P306/P307 Integrator’s Guide
Chapter 2-Board Overview
Page 17 of 39
Signals
This section provides information on the signals available via connectors.
RF Input
The P306/P307 is designed to work with active GNSS antennas with an LNA gain range of 10 to
40 dB. The purpose of the range is to accommodate for losses in the cable system. Essentially,
there is a maximum cable loss budget of 30 dB for a 40dB gain antenna. Depending on the
chosen antenna, the loss budget will likely be lower (a 24dB gain antenna would have a 14 dB loss
budget).
When designing the internal and external cable assemblies and choosing the RF connectors, do
not exceed the loss budget; otherwise, you will compromise the tracking performance of the
P306/P307.
Serial Ports
The P306/P307 has four serial communication ports:
Port A, Port B, Port C – main ports
Port D - Exclusively used to interface with the SBX beacon board or an external
corrections source. This port will not output normal GNSS-related NMEA messages.
When communicating into either Port A, B, or C, a virtual connection may be
established to the device on Port D using the $JCONN command. See
“Communication Port D” below for more information on Port D.
The P306/P307 serial ports’ 3.3 V CMOS signal level can be translated to interface to other
devices. For example, if serial Ports A, B, and/or C are used to communicate to external devices
(such as PCs) you must translate the signal level from 3.3 V CMOS to RS-232.
Communication Port D
Port D is exclusively for external DGPS correction input to the P306/P307, such as from
Hemisphere GNSS’ SBX beacon board.
USB Ports
The Eclipse P306 has both a USB host port and a USB device port while P307 has only a USB
device port, where:
USB device port (data communication) shown in Figure 2-5 serves as a high-speed data
communications port, such as for a PC
USB host port (data storage) shown in Figure 2-6 serves as a data storage port, such as
with a USB flash drive
The USB data lines are bidirectional and are differential pairs. The USB data lines should be laid
out on Printed Wire Board (PWB) with 90 Ω ±15% differential impedance. The traces should be
over a solid continuous ground plane. Maintain parallel traces and symmetry. There shall be no
traces or breaks in the ground plane underneath the D+ and D- traces. It is also recommended to
leave a minimum 100 mil spacing between USB signals and other signals. Treat the data lines as
if they are RF signals.
Summary of Contents for P306
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