17
MN002000A © 2004 Navman NZ Ltd. All rights reserved. Proprietary information and specifications subject to change without notice.
Message ID: 1003
Rate: Variable; default on update
Message Length: 51 words
Word No.
Name
Type
Units
Range
Resolution
1-4
Message header
5
Header checksum
6-7
Set time (Note 1)
UDI
10 ms ticks
0 to
4 294 967 295
8
Sequence number (Note 2)
I
0 to 32 767
9
Best possible GDOP
I
0 to 99
10
-2
10
Best possible PDOP
I
0 to 99
10
-2
11
Best possible HDOP
I
0 to 99
10
-2
12
Best possible VDOP
I
0 to 99
10
-2
13
Best possible TDOP
I
0 to 99
10
-2
14
Number of visible satellites
UI
1 to 12
Visible satellite set (Note 3)
15 + (3*j)
Satellite PRN (Note 4)
UI
0 to 32
16 + (3*j)
Satellite azimuth
I
rad
±�
10
-4
17 + (3*j)
Satellite elevation
I
rad
±�/2
10
-4
51
Data checksum
Note 1: Set time is an internal 10 millisecond (T10) count since power-on initialisation enabled the processor interrupts. It is not
used to derive GPS time, but only serves to provide a sequence of events knowledge. The set time or T10 count references the
receiver’s internal time at which the message was created for output. The T10 range is approximately 71 weeks.
Note 2: The sequence number is a count that indicates whether the data in a particular binary message has been updated or
changed since the last message output.
Note 3: Only the satellite sets for the number of satellites reported in word 14 of this message are valid.
Note 4: j = the number of visible satellites minus one when the number of visible satellites is greater than zero.
Table 3-7 Message 1003 (visible satellites)
3.5.1.3 Message 1003 (visible satellites)
This message outputs the list of satellites visible
to the receiver and their corresponding elevations
and azimuths. The best possible DOPs, calculated
from this visible list, are also provided. The
contents of the ‘visible satellites’ message are
described in Table 3-7.
