14.3 Satellite Radio Navigation Systems
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operation organization of various systems, primarily GPS, GLONASS and Galileo,
is similar. The e SRNS consists of three main segments:
• subsystems of space vehicles, that is, NSV;
• control and management subsystem, which includes a control center and a network
of ground stations for measurement, control and monitoring;
• navigation equipment of users, including onboard receivers of the SRNS.
Ground stations SRNS solve the following main tasks:
• determination and forecasting of NSV coordinates (ephemeris) and parameters
of its orbits,
• synchronization of the time scales of each satellite with the system time,
• transfer of an array of service information to the NSV,
• transfer of an array of service information to the NSV,
The information transmitted from the ground to each satellite includes the parameters of the orbits of all the NSV and its state (serviceability), corrections to time
scales and to the carrier frequency, as well as other data. Since, due to gravitational
perturbations, the orbital elements are continuously changing, not only the orbital
parameters themselves are transmitted, but also the coefficients of the polynomials,
which can be used to calculate the rate of change of these parameters and refine the
orbital elements at any time. The NSV includes an onboard navigation transmitter,
chronizer (i.e., NSV clock), orientation and stabilization system, control complex,
and other systems that ensure the operation of the NSV.
Users’ navigation equipment consists of navigation receivers and computing
devices intended for processing of navigational signals. This equipment performs
non-query measurements of the pseudo-ranges and radial velocities of the satellite,
as well as the calculations necessary to obtain navigation information by users.
Below we will briefly examine the main SRNS and perform its characteristics.
Global satellite navigation system GLONASS.
The GLONASS system provides the user with two types of services—standard
and high precision. Standard precision services are provided to users by transmitting standard precision signals in the L-band. Each GLONASS-M satellite transmits
navigation radio signals with frequency division in two bands: L1 (1.6 GHz) and L2
(1.25 GHz).
A standard accuracy signal with a clock frequency of 0.511 MHz, intended for
use by domestic and foreign civilian users, is available to all consumers equipped
with the appropriate airborne instrument, in the observation zone of which there are
GLONASS satellites.
The regular GLONASS orbital constellation consists of 24 satellites (see Fig. 14.4)
located in medium-altitude near-circular orbits with nominal altitudes of 19,100 km,
inclination of 64.8° and a period of 11 h 15 min 44 s. The value of the period
made it possible to create a stable orbital system that does not require, in contrast to
GPS orbits, for its maintaining of correcting impulses, practically during the entire
period of active orbital lifetime. The nominal inclination ensures 100% availability
251
operation organization of various systems, primarily GPS, GLONASS and Galileo,
is similar. The e SRNS consists of three main segments:
• subsystems of space vehicles, that is, NSV;
• control and management subsystem, which includes a control center and a network
of ground stations for measurement, control and monitoring;
• navigation equipment of users, including onboard receivers of the SRNS.
Ground stations SRNS solve the following main tasks:
• determination and forecasting of NSV coordinates (ephemeris) and parameters
of its orbits,
• synchronization of the time scales of each satellite with the system time,
• transfer of an array of service information to the NSV,
• transfer of an array of service information to the NSV,
The information transmitted from the ground to each satellite includes the parameters of the orbits of all the NSV and its state (serviceability), corrections to time
scales and to the carrier frequency, as well as other data. Since, due to gravitational
perturbations, the orbital elements are continuously changing, not only the orbital
parameters themselves are transmitted, but also the coefficients of the polynomials,
which can be used to calculate the rate of change of these parameters and refine the
orbital elements at any time. The NSV includes an onboard navigation transmitter,
chronizer (i.e., NSV clock), orientation and stabilization system, control complex,
and other systems that ensure the operation of the NSV.
Users’ navigation equipment consists of navigation receivers and computing
devices intended for processing of navigational signals. This equipment performs
non-query measurements of the pseudo-ranges and radial velocities of the satellite,
as well as the calculations necessary to obtain navigation information by users.
Below we will briefly examine the main SRNS and perform its characteristics.
Global satellite navigation system GLONASS.
The GLONASS system provides the user with two types of services—standard
and high precision. Standard precision services are provided to users by transmitting standard precision signals in the L-band. Each GLONASS-M satellite transmits
navigation radio signals with frequency division in two bands: L1 (1.6 GHz) and L2
(1.25 GHz).
A standard accuracy signal with a clock frequency of 0.511 MHz, intended for
use by domestic and foreign civilian users, is available to all consumers equipped
with the appropriate airborne instrument, in the observation zone of which there are
GLONASS satellites.
The regular GLONASS orbital constellation consists of 24 satellites (see Fig. 14.4)
located in medium-altitude near-circular orbits with nominal altitudes of 19,100 km,
inclination of 64.8° and a period of 11 h 15 min 44 s. The value of the period
made it possible to create a stable orbital system that does not require, in contrast to
GPS orbits, for its maintaining of correcting impulses, practically during the entire
period of active orbital lifetime. The nominal inclination ensures 100% availability