Using a technique like spectroscopy to monitor crops has a number of benefits — there’s much information to be gleaned from even a simple reflection spectrum – but it’s a challenge, too, especially if the farmland covers thousands of acres. What if you could bridge the gap between airborne and field measurements to make crop monitoring easier?
Researchers around the world are doing just that, thanks to the availability of unmanned aerial vehicles (UAVs) and the release of our STS Developers Kit. This spectroscopy kit comprises the powerful yet compact STS spectrometer, a Raspberry Pi microcomputer, customizable software and wireless capabilities — a versatile combination of components for integrating spectral sensing quickly and easily.
In September 2014, a team from VOXearch, a California-based sensor developer and technology integrator, used a UAV-based Ocean Optics spectrometer to identify pesticides and pollutants at an organic farm in Santa Barbara, California. Organic farming in particular places a great premium on precise monitoring of natural fertilizers and pesticides, which can affect plant health. See the drone in action!
Earlier, a multinational team of researchers in New Zealand developed a system for UAV-based crop measurement that consists of two wirelessly synchronized spectrometers. The first spectrometer flying aboard the UAV measures the sunlight reflected from the crops and the second, ground-based spectrometer uses sunlight levels as a reference. The ratio of reflected sunlight to the sunlight reference gives the reflection spectrum from which all the critical crop parameters are derived.
Similar agricultural and forest monitoring projects are now in progress in the U.S., United Kingdom and around the world.
Opportunities Take Off
Drone-based spectroscopy systems take advantage of three important developments:
- first, the growing demand for UAVs for civilian applications, which has helped lower UAV cost;
- second, the shrinking footprint and lighter weight of modular spectrometers, which provide manageable UAV payloads;
- and last, the availability of open-source and low-cost microcomputing technology such as Arduino and Raspberry Pi, which allow users to more easily manage custom electronics projects.
Indeed, with a relatively modest investment, the New Zealand team was able to configure a system capable of detecting reflected light at up to 200 meters above the land. That capability suggests the possibility of additional, non-agricultural applications with a similarly designed system: exploration of sites for oil and gas deposits; monitoring of industrial runoff in surface waters; and investigation of abandoned swimming pools for potentially disease-carrying insect larvae.
Like the farmer monitoring his crops to manage the harvest, users are discovering how miniature, modular spectrometers and the tools that put them on a UAV, or inside another device, or networked with other devices on the Internet, are making a difference.