NavCom LAND-PAK Rev.N - Manual (Page 19)

Technical Reference Manual Rev. N
Blk = All; Blu = IOP w/Internal Radio ; Red = IOP & LBM ; Grn = Engine only
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GPS Time of week [in seconds] of collected ephemeris, IODC, and sub-frame 1, 2, and 3
data.
86 Channel Status:
Receiver channel status information containing: the GPS week, GPS Time of Week, NCT-
2100 Engine status, number of satellites viewed/tracked, PDOP, tracked satellite identity,
satellite elevation and azimuth, C/No for the L1 and L2 signals, and correction age for each
satellite.
A0 Alert Text Message:
Details message receipt and processing.
AE Identification Block:
Details the receiver software versions (NCT-2100, and IOP) and digital serial numbers.
B0 Raw Measurement Data:
Raw Measurement Data Block containing: the GPS Week, GPS Time of Week, Time Slew
Indicator, Status, Channel Status, CA Pseudorange, L1 Phase, P1-CA Pseudorange, P2-CA
Pseudorange, and L2 Phase. This data stream is repeated for each individual tracked
satellite.
B1 PVT (Position, Velocity, and Time):
Provides: GPS Week number, satellites used, latitude, longitude, navigation mode, and
DOP information.
GPS Week Number
The GPS Week Number count began at midnight on the evening of 05 January 1980 / morning
of 06 January 1980. Since that time, the count has been incremented by 1 each week, and
broadcast as part of the GPS message. The GPS Week Number field in the data stream is
modulo 1024. This meant that at the completion of week 1023, the GPS week number rolled
over to 0 on midnight GPS Time of the evening of 21 August 1999 / morning of 22 August 1999.
The NCT-2000D and NCT-2100D use an adjusted 16-bit integer (U16) in the data to avoid this
confusion. They can handle up to week 65535.