General Information
STANAG-4481 is a NATO standard for maritime shore-to-ship broadcast digital data communication. Data are sent by a single land-based transmitting station and received by many stations aboard ships.
There are two variants, one with a FSK modulated signal, the other with PSK modulation.
Usage:
§ Transfer of maritime related digital information over HF.
Mode Details
|
|
Item |
Value |
|
|
Standard |
Modulation |
FSK |
BPSK |
|
|
Tones |
2 |
- |
|
|
Shift (Hz) |
850 |
- |
|
|
Bandwidth (Hz) |
1500 |
3000 |
|
|
Symbol rate (Bd) |
75 / 100 / 150 / 300 / 600 |
2400 |
|
|
Data rate (bit/s) |
- |
300 |
|
|
Error correction |
- |
FEC rate 1/4 |
|
Demodulator Settings |
Demodulator |
FSK 2 matched |
PSK data aided |
|
|
Symbol rate (Bd) |
75 |
2400 |
|
|
SR tolerance (Bd) |
5 |
24 |
|
|
Shift (Hz) |
850 |
- |
|
|
Shift tolerance (Hz) |
10 |
- |
|
|
Modulation order |
- |
8 |
|
|
Version |
- |
A |
|
|
Min. burst length (s) |
0.100 |
0.100 |
|
|
Max. burst length (s) |
1.000 |
1.000 |
|
|
Min. pause length (s) |
0.100 |
0.100 |
|
Features |
Demodulation |
yes | |
|
|
Recognition |
yes | |
|
|
Decoding |
yes | |
|
|
Automatic Polarity Adjustment |
no | |
|
|
Combination with other modems (modem list) |
yes | |
|
Tuning |
Tuning frequency (Hz) |
Center |
1800 |
Table 21: STANAG-4481
Figure 20: STANAG-4481 FSK Spectrogram
Figure 21: STANAG-4481 PSK Spectrogram
Modem Version History
|
Release |
Date |
History |
|
2.0.0 |
2013-01-10 |
Modem added |
|
2.2.0 |
2014-03-19 |
Data format 7N2 added |
|
|
|
All specified symbolrates supported |