EchoLogger ECT 400S echo sounder

The EchoLogger ECT 400S is a single-frequency (450 kHz) single-beam echo sounder for SPH Engineering's integrated drone system for bathymetry, which measures the depth of water in rivers and lakes. HobiTech supplies it in India as an Official Partner of SPH Engineering.

What is the EchoLogger ECT 400S used for?

Bathymetry measures the depth of water in oceans, rivers or lakes. The standard tool is an echo sounder, usually carried by a ship, boat or unmanned surface vehicle (USV). On small or hard-to-reach rivers and lakes, a boat can be hard to use. A USV needs a good entry point to the water, may not work in shallow lakes with a lot of seaweed, and may need a big car to transport it.

A drone is the alternative. It is compact, easy to transport and deploy, and follows planned survey lines with high precision. It can work anywhere there is a small area for take-off and landing near the water. The ECT 400S is one of three single-beam echo sounders SPH Engineering offers for this integrated drone system. All three are made by EofE Ultrasonics Ltd. of Korea, which specialises in survey-grade sonar products.

How do the ECT 400S, ECT D052S and ECT D024S compare?

All three models have a nominal accuracy of 0.2% of the depth, a resolution of <1 mm, integrated tilt and temperature sensors and an RS232 interface. Measurement range is from the bottom of the transducer.

Key features

• Integrated tilt sensor, so data can be rejected when the sensor is not close to vertical.
• Integrated temperature sensor; water temperature is logged with every depth reading.
• Nominal accuracy of 0.2% of the depth and resolution of <1 mm.
• RS232 interface for robust data transmission via a long cable.
• Data logging starts automatically when the sensor is submerged and stops when it leaves the water.
• Current depth is sent to the ground station during the flight.
• Measurements are geotagged, with centimetre-level coordinates when the drone has an RTK/PPK receiver.

How does it work with SkyHub, UgCS and your drone?

SPH Engineering's integrated drone system for bathymetry includes:

• Drone: a commercially available drone such as the DJI M350/M300 RTK, or a drone based on the Pixhawk autopilot.
• Echo sounder: the ECT 400S on a rope (cable).
• Radar altimeter: measures the precise altitude of the drone over the water surface.
• On-board computer: the SkyHub on-board computer with special software (see the SkyHub software package for echo sounder). It controls the mission and stores geotagged measurements.
• Software: UgCS ground control software with a companion application that controls the echo sounder. The operator sees the current depth during the flight.

SkyHub has two jobs. First, it keeps the drone at a constant altitude over the water using the radar altimeter and a terrain (surface) following algorithm. Standard DJI drones rely on a barometric altimeter, which can drift by several metres in one flight. With the radar altimeter, altitude drift is about 10 cm. Second, SkyHub logs the echo sounder measurements in geotagged form using the drone's GPS receiver.

Survey modes

• Continuous measurements along survey lines: plan a survey grid (or separate lines) over the water. When the sensor is submerged, logging starts automatically. The drone tows the sensor at low speed (0.5–0.7 m/s) and measures depth continuously.
• Measurements at specified waypoints: for water where continuous measurement is not possible, for example with a lot of seaweed. The drone flies between waypoints, descends to submerge the sensor, takes a measurement, climbs to a safe altitude and moves on.
• Manual measurement: the operator takes measurements when the drone is not on an automatic mission.

What data do you get?

Measurements are stored in three formats:

• CSV text with coordinates, depth and additional information, for import into XYZ software such as Surfer, Oasis Montaj or Excel.
• NMEA 0183, compatible with hydrographic software such as HydroMagic and Reefmaster.
• SEG-Y with full echo sounder data.

Water temperature and the tilt angles of the sensor are logged with the depth. SPH Engineering shows a coloured depth map processed in HydroMagic as an example output.

Why buy the ECT 400S from HobiTech?

HobiTech is an Official Partner of SPH Engineering based in Bengaluru, India. Every order comes with a GST invoice, and you have a local team for the sensor, the drone and the software. SPH's bathymetry training courses cover echo sounder data collection (BATHY-1) and processing (BATHY-2). See all sensors in our bathymetry collection.

Frequently Asked Questions

What depth range does the ECT 400S measure?

0.15 to 100 m, measured from the bottom of the transducer. The practical minimum depth is around 15 cm deeper, because the sensor must be submerged.

How accurate is the ECT 400S?

Nominal accuracy is 0.2% of the depth, and resolution is <1 mm.

How much does the ECT 400S system weigh?

The echo sounder weighs 275 g in the air. All components in the air (echo sounder, SkyHub, altimeter, housing, cables and mountings) weigh 1.6 kg (light housing) or 2.6 kg (heavy housing).

Which drones can carry it?

SPH Engineering's system description names commercially available drones such as the DJI M350/M300 RTK, or drones based on the Pixhawk autopilot.

Can it survey water with a lot of seaweed?

Yes, using the waypoint mode. Where seaweed prevents continuous towing, the drone descends at each planned waypoint, takes a measurement and moves on.

How do I buy the EchoLogger ECT 400S in India?

Use Request a quote on this page, or call HobiTech on +91 70225 26509. We confirm the price and configuration, and every order comes with a GST invoice.