Over the past several years, some users of the GPS navigation system have already benefitted from the addition of various new signals in addition to the legacy C/A- and P(Y)-code. With the introduction of the Block IIR-M satellites in 2005, a new civil signal (L2C) was transmitted on the L2 frequency, and a new signal on a new frequency (L5) was introduced as a standard signal with the Block IIF satellites beginning in 2010. These new signals provide direct access to dual-frequency observations and thus enable improved ionospheric corrections for civil, including aeronautical, users. In addition, a new Civil Navigation (CNAV) broadcast message has been defined in the GPS Interface Specifications (IS-GPS-200 and IS-GPS-705).
DLR German Space Operations Center, Oberpfaffenhofen, Germany
Richard B. Langley
University of New Brunswick, Fredericton, New Brunswick, Canada
Technische Universität München (TUM), Munich, Germany
The full article is available on the GPS World website: 2C or Not 2C: The First Live Broadcast of GPS CNAV Messages