Optical Sensors Mounted On GPS Equipped Cars Help Measure Rainfall

Optical Sensors Mounted On GPS-Equipped Cars Help Measure Rainfall

24 December 2013

Researchers in Germany have made use of optical sensors to measure rainfall across the country by fitting them to GPS-equipped cars, optics.org reports.

The idea for the project stemmed from the team's ambitions to provide a clearer picture of rainfall intensity than the information that can be obtained with conventional rain gauges, which are generally accurate but often distributed too widely to provide detailed data about the variations in precipitation. The researchers hope that the new technology would help improve flood prediction and prevention measures.

The use of rain-detecting optical sensors on moving vehicles is promoted under the RainCars initiative, which was put to the test in a lab equipped with a rain simulator. The researchers, from the University of Hanover, put cars with different wiper systems under a rain machine using a sprinkler irrigation system to simulate light to heavy rain and see how wiper speed is linked to rainfall intensity.

One of the stages of the experiments showed that the person in the vehicle changed the wiper speed based on the windshield visibility, confirming that a driver's forward visibility is a strong indicator of rainfall intensity, said Ehsan Rabiei, lead author of the project paper, which was published in the journal Hydrology and Earth System Sciences.

Another stage of the experiment involved testing the optical sensors fitted in many modern cars to automate wipers, using the rain machine. The sensors are powered by infrared laser beams that can feel when rain drops fall on the device's surface, with each sensor reading being equal to a certain amount of water and more frequent readings meaning more intense rainfall.

Uwe Haberlandt, leader of the project, explained that the optical sensors that measure the rain on the windshield deliver more direct and continuous readings, suggesting they are the better tool to use for rain sensors in cars.