01 Oct 1998
pseudorange corrections generated by the reference station, the
user needs to have a MSK Radiobeacon receiver with antenna and,
at a minimum, a L1 C/A code GPS receiver with antenna.
a. The MSK receiver demodulates the signal from the
reference station. Most MSK receivers will automatically select
the reference station with the strongest signal strength to
observe from or allow the user to select a specific reference
station. A MSK receiver can be connected to most GPS receivers.
b. The GPS receiver must be capable of accepting RTCM Type
9 messages and applying these corrections to compute a "meter
level" position. Since the reference station generates
corrections only for satellites above a 7.5 degree elevation,
satellites observed by the user's GPS receiver below a 7.5 degree
elevation will not be corrected. Some receiver manufacturers
have developed a combined MSK radiobeacon and GPS receiver with a