GLOBAL 

POSITIONING 

SYSTEM

Better Planning and 

Coordination Needed 

to Improve Prospects 

for Fielding 

Modernized Capability

Report to Congressional Committees

December 2017

GAO-18-74

United States Government Accountability Office
United States Government Accountability Office

Highlights of GAO-18-74, a report to 

congressional committees 

December 2017

GLOBAL POSITIONING SYSTEM

Better Planning and Coordination Needed to Improve 

Prospects for Fielding Modernized Capability

What GAO Found

The Department of Defense’s (DOD) acquisition of the next generation Global 

Positioning System (GPS) satellites, known as GPS III, faces a number of 

acquisition challenges, but these challenges do not threaten DOD's ability to 

continue operating the current GPS system, which DOD refers to as the

constellation, in the near term. Projections for how long the current constellation 

will be fully capable have increased by nearly 2 years to June 2021, affording 

some buffer to offset any additional satellite delays. While the first GPS III 

satellite has a known parts problem, six follow-on satellites—which do not—are 

currently scheduled to be launched by June 2021.

DOD is relying on a high-risk acquisition schedule to develop a new ground 

system, known as OCX, to control the broadcast of a modernized military GPS 

signal. OCX remains at risk for further delays and cost growth. To mitigate 

continuing delays to the new ground control system, the Air Force has begun a 

second new program—Military-code (M-code) Early Use—to deliver an interim,

limited broadcast encrypted GPS signal for military use by modifying the current 

ground system. GAO will continue to monitor OCX progress.

DOD has made some progress on initial testing of the receiver cards needed to 

utilize the M-code signal. However, additional development is necessary to make 

M-code work with over 700 weapon systems that require it. DOD has begun 

initial planning for some weapon systems, but more remains to be done to 

understand the cost and schedule needed to transition to M-code receivers. The 

preliminary estimate for integrating and testing a fraction of the weapon systems

that need the receiver cards is over $2.5 billion through fiscal year 2021 with only 

28 fully and 72 partially funded (see figure). The cost will increase by billions

when as yet unfunded weapon systems are included. 

Status of Weapon Systems That Have Determined the Cost Needed to Transition to M-code 

Receivers through Fiscal Year 2021, as of February 2017

The level of development and procurement effort beyond the initial receiver 

cards is significant and will require close coordination across DOD. After the Air 

Force develops initial cards, the breadth and complexity of this acquisition will 

multiply, as the offices responsible for upgrading hundreds of weapon systems 

begin their own individual efforts to further develop and test the cards. However, 

DOD does not have an organization assigned to collect test data, lessons 

learned, and design solutions so that common design solutions are employed to

avoid duplication of effort as multiple entities separately mature receiver cards.

DOD therefore risks paying to repeatedly find design solutions to solve common 

problems because each program office is likely to undertake its own 

uncoordinated development effort.

View GAO-18-74. For more information, 

contact Cristina Chaplain at (202) 512-4841 or 

chaplainc@gao.gov.

Why GAO Did This Study

GPS provides positioning, navigation, 

and timing data to civilian and military 

users who depend on this satellitebased system. Since 2000, DOD—led 

by the Air Force—has been working to 

modernize GPS and to keep the 

current system of satellites—known as 

the GPS constellation—operational,

although these efforts have

experienced cost and schedule growth.

The National Defense Authorization 

Act for Fiscal Year 2016 contained a 

provision that the Air Force provide 

reports to GAO on GPS acquisition 

programs and that GAO brief the 

congressional defense committees. 

GAO briefed the committees in 2016 

and 2017. This report summarizes and 

expands on information presented in 

those briefings. 

This report assesses the extent to 

which DOD faces acquisition 

challenges (1) sustaining the GPS 

constellation; (2) developing a new 

ground control system; and (3) 

developing and fielding modernized 

receivers. GAO analyzed GPS 

quarterly acquisition reports and data, 

acquisition strategies, software and 

test plans, and other documents, and 

interviewed DOD and contractor 

officials.

What GAO Recommends

DOD should assign responsibility to an 

organization to collect test data, 

lessons learned, and design solutions 

so they may be shared. DOD 

concurred with the recommendation. 
Page i GAO-18-74 GPS Modernization

Letter 1

Background 2

Acquisition Risks Persist on GPS III Satellites but Do Not 

Threaten Sustainment of the Constellation in the Short Term 15

Modernizing GPS Military Broadcast Challenged by High-Risk 

Development Schedules 23

Greater Coordination Needed to Prevent Duplication of Effort 

Developing and Fielding M-code Receivers 28

Conclusions 37

Recommendations for Executive Action 37

Agency Comments and Our Evaluation 38

Appendix I Objectives, Scope, and Methodology 40

Appendix II Comments from the Department of Defense 44

Appendix III GPS Modernization Cost Increases, Original Baseline vs. Current 

Estimate 46

Appendix IV GAO Contact and Staff Acknowledgments 47

Tables

Table 1: Current Global Positioning System Modernization 

Programs 5

Table 2: Modifications to Current Operational Control Segment 6

Table 3: Schedule Challenges in Modernized GPS Programs 7

Table 4: Forecasts for the Next Generation Operation Control 

System (OCX) Blocks 1 and 2 Delivery with Subsequent 

Operational Date, as of July 2017 28

Table 5: GPS Modernization Costs 46

Figures

Figure 1: GPS Operational System 4

Contents
Page ii GAO-18-74 GPS Modernization

Figure 2: Current Key Global Positioning System Modernization 

Points 8

Figure 3: Active and Future GPS Satellite Generations 11

Figure 4: MGUE Receiver Card 13

Figure 5: Selected Weapon Systems That Require Military Code 

Receiver Cards 14

Figure 6: Schedule to Modernize and Sustain the GPS Satellite 

Constellation 15

Figure 7: Global Positioning System (GPS) Challenges and 

Deliveries Needed to Launch the First GPS III Satellite 17

Figure 8: Path to Global Positioning System (GPS) Constellation 

Sustainment 21

Figure 9: Schedule to Achieve Limited and Full M-code Broadcast 23

Figure 10: Schedule for Fielding Military Code Receiver Cards 30

Figure 11: Status of Weapon Systems That Have Determined the 

Cost Needed to Transition to M-code Receivers through 

Fiscal Year 2021, as of February 2017 35
Page iii GAO-18-74 GPS Modernization

Abbreviations

COps Contingency Operations

DOD Department of Defense

DOT&E Director, Operational Test and Evaluation

GPS Global Positioning System

IBR integrated baseline review

JLTV Joint Light Tactical Vehicle

MCEU M-code Early Use

M-code military code

MGUE military GPS user equipment

OCS operational control system

OCX next generation operational control system

PNT positioning, navigation, and timing

SAASM Selective Availability/Anti-Spoofing Module

SMC Space and Missile System’s Center

USD AT&L Under Secretary of Defense for Acquisition, Technology, 

and Logistics

This is a work of the U.S. government and is not subject to copyright protection in the 

