User Manual

RF-Orchestra!™ Transmitter Installation and Operation Preinstallation
July 2000 6880493G02-C 3-13
GPS Evaluation Kit
The Motorola GPS evaluation kits (model numbers VPEVAL0002, GTEVAL0001, and
UTEVAL0001) provide a means of evaluating potential site and antenna mounting locations
before site acceptance and construction begins.
The evaluation kits include the hardware, software programs, and instructions necessary for
collecting site evaluation data. Use the kit to collect the following necessary data:
• Number of visible satellites
• Signal strength of tracked satellites
• Number of satellites being tracked
• Dilution of Precision (DOP) type (position or horizontal)
GPS Tracking Criteria
The GPS receiver must have a Position Dilution of Precision (PDOP) of less than 10 to
successfully initialize. A PDOP greater than 10 can delay start-up. To minimize delay, a PDOP
of greater than 10 for more than 30 minutes is not recommended.
Large PDOP values typically occur when tracking less than four satellites. However, when the
system is operating, a PDOP of greater than 10 does not affect the site performance as long as
at least one satellite is being tracked for the timing signal.
The GPS receiver providing synchronization signals to the RF-O! transmitter must perform
the following:
• Track a minimum of four satellites during initial start-up
• Have no period greater than 96 minutes without tracking any satellite
GPS Antenna Requirements
The GPS antenna must be mounted with an unrestricted aerial down view to within 10° of the
horizon in all directions and high enough to clear the peak of any site roof.
For systems in the northern hemisphere, GPS antennas must be mounted to provide a clear
view of the southern sky. For systems in the southern hemisphere, GPS antennas must be
mounted to provide a clear view of the northern sky.