Garmin GPS II - Manual (Page 85)

79
DGPS Interface
The last two format settings allow the differential-ready GPS II to accept RTCM
DGPS corrections in RTCM 104 version 2.0 format. Using DGPS corrections will
improve receiver accuracy to 5-10 meters, regardless of errors induced by the gov-
ernment’s Selective Availability (SA) program. The RTCM/NONE format will allow
connection to any manually-tuned beacon receiver by using the proper output inter-
face. The baud rate is selectable from the GPS II.
The RTCM/NMEA selection controls the GARMIN GBR-21 differential beacon
receiver. Once a RTCM setting has been selected, the GPS II will either automatically
try to tune the last frequency and bit rate you selected or will switch to the default
frequency of 304.0 kHz with a bit rate of 100 bps if no previous beacon has been
tuned. You may also enter your own frequency and bit rate if desired.
To enter a DGPS beacon frequency:
1. Highlight the ‘freq’ field (Fig. 79a), and press ENTER.
2. Enter the desired frequency, and press ENTER.
3. Highlight the ‘rate’ field (Fig. 79b), and press ENTER.
4. Select the desired transmission rate, and press ENTER.
Fig. 79a
Fig. 79b
REFERENCE
GPS II 7/23/98 4:05 PM Page 79