Section 5 - Beacon receivers
05/01/97 REV H
PAGE 17
•
Signal detection: acquisition via frequency-locked loop (FLL); track-
ing via phase-locked loop (PLL)
Data processing
•
Minimum shift keying (MSK) demodulation
•
Data decoding: parallel-matched digital filters
•
MSK bit rates: 25, 50, 100, 200 (automatically selected)
Data ports
•
Control input port: RS-232-C and RS-422 or NMEA 0183; 9600 or
4800 baud (jumper-selectable)
•
DGPS correction output port: RTCM SC-104 Version 2.1; 6 of 8
RS-232-C and RS-422; 9600 or 4800 baud (jumper-selectable)
•
Monitor/control port: Bi-directional RS-232-C or RS-422 at 9600
baud
Environment
•
Operating temperature: Zero to 55
°
C
•
Relative humidity: 95 percent (non-condensing)
Electrical requirements
The 8800’s power supply is protected against reverse-polarity power
inputs, and features a remote turn-on ability. The 8800 turns on when-
ever power is applied to pin 25, ground to pin 13, and remote turn-on pin
12 is connected to a source of 5 to 40 VDC.
5.1.4 Operating
modes
The 8800 runs in two operating modes:
•
Automatic
•
Manual
Automatic mode
At power-up, the 8800 enters automatic mode, requiring no further
supervision from the host GPS receiver. The 8800 operates automatically
by using two independent channels: Channel 1 tracks the best beacon
signal available (the signal with the lowest data error rate), and sends the
demodulated DGPS corrections to the GPS receiver; Channel 2
continu-
ously
scans the entire beacon frequency band (283.5 kHz to 325 kHz),
locating and measuring received DGPS beacon signals.
The 8800 then stores this information as a DGPS beacon “directory” in
battery-powered memory. If the signal that’s received and monitored by
Channel 1 degrades for any reason, the 8800 selects a better frequency
from its beacon “memory.” This function lets the 8800 automatically
switch to the best beacon signal before affecting your GPS accuracy.
Automatic mode can be used for all applications except specialized ones,
and is the only mode supported by most commercially-available GPS
receivers.
Summary of Contents for 8700
Page 2: ......
Page 10: ......
Page 16: ...Section 2 Introduction PAGE 6 05 01 97 REV H ...
Page 20: ...Section 3 Packaging PAGE 10 05 01 97 REV H ...
Page 32: ...Section 6 GPS beacon combination receivers PAGE 22 05 01 97 REV H ...
Page 46: ...Section 8 Input output configurations PAGE 36 05 01 97 REV H ...
Page 52: ...Section 9 Connector pinouts PAGE 42 05 01 97 REV H ...
Page 76: ...Section 12 8X00 engine monitor program PAGE 66 05 01 97 REV H ...
Page 78: ...Section 13 Glossary PAGE 68 05 01 97 REV H ...
Page 80: ...Section 14 Abbreviations and initialisms PAGE 70 05 01 97 REV H ...
Page 85: ...Index 05 01 97 REV H PAGE 75 ...