United States. The published product may be reproduced and distributed in its entirety 

without further permission from GAO. However, because this work may contain 

copyrighted images or other material, permission from the copyright holder may be 

necessary if you wish to reproduce this material separately.
Page 1 GAO-18-74 GPS Modernization

441 G St. N.W.

Washington, DC 20548

December 12, 2017

Congressional Committees

For more than two decades, the satellite-based Global Positioning 

System (GPS) has provided positioning, navigation, and timing (PNT) 

data to civilian and military users worldwide. Given its ubiquity throughout 

the world, failure, malfunction, or jamming of GPS can severely disrupt 

day-to-day civilian and military activities across the globe. The 

Department of Defense (DOD) maintains and operates GPS, which 

consists of three segments: orbiting satellites that continuously broadcast 

position and time data; a ground control system that operates the 

satellites and monitors and corrects signal data; and receivers used by 

civilians and the military in aircraft, ships, land vehicles, munitions, and 

hand-held units. Since 2000, the Air Force has led the multi-billion dollar 

effort to modernize GPS to sustain the satellite constellation—currently 

comprised of 31 satellites—by providing new civilian and military signals, 

enhancing cybersecurity, developing modernized military receivers, and 

countering known threats.

The National Defense Authorization Act for Fiscal Year 2016 contained a 

provision that the Air Force provide quarterly reports to GAO on the next 

generation GPS acquisition programs.1 The Act also contained a 

provision that GAO brief congressional defense committees on the first 

report, and at GAO’s discretion, on subsequent quarterly reports. The Air 

Force delivered the first quarterly report to us on April 22, 2016. We 

assessed the report, briefed congressional committees in June 2016, and 

issued a report on that briefing.2 During fiscal years 2016 and 2017, we 

briefed the congressional defense committees several additional times 

regarding the ongoing work. This report summarizes and expands on 

those briefings. This report assesses the extent to which DOD faces 

acquisition challenges (1) sustaining the GPS constellation; (2) 

developing a new ground system to control the broadcast of a 

modernized military GPS signal called military-code, or M-code; and (3) 

 1

Pub. L. No. 114-92, § 1621 (2015).

2

GAO, Global Positioning System: Observations on Quarterly Reports from the Air Force, 

GAO-17-162R (Washington, D.C.: Oct. 17, 2016). 

Letter
Page 2 GAO-18-74 GPS Modernization

developing and fielding modernized receiver cards across the 

department.3

To conduct our work, we reviewed Air Force GPS fiscal year 2016 and 

2017 quarterly acquisition reports, program acquisition baselines, 

integrated master schedules, acquisition strategies, software 

development plans, test plans, and other documents for five programs:

• GPS III,

• Next generation operational control system (OCX),

• Military GPS user equipment (MGUE),

• Contingency Operations (COps), and

• M-code Early Use (MCEU) programs.

We also interviewed officials from the GPS III, OCX, MGUE, COps, and 

MCEU programs; the prime contractors from all five programs; the 

Defense Contract Management Agency; and, where applicable, officials 

from DOD’s Office of Cost Assessment and Program Evaluation; the 

Office of the Director, Operational Test and Evaluation (DOT&E); Under 

Secretary of Defense for Acquisition, Technology, and Logistics (USD 

AT&L); Joint Staff / J-6 Space Branch; Air Force Space Command; and 

each of the military services involved with the planning and procurement 

of the MGUE program. Appendix I contains a more detailed description of 

our scope and methodology.

We conducted this performance audit from February 2016 to December 

2017 in accordance with generally accepted government auditing 

standards. Those standards require that we plan and perform the audit to 

obtain sufficient, appropriate evidence to provide a reasonable basis for 

our findings and conclusions based on our audit objectives. We believe 

that the evidence obtained provides a reasonable basis for our findings 

and conclusions based on our audit objectives.

Collectively, the ongoing GPS acquisition effort aims to (1) modernize and 

sustain the existing GPS capability and (2) enhance the current GPS 

 3

M-code is a stronger, encrypted, military-specific GPS signal designed to meet military 

PNT needs. 

Background
Page 3 GAO-18-74 GPS Modernization

system by adding an anti-jam, anti-spoof cybersecure M-code capability.4

Figure 1 below shows how GPS satellites, ground control, and user 

equipment—in the form of receiver cards embedded in systems—function 

together as an operational system.

 4

Anti-jam capability blocks signal interference (jamming). Anti-spoof capability protects 

users against false signals that adversaries may employ to imitate friendly GPS systems 

(spoofing).
Page 4 GAO-18-74 GPS Modernization

Figure 1: GPS Operational System

Modernizing and sustaining the current GPS broadcast capability requires 

launching new satellites to replace the existing satellites that are near the 

end of their intended operational life as well as developing a ground 

control system that can launch and control both existing and new 

satellites. Sustaining the current GPS broadcast capability is necessary to 

ensure the quality and availability of the existing broadcast signals for 
Page 5 GAO-18-74 GPS Modernization

civilian and military GPS receivers. The ongoing modernization of GPS 

began with three programs: (1) GPS III satellites; (2) OCX to control the 

satellites; and (3) MGUE increment 1 (which develops initial receiver test 

cards for military ships, ground vehicles, or aircraft).5 Table 1 describes 

these programs.

Table 1: Current Global Positioning System Modernization Programs

Program Description 

Space Segment

Global Positioning 

System

(GPS) III

GPS III satellites will supplement and eventually replace the constellation of GPS satellites now in orbit, 

sustaining current capabilities and providing new signals. The GPS constellation currently consists of multiple 

satellite generations. Previous generations of satellites have been transmitting the military code—or M-code—

signal for more than 11 years. GPS III satellites will provide a stronger M-code signal. Lockheed Martin was 

awarded the contract to build the first 10 GPS III satellites. The Air Force plans to competitively award satellites 

11 through 32 in fiscal year 2018.

Ground Control Segment

Next Generation 

Operational 

Control System

(OCX)

OCX will replace the current ground control system, known as the operational control segment (OCS). OCS lacks 

modern cybersecurity protections and cannot control–or enable–modernized features of the two latest 

generations of GPS satellites now in orbit, including M-code and some new civilian signals. Raytheon is the 

prime contractor. OCX is being developed in a series of blocks:

1. Block 0—will provide the launch and checkout system and supports initial testing of GPS III satellites. GPS 

III satellites cannot be launched without OCX block 0. It also provides most of the modern cybersecurity—a 

key advancement in securing the system.

