User Manual

PLUS System Manual Location Software Library 67
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4.2 Tracker Object Overview
The PLUS Location Software OCX contains a single object, called Tracker. The Tracker Object
performs the following functions:
1. Receives data from the Readers either over Ethernet (live data), or from a logfile
(recorded/simulated data).
2. Provides access to TOA message data through a COM event.
3. Manages a database of PLUS Tags, Calibration Tags, Readers, Groups and Maps:
o Tags are mobile entities whose positions are maintained in the database and updated as
new TOA messages are received.
o Calibration Tags have preconfigured positions; i.e. the position to be used during
calibration must be set. However, these Tags can also be mobile Tags when not being
used for calibration; the same Tag can exist in both the Tag and Calibration Tag
database.
o Readers’ positions must be known and preconfigured. Readers must be assigned to a
group and groups must be assigned to maps.
o Groups are a set of Readers that share a common synchronization source.
o Maps are a set of groups that share a common point of origin.
4. Performs calibration of the Readers. Calibration compensates for any timing offsets due to
cable length delays between the Readers. Readers and Calibration Tags must be configured for
the calibrator to function.
5. Solves for Tag positions using the TOA messages and the Reader locations.
The Readers must be configured and calibrated for the location engine to function properly.
6. Triggers events whenever a Tag’s position is updated.
7. Generates alarms when Reader and Tag events occur.
Any functions, properties, or events available in the COM object but not documented are not currently
supported.
Note that all distance units are in meters; this includes x, y, and z position values.
4.3 Groups, Maps and Tracking Cells
In order to effectively use the PLUS Location Software Library, it is important to understand the
concept of and interaction between Reader Groups, Maps, and Tracking Cells. Groups make it easier to
install PLUS in a large or multi-floor facility by dividing a large installation into smaller sections. A
Reader can be a member of multiple Groups.
Each Group can be configured independently to provide a 2D solution (x and y), a 1D solution (limited
to a line between Readers), or a 0D solution (presence detection). If a Group is configured to produce
2D or 1D solutions, all Readers in the Group must share the same SDP (so that they can be
synchronized together). The Readers in a Group that is configured to produce 0D solutions do not need
to be synchronized together.