3.2 Antenna
Although the A1035-H offers an on-module antenna, an additional external active
antenna can be used. Switching between both antennas is done via pin 12 (see
also “
5.2 Description A1035-H Signals”). It is recommended to use an active GPS
antenna with supply voltage of 3 to 5 VDC and a current draw of 50 mA maximum.
The quality of the GPS antenna chosen is of paramount importance to the overall
sensitivity of the GPS system. An active antenna should have a gain
≥
20 dB and a
noise figure
≤
1.5 dB, which applies to more than 95% of the active antennas avail-
able in the market.
3.3 Serial Port Settings
The default configuration within the custom-specific GPS firmware is:
•
Serial 0 (NMEA) 4800 baud, 8 data bits, no parity, 1 stop bit, no flow control
3.4 Improved TTFF
In order to improve the TTFF (Time To First Fix), it is recommended to support the
RTC and SRAM with a back-up power when no system power is available.
Furthermore, starting with FW revision 3.5.0 “Ephemeris Push” is supported. Please
see according application note!
V1.5 – Dec-09
User’s Manual
Page 14 of 37