2. Blocks 1 and 2—will provide command and control for previous generations of satellites and GPS III 

satellites, as well as monitoring and control for both current and modernized signals. Block 2 will provide the 

full M-code broadcast capability. The planned operational date for block 2 is January 2022.

User Segment

Military GPS User 

Equipment

(MGUE)

MGUE is developing the M-code capable receiver cards with enhanced positioning, navigation, and timing (PNT) 

capabilities and improved resistance to existing and emerging threats, such as jamming. The Air Force is 

developing MGUE in two increments:

1. Increment 1—will provide initial ground, maritime, and aviation security-certified receiver cards. It entered 

system development in January 2017 and is scheduled to conduct operational testing on four military 

service-nominated lead platforms by April 2021. Three contractors—L3 Technologies, Raytheon, and 

Rockwell Collins—are building initial receiver cards. The cards consist of hardware—the physical card 

itself—and software—the coding within the card—that must be developed, tested, and integrated.

2. Increment 2—will provide more compact receiver cards to be used when size, weight, and power must be 

minimized, such as on handheld receivers, space receivers, and precision munitions. The Air Force plans to 

deliver the acquisition strategy for increment 2 in March 2018. 

Source: GAO analysis of Department of Defense data. | GAO-18-74

 5

The MGUE increment 1 program is developing two receiver card types for (1) ground and 

(2) aviation/maritime applications on four military service-nominated “lead platforms,”

which serve as initial representatives for all platforms’ integration.
Page 6 GAO-18-74 GPS Modernization

Delays to OCX of more than 5 years led the Air Force to create two 

additional programs in 2016 and 2017 to modify the current GPS ground 

system to control GPS III satellites and provide a limited M-code 

broadcast. As a result, there are currently five total GPS modernization 

programs. Table 2 provides a description of the two new programs.

Table 2: Modifications to Current Operational Control Segment

Program Description

Contingency Operations (COps) COps will be a software modification to the existing operational control segment (OCS) 

started in 2016 to sustain the GPS constellation’s capabilities. COps is planned to enable 

operational control of GPS III satellites and the legacy signals they will broadcast, while 

OCS will continue to control GPS II satellites and their signals. COps is a bridge 

capability needed to fill in the gap created by OCX development delays. Lockheed Martin 

is the prime contractor for this work and also built and maintains OCS. 

M-code Early Use (MCEU) MCEU will be an additional software modification to OCS after COps is completed. It will 

provide some operational control of specific M-code broadcast signals, but will lack the 

cybersecurity of OCX, among other features. This is a bridge capability needed to fill in 

the gap created by the OCX development delays. Lockheed Martin is the prime 

contractor.

Source: GAO analysis of Department of Defense data. | GAO-18-74
Page 7 GAO-18-74 GPS Modernization

All of the original GPS modernization programs—GPS III, OCX, and 

MGUE—have experienced significant schedule growth during 

development. Table 3 outlines several schedule challenges in the 

modernized GPS programs.

Table 3: Schedule Challenges in Modernized GPS Programs

Program Challenges

Global Positioning 

System (GPS) III

Since the program’s original 2008 baseline, the first GPS III satellite’s planned launch date has been delayed by 

four years—from April 2014 to May 2018.

The Air Force and Lockheed Martin had repeated delays due to technical challenges with the navigation 

payload, resulting in a January 2016 cost and schedule rebaseline—or a recalculation by the program of new 

costs based on the new schedule.

Next Generation 

Operational Control 

System

(OCX)

Since the program’s original 2012 baseline:

OCX block 1 ready to transition to operations date has been delayed by 63 months—from October 2016 to 

January 2022.

The program’s cost increases prompted a cost and schedule rebaseline in 2015 and declaration of a critical 

Nunn-McCurdy unit cost breach in 2016.a

The Air Force and Raytheon have struggled with OCX development hurdles and unrealistic schedules with 

numerous root causes.

Military GPS User 

Equipment

(MGUE)

Increment 1

The Air Force began MGUE technology development in April 2012, but the cost and schedule baseline for the 

program was not approved until January 2017, over a year later than originally planned.

The Air Force and the MGUE contractors—L3 Technologies, Raytheon, and Rockwell Collins—have 

experienced varying degrees of schedule delays, in part, due to lack of software engineering rigor and 

technology readiness shortcomings. The Air Force pursued an accelerated MGUE development and eliminated a 

key milestone based on early optimistic assessments of technology maturity. However, independent reviews 

highlighted concerns over development maturity and the characterization of demonstration test results. 

Source: GAO analysis of Department of Defense data. | GAO-18-74

a

10 U.S.C. § 2433, commonly referred to as Nunn-McCurdy, requires the Department of Defense to 

notify Congress whenever a major defense acquisition program’s unit cost experiences cost growth 

that exceeds certain thresholds.

We found in 2015 that unrealistic cost and schedule estimates of the new 

ground control system and receiver card development delays could pose 

significant risks to sustaining the GPS constellation and delivering Mcode.6 At that time, we also made five recommendations so that DOD

would have the information necessary to make decisions on how best to 

improve GPS modernization and to mitigate risks to sustaining the GPS 

constellation. We made four OCX-specific recommendations targeted to 

identify underlying problems, establish a high confidence schedule and 

 6

GAO, GPS: Actions Needed to Address Ground System Development Problems and 

User Equipment Production Readiness, GAO-15-657 (Washington, D.C.: Sept. 9, 2015).
Page 8 GAO-18-74 GPS Modernization

cost estimate, and improve management and oversight. For MGUE, we 

recommended the Air Force add a critical design review before 

committing resources to allow the military services to fully assess the 

maturity of the MGUE design before committing test and procurement 

resources. DOD concurred with the four recommendations on OCX and 

partially concurred on the MGUE recommendation. Since 2015, our 

annual assessment of DOD weapon systems has shown that some of the 

original GPS programs have continued to face cost or schedule 

challenges, increasing the collective cost to modernize GPS by billions of 

dollars.7 Appendix III outlines the cost increases that have resulted.

According to our analysis, over the next decade or more, DOD plans to 

achieve three key GPS modernization points: (1) constellation 

sustainment, (2) M-code broadcast, and (3) M-code receivers fielded. 

Figure 2 shows the current sequencing of the three points and the 

intervals when they are planned to be achieved, if known.

Figure 2: Current Key Global Positioning System Modernization Points

Note: This depiction reflects the current plan after numerous delays, not the original planned dates for 

all capabilities.

Throughout this report, we will use figures based on this one to highlight 

the separately-managed programs DOD plans to synchronize to achieve 

each of the three identified modernization points. Some GPS capabilities 

 7

GAO, Defense Acquisitions: Assessment of Selected Weapon Programs, 

GAO-17-333SP (Washington, D.C.: Mar. 30, 2017); Defense Acquisitions: Assessment of 

Selected Weapon Programs, GAO-16-329SP (Washington, D.C.: Mar. 31, 2016). 

