PALO ALTO, Calif. In an exploratory project, Hewlett Packard Laboratories here is exploring the implications of Web access using a mobile, continuously-connected handheld device as a navigation tool for finding places, people and services. The project illustrates both the explosive potential for interaction between a moving human and a Web database, and the difficulty of firmly connecting a mobile device to the real world.
The concept behind the demonstration is elegant. Why couldn't a user of a palmtop computer request a particular kind of service an Indian restaurant, say, or a tire repair shop that is open point the handheld down the street and have the display show him what lies in that direction?
The device would be the virtual equivalent of a sign on the outside of the building, hence HP's project name, Websign. It could be used either to explore a neighborhood for a particular category of services or to navigate to a particular location, an address, a restaurant or an available parking place.
The service as prototyped by HP Labs has two major components: the hardware, based on an HP Jornada handheld PC, and the Web service, an internal HP development. In practice, vendors would create the equivalent of Web pages that would serve as the virtual signs.
The page would include keywords to identify the type of service bar, tire shop, parking lot, hotel and the physical location. Dynamic data could also be included, such as whether seating was currently available, whether the shop was open, or even an image of the featured Mahi-Mahi with asparagus fennel relish.
The user, walking through downtown San Francisco, for instance, would turn on the palmtop and set a filter to select a particular kind of services, say, restaurants. This information, together with the location of the palmtop and the direction in which it was being pointed, would be transmitted back to the server farm containing the database. The servers would select from the database locations meeting the filter requirements restaurants within so many meters of the user in the direction in which the device was pointing.
In addition local service hotspots could be informed of the device's location and could send data to the palmtop directly.
Thus by requesting restaurants, standing on the street corner and slowly turning around, the user could get a quick survey of all the restaurants in the neighborhood, right on the screen.
Extensions to the idea are under investigation, including how to deal with privacy issues. On one hand, many users might be sensitive about telling a server farm their exact location. On the other, if users permitted release of their location data, the devices could be used to locate friends during rush hour, to summon taxis or medical assistance.
Interestingly, much of the complexity of the system occurs not in the database, which is challenging enough, but in the handheld device. In order to function in this application, the palmtop must include a CPU with modest memory and a limited Web browser capability, a Cellular-Data-Packet-Data (CDPD) wireless connection, a Global Positioning System (GPS) receiver and some sort of orientation device in the HP demonstration, a magnetic compass.
Not only is this a job at the edge of current component density, but it is rife with complications. GPS receivers, for example, are often unreliable in dense urban environments. And the more compact they are, the more trouble they tend to have with obstructed skies or rapid motion. Magnetic compasses are notoriously fickle about orientation, motion, local magnetic variations and the presence of large ferrous objects in the vicinity.
The HP researchers' approach to this latter problem shows the struggle to balance complexity against space and battery life. The team used a pair of magnetometer sensors to create an electronic compass. The then added accelerometers to measure the motion of the hand-held, in order to correct the magnetometer data for inaccuracies caused by motion or orientation.
Software refinements help to make further corrections for the magnetic environment inside the palmtop's case, and for large metal objects passing by. But in the end, not much can be done if the user decides to lean against a lamp post in order to see the display.
Research is continuing in a variety of areas, including how to handle the GPS locating function from inside cars or buildings, graceful switching between CDPD and 802.11 when the device is within a Wi-Fi hotspot, addition of image capability into the system and integration of the capabilities into not a palmtop but a cell phone.
In addition, the lab is investigating a shift from a central database concept to a peer network, in which information about services and locations could move among mobile devices in an area.