This is a video demonstration of how to create a 3D map of a lake using ArduPilot.
The frame is an EAMS Lab low-cost mapping boat which is made from a Morey boogie board, Cube autopilot, EchoLogger.com’s ECT 400 echosounder (directly connected to the autopilot) and BlueRobotics thrusters.
The water depth information is captured onboard the flight controller in the dataflash log and then post mission, the DPTH log messages are extracted and turned into a map using ReefMaster. There are probably other tools that are capable of producing 2D and 3D maps but ReefMaster is apparently quite popular perhaps because it has some unique features including the ability to compensate the data for the tide level at the time the data was captured.
I learned a few things as part of this test:
- be sure to check the Ecologger settings before your first mission. The sensor has a default range of only 10m when it comes from the factory. The way to set it up is now documented here on the wiki
- object avoidance is important even for boats! During the 1.6km of the mission, It bumped into three things in the water.
- there are apparently some 30m trenches on the far side of the lake either that or something is causing interference with the sensor. I don’t know which yet.
Here’s the echosounder datafile in case it is of interest to anyone.
This was my first serious attempt at doing this so all advice is more than welcome!