ashtech ZY-12 Information Supplement page 100

<Data Length> = ceil ((94 + 72*2*Nsvs)/16) * 2, in which ceil (a) means truncates
to +Inf, e.g., ceil (3.1) = 4, ceil (3.5) = 4, ceil (3.95) = 4. Nsvs is number of
satellites.
Table 4.13 shows DBEN message sizes in relation to the number of satellites
being tracked:
EPB Message
The EPB message contains actual broadcast ("raw") ephemeris data. See the
ICD-GPS-200 for a definition of the parameters. Each subframe word is right-
justified in a 32-bit long integer.
The structure of the EPB message is shown below:
$PASHR,EPB,d,<Ephemeris Data + Checksum>
94
Table 4.13. DBEN Message Sizes
# of Satellites bits
4 808
5 952
6 1096
7 1240
8 1384
9 1528
10 1672
11 1816
12 1960
bytes
101
119
137
155
173
191
209
227
240
ZY-12 GPS Receiver