Global Positioning System Reference
In-Depth Information
A
B
C
D
E
F
Plane
degrees
180
120
80
40
Longitude of
ascending node
degrees
Equator
272.8
32.8
92.8
332.8
152.8
212.8
320
280
240
200
Figure 3.2
GPS constellation planar projection.
Table 3.1
Reference Orbit Slot Assignments as of the Defined Epoch
Argument of
Latitude (°)
Argument of
Latitude (°)
Slot
RAAN (°)
Slot
RAAN (°)
A1
272.847
268.126
D1
92.847
135.226
A2
272.847
161.786
D2
92.847
265.446
A3
272.847
11.676
D3
92.847
35.136
A4
272.847
41.806
D4
92.847
167.356
B1
332.847
80.956
E1
152.847
197.046
B2
332.847
173.336
E2
152.847
302.596
B3
332.847
309.976
E3
152.847
66.066
B4
332.847
204.376
E4
152.847
333.686
C1
32.847
111.876
F1
212.847
238.886
C2
32.847
11.796
F2
212.847
345.226
C3
32.847
339.666
F3
212.847
105.206
C4
32.847
241.556
F4
212.847
135.346
Defined epoch: 0000Z, July 1, 1993; Greenwich hour angle: 18 hours, 36 minutes, 14.4 seconds
referenced to FK5/J2000.00 coordinates.
Groundtrack equatorial crossing:
±
2°;
•
Eccentricity: 0.00-0.02;
•
Inclination: 55°
±
3°;
•
Semimajor axis: 26,559.7 km
±
50 km for Block IIR,
±
17 km for Block II/IIA;
•
•
Longitude of the ascending node:
±
2°;
•
Argument of perigee:
±
180°.
Several different notations are used to refer to the satellites in their orbits. One
nomenclature assigns a letter to each orbital plane (i.e., A, B, C, D, E, and F) with
each satellite within a plane assigned a number from 1 to 4. Thus, a satellite refer-
enced as B3 refers to satellite number 3 in orbital plane B. A second notation used is
a NAVSTAR satellite number assigned by the U.S. Air Force. This notation is in the
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