Hemisphere GPS Crescent Vector H220 - Signals; RF Input; Serial Ports; Communication Port D

H220 Integrator Guide Chapter 2
–
Board Overview
Page 14 of 28
Signals
This section provides more detail on the signals available via connectors.
RF Input
The H220 is designed to work with active GNSS antennas with a Low Noise Amplifier(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 40-dB gain antenna. Depending
on the chosen antenna, the loss budget will likely be lower (a 24-dB 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; or you will compromise the tracking performance of the H220.
Serial Ports
The H220 has four UART serial communication ports, all 3.3V CMOS:
Port A
Pin 10 (RX), input
Pin 9 (TX), output
Port B
Pin 12 (RX), input
Pin 11 (TX), output
Port C
Pin 32 (RX), input
Pin 31 (TX), output
Port D - Exclusively used to interface with Hemisphere’s 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” for more information on
Port D.
Pin 14 (RX), input
Pin 13 (TX), output
If the serial ports which are 3.3V CMOS are used for external devices which utilize RS-232, an
RS-232 transceiver is required.
Communication Port D
The exclusive function of Port D is for external correction input to the H220. The source of
corrections may depend on the geographical use of your final product, market, customer, and
positioning performance requirements. If you intend to market products outside of SBAS
coverage, you may want to allow your product to be used with external correction input or
integrate a second source of corrections along with H220, such as the Hemisphere SBX beacon
module. For more information on SBAS refer to the Hemisphere GNSS Technical Reference
Guide.