Key GPS Modernization 

Points
Page 9 GAO-18-74 GPS Modernization

require the delivery of more than one program, which must compete for 

limited resources, such as testing simulators. The Air Force coordinates 

the interdependent activities of the different programs and contractors in 

order to achieve each modernization point.

The satellites in the GPS constellation broadcast encrypted military 

signals and unencrypted civilian signals and move in six orbital planes 

approximately 12,500 miles above the earth. 

The GPS constellation availability performance standards commit the 

U.S. government to at least a 95 percent probability of maintaining a 

constellation of 24 operational GPS satellites to sustain the positioning 

services provided to both civilian and military GPS users. Therefore, while 

the minimum constellation consists of satellites occupying 24 orbital 

slots—4 slots in each of the six orbital planes—the constellation actually 

has 31 total satellites, generally with more than four in each plane to meet 

the 95 percent probability standard. These additional satellites are 

needed to provide uninterrupted availability in case a satellite fails. The 

constellation includes three generations of satellites with varying 

capabilities and design lives.

We found in 2010 and 2015 that GPS satellites have proven more reliable 

than expected, greatly exceeding their initially predicted life 

expectancies.8 Nevertheless, the Air Force must regularly replace 

satellites to meet the availability standard, since operational satellites 

have a finite lifespan. Excluding random failures, the operational life of a 

GPS satellite tends to be limited by the amount of power that its solar 

arrays can produce.9 This power level declines over time as the solar 

arrays degrade in the space environment until eventually they cannot 

produce enough power to maintain all of the satellite’s subsystems. 

Consequently, the Air Force monitors the performance of operational 

satellites in order to calculate when new satellites need to be ready to join 

the constellation.

 8

GAO, Global Positioning System: Challenges in Sustaining and Upgrading Capabilities

Persist, GAO-10-636 (Washington, D.C.: Sept. 15, 2010); GAO-15-657.

9

The solar array is the component of the satellite’s power subsystem upon which the solar 

cells are mounted. 

GPS Satellite 

Constellation

What is a Global Positioning System (GPS) 

satellite orbital plane and how many are 

there?

An orbital plane is an imaginary flat disc 

containing an Earth satellite’s orbit. One 

orbital plane, as is shown above, represents 

the trajectory a GPS satellite follows as it 

circles the Earth in space.

The GPS constellation has six orbital planes. 

Each contains at least 4 satellites that allow 

the constellation to meet the minimum 

requirement of 24 satellites.

Source: Department of Defense (data); Art explosion 

(images). | GAO-18-74
Page 10 GAO-18-74 GPS Modernization

The 10 GPS III satellites currently under contract and in production with 

Lockheed Martin will provide a range of performance enhancements over 

prior GPS satellite generations. The GPS III satellites were designed to 

provide a longer life than previous generations, greater signal accuracy, 

and improved signal integrity—meaning that the user has greater 

assurance that the broadcast signal is correct. When they are eventually 

controlled through the OCX ground control system, the satellites will also 

offer a stronger M-code signal strength than prior GPS satellite 

generations. They will also include an additional civilian signal known as 

L1C, which will permit interoperability with European, Japanese, and 

other global navigation satellite systems for civilian users. Figure 3 

describes the evolution of GPS satellite generations, including capabilities 

and life-span estimates.
Page 11 GAO-18-74 GPS Modernization

Figure 3: Active and Future GPS Satellite Generations

a

Design life is the period of time during which the satellite is expected to meet its mission objectives.

b

Mean life estimate figures reflect the average of the predicted lifespans for the satellites of a given 

GPS satellite generation.

The current GPS ground control segment, OCS, primarily consists of 

software deployed at a master control station at Schriever Air Force Base, 

Colorado, and at an alternate master control station at Vandenberg Air 

Force Base, California. The ground control software is supported by 6 Air 

Force and 11 National Geospatial-Intelligence Agency monitoring stations 

located around the globe along with four ground antennas that 

communicate with the moving satellites. Information from the monitoring 

stations is processed at the master control station to determine satellite 

clock and orbit status. As each of the three ground control segment 

Ground Control Segment
Page 12 GAO-18-74 GPS Modernization

programs—COps, MCEU, and OCX—is completed or partially completed, 

they will each introduce new capabilities, eventually culminating in the 

delivery of the full M-code broadcast planned for January 2022.

GPS receiver cards determine a user’s position and time by calculating 

the distance from four or more satellites using the navigation signals on 

the satellites to determine the card’s location. All warfighters currently 

acquire, train with, and use GPS receivers. Until MGUE receiver cards 

are developed and available for production, all DOD weapon systems that 

use GPS will continue to use the current GPS Selective Availability/AntiSpoofing Module (SAASM) receiver card or an older version.10 The Ike 

Skelton National Defense Authorization Act for Fiscal Year 2011 generally 

prohibits DOD from obligating or expending funds to procure GPS user 

equipment after fiscal year 2017 unless that equipment is capable of 

receiving M-code.11 Under certain circumstances this requirement may be 

waived or certain exceptions may apply. The increment 1 receiver cards 

range in size from approximately 2 inches by 3 inches for the ground card 

up to 6 inches by 6 inches for the aviation/maritime card. Figure 4 below 

shows an illustration of a MGUE receiver card.

 10For the purposes of this report, weapon systems include all DOD programs, platform 

systems, and subsystems that incorporate GPS. 

11Pub. L. No. 111-383, § 913 (the Act) provides that none of the funds authorized to be 

appropriated or otherwise made available under the Act or any other act for DOD may be 

obligated or expended to purchase GPS user equipment during the fiscal years after fiscal 

year 2017 unless the equipment is capable of receiving M-code. This limitation does not 

apply to purchases of passenger or commercial vehicles in which GPS equipment is 

installed. Additionally, the Secretary of Defense may waive this limitation under certain 

circumstances.

Receiver Cards
Page 13 GAO-18-74 GPS Modernization

Figure 4: MGUE Receiver Card

DOD has previously transitioned its weapon systems gradually from one 

generation of GPS receivers to the next. For example, some weapon 

systems have either upgraded or are still in the process of upgrading to 

the current SAASM receivers that were introduced in 2003, while others 

are still equipped with older cards. DOD anticipates that the length of time 

necessary to transition to MGUE will require users to operate with a mix 

of receiver cards. Hundreds of different types of weapon systems require 

GPS receiver cards, including ships, aircraft, ground vehicles, missiles, 

munitions, and hand-held devices, among others, across all military 

services. The Air Force funds the MGUE program, providing funding to 

the military services so they can acquire, integrate, and operationally test 

the receiver cards on four service-specific lead platforms. These 

platforms are intended to test the card in the military services’ ground, 

aviation, and maritime environments: (1) Army—Stryker ground combat 

vehicle; (2) Air Force—B-2 Spirit bomber; (3) Marine Corps—Joint Light 

Tactical Vehicle (JLTV); and (4) Navy—DDG-51 Arleigh Burke destroyer. 

