ashtech DG14, Справочное руководство

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30 DG14 and DG16 Board & Sensor Reference Manual
exclusive OR-ing all of the bytes in the message between, but not
including, the dollar sign ($) and the asterisk (*).
• Messages end with the standard NMEA message terminator characters,
[CRLF] (carriage return/line feed).
Input messages deviate from the NMEA standard as follows:
• Headers are Ashtech format
• Message IDs are Ashtech format
• Message length may exceed 80 characters
• Messages defined by the user with the UDM Utility and the [X] option
installed
All command messages—set or query—can be composed in uppercase or
lowercase characters. All command messages are sent by pressing
<Enter> . A
valid set command causes the DG16 to return the $PASHR,ACK*3D
(acknowledge) response message. A set command containing a valid $PASHS
header followed by character combinations unrecognized by the DG16 causes
the receiver to respond with
$PASHR,NAK*30 , a “not acknowledge” response
message indicating that the command is invalid. Valid query and messages are
acknowledged by return of the requested information. All invalid query and
general commands cause the DG16 to return the
$PASHR,NAK*30 “not
acknowledged” response message.
DG16 Message Output
The DG16 can be programmed to send data to another device. Output messages
include general receiver status messages, ACK/NAK messages, and GPS data
messages. The general receiver status messages have free-form Ashtech
formats. The acknowledged/not acknowledged messages and GPS data
messages comply with NMEA 0183 standards as follows:
• NMEA ASCII byte strings following a dollar sign ($) character
• Headers are standard NMEA or Ashtech-format NMEA
• Message IDs are standard NMEA or Ashtech-format NMEA
• Standard NMEA format messages contain hexadecimal checksum bytes
• Data items are separated by commas; successive commas indicate invalid
or missing data (null fields)
• Messages end with [CRLF] (carriage return/line feed), the standard NMEA
message terminator characters
User-Defined Messaging
If you have the User-Defined Messaging option [X] installed on your DG16, you
can use the UDM Utility to define custom receiver commands to output receiver
information to fit your specific application. This feature can minimize the number