Development of drone-type float for surface-velocity measurement in rivers

The present study develops a safety survey system for measuring natural river discharge. Monitoring of rivers is very important for river environment conservation and flood prevention. The new system is a drone-type float with a Global Positioning System (GPS) receiver, which can safely and quickly monitor a river. This float flies to the target point on a free surface according to the operator's control. After which, it runs freely downstream, detecting the time-series of self-position with a centimeter-order accuracy using the real-time kinetic GPS method. It also measures the local water depth using an ultrasonic sensor during the drifting downstream. The same works are repeatedly conducted on all survey lines to evaluate the discharge through a target cross-section. The data correction formula considering the wind effects is introduced to improve the measurement accuracy. We performed field tests in natural rivers and obtained reliable results for practical application. The present system can evaluate the discharge in a 250 m width large-scale river without using an observation bridge or a rubber boat.

Automated summary

The present study developed a safety survey system for measuring natural river discharge. The system utilizes a drone-type float with a GPS receiver to monitor the river and measure the discharge. Field tests have confirmed the reliability and practical application of this system.