Figure 5 depicts selected weapon systems that will need to install M-code 

capable receiver cards.
Page 14 GAO-18-74 GPS Modernization

Figure 5: Selected Weapon Systems That Require Military Code Receiver Cards
Page 15 GAO-18-74 GPS Modernization

The Air Force has made some progress toward ensuring continued 

constellation sustainment since our September 2015 report and should be 

able to sustain the current service because of the length of life of the 

current satellites. The current GPS constellation is now projected to meet 

its availability performance standard (in the absence of operational GPS 

III satellites) into June 2021—an increase of nearly 2 years over previous 

projections. This increase will give the Air Force more schedule buffer in 

the event of any additional delays to the GPS III satellite program. 

However, the Air Force still faces technical risks and schedule pressures 

in both the short and long term. In the short term, schedule compression 

with the first GPS III satellite is placing the satellite’s launch and operation 

at risk of further delays. In the long term, most of the satellites under 

contract will have been launched before operational testing is completed, 

limiting Air Force corrective options if issues are discovered. Figure 6 

shows the schedule for programs that need to be delivered to modernize 

and sustain the GPS satellite constellation.

Figure 6: Schedule to Modernize and Sustain the GPS Satellite Constellation

The Air Force has made progress since our last report in September 2015 

on the three programs (GPS III, OCX, and COps) needed to support GPS 

constellation sustainment, readying both ground control and the satellite 

for the first GPS III satellite’s launch, testing, and eventual operation. 

Raytheon delivered OCX block 0, the launch and checkout system for 

GPS III satellites, in September 2017. The Air Force took possession of 

Acquisition Risks 

Persist on GPS III 

Satellites but Do Not 

Threaten Sustainment 

of the Constellation in 

the Short Term

Progress: Programs 

Advancing to Support 

Constellation Sustainment 

Requirements
Page 16 GAO-18-74 GPS Modernization

OCX block 0 in October 2017 and will finally accept it at a later date after 

OCX block 1 is delivered.

12 Lockheed Martin completed the assembly, 

integration, and testing for the first GPS III satellite and in February 2017 

the Air Force accepted delivery in advance of its currently scheduled May 

2018 launch. As noted earlier, because of delays to OCX block 1, the Air 

Force initiated the COps program to ensure an interim means to control 

GPS III satellites. Without COps, no GPS III satellites can join the 

constellation to sustain it until OCX block 1 is operational in fiscal year 

2022. In September 2016, COps formally started development, 

establishing a cost baseline of approximately $162 million to meet an 

April 2019 delivery. The COps program began software coding in 

November 2016, after a design review established that the product design 

would meet the Air Force’s intended needs.

The Air Force continues to struggle with keeping multiple, highly 

compressed, interdependent, and concurrent program schedules 

synchronized in order to sustain and modernize the GPS constellation. 

Figure 7 shows some of the schedule challenges of the three programs 

needed for constellation sustainment and modernization. 

 12The Air Force took possession after inspection by signing a Certificate of Conformance.

Short-Term Challenges: 

Compressed and 

Concurrent Schedules, 

Component Issues with 

the First GPS III Satellite
Page 17 GAO-18-74 GPS Modernization

Figure 7: Global Positioning System (GPS) Challenges and Deliveries Needed to Launch the First GPS III Satellite 

Launching and operating the new GPS III satellite is a highly complex 

effort, since it requires synchronizing the development and testing 

schedules of OCX block 0, the first GPS III satellite, and the COps 

programs. For the Air Force to achieve its objective of making the first 

GPS III satellite operational by September 2019, numerous challenges 

(discussed below) must be addressed in the next 18 months on all three 

programs. If any of the three programs cannot resolve their challenges, 

the operation of the first GPS III satellite—and constellation 

sustainment—may be delayed.

OCX Block 0 and Pre-Launch Testing Schedules

With the goal of launching the first GPS III satellite in March 2018, the Air 

Force restructured its pre-launch integrated satellite and ground system 

testing in the summer of 2016, compressing the overall testing timeframe 
Page 18 GAO-18-74 GPS Modernization

from 52 weeks to 42 weeks.13 More OCX block 0 delays in early fiscal 

year 2017 complicated Air Force test plans, resulting in changes to the 

sequence and timing of events, the introduction of concurrency at various 

points throughout the testing, the use of incomplete software in early 

testing, and an increase in the likelihood of discovering issues later in prelaunch integrated testing. Air Force officials stated that some pre-launch 

testing revisions streamlined the overall test plan since the merging of 

certain test events allowed multiple objectives to be met by the same 

event. Raytheon delivered OCX block 0, the launch and checkout system 

for GPS III satellites, in September 2017. The Air Force took possession 

of OCX block 0 in October 2017 and will finally accept it at a later date 

after OCX block 1 is delivered. However, if issues requiring corrective 

work are discovered during subsequent integrated testing, the GPS III 

launch schedule may be delayed further since there is minimal schedule 

margin on OCX block 0 for correcting any additional problems that may 

be found.

First GPS III Satellite Capacitors

There are hundreds of capacitors—devices used to store energy and 

release it as electrical power—installed in each GPS III satellite. In 2016, 

while investigating capacitor failures, the Air Force discovered that the 

subcontractor, then known as Exelis (now Harris Corporation), had not 

conducted required qualification testing for the capacitor’s operational use 

in GPS III satellites. The Air Force conducted a review of the components 

over many months, delaying program progress while a subcontractor 

qualified the capacitor design as suitable for use on the GPS III satellite. 

However, the Air Force concluded that Harris Corporation failed to 

properly conduct a separate reliability test of the particular production lot 

from which the questionable capacitors originated. The Air Force directed 

the contractor to remove and replace the capacitors from that production 

lot from the second and third GPS III satellites. After weighing the 

technical data and cost and schedule considerations, the Air Force 

decided to accept the first satellite and launch it “as is” with the 

questionable capacitors installed.

 13Independent of OCX development, the Air Force moved the first GPS III target launch 

date from March to May 2018 in the spring of 2017. According to Air Force officials, the 

change was the result of a decision to launch the first GPS III satellite on a Falcon 9 

rocket, rather than a Delta IV. 
Page 19 GAO-18-74 GPS Modernization

Contingency Operations Schedule

The COps program is also pursuing a compressed and concurrent 

development and testing schedule to be operational as planned in 

September 2019. The COps acquisition strategy document acknowledges 

that the program’s timeline is aggressive. DOT&E has highlighted the 

compressed COps schedule as a risk, since the limited time between the 

developmental and operational testing permits little time for the evaluation 

of test results and resolution of any deficiencies found. The COps 

program has already begun drawing from its 60-day schedule margin, 

with a quarter of this margin used within the first 5 months after 

development started. According to Air Force officials, this margin use was 

the result of unplanned delays certifying a software coding lab. 

