ES300 - Upward Looking Sonar
The ES300 instrument is an upward looking sonar used in the arctic/antarctic for measuring ice thickness. It has an battery lifetime of 1-5 years. The first versions were made in 1989 continuously developed since.
The ES300`s are developed in prototype series, and are capable of measuring ice thickness by combining measurements of acoustic pulse transit-time (Time-of-Flight) and static pressure. In addition, the tilt of the instrument is registered. The instrument is moored to the ocean floor via a mooing line. It is kept into position at depths ranging from 10-190 metres underneath the Sea Level by means of a flotation collar.
The instrument operates in the ultrasonic frequency band (300 kHz) transmitting 4 very short pulses (66 mS) transmitted at user –specified intervals, normally every 5-60 seconds. The transducer is highly directional with narrow beam, pointing directly or nearly directly upwards (normally +/- 1-2°).Once deployed, the instrument operates unattended for 1-3 years depending on the lograte.
Picture: ES300 VIII.
The ES300 series is designed for standalone operation, easy handling and software controlled parameter settings. PC communications permit in-field settings, instrument checkout, data dumping, initial data analysis and processing. The ES300 is started and stopped using a PC. It has an battery lifetime of 1-5 years.
Did you know – The Norwegian Polar Institute and Alfred Wegner Institute have used the ES300 for ice thickness measurements in Framstredet since the end of the 1980s. The upward looking sonar is anchored 50 m below the sea surface and measures the distance to the interface between ice and water. In 2004, a new prototype was developed in order to optimize the detection of open sea surface and different types of ice. A successful test was performed in the Samnangerfjord during the autumn and winter 2004.