Rikaline 24A User Manual page 21

GPS Receiver Board
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C.11 $PNMRX301, Ephemeris Data Transfer
This message format is used to transfer the ephemeris data between nodes; it uses a packed hexadecimal
format to transfer ephemeris data for each of the available SV's. Since the Ephemeris data is large and can
take time to transfer over a slow serial interface, the data is divided into individual messages for each of the
SV's. These messages are transmitted sequentially and can be interleaved with other messages to prevent
the Ephemeris data blocking higher priority messages such as scheduled PVT information. The data for
these messages is expressed as signed or unsigned fixed point values which have been scaled from the
floating point values used in the position solution. The appropriate scaling factors are included in the table.
The ephemeris data for each satellite is divided into 3 separate messages with sequence numbers to
identify them, the contents of these frames reflects the contents of the appropriate subframes 1,2,3
transmitted from the SV's. When transmitted these messages are generated in ascending order of SV Id and
sequence number, when being sent to the node these can be sent in any order, provided that the 3
messages for any individual satellite are grouped together, each message is individually interpreted and
after a group of 3 valid messages for an SV the ephemeris for that SV is updated independently. The 3
message formats are illustrated in the following tables
PNMRX301 message 1 field list
Field
Message ID $PNMRX301
Satellite vehicle Id Int
Subframe Id Int
Week number Hex
Health Hex
URA Hex
Time Group Delay Hex
IODC Hex
Toc Hex
Af2 Hex
Af1 Hex
Af0 Hex
Checksum *xx
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PNMRX301 message 2 field list
Field
Message ID $PNMRX301
Satellite Vehicle Id Int
Subframe Id Int
Iode Hex
Crs Hex
Motion difference Hex
(△n)
Mean anomaly Hex
Cuc Hex
E Hex
Cuc Hex
Root A Hex
Toe Hex
Checksum *xx
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Rikaline International Corp.
Tel: ++886 2 2370 4688 Fax: ++886 2 2370 4686 E-Mail:
GPS-24 / 24A Operating Manual
2
Format width
8
2
1
3
2
1
2
3
4
2
4
6
(0) 3
2
Format width
8
2
1
2
4
4
8
4
8
4
8
4
(0) 3
2
10F, 64, Kang-Din Road, Taipei 108, Taiwan
ASCII 13, ASCII 10.
scale Units
Weeks
-31
2 Seconds
-4
2
-31 2
2 sec/sec
-43
2 sec/sec
-31
2 Seconds
scale units
-5
2 Meters
-43
2 Semi-
circles/sec
-31
2 Semi- circles
-29
2 Radians
-33
2
-29
2 Radians
-19 1/4
2 Meters
4
2 seconds
Specifications subject to change without prior notice
info@rikaline.com.tw
Rikaline
Notes
PNMRX301 protocol header.
Decimal satellite vehicle Id
from 1 to 32.
Subframe number 1.
10 bit week number.
6 bits.
User range accuracy.
8 bits.
10 bit integer.
16 bits.
8 bit signed integer.
16 bit signed integer.
22 bit signed integer.
2 digits.
ASCII 13, ASCII 10.
Notes
PNMRX301 protocol header.
Decimal satellite vehicle id from
1 to 32.
Subframe number 2.
8 bits, lower 8 bits of matching
iodc.
16 bit signed integer.
16 bit signed integer.
32 bit signed integer.
16 bit signed integer.
32 bit signed integer.
16 bit signed integer.
32 bit signed integer.
16 bit unsigned integer.
2 digits.
ASCII 13, ASCII 10.
Web: www.rikaline.com.tw
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