Additionally, the program schedule has concurrent development and 

testing, which in our previous work we have noted is often a high risk 

approach but is sometimes appropriate for software development.14

COps faces further schedule risk from its need for shared test assets, 

particularly the GPS III satellite simulator, a hardware- and softwarebased ground system that simulates GPS III function, which is also 

required by the GPS III and OCX programs. According to a DOT&E 

official, the OCX program receives priority over COps for the use of the 

GPS III satellite simulator, since the testing asset is heavily needed in the 

development of the ground control system. Because of the competing 

demands for this resource, which Air Force and DOT&E officials maintain 

requires lengthy and complex software reconfigurations to repurpose the 

simulator from one test event to the next, the Air Force is using a less 

realistic and purely software-based simulator for the testing of COps,

where possible.

Recent data show that the current satellites in the GPS constellation are 

expected to remain operational longer than previously projected, creating 

an additional, nearly 2-year schedule buffer before the first GPS III 

satellite needs to be operational to sustain the current GPS constellation 

capability. The Air Force projected that the first GPS III satellite needed to 

be operational by September 2019 based on 2014 satellite performance 

data. However, our analysis of the Air Force’s more recent May 2016 

GPS constellation performance data indicates that, in order to continue 

 14GAO, Missile Defense: Opportunity Exists to Strengthen Acquisitions by Reducing 

Concurrency, GAO-12-486 (Washington, D.C.: Apr. 20, 2012); GAO-16-329SP.

Short-Term Risk 

Mitigation: Nearly 2 Years 

of Schedule Buffer to 

When First GPS III 

Satellite Needed
Page 20 GAO-18-74 GPS Modernization

meeting the constellation availability performance standard without

interruption, the operational need for the first GPS satellite is now June 

2021. This projection incorporates updated Air Force data from the 

current satellites that take into account an increase in solar array 

longevity expected for IIR and IIR-M satellites, according to Air Force 

officials. The Air Force is likely to meet the constellation’s June 2021 

operational requirement because there are seven GPS III satellites 

planned to be launched by June 2021. Figure 8 shows the events leading 

to the launch and operation of the first GPS III satellite, achieving 

constellation sustainment once the first GPS III is operational, and 

subsequent GPS III launches that continue to support sustainment.
Page 21 GAO-18-74 GPS Modernization

Figure 8: Path to Global Positioning System (GPS) Constellation Sustainment

a

Pre-launch testing entails operational-like testing of the OCX block 0 launch and checkout system 

and the GPS III satellite to demonstrate launch and satellite checkout capabilities prior to the May 

2018 launch.

b

On-orbit testing is the post-launch checkout testing of the GPS III satellite with OCX block 0 to 

provide early verification of some satellite subsystem functions.

c

After completion of on-orbit testing, the GPS III satellite will orbit in a non-operational state until 

operational testing begins.

d

Operational testing entails the testing of both the Contingency Operations (COps) ground control and 

the GPS III satellite to support an operational acceptance decision for both systems for nonmodernized navigation signal capabilities.

The nearly 2-year buffer between planned operation and actual need for 

the first GPS III satellite permits the Air Force additional time to resolve 

any development issues. Because of this additional 2-year schedule 

buffer, we are not making a recommendation at this time to address the 

short term challenges we have identified but will continue to assess the 

progress of each of the programs and risks to constellation sustainment in 

our future work.
Page 22 GAO-18-74 GPS Modernization

The Air Force risks additional cost increases, schedule delays, and 

performance shortfalls because operational testing to confirm that GPS III 

satellites work as intended with OCX blocks 1 and 2 will not be completed 

until after the planned launch of 8 of the 10 GPS III satellites currently 

under contract. Due to delays to the OCX final delivery, the new ground 

control system will not be completed in time to control the GPS III 

satellites for the first few years they are in orbit (approximately 3.5 years). 

Consequently, GPS III operational testing will now occur in three 

phases—

1. in late fiscal year 2019 to confirm the satellites can perform similarly to 

the existing GPS satellites with COps;

2. in fiscal year 2020 to confirm the GPS III satellites can perform some 

of the new M-code capabilities with MCEU; and

3. in fiscal year 2022 to confirm the GPS III satellites can perform all of 

the new M-code capabilities with OCX blocks 1 and 2.

The first GPS III satellite is projected to complete operational testing of 

legacy signal capabilities in September 2019. By that point, the Air Force 

plans to have launched 3 of the 10 GPS III satellites, the fourth satellite is 

expected to be delivered, and major integration work will be underway on 

satellites 5 through 8. Therefore, if satellite shortcomings are discovered 

during any phase of the operational testing, the Air Force will be limited to 

addressing such issues through software corrections to satellites already 

on orbit. If any of the three phases of operational testing reveals issues, 

the Air Force may face the need for potentially costly contract 

modifications and delivery delays for satellites not yet launched. To offset 

this risk, the Air Force has obtained performance knowledge of GPS III 

satellites through ground testing of the first satellite, and findings from this 

testing have driven modifications to all ten satellites. Because of the rigor 

of the ground testing of the first satellite, Air Force officials maintain that 

the knowledge that might be obtained through on-orbit operational testing 

of the first GPS satellite would be minimal. However, a DOT&E official 

said that ground testing is limited to assessing system responses that are 

induced through the testing process and therefore may omit phenomena

that might be experienced in actual system operation on orbit. We will 

continue to track the progress of operational testing in our future work.

Long-Term Challenge: 

Most GPS III Satellites 

Under Contract Will Have 

Launched before 

Operational Testing 

Confirms Satellite 

Performance
Page 23 GAO-18-74 GPS Modernization

DOD has established high-risk schedules for modernizing the GPS 

broadcast, or M-code signal, produced by GPS satellites. These risks are 

manifest in different ways. In the near term, the Air Force plans to provide 

a limited M-code broadcast—one that does not have all of the capabilities 

of OCX—in the MCEU program in fiscal year 2020. However, the MCEU 

schedule is high risk for its dependency on the timely completion of the 

COps program, for its aggressive schedule, and because of competition 

for limited test resources. Further, the full M-code broadcast capability, 

planned for fiscal year 2022, is at high risk of additional delays because 

(1) it is dependent on unproven efficiencies in software coding, (2) the 

program has not yet completed a baseline review, which may identify 

additional time needed to complete currently contracted work, and (3) 

there are known changes to the program that must be done that are not 

included in the proposed schedule.

