Bats never hit any obstacle. They shout and modulate their frequency to distinguish from others. This technique will be used to improve sonar and industial radars.
In the field of transports, bats naturally succeed to position at night thanks to a sonar system, a sophisticated guidance system inspired many scientists to position submarines or military ships. However, it works better in the air because because in the sea it confuses whales and orcas.
You can download the Biomimicards :