Читать книгу Global Navigation Satellite Systems, Inertial Navigation, and Integration - Mohinder S. Grewal - Страница 25

The legacy GLONASS system uses frequency‐division multiplexing of independent satellite signals. Each GLONASS satellite transmits two navigation signals in the L1 and L2 frequency bands, corresponding to f₁ = (1.602 + 9k/16) GHz and f₂ = (1.246 + 7k/16) GHz, where k = −7, −6, … 5, 6 is the satellite number. These frequencies lie in two bands at 1.598–1.605 GHz (L1) and 1.242–1.248 GHz (L2). The L1 code is modulated by a C/A‐code (chip rate = 0.511 MHz) and by a P‐code (chip rate = 5.11 MHz). The L2 code is presently modulated only by the P‐code. The GLONASS satellites also transmit navigational data at a rate of 50 baud. Because the satellite frequencies are distinguishable from each other, the P‐code and the C/A‐code are the same for each satellite. The methods for receiving and analyzing GLONASS signals are similar to the methods used for GPS signals. Further details can be found in the patent by Janky [21].