Last year I was searching how to fly at safe low altitude to take the higher resolution photos that possible, to identify weeds and insects in crops and trying to know if a laser altimeter can do the task, first I bought a Lidar lite but looks unstable over rought terrain perhaps bad installed or configured and no more support to ask, but, in the way, Laserdeveloper offer me to test the SF11 and send me one, I was little nervous because I'm not have much electronic knowledge, I couldn't make Lidar work yet, and SF11 looks more professional with PC connection and configuration capable, but results an RTF tool, very easy to install, Pixhawk configuration I use as instructions said, I use serial connection http://ardupilot.org/copter/docs/common-lightware-sf10-lidar.html?highlight=sf10 and SF11 configuration I don't change nothing but have many things for different tasks, standard ones looks nice for me.
It have an intuitive software to test with the pc too, you plug to USB with provided cable, open the program and look readings, I them took a ruler and measured the SF11 with the floor and looks near perfect :O ; many rainy days them (I'm in winter :( ) I did a first little fly with strong wind, the wind hit the copter but altitude didn't change, a better day I can fly more to test and take this video flying over a rought terrain; I'm going to test over different crops with different stages, and different slopes to see what happend.
Thank's to Laser developer to give me the opportunity to test this great altimeter :DNow I test the SF11 over dry corn and, as Laserdeveloper explain here: http://diydrones.com/group/agricultural-uavs/forum/topics/testing-sf11-altimeter-over-soybean the laser reads the floor instead dry plants so, no issues when little spaces between plants appears, wind isn't a complication too.
3 Nov: Now time to fly wheat, searching for insects and diseases, windy, as always, is present
It's curious to compare sonar altimeter with Baro