NavCom LAND-PAK Rev.N - Manual (Page 54)

Technical Reference Manual Rev. N
Blk = All; Blu = IOP w/Internal Radio ; Red = IOP & LBM ; Grn = Engine only 52
0x46 - Initial Time and Position - 32 bytes
GPS Navigation is accelerated if the receiver has time, date, position, and almanac. This
message presents the time of day and the initial position to the receiver by entering the GPS
Week, Time of Week, Latitude and Longitude.
Record
Usage Command - Yes
Response - No Input this record when the receiver has been moved by 500 miles (800 km) or
more without navigating. Use with 0x44 to input a current almanac
Ref Message Field Description Data Type Units Range Scale
Byte
Count
STX 02 (hex) U08 1
PRA1 99 (hex) U08 1
PRA2 66 (hex) U08 1
ID 46 (hex) U08 1
Length 0x0020 U16 2
W1
Command Action
B2=0: Do not use ACK/NAK
1: Use ACK/NAK
U08 1
W2
Usage flags
B0=0: Do not set time
1: Set time
B1=0: Do not set initial position
1: Set initial position
U08 1
W3 GPS week U16 0 - 65535 2
W4 GPS time of week U32 seconds 0 - 604800 4
W5 WGS84 Latitude R64 radians +North 8
W6 WGS84 Longitude R64 radians +East 8
W7 WGS84 Ellipsoidal height R32 meters 4
CKSM Checksum U08 1
ETX 03 (hex) U08 1
1. For multiple command actions, the bits in W1 may be OR’ed.
2. W7 may be set to 0 or an estimation of Ellipsoidal height. It is more important
to input a relatively accurate position (degrees minutes, minimum).
3. Use this record when the receiver has been moved by 500 miles (800 km) or
more without navigating to aid in satellite reacquisition.