REFERENCE MANUAL - FTP Directory Listing - Trimble
REFERENCE MANUAL - FTP Directory Listing - Trimble
REFERENCE MANUAL - FTP Directory Listing - Trimble
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TRIMBLE STANDARD INTERFACE PROTOCOL (TSIP)<br />
A<br />
TSIP Superpackets<br />
Several packets have been added to the core TSIP protocol to provide additional<br />
capability for OEM receivers. In OEM Packets 0x8E and their 0x8F responses, the<br />
first data byte is a sub-code which indicates the superpacket type. For example, in<br />
Packet 0x8E-15, 15 is the sub-code that indicates the superpacket type. Therefore the<br />
ID code for OEM packets is 2 bytes long followed by the data. Command packet<br />
0x35 is used to enable superpackets.<br />
Command Packet 8E-15 - Set/Request Datum<br />
This packet allows the user to change the default datum from WGS-84 to one of 180<br />
selected datums. The datum is a set of 5 parameters which describe an ellipsoid to<br />
convert the GPS receiver’s internal coordinate system of XYZ ECEF into Latitude,<br />
Longitude, and Altitude (LLA). This affects all calculations of LLA in packets 0x4A<br />
and 0x84.<br />
The datum can be changed to match coordinates with another system such as a map.<br />
Most maps are marked with the datum used. In the US, the most popular datum for<br />
maps is NAD-27. You may choose a datum optimized for the local shape of the earth,<br />
however optimized datums are truly local and provide very different results when<br />
used outside of the area for which they are intended. WGS-84 is an excellent general<br />
ellipsoid valid around the world. To request the current datum setting, one data byte is<br />
sent. Report Packet 0x8F is returned.<br />
Table A.56 Command Packet 8E-15<br />
Byte Type Meaning<br />
0 Superpacket 0x15<br />
To change to one of the internally held datums, the packet must contain exactly 2<br />
bytes representing the integer value of the index of the desired datum.<br />
Table A.57 Command Packet 8E-15<br />
Byte Type Meaning<br />
0 Superpacket ID 0x15<br />
1-2 INT16 Datum index<br />
Note – To request the current datum, send Packet 8E015 with no data bytes.<br />
Copernicus GPS Receiver 165