Air based emergency monitor, multimode communication, control and position finder system with a receiver having multiple inputs for reception and demodulation of position finder signals to position finder baseband signals. One or more cameras or microphones or data signal generation devices, storage...http://www.google.com.hk/patents/US7561881?utm_source=gb-gplus-share專利 US7561881 - Air based emergency monitor, multimode communication, control and position finder system