As noted above, the Air Force’s plans for delivering the M-code broadcast 

involve two separate high-risk programs—MCEU and OCX blocks 1 and 

2—delivered at separate times to make an operational M-code signal 

available to the warfighter. Figure 9 highlights the current forecasted 

operational schedules to deliver limited M-code broadcast capabilities 

with MCEU and full M-code broadcast with OCX.

Figure 9: Schedule to Achieve Limited and Full M-code Broadcast

Modernizing GPS 

Military Broadcast 

Challenged by HighRisk Development 

Schedules

High-Risk Programs 

Underlie Strategy to 

Deliver M-code Broadcast 

Capability
Page 24 GAO-18-74 GPS Modernization

MCEU

The MCEU program, created because of multiple delays to OCX and to 

partially address that program’s remaining schedule risk, is itself a highrisk program that is dependent on the timely development of COps. 

Estimated to cost approximately $120 million, MCEU formally entered the 

acquisition process in January 2017 as a software-specific program to 

modify OCS. To develop MCEU, Lockheed Martin officials stated they will 

leverage personnel with expertise maintaining and upgrading OCS as 

well as utilize the staff working on COps. With a planned December 2019 

delivery for testing and a September 2020 target to begin operations, the 

MCEU program faces several schedule risks. The Air Force’s proposed 

plan anticipates a compressed software development effort, which the Air 

Force describes as aggressive. The Air Force has also identified potential 

risks to the MCEU schedule from competing demands by GPS III, OCX, 

COps, and MCEU for shared test resources. Air Force officials specifically 

noted competing demands for the GPS III simulator test resource. If 

development or testing issues arise in these other programs, those issues 

could delay the availability of the satellite simulator and thereby disrupt 

the planned MCEU development effort. According to program officials, the 

Air Force is working to mitigate this threat to the MCEU program through 

the use of a software-based simulator, when possible. Additionally, 

MCEU software development work is dependent on the timely conclusion 

of the COps effort—which, as previously mentioned, itself has an 

aggressive schedule and faces competition for a limited test resource. Air 

Force program officials have said that some Lockheed Martin staff 

planned to support MCEU will need to transfer from the COps effort. 

However, after reviewing the staffing plans at the MCEU contractor 

kickoff, Air Force officials said this is no longer viewed as a significant 

risk.

OCX blocks 1 and 2

Raytheon has made some progress starting coding for OCX block 1 and 

taken the first steps toward implementing and demonstrating initial 

software development efficiencies that may benefit development for OCX 

blocks 1 and 2. The software efficiencies are built up in seven phases and 

need to be completed before the development process reaches each of 

the phases to take full advantage of the efficiencies they will create. Once 

ready, the efficiencies are inserted at different points in the software 

development schedule. For example, as of August 2017, the first of seven 

phases implementing the software development improvements was 

nearly complete, while the second phase was approximately two-thirds 
Page 25 GAO-18-74 GPS Modernization

complete. Both are needed in place for insertion when the next phase of 

coding begins.

Further, the Air Force proposed a new rebaselined schedule in June 2017 

as the final step to getting the program back on track after declaring a 

critical Nunn-McCurdy unit cost breach in 2016 when the program 

exceeded the original baseline by more than 50 percent. A NunnMcCurdy unit cost breach classified as critical is the most serious type of 

breach and requires a program to be terminated unless the Secretary of 

Defense submits a written certification to Congress that, among other 

things, the new estimate of the program’s cost is reasonable and takes 

other actions, including restructuring the program. In October 2016, DOD 

recertified the program, with a 24-month schedule extension. Under this 

newer proposed schedule Raytheon forecasts delivering blocks 1 and 2 in 

December 2020 with 6 months of extra schedule—a 30-month schedule 

extension—to account for unknown technical issues before OCX blocks 1 

and 2 are due to the Air Force in June 2021. The Air Force projects 

operating OCX in fiscal year 2022 after completing 7 months of 

operational testing post-delivery.

Three factors place delivery of OCX blocks 1 and 2 in June 2021 at high 

risk for additional schedule delays and cost increases:

• First, the newly proposed June 2017 rebaselined schedule assumes 

significant improvements in the speed of software coding and testing 

that have not yet been proven, but will be introduced at various 

periods as software development proceeds. Whether Raytheon can 

achieve the majority of these efficiencies will not be known until the 

end of fiscal year 2018. However, the Defense Contract Management 

Agency, which independently oversees Raytheon’s work developing 

OCX, noted in July 2017 a number of risks to the schedule, including 

that some initial assumed efficiencies had not been demonstrated. 

Specifically, they noted for initial coding on block 1 that Raytheon had 

achieved only 60 percent of the software integration maturity planned 

to that point in time in conjunction with greater numbers of software 

deficiencies that will require more time than planned to resolve.

• Second, the proposed rebaseline schedule has not yet undergone an 

integrated baseline review (IBR) to verify all of the work that needs to 

be done is incorporated into that schedule. The IBR is a best practice 

required by the Office of Management and Budget on programs with 
Page 26 GAO-18-74 GPS Modernization

earned value management.15 An IBR ensures a mutual understanding 

between the government and the contractor of the technical scope, 

schedule, and resources needed to complete the work. We have 

found that too often, programs overrun costs and schedule because 

estimates fail to account for the full technical definition, unexpected 

changes, and risks.16 According to prior plans, the IBR would have 

taken place in early 2017, but it has been delayed multiple times for a 

number of reasons. A significant and recurring root cause of delays on 

the OCX program has been a lack of mutual understanding of the 

work between the Air Force and Raytheon.

The IBR start was scheduled for November 2017 with completion in 

February 2018. Once conducted, the review may identify additional 

work not in the proposed schedule that needs to be completed before 

delivery. For example, Raytheon is conducting a review of hardware 

and software obsolescence. If significant additional obsolescence 

issues are found that need to be resolved before OCX blocks 1 and 2 

are delivered, the projected delivery date may need to be delayed 

further at additional cost.

• Third, the OCX contract will likely be modified because the Air Force 

needs to incorporate into its contract with Raytheon a number of 

changes that are not currently a part of the proposed schedule. 

According to Air Force and contractor officials, negotiations are under 

way to determine which of these changes will be incorporated before 

OCX blocks 1 and 2 are delivered and which may be added after 

delivery. Air Force officials said that the incorporation of changes 

should be completed by February 2018.

Schedule risk assessments for OCX blocks 1 and 2 delivery vary, making 

it unclear when the full M-code broadcast will finally be operational. 

Government assessments of Raytheon’s performance continue to 

 15Earned value management is a project management tool that integrates the technical 

scope of work with schedule and cost elements for investment planning and control. It 

compares the value of work accomplished in a given period with the value of the work 

expected in that period. Differences in expectations are measured in both cost and 

schedule variances. The Office of Management and Budget requires agencies to use 

earned value management in their performance-based management systems for major 

acquisitions with developmental effort. Office of Management and Budget, Capital 

Programming Guide v. 3.0, Supplement to Office of Management and Budget Circular No. 

