Development of the Smart Bathymetric Survey Kit

Abstract

Conventionally hydrographic sensors are connected to an onboard computer preloaded with a proprietary software tool for the data collection and the data need to be transferred manually to the post processing computer using emails or flash drives. The gathered data can then be processed utilizing the post processing software which requires a paid license. Evolution of Smart Bathymetry is important where the automated aggregation of whatever type of National Marine Electronics Association (NMEA) based hydrographic sensor data as per the survey requirements. The Smart Bathymetric Survey Kit (SBK) is a compact unit and consists of a built-in pre-processing unit with real-time file transfer mechanism by Message Queuing Telemetry Transport (MQTT) and File Transfer Protocol (FTP) using a wireless MODEM. This avails a near real-time post processing of the survey data and the possibility to concentrate or resurvey a specific location in case of the bad quality data during the survey. Thereby avoids the unnecessary survey reattempts which involves the cost, time and human effort. Also, the kit is developed to provide cost effective data collection and the possibility to make fast and reliable decisions on the studies such as dredging estimates without much survey effort. Since the GPS interface is required for any type of bathymetry, a web application with the offline map featured with the customizable bathymetric grids with the real time course, velocity and heading details of the survey boat. This enables the surveyor precisely to follow the grid knowing the real time location of the survey boat. Few modern telemetry systems take advantage of the low price and ubiquity of GSM networks by using SMS to receive and transmit telemetry data to the host. But the type of wireless transmission is site specific, hence the kit was developed with the flexibility to interface with 2.5/5 GHz or a VHF/UHF MODEM. The kit contains a Single Board Computer (SBC) coded with LabVIEW to acquire and pre-process the NMEA sentences from the hydrographic sensors such as single beam echo sounder, Acoustic Doppler Current Profilers (ADCP), Motion Reference Unit (MRU) and Differential GPS etc., a wireless MODEM and a DC-DC converter-based power supply unit to regulate the auxiliary power supply to the kit. Lead-acid battery or a mobile power bank can be used as the auxiliary power supply. The kit is designed to interface with a maximum of ten hydrographic sensors with the auto identification of COM ports and the baud rates. The sample collection rate and file size can be configured as per the survey requirements. All the printed circuit boards and interconnecting cables are housed inside an IP68 enclosure. LabVIEW was used to program to implement the required algorithm for the digital interface of the hydrographic sensors, auto scanning and identification of COM ports, encoding and pre-processing, DATA handling, redundancy storage and file management. The paper details the development of the compact bathymetry kit using a Single Board Computer (SBC) and the field test results.