Trimble Outdoors SK8 - Manual (Page 161)

Lassen-SK8 Embedded GPS Module C-15
Trimble ASCII Interface Protocol (TAIP)
C.13 IP Initial Position
Data String Format:
AAABBBBCCCCC
Table C-13. Initial Position Data String Descriptions
This is a very coarse initial position that the user can provide to aid the sensor in obtaining
its first fix. This is specially useful with sensors that do not have non-volatile (Battery
Backed-up) memory. In such cases, every time the unit is powered up, it goes through a
complete cold-start and it has absolutely no knowledge of where it is. Providing this
message improves performance by decreasing the time to first fix and enhances the
accuracy of the initial two dimensional navigation solutions by providing a reference
altitude. In case of units with non-volatile memory, sending this message is only helpful if
the unit has moved more than 1,000 miles since its previous fix. In either case, the sensor
can initialize itself appropriately without any data from the user; It merely requires more
time.
*
Note – For all the above values, the first character specifies the sign (+/-).
Example:
The following message will set the initial position to 37
o
North, 122
o
West, altitude 10
meters.
>SIP+37-122+0001<
Item # of Char UNITS Format
Initial Latitude 3 Deg AAA
Initial Longitude 4 Deg BBBB
Initial Altitude 5 10 Meters CCCCC
Total 12