for years people have relied on GPS equipment for generating positioning information. Unfortunately, GPS cannot be used indoors, and there is a significant time lag before positioning can begin. PlaceEngine technology offers a viable solution by taking advantage of the growing popularity of wireless LAN (Wi-Fi) systems. It determines a user's location by using signals emitted by numerous Wi-Fi access points. This approach can be used to estimate positions even in indoor or underground locations, where GPS is not an option.
the PlaceEngine Service The PlaceEngine Service consists of the PlaceEngine server (where location estimation is performed), a terminal with a built-in Wi-Fi device, and the PlaceEngine client (which runs on the terminal to collect Wireless LAN signal information).
As outlined below, the PlaceEngine service uses Wireless LAN signals from nearby Wi-Fi access points to estimate the user's position and display related information.
Users can obtain positioning information through PlaceEngine even when not connected to the network (offline). The PlaceEngine client determines latitude and longitude by referring to a locally stored database (PlaceEngine local database), and the resulting information is transmitted to the application. This method has been implemented on portable computer entertainment systems, such as PlayStation Portable (PSP). Users can periodically download the latest PlaceEngine local database and store it on their devices.
Figure 1: The PlaceEngine Service
1. The first step is to install the PlaceEngine client software on a Wi-Fi terminal.
2. The PlaceEngine client software monitors signals from nearby Wi-Fi access points and acquires Wi-Fi data, including MAC addresses, SSIDs and field strengths.
3. The client software transmits the Wi-Fi information to the PlaceEngine server.
4. The PlaceEngine server estimates the user's position (including longitude, latitude and street addresses) by comparing this data with Wi-Fi information stored in its database. The results are sent back to the client software.
5. If no estimation results are returned from the PlaceEngine server, or if the results are incorrect, the user can register the current location to correct PlaceEngine's location estimation.
6. The PlaceEngine client software also works in conjunction with websites configured to support the PlaceEngine API. When visitors hit the "current location" button on these websites, various web-based positioning services can be provided, including maps displaying the user's current location, or downloads of local information, such as traffic data or locations of nearby restaurants.
A Website Linked to the PlaceEngine API
