USER MANUAL
URM18PH392 Rev A. May 2020 Page 19 of 86
2. OPERATION
With the ability to drive multiple Sources and sixteen Sensors, VIPER™ can be operated in many configurations.
Modes of operation can be configured on a per-Sensor basis. Typical modes of operation are described below.
Standard Single-Source operation: A single Source is used. All Sensor position and orientation (P&O) is referenced
to that one Source. On a VIPER™ 8 or VIPER™ 16 system, the one Source must be connected to Source port 1.
This is the traditional way that most legacy Polhemus trackers operate.
Standard Multi-Source modes of operation: Two, three, or four Sources of differing frequencies are used on a
VIPER™ 8 or VIPER™ 16 system. Each Sensor P&O is referenced to the nearest connected Source. In this mode,
one VIPER™ system can effectively behave as the equivalent of up to four individual and independent
conventional tracking systems. This is a new and unique capability of VIPER™ over earlier tracking systems. These
modes of operation are discussed in detail in Section 3.5.
Expanded Multi-Source operation: Multiple Sources are configured together to define an expanded tracking
area. By default, each Sensor operates with all Sources. If desired, each Sensor may be configured to operate
with any combination of Sources.
VIPER™ Sensor and Source configuration commands allow the user to configure and modify these basic modes of
operation. These commands and modes of operation are discussed in detail in Sections 3.5 and 4.2.13 below.
2.1 FTT® MODE
FTT® (Fly True Technology) is a revolutionary real-time magnetic distortion mitigation method exclusive to
Polhemus. The benefits are most noticeable in a tracking environment with electromagnetic distorting
conditions, namely the presence of certain conductive metals that support magnetic eddy currents. These
conditions, when in proximity to the Sensor or Source can cause errors in the position and orientation outputs
from the VIPER™ tracking system until removed.
HOW IT WORKS:
FTT® Mode is an iterative filter that uses measured magnetic fields emitted from the VIPER™ Source, known
environmental conditions, and electromagnetic hemispheric frequencies detected by the FT Sensor to recognize
the negative influence of magnetic distortion and apply a real-time filtered correction. The resulting tracking
performance can be stunningly good in environmental conditions that might otherwise limit the utility of the
tracker (examples include tracking near large metal objects like desks, filing cabinets, steel walls, and rebar
concrete floors).
To use FTT®, the VIPER™ tracker must have FTT® Mode enabled and the FT Sensor in a “Home” location near a
Source. When FTT® is enabled in this way, the LED light for the FT Sensor port in use on the VIPER™ SEU (System
Electronics Unit) will be green in color. The LED will blink in a green and blue pattern until “Homing” has
occurred.
As the FT Sensor is moved away from the Source or a distortion-inducing object is brought close to the FT Sensor
or Source, FTT® will engage and the LED light for the FT Sensor port in use will turn blue. FTT® is now actively
working to sense the electromagnetic distortion and apply a correction filter in real-time to the Position and
Orientation tracking output. FTT® corrects for both position and orientation data output.
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