detection depth of 50 m with measurement accuracy of 166 mm in the daytime and with the maximum detection depth of 70 m with measurement accuracy of 172 mm at night for laser bathymetry system.

  Conclusions  The results show that the adaptive matched filtering algorithm can improve the measurement accuracy and serve the marine surveying and mapping of China.