Trimble Outdoors SK8 - Manual (Page 152)

C-6 Lassen-SK8 Embedded GPS Module
Trimble ASCII Interface Protocol (TAIP)
The D message qualifier was designed by Trimble for use by Ambulance Companies to
limit communication traffic between mobile units and the base when the ambulances are
stationary on-station. When the ambulance has reached its stationary dispatch site, the
operator signals the base by voice or by pushing a button on a Mobile Data Terminal
(MDT) signifying that the unit is now on station. Once this communication is made, the
base operator issues a D qualifier and message so that the ambulance will only report
either when it moves off-station or at specific reporting intervals.
C.4 Latitude and Longitude Conversion
The TAIP protocol reports latitude as positive north decimal degrees and longitude as
positive east decimal degrees, using the WGS-84 datum. For your application, you may
wish to convert to degrees, minutes and seconds. The following example illustrates the
conversion of decimal degrees to degrees, minutes and seconds.
Example:
Given latitude and longitude in decimal degrees,
Convert latitude by multiplying the decimal fraction of degrees by 60 to convert to
minutes
0.39438 x 60 = 23.6628 minutes
Retain the integer (23) portion as the minutes then multiply the decimal fraction by 60 to
convert to seconds,
0.6628 x 60 = 39.768 seconds
Since the sign of the latitude in this example is positive the result is:
Latitude: N 37
o
23' 39.77"
The longitude is converted in the same fashion:
Longitude: W 122
o
02' 18.46"
Note – At the earth's equator, one degree of latitude and longitude represents 68.7 miles;
therefore, 0.00001 degrees represents approximately 3.6 feet or 1.1 meters. Each second
represents approximately 100.76 ft. (30.7 m).
Latitude: +37.39438 degrees
Longitude: -122.03846 degrees