User's Manual

SPSx80 and SPSx81 Smart GPS Antennas User Guide 35
Setup Guidelines 4
• The SPS850 Extreme/SPS851 Extreme and the SPS880 Extreme/SPS881 Extreme
can track the GPS L2C modernization signal. Additionally, these receivers can
track the GPS L5 modernization signal and some receivers can also track the
GLONASS satellite constellation ( for more information, see
GPS satellite signal
tracking, page
75
). These signals help you to get positions at the worst times of
the day and in the worst GPS locations, but do not guarantee that you will.
• To get a fixed position solution with centimeter accuracy, initialize the rover
receiver. For initialization to take place, the receiver must track at least five
satellites that the base station is also tracking. In a dual-satellite constellation
operation, for example, GPS and GLONASS, the receiver must track at least six
satellites.
• To maintain a fixed position solution, the rover must continuously track at least
four satellites that the base station is also tracking. In a dual-satellite
constellation operation, for example, GPS and GLONASS, the receiver must
track at least five satellites.The radio link between the base and rover receivers
must also be maintained.
• Loss of the satellite signals or loss of the radio link results in a loss of centimeter
position accuracy. From Fixed, the receiver changes to Float or Autonomous
mode:
– In Float mode, the rover has connection to the base station through a radio,
but has not yet initialized.
– In Autonomous mode, the rover has lost radio contact with the base
station receiver, and is working by itself with the available GPS signals.
• On a vehicle or marine vessel, place the GPS antenna in a location as free from
shock and vibration as possible. For the modular GPS receivers, a single
magnetic mount is normally sufficient to hold the antenna in a suitable
location, whereas for the larger smart antenna, a triple magnetic mount is
normally recommended. Good alternatives include a 5/8" thread bolt in a
suitable location on the roof bars, or a door-mounted pole bracket.
C
CAUTION – The SPS880 Extreme and SPS881 Extreme are not suited to on-vehicle
operation where it will be subject to heavy vibration, that is, operation in rough
ungraded terrain. Use in these conditions can damage the receiver.
• To mount the modular GPS receiver on a pole, use two pole mounting brackets
and a second tripod clip (P/N 571
204 300). See
Figure 4.1.