Lassen SQ, Справочное руководство

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2 Hardware Integration
3 0 Lassen SQ GPS Receiver
2.7
GPS Antennas
The antenna receives the GPS satellite signals and passes them to the
receiver. The GPS signals are spread spectrum signals in the 1575
MHz range and do not penetrate conductive or opaque surfaces.
Therefore, the antenna must be located outdoors with a clear view of
the sky. The Lassen SQ GPS receiver requires an active antenna. The
received GPS signals are very low power, approximately -130 dBm, at
the surface of the earth. Trimble's active antennas include a
preamplifier that filters and amplifies the GPS signals before delivery
to the receiver.
Trimble offers three antennas for use with the Lassen SQ GPS receiver
described below and in Appendix D.
1. The Ultra-Compact Embedded GPS Antenna with an HFL
connector, is ideal for portable and mobile applications. This
unpackaged antenna is approximately the same size as the
module itself, and can be easily integrated into mobile
applications. This antenna is supplied with the Starter Kit (see
Figure 2.4).
2. A Compact Unpackaged Antenna with an MCX connector,
slightly larger than the ultra-compact model (see #1 above),
mates to the Hirose connector on the Lassen SQ GPS module
with an optional RF transition cable (see Figur e2.5).
3. A Compact Magnetic-Mount GPS Antenna with a 5 m cable
and an MCX connector. This antenna provides for a flexible,
movable installation. The MCX output connector mates to the
Hirose connector on the Lassen SQ GPS module with an
optional RF transition cable. This antenna is supplied with the
Starter Kit (see Figure 2.6). The MCX connector on the end of
the antenna cable mates to the MCX connector in the front of
the Starter Kit interface unit.
Warning – When magnetic-mount or permanent-mount GPS antennas
are installed on a metal surface for prolonged periods, care must be taken
to insulate the antennas in order to prevent galvanic corrosion.