Drones have become an important tool for conservation work and we have seen them applied in game counting in Kenya, seal monitoring in the Arctic and for anti-poaching work in Southern Africa. One area of particular interest is in getting accurate size measurements of animals without direct human contact. LightWare has been assisting conservation groups with laser altimeters to improve the scaling accuracy of photographs taken from both drones and full size aircraft.
We recently did some work with the Center for Research into Ecological and Environmental Modelling at the University of St Andrews in Scotland. Their requirement was particularly demanding as they needed to fly over sandy beaches, wetlands and the sea in order to capture their images. Using a laser altimeter under these conditions is very challenging as water tends to absorb the laser light and scatter the remaining signals away. Initial test flights over the beach pictured above were done with one of our standard SF02 lasers and gave the following results:
You can see that the laser continuously loses signal when operating at around 30 m above the beach. The lost signal is shown as a reading of 40 m as defined in the recorder. There are periods of several seconds where the reading is lost completely.
The conventional solution to this problem is to use a higher power laser system with larger optics, but in this case we didn't want to add any extra weight. So we decided to go back to the drawing board and develop a new way of handling the intermittent signals, as well as improving the sensitivity of the laser detector. The results are shown below:
In this test the drone was flown over rock-pools and out over the ocean. You can see that the results are dramatically better, with no loss of signal recorded right up to the 40 m recorder limit. Additional tests have shown that the improved capabilities over water have also lead to greater altitude measurements over solid ground with distance readings in excess of 120 m possible.
Tests are continuing with this new product, called the SF11, and a limited number of "beta" units are available to the public at a price of $249.00. Contact Tracy at: firstname.lastname@example.org for further information.