Higher mobility, more comfort and independence for blind and visually handicapped people - that is what the InMoBS app promises.

"It helps them, and tells them where they are, gives hints in which direction they have to go, and explains what their surroundings look like, or if there are any risks for them," Jörg Belz told DW.

Belz works for the German Aerospace Center (DLR) in Braunschweig and was involved in the development process.

"People who are blind are dependent on those who are able to see in order to get to know new routes. When they don't know a route, it is very difficult for them to walk there alone."

The app is meant to be an additional tool but not a panacea - something similar to a guide dog or a walking sticks.

Very helpful

Gerhard Renzel suffers from retinitis pigmentosa. He is completely blind. The 68-year-old is one of the few who have tested the app.

"I prepared my route with a special program on my PC, and I send it to my smart phone. After that I wore a GPS device on my arm, which can send information via Bluetooth to my smart phone. And then I left the house, all by myself."

To do so he visited a special test location in Braunschweig in northern Germany. There, the traffic lights are equipped with WiFi that can send information directly to Renzels' smart phone.

"The app told me, for example, what the surroundings looked like - if there was a bus stop, an intersection or a bakery on my route. And the smart phone vibrated when I walked in the wrong direction."

Renzel was quickly convinced that the app represents a big improvement. Before familiarizing himself with it, he used conventional navigation systems. He wasn't satisfied.

"When you're blind, they are not very convenient, because they're highly imprecise."

Not ready

But the app is only a prototype. It still needs modifications, says project coordinator Steffen Axer at the University of Technology in Braunschweig.

"Our location technology still has to be improved. We need to make sure that the user receives precise information."

Preparing the app for the general market will take at least five more years.

"We also need to find a way we can help blind people take public transportation without assistance," he says.

Another disadvantage is the fact that the users have to wear a GPS device on their arms, which sends information to their smart phones. One of the developer's goals is to integrate the GPS device with the phone.

The InMoBS app is being developed and tested by the Braunschweig University of Technology, the DLR's Braunschweig location and the Siemens company