Space


GPS III Operational Control Segment (OCX)

The current GPS consists of three major segments. These are: a space segment (SS), a control segment (CS), and a user segment (US). GPS is a dual use, military and civil system whose primary mission is to provide Position, Navigation and Time (PNT) services. The Nuclear Detonation (NUDET) Detection System (NDS) is carried as a secondary payload.

Future additional payloads may also include the Distress Alerting Satellite System (DASS) and others. DASS relays search and rescue data and is planned as a component of the international Cospas-Sarsat search and rescue system.

The key capabilities for the future GPS system include high availability of military accuracy in a jammed environment, increased time transfer accuracy, increased position accuracy, higher system integrity, backward compatibility, survivability, L1 signal common with Galileo, and interoperability with the Global Information Grid.

The Control Segment (CS) provides command, control, and maintenance services to the space segment and supports both the PNT and the NDS missions. The current operational CS is also known as the "legacy Control Segment" and is composed of a primary Master Control Station (MCS), a Back-Up MCS (BMCS) located at the contractor's facility, six dedicated Monitor Stations and five dedicated Ground Antennas that are located at remote sites.

The CS that is currently in development consists of the following elements: an AEP-based Operational Control Segment (OCS), a Launch Early Orbit Anomaly and Disposal Operations (LADO) capability, a GPS System Simulator (GSS), an AEP-based Alternate Master Control Station (AMCS) and an Integrated Mission Operations Support Center (IMOSC). AEP versions 5.2/5.5 are currently under development and expected to go operational in CY06/08. LADO is expected to go operational in CY06.

The Navstar Global Positioning System (GPS) Joint Program Office (JPO) is considering alternative strategies for acquisition of the next generation GPS space and control segments. The new acquisition strategy under consideration will compete the next generation space and control segments separately. The overall systems integration (SI) function may be performed by one of the segments, by a stand-alone SI contract, or by the government. Under this strategy, the current control segment development will stop after delivery of Architecture Evolution Plan (AEP) Version 5.5 and be shifted to a new development referred to as GPS III Operational Control Segment (OCX).

OCX will be acquired in an evolutionary fashion that will incrementally deliver capabilities to the field and require growth and flexibility to meet military and civil needs for the next 30 years. Initially, OCX will focus on early fielding of control segment support for the GPS modernization signals (L2C, L5, and M-code) and the first increment of new space segment development, GPS Block IIIA.

Nominally, the OCX will provide all control segment support for GPS Block IIR, GPS Block IIR-M, GPS Block IIF and GPS Block III, and facilitate the addition of future satellite blocks with new capabilities (new signals, Navwar capabilities, additional payloads).

Alternative OCX acquisition strategies also require investigation. For instance, early OCX increments could be augmented by AEP to support command and control of the Block II satellites.

The OCX may be divided into subsystems supporting the following functions: Telemetry, Tracking, and Commanding (TT&C) that is common to all space vehicles (SVs), SV-specific TT&C, mission planning, and the navigation mission. The OCX will be expected to support Navigation Warfare (Navwar) Mission Planning and to have connectivity with a classified facility from which Navwar, Selective Availability/Anti-Spoofing Module (SAASM) and other sensitive capabilities can be planned and executed.

OCX capabilities may be incrementally fielded, but the OCX must evolve to support full GPS III capability. Notionally, the first OCX increment should: 1) expand monitoring from P(Y) only to all navigation signals; 2) provide for generation of the modernized navigation messages; 3) account for aviation safety certification requirements; 4) provide TT&C support for GPS IIIA; and 5) provide a level of automation for mission planning.

The purpose of the 18 February 2005 announcement was to assist the government in identifying interested potential offerors or teams capable of achieving the OCX program objectives with acceptable risks and costs. This announcement also seeks feedback on: 1) how best to develop and deliver the OCX control segment capability; 2) whether to split the OCX functions (TT&C, Navigation Mission, Mission Planning) into several separate acquisitions; 3) alternative operations and maintenance concepts using different mixes of government and contractor employees; and 4) how to best address system integration responsibilities.

Interested and potential offerors were requested to submit a response package that provides the following information: 1) experience and summary of capabilities in developing space segments and control segments including specific experience with certifications (system security/information assurance, net ready/interoperability, and aviation safety); 2) experience as a system integrator; 3) input on how to allocate the roles and responsibilities between potential space and control segment contractors; 4) input on how the system integrator's roles and responsibilities should be defined; 5) input on the advantages and disadvantages associated with further splitting and executing of the control segment functions (TT&C, Navigation Mission, and Mission Planning) under separate contracts and suggestions for how to split it; 6) interest in proposing on any or all of the control, or system integrator responsibilities if submitted under separate solicitations (to include the level of expertise the company would provide for each responsibility); 7) recommendation for the most effective (cost, schedule, performance, risk) transition path from the AEP control segment to full OCX capability; and 8) an estimated schedule to incrementally develop and deliver the OCX capabilities, in Gantt-chart format (timelines should be independent of program start date and reflect contractor's past ground segment development experiences -- reference programs and complexity).

Officials from the Space and Missile Systems Center's Global Positioning Systems Wing announced the award on 21 November 2007 of the Next Generation GPS Control Segment (OCX) contracts to Northrop Grumman Corporation Space & Mission Systems of Redondo Beach, Calif., and Raytheon Company Intelligence & Information Systems of Aurora, Colo. These two OCX contracts will each deliver prototypes and lead to a competitive selection of a single contractor in late FY09.

The two OCX contracts are planned to be 18 months in duration and worth $160 million each. These contract efforts will reduce the risks of developing OCX and will include a System Requirements Review, System Design Review, Modernized Capability Engineering Model and will support Key Decision Point B. At the KDP-B milestone, the Air Force will down-select to a single prime contractor to continue development of OCX.

OCX will replace the current Operational Control System, maintaining backwards compatibility with the Block IIR and IIR-M constellation and enabling new modernized capabilities onboard the Block IIR-M and IIF satellites. In addition, OCX will provide command and control (C2) of new capabilities associated with the new GPS III family of satellites.

The new capabilities provided by OCX will be the cornerstone for revolutionizing GPS C2 and mission capabilities. OCX will shift the focus of GPS operations from satellite C2, transforming the C2 to user-oriented, effects-based operations, enabling Air Force Space Command to greatly enhance GPS operational services to our nation's combat forces, civil partners and myriad of domestic and international users.

OCX will allow AFSPC to effectively and efficiently plan and control full spectrum precision position, navigation and timing information for all GPS user communities. OCX will achieve this vision by implementing an incremental development approach, based on an architectural foundation that allows the system to responsively and gracefully evolve to meet growing GPS mission requirements.



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