News


NAVSTAR Global Positioning System(GPS) Block IIF (U)

Overview (U):

(U) NAVSTAR Global Positioning System (GPS) is a satellite-based radio positioning/navigation (POS/NAV) system that provides extremely accurate, three dimensional, common grid position, velocity and time of day information to users anywhere on or near the earth. The system uses a constellation of 24 satellites which provides navigation data to both military and civilian users worldwide. The system provides reliable and accurate passive worldwide positioning, navigation, and timing information in all weather conditions, in real time, using a common grid reference system.

(U) The BLOCK IIF satellites are the third series of operational satellites being developed.

(U) The Block IIF Program incorporates current and leading edge technology to sustain the GPS utility for military and commercial use. The IIF contract allows the Air Force to purchase 33 satellites. The Block IIF system allows affordable technology insertion and block upgrades, while emphasizing compatibility and interoperability with the current space vehicles, ground control system, and user equipment. The system will interface with the new GPS Operational Control System (OCS) architecture currently under development, and with the Air Force Satellite Control Network (AFSCN).

Details (U):

Description User Impact Programmatics Images
Related Initiatives Related Requirements Related Categories Road Map Placements
Additional Hotlinks Lead Office POC  


Description (U):

(U) The Space Segment is an earth-orbiting constellation of 24 NAVSTAR satellites in six planes. The nominal circular orbit has a 20,200 kilometer (10,900 nautical mile) altitude and the orbits are inclined at an angle of 55 degrees with a 12-hour period. The spacing of satellites in their orbital planes are arranged such that a minimum of four satellites will be in view everywhere on and near the surface of the earth at any time. Each NAVSTAR satellite is designed to broadcast a pair of L-band radio frequency (RF) signals, known as Link 1 (L1 = 1575.42 MHz) and Link 2 (L2 = 1227.6 MHz). The L1 signal carries a precision ranging code and coarse / acquisition code, while L2 carries only the precise ranging code. The signals are broadcast using spread spectrum techniques, employing two different spreading functions: a 1.023 MHz coarse / acquisition (C/A) code on L1 only and a10.23 MHz precision (P) code on both L1 and L2. The minimum signal power for the different signals at a GPS receiver are: L1 C/A = -160 dBW; L1 P = -163 dBW; and for L2 P = -166 dBW. Superimposed on these codes are low-rate navigation message data, including satellite clock and ephemeris parameters, satellite signal health data, and Coordinated Universal Time (UTC) synchronization information.

(U) The Block IIF Program incorporates current and leading edge technology to sustain the GPS utility for military and commercial use.

(U) The Block IIF system allows affordable technology insertion and block upgrades, while emphasizing compatibility and interoperability with the current space vehicles, ground control system, and user equipment. The system will interface with the new GPS Operational Control System (OCS) architecture currently under development, and with the Air Force Satellite Control Network (AFSCN).

(U) The Air Force will use the Evolved Expendable Launch Vehicle (EELV) as the booster to place these satellites in orbit.

(U) The requirement to maintain a worldwide navigation service provided by a 24 satellite constellation for military and civilian users drives the Block IIF program.

(U) The GPS control or ground segment consists of five unmanned monitor stations located around the world (Hawaii; Kwajalein in the Pacific Ocean; Diego Garcia in the Indian Ocean; Ascension Island in the Atlantic Ocean; and Colorado Springs, Colorado); a master ground station at Schriever Air Force Base in Colorado Springs, Colorado; and four large ground antenna stations that broadcast signals to the satellites. The stations also track and monitor the GPS satellites.

User Impact (U):

(U) GPS provides an all-weather, global, protected (encrypted) navigation signal to all DoD users and allies. The signal provides positioning accuracy's to about 7m 50 percentile spherical error probable and a timing signal for DoD communications and command and control systems to a precision of <100ns dual root mean square. GPS receivers vary in capability and performance but are being integrated into many operational systems at costs under $3,000/platform.

Programmatics (U):

(U) Programmed.

Images (U):

NameTitle
Added Value to the WarfighterAFSPC Vision
Global Positioning System (GPS)Five Principles of Global Positioning
NAVSTAR GPS Block IIFNAVSTAR GPS Block IIF
This Table Is Unclassified.

Related Initiatives (U):
NameTitle
3A Airborne Receiver3A Airborne Receiver
3S Shipborne Receiver3S Shipborne Receiver
Arnold Engineer Dev Cntr (AEDC)Arnold Engineering Development Center (AEDC)
Combat Survivor Evader LocatorCombat Survivor Evader Locator (CSEL)
CRPA/AE-1Controlled Reception Pattern Antenna (CRPA/AE-1)
Defense Advanced GPS ReceiverDefense Advanced GPS Receiver (DAGR)
Delta IIDelta II
Eastern RangeEastern Range
Embedded GPS Inertial Nav. Sys.Embedded Global Positioning System (GPS) Inertial (EGI) Navigation System
FRPA./AE-4Fixed Reception Pattern Antenna (FRPA)/Antenna Electronics (AE-4)
GAS-1 CRPA/AEGAS-1Controlled Reception Pattern Antenna (CRPA)/AE
GPS Block IIRNAVSTAR Global Positioning System(GPS) Block IIR
GPS Receiver Applications ModuleGlobal Positioning System (GPS) Receiver Applications Module (GRAM)
GPS VME Receiver Card (GVRC)GPS Versa Modula Eurocard (VME) Receiver Card (GVRC)
Miniature Airborne GPS Rec. 2000Miniature Airborne Onboard Processing (GPS) Receiver 2000 (MAGR-2000)
Miniaturized Airborne GPS Rec.Miniaturized Airborne Global Positioning System (GPS) Receiver (MAGR)
Precision Lightweight GPS Rec.Precision Lightweight GPS Receiver (PLGR)
This Table Is Unclassified.

Related Requirements (U):None.

Related Categories (U):
NameTitle
NavigationDoD Space Navigation Programs
Satellite OperationsSatellite Operations
Space SystemsSpace Systems
Space-Based WarningSpace-Based Warning Systems
This Table Is Unclassified.

Road Map Placements (U):

NameTitle
Major DoD Space ProgramsEvolution of the Selected Space Programs
National Security Space Road MapIntegrated System Road Map
NAVIGATIONSPACE FORCE ENHANCEMENT: NAVIGATION
This Table Is Unclassified.

Requirements, Funding and Additional Hotlinks (U):

Name
GPS-Army Info
NAVSTAR GPS Block IIF
RDT&E Budget Item Project 0005
Sattelite Control ORD (95)
This Table Is Unclassified.

Lead Office (U):

(U) Air Force.

(U) DoD: OASD(C3I), Pentagon, Washington, DC
(U) Service Staff: SAF/AQS, Pentagon, Washington, DC
(U) Major Command: HQ AFSPC/DR, Peterson AFB, CO; HQ ACC/DR, Langley AFB, VA
(U) Program Management: SMC/CZ, Los Angeles AFB, CA

Point of Contact (U):

(U) Maj Chuck Kastenholz, SMC, Open Phone: (310) 363-6402.

Date Of Information (U):

(U) 18 May 1998





(U) Road Map Production Date: 12 July 1999