NavCom Sapphire Rev.J - Manual (Page 373)

Sapphire Technical Reference Manual Rev. J
373
2.112 STARFIREALM1B
SF-3050 Sapphire SF-3040
This message outputs the StarFire over the air (OTA) almanac that is currently in use.
The TOW and GPS time represented in the header of the message represents the time (system
time) at which a full StarFire OTA almanac (verified complete and valid) is committed to the
receiver. This time is saved into NVRAM. This time is only updated upon the receipt of a NEW
full valid set of StarFire OTA almanac and committed/applied to the receiver.

When the StarFire almanac is updated in the receiver, the receiver automatically
acts upon it immediately. The receiver will compare its current position against the
new almanac and select the highest in-network satellite in the new list. Further, the
table in SFSATLIST1B will be updated with the relevant new data from this
almanac message.

Number of entries included in STARFIREALM1B is fixed to 16 in older code.
Table 200: STARFIREALM1B binary message data
Data Item Data Type
Almanac set number (0-15) U08
Number of valid data in almanac table (0-15) = N U08
N entries of packed almanac data

All values are big-endian byte ordering. Low order bit 0 is LSB and high order bit is
MSB. Bit 0 is LSB and bit 7 is MSB.
Longitude
(Bits 11-4)
Channel
(Bits 15-8)
Channel
(Bits 7-0)
C
h
a
n
Byte
0
4 Longitude
(Bits 3-0)
Rec ID
(3-0)
7 6 5 4 3 2 1 0
0 1 2 3
NetID
H
e
a
l
Service
Flags
(Bits 3-0)
Serv Flags
(Bits 7-4)
Bit Rate
(Bits 2-0)
Bits
T
im
e
In
c
.
Week
(Bits 9-2)
Time
(Bits 7-0)
Week
(1-0)
Time
(Bits 13-8)
8
Figure 5: OTA StarFire Almanac Satellite Record
Table 201: OTA Almanac Satellite Record
Byte
Position
Bit
Position
Name
Valid
Range
Description
0 4-7 Record ID 0-15
Satellite record identifier number. Describes the
ordering of the records in a set. Records with the
same record ID imply no particular order.
Note: Currently, receivers do not use this field.
Note: May be assigned another purpose in the future.
3 Health 0 or 1 Value and meaning
Reserved