Hemisphere GPS P306, Integrator Manual

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P306/P307 Integrator’s Guide Appendix A-Frequently Asked Questions Page 31 of 39
Hemisphere GNSS recommends using a dual frequency antenna with the P306/P307. While some
receiver function is possible with an L1-only antenna, full receiver performance will only be
realized with a dual frequency antenna.
External Corrections
My P306/P307 system does not appear to be using DGPS or RTK corrections from an
external correction source. What could be the problem?
This could be due to several factors. To isolate the issue:

Make sure DGPS corrections are RTCM v2.3 protocol.

Make sure RTK corrections are either ROX, RTCM v3, CMR, or CMR+ protocol.

Verify the baud rates used by the P306/P307 match that of the external correction
source.

The external correction should be using an 8-data bit, no parity, 1 stop bit (8-N-1)
serial port configuration.

Inspect the cable connection to ensure there is no damage.

Check the pinout information for the cables to ensure the transmit line of the external
correction source is connected to the receive line of the P306/P307’s serial port and
that the signal grounds are connected.

Make sure the P306/P307 has been set to receive external corrections by issuing the
$JDIFF, INCLUDE command. Refer to the Hemisphere GNSS Technical Reference
for more information.
Installation
Does it matter where I mount the P306/P307’s antenna?
Yes, the mounting location must provide a clear view of the sky for satellite tracking. Additionally,
the position that it computes is based on the center of the antenna. It should be placed in the
location for which the user would like a position. Often antennas are mounted on the centerline of
a vehicle or on a pole-mount for geo-reference.
How will the antenna selection and mounting affect P306/P307 performance?
For best results select a multipath-resistant antenna. Ensure the antenna tracks all the available
signals for the receiver. Mount the antenna:

With the best possible view of the sky

In a location with the lowest possible multipath
Using a magnetic mount for the antenna will not affect performance.