We've heard of GPS navigation where you are guided along a path based on a map and satellite signals. Microsoft has come out with something totally new, which enables "activity based navigation". This kind of navigation does not require pre-recorded data like maps. Based on the activities of the user, like walking certain number of steps in a particular direction, or climbing up a fleet of stairs and other such data, trails are recorded, which is used to guide the user. Greenfield is a user interface which provides activity based navigation on a mobile phone or mobile device.

When a user with a device having the activity based navigation app on it, traverses a certain path, the sensors on the device will automatically record the trail. This trail data will contain information like number of steps walked and the number of floors of a building climbed up/down. This recorded data does not depend on any pre-existing data, like maps. Position based navigation (GPS), on the other hand requires maps. Trails are created on the go and stored in the mobile device. When the user has to return, he can as well get the recorded data in reverse order. This data can also be shared with other users. For example, if one member of the family parks the car in a particular location, the trail data can be shared with other members for finding the parking area. Similarly, this kind of activity based navigation can help people find objects that they misplace accidentally too, by retracing their path to where the object was last seen.

There is no news presently about when activity based navigation will be available in the market. However, Microsoft has been conducting tests on a prototype mobile device called Menlo, with Greenfield installed on it. Menlo has a 4.1" capacitive touchscreen with a resolution of 480x800 pixels. It runs 'Microsoft Windows Embedded CE 6.0 R2 which incorporates a Bosch BMA150 3-axis accelerometer & Bosch BMP085 digital pressure sensor (barometer) '. Microsoft have named the series of activities in a trail as breadcrumbs (figure). Menlo is just a prototype and might not see the market shelves. For more details on activity based navigation and Greenfield, head to the Microsoft Research File.