Appendix A Outdoor GPS Antenna Installation
Verizon 4G LTE Network Extender 2 for Enterprise User Guide v1.0
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Signal Interference
The GPS system is designed so that it has a strong immunity to noise and can
endure interference.
The Samsung GPS receiver provides a quality timing clock in most installations.
However, to ensure that the GPS receiver performs locking successfully and
guarantees uninterrupted timing performance, an interference-free environment is
required for frequencies near the GPS L1 frequency (1575.42 ± 1 MHz).
Interference Types
There are two types of interference which affect the GPS L1 frequency:
•
Narrowband (inband) interference
When a frequency deviation (3.5 kHz), such as an FM wave, inflows in around
the GPS L1 frequency (1575.42 MHz), it is called narrow band (inband)
interference. Narrowband interference is monitored by the spectrum analyzer.
Because it has a time lag, a locking failure or a different type of alarm can
occur.
•
Wideband interference
When around the GPS L1 frequency (1575.42 MHz) and the frequency
deviation is more than 7 kHz, this is called wide band interference.
Wideband interference includes the interference induced by the harmonics
from a communication service with a different frequency bandwidth, increased
thermal noise from communication services around the L1 band, inflow of
interference due to unauthorized communication, saturation due to oscillation
of an accessory device, and so on.
You cannot monitor these kinds of interferences with a device such as a
spectrum analyzer. If the system has a wideband interference problem, you
should consult an expert in this area.
For other bandwidths, except the GPS L1 frequency (1575.42 ± 1 MHz), a GPS
Band Pass Filter (BPF) must be included within the GPS antenna to remove the
interference from the GPS bandwidth. No outband interference must affect the
GPS signals.
