The SN90 is an efficient forward-looking sonar with good real-time performance, high detection accuracy and long range, which enables real-time understanding of distribution of marine biomes and underwater obstacles in front of the ship. SN90’s operating range is up to 2000m, and it is used as a forward-looking navigation sonar, which greatly improves the safety of ships sailing in polar regions and other complex dangerous areas. For polar navigation, SN90 scans up to 160° wide horizontally to monitor the distribution of icebergs and ice floes along the route. Its vertical beam tilt is 80 degrees, which can further help determining the situation of underwater icebergs, ice floes and reefs ahead. The distribution of icebergs, obstacles and biomes in front of the course is measured, and the result of scanning is superimposed on the nautical chart for hedging navigation.