The vector hydrophone technique is widely used in the direction of arrival（DOA） estimation field. Because its directivity is independent of frequency

even a single vector hydrophone can measure the DOA of target of interest in very low frequency band till tens of Hz.The scalar hydrophone needs to form a large aperture to fulfill the same ability at this frequency band.Due to this advantage

a sea trial study on DOA in such low frequency（100～300 Hz） band is conducted.Combined with the synchronized compass data

the absolute direction of the target in geodetic coordinate system is given.The sea trial results indicate that the performance of DOA based on vector hydrophone in low frequency is consistent with the GPS result.Within the radius of 3.6km

the standard deviation of DOA estimation is less than 5°.