Ebyte E108-GN Series, Руководство пользователя, Страница: 28 / 33

Chengdu Ebyte Electronic Technology Co.,Ltd.
E108-GN User Manual
Copyright ©2012–2021
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Chengdu Ebyte Electronic Technology Co.,Ltd.
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can clear the GPD data in the chip by sending serial commands. Of course, every time new GPD data is uploaded, the original old GPD data
will be cleared first.
Delete GPD data command: Enter "PGKC047" in the command input box of the naviTrack navigation tool.
8.5 The effect after using GPD
Since the ephemeris data of the currently visible satellites have been acquired, the positioning time can be effectively
reduced. After using GPD, the cold start positioning time can be improved by about 10~15 seconds. Especially in the case of
weak signal, it is possible to improve the positioning speed even more.
8.6 Assisted localization methods to accelerate GPD
Since pure GPD assistance also needs to rely on the GPS time information of the search sky, sometimes when the signal is poor, it still
consumes too much time. Setting the current time information and rough coordinate information through the PGKC639 command can
achieve faster positioning time.
Note: When setting by the 639 command, the range of latitude and longitude should be within 20km of the actual position, and the time
deviation should not exceed 5 minutes.
Command: 639
Set approximate location and time information for faster positioning.
Arguments:
Arg1: Latitude, eg: 28.166450
Arg2: Longitude, for example: 120.389700
Arg3: height, eg: 0 Arg4: year
Arg5: month
Arg6: day
Arg7: Hour, time is UTC time
Arg8: points
Arg9: seconds
Example:
$PGKC639,28.166450,120.389700,0,2017,3,15,12,0,0*33<CR><LF>
After the 639 command is successfully executed, GK9501 will return the following format:
$PGKC001,639,3*21
8.7 GPD communication
Mainly through serial communication to transmit GPD data to the chip in blocks. The main process is as follows:
8.7.1 Switch NMEA reception to BINARY reception mode
(For the command format, please refer to GK9501 Input and Output Format.pdf)
Send: message type + toggle mode + baud rate + CheckSum
Data: $PGKC149,1,115200*15
(Message type 149 for GPD transport)
Receive: packet header (2B) + packet length (2B) + ACK type (2B) + message type (2B) + valid flag (1B) + CheckSum (1B) + packet
tail (2B)
Data: 0xaa, 0xf0, 0x0c, 0x00, 0x01, 0x00, 0x95, 0x00, 0x03, (chk), 0x0d, 0x0a
(checksum is a byte-by-byte XOR from the start of the packet length field to the field before the checksum)