RS-Helios-16P User Manual
15
Table 7 GPS Receive Pin Definition
Level
Receive Pin Definition
GPS REC
GPS PULSE
RS232
Receive the RS232 serial data
output by the GPS module
Receive
the
positive
synchronization pulse signal
output by the GPS module, the
level
is
required
to
be
3.0V~15.0V
Note 1:
The GPS_REC interface in the RS-Helios-16P Interface Box is the SH1.0-6P female connector, and the pin
definition is as shown in Figure 2.
The external GPS module needs to set the serial output baud rate to 9600bps, 8 bits, no parity, 1
stop bit. RS-Helios-16P only accepts the GPRMC sentence sent by the GPS module. The standard
structure of the GPRMC sentence is as follows:
$GPRMC,<1>,<2>,<3>,<4>,<5>,<6>,<7>,<8>,<9>,<10>,<11>,<12>*hh
<1> UTC Time
<2> Receiver status, A=active, V=void
<3> Latitude
<4> Latitudinal hemisphere N (northern hemisphere) or S (southern hemisphere)
<5> Longitude
<6> Longitudinal hemisphere E (east longitude) or W (west longitude)
<7> Speed over the ground(knots)
<8> Track made good (degrees True)
<9> UTC date
<10> Magnetic declination
<11> Magnetic declination direction, E (east) or W (west)
<12> Mode indicator (A=autonomous, D=differential, E=estimated, N=not valid)
* The last hh is the XOR sum of all characters from $ to *
Note:
1. The sending time interval of 1 PPS pulse needs to be controlled within 1s±100us;
2. The status bit in the GPRMC message must be A valid before time synchronization is allowed;
3. The length of GPRMC messages sent by existing GPS modules on the market is not consistent.
The length of GPRMC messages reserved in the DIFOP packet of RS-Helios-16P is compatible with
the GPRMC message format sent by most GPS modules on the market. If any incompatibility occurs,
please contact RoboSense technical support.
5.6.3
PTP Time Synchronization
PTP (Precision Time Protocol) is a time synchronization protocol, which itself is only used for high-
precision time synchronization between devices, but it can also be borrowed for frequency
