Table of Contents
Advertisement
1 Introduction
Table 1.2 Comparison of GLONASS and GPS Characteristics
Parameter
Satellites
Number of satellites
Number of orbital planes
Orbital plane inclination (degrees)
Orbital radius (kilometers)
Signals
Fundamental clock frequency (MHz)
Signal separation technique
Carrier frequencies (MHz) L1
Code clock rate (MHz)
Code length (chips)
C/A-code Navigation
Superframe duration (minutes)
Superframe capacity (bits)
Message
Superframe reserve capacity (bits)
Word duration (seconds)
Word capacity (bits)
Number of words within a frame
Technique for specifying satellite
ephemeris
Time reference
Position reference (geodatic datum)
1
Each satellite in the full 24-satellite GLONASS constellation is assigned an antipodal frequency. Such a system of simultaneous multiple
transmissions is known as frequency division multiple access (FDMA) and distinguishes GLONASS from GPS, which is a code division multiple
access (CDMA) system.
2
GLONASS and GPS use different time systems. GLONASS time is referenced to UTC (SU), the Russian National Etalon timescale, whereas, GPS
time is referenced to UTC as maintained by the U.S. Naval Observatory – UTC (USNO). The GLONASS control segment periodically applies a
time step to bring the system's time within several hundred nano-seconds of UTC time.
3
GLONASS ephemerides are referenced to the Parametry Zemli 1990 (PZ-90 or in English translation, Parameters of the Earth 1990, PE-90)
geodetic datum. The realization of the PZ-90 frame through adopted reference station coordinates has resulted in offsets in origin and orientation as
well as a difference in scale with respect to WGS 84 used by GPS. Relationships between the PZ-90 and WGS 84 have now been established.
14
Detail
21 + 3 spares
3
64.8
25 510
5.0
1
FDMA
1602.0 - 1615.5
C/A
0.511
P
5.11
C/A
511
P
5.11 x 10
2.5
7 500
~620
2.0
100
15
Geocentric Cartesian
coordinates and their
derivatives
2
UTC (SU)
3
PZ-90
NOTES:
GPS/GLONASS Receiver User Manual Rev 1
GLONASS
21 + 3 spares
6
55
26 560
10.23
CDMA
1575.42
1.023
10.23
1 023
6
6.187104 x 10
12.5
37 500
~2 750
0.6
30
50
Keplarian orbital
elements and
perturbation factors
UTC (USNO)
WGS 84
GPS
12
Advertisement
Table of Contents
