The Parrot: Sonar based multiple-direction ranging system

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The Parrot system provides a low-cost accurate multiple-direction ranging platform for the localization applications where the GPS doesn't work well and the range accuracy requirement is centimeters. The Parrot is built on our SensorWebs wireless sensor network technology that offers the Parrot the capability of formulating an ad hoc multi-hop wireless network to share the range information.

Each Parrot node is equipped with up to 6 ultrasonic sensor sticks, which both transmits and receives ultrasonic signals. In a typical Parrot node based localization application, each Parrot node in turn sends out a radio signal followed by an ultrasonic signal as a sender. By measuring the arrival time difference in receiving the radio signal and the ultrasonic signal, the other Parrot nodes as the receivers calculate the distance between themselves and the Parrot node as the sender. A Parrot node as receiver not only measures distance between itself and the sender, it also knows from which direction comes the ultrasonic signal. This is one of the unique features that distinguish Parrot from other sonar-based ranging systems

The Parrot is also intended to provide a wireless communication backbone for the localization applications, which by nature will have multiple nodes. For more information about how multiple Parrot nodes work together to formulate a multi-hop ad hoc wireless network, please refer to our SensorWebs project web site at


A set of Parrot nodes