ZED-F9P - Integration Manual
UBX-18010802 - R01
5 Design
Page 46 of 64
Objective Specification - Confidential
Figure 46: ZED-F9P antenna bias
5.5 Layout
This section details layout and placement requirements of the ZED-F9P high precision receiver.
5.5.1 Placement
GNSS signals at the surface of the Earth are about 19 dB below the thermal noise floor. A very
important factor in achieving maximum GNSS performance is the placement of the receiver on
the PCB. The Placement used may affect RF signal loss from antenna to receiver input and enable
interference into the sensitive parts of the receiver chain, including the antenna itself. When
defining a GNSS receiver layout, the placement of the antenna with respect to the receiver, as well
as grounding, shielding and interference from other digital devices are crucial issues and need to
be considered very carefully.
Signal loss on the RF connection from antenna to receiver input must be minimized as much as
possible. Hence, the connection to the antenna must be kept as short as possible.
Make sure that RF critical circuits are clearly separated from any other digital circuits on the system
board. To achieve this, position the receiver digital part towards your digital section of the system
PCB and have the RF section and antenna placed as far as possible away from the other digital
circuits on the board.
A proper GND concept shall be followed: The RF section should not be subject to noisy digital supply
currents running through its GND plane.
Care must also be exercised with placing the receiver in proximity to circuitry that can emit heat. The
RF part of the receiver is very sensitive to temperature and sudden changes can have an adverse
impact on performance.
Attention
The TCXO of a GNSS receiver is a temperature sensitive device. Avoid high
temperature drift and air convection.