A-11, Preparation, Submission, and Execution of the Budget, para. I.5.5.4 & I.5.5.5 (July 

2017).

16GAO, Cost Estimating and Assessment Guide: Best Practices for Developing and 

Managing Capital Program Costs, GAO-09-3SP (Washington, D.C.: Mar. 2009). 
Page 27 GAO-18-74 GPS Modernization

indicate more schedule delays are likely. Table 4 shows the varying 

assessments of potential schedule delays by the Defense Contract 

Management Agency and the Air Force to the proposed June 2021 

delivery date and the subsequent operational date that occurs 7 months 

later.
Page 28 GAO-18-74 GPS Modernization

Table 4: Forecasts for the Next Generation Operation Control System (OCX) Blocks 1 and 2 Delivery with Subsequent 

Operational Date, as of July 2017

Forecaster Schedule risk to current 

delivery of June 2021

Forecast delivery with 

schedule risk included

Operational

datea

Defense Contract Management 

Agency

14 months August 2022 March 2023

Air Force 6-7 months January/February 2022 August/September 2022

Source: GAO analysis of Department of Defense data. | GAO-18-74

a

Air Force estimates that after delivery from Raytheon, the government will need an additional 7 

months to test and prepare OCX to be operational.

In 2015, we made four recommendations to the Secretary of Defense, 

one of which was to use outside experts to help identify all underlying 

problems on OCX and develop high confidence cost and schedule 

estimates, among others, in order to provide information necessary to 

make decisions and improve the likelihood of success.17 To date, none of 

these recommendations have been fully implemented but DOD has taken 

steps to address some of them. Further, because the Air Force has 

undertaken the COps and MCEU programs to provide interim capabilities 

to mitigate OCX delays for the full broadcast capability, we are not 

making additional recommendations at this time but will continue to 

monitor progress and risks to the acquisition of OCX.

While technology development for the M-code receiver cards is 

underway, DOD has developed preliminary—but incomplete—plans to 

fully develop and field M-code receiver cards across the more than 700 

weapon systems that will need to make the transition from the current 

technology. DOD has prepared initial cost and schedule estimates for 

department-wide fielding for a fraction of these weapon systems. While 

the full cost remains unknown, it is likely to be many billions of dollars 

greater than the $2.5 billion identified through fiscal year 2021 because 

there is significant work remaining to verify the initial cards work as 

planned and to develop them further after the MGUE increment 1 

program ends. Without greater coordination of integration test results, 

lessons learned, and design solutions DOD is at risk of duplicated 

development work as multiple weapon system programs separately 

 17GAO-15-657.

Greater Coordination 

Needed to Prevent 

Duplication of Effort 

Developing and 

Fielding M-code 

Receivers
Page 29 GAO-18-74 GPS Modernization

mature and field similar technologies on their own. Further, with the full 

M-code broadcast available in fiscal year 2022, a gap—the extent of 

which is unknown—between operationally broadcasting and receiving Mcode exists. Figure 10 highlights the gap between the time the M-code 

signal will be operational and the undefined time M-code can be used by 

the military services.
Page 30 GAO-18-74 GPS Modernization

Figure 10: Schedule for Fielding Military Code Receiver Cards

The Air Force program to develop initial M-code receiver test cards has 

made progress by establishing an acquisition strategy for this effort and

maturing receiver test cards. In January 2017, DOD approved the MGUE 

increment 1 program to formally begin development, and it defined the 

criteria to end the program as (1) verifying technical requirements on all 

types of final receiver test cards; (2) certifying readiness for operational 

testing by the Air Force Program Executive Officer; (3) completing 

operational testing for the four lead platforms for, at a minimum, at least 

the first card available; and (4) completing manufacturing readiness 

assessments for all three contractors.

Within the MGUE increment 1 program, contractors are making progress 

toward delivering final hardware test cards and incremental software 

capabilities. For example, one contractor has achieved its initial security 

certification from the Air Force, which is a key step toward making the 

MGUE increment 1 receiver test card available for continued 

development and eventual procurement. Further, the MGUE increment 1 

program is also conducting risk reduction testing in preparation for formal 

developmental verification testing, an important step that ensures the 

receiver cards meet technical requirements. Programs throughout DOD 

DOD Has Made Some 

Progress in Developing 

Technology for New Mcode Receiver Cards
Page 31 GAO-18-74 GPS Modernization

can make risk-based decisions to develop and test the receiver test cards 

after technical verification of the card’s hardware and software. According 

to MGUE program officials, this is significant because it allows non-lead 

platforms to obtain and work with the cards sooner than the end date of 

operational testing on lead platforms.

Although the Air Force has made progress in maturing receiver test 

cards, significant development work remains to reach the point where the 

cards can ultimately be fielded on over 700 different weapon systems. For 

example, for MGUE increment 1, the Air Force must define additional 

technical requirements in order for the M-code receiver cards to be 

compatible and communicate with existing weapon systems. The Air 

Force will also need to conduct operational tests for each of the lead 

platforms—the Stryker ground combat vehicle; B-2 Spirit bomber; JLTV; 

and DDG-51 Arleigh Burke destroyer—before the full M-code signal is 

available with OCX. Because these tests will instead be conducted with 

the limited signal provided by MCEU, DOD risks discovering issues 

several years later once full operational testing is conducted. Further, 

according to military service officials and assessments by DOT&E, this 

operational testing will only be minimally applicable to other weapon 

systems because those other weapon systems have different operational 

requirements and integration challenges than the four lead platforms. As 

a result, additional development and testing will be necessary on an 

undetermined number of the remaining weapon systems to ensure the 

receiver cards address each system’s unique interfaces and 

requirements. In 2018, DOD will also formally begin development for 

MGUE increment 2. Increment 2 will provide more compact receiver 

cards to be used when size, weight, and power must be minimized, such 

as on handheld receivers, space receivers, and munitions where 

increment 1 receiver cards are too large to work.

The military services are working to mitigate some of these development 

challenges. For example, Army officials told us they do not plan to field 

MGUE receiver cards on its lead platform, the Stryker, due to ongoing 

gaps in technical requirements. In addition, there is not a lead platform to 

demonstrate increment 1 on munitions since munition requirements were 

planned to be addressed in increment 2. However, to address its needs, 

the Army has initiated efforts to modify the MGUE increment 1 receiver 

card for some munitions that would otherwise need to wait for MGUE 

increment 2 technologies. Individual munition program offices within other 

military services have begun to do so as well. According to military 

service officials from the Army, Navy, and Marine Corps, it is essential 

Significant Development 

Work Remains to 

Eventually Field M-code 

Receiver Cards
Page 32 GAO-18-74 GPS Modernization

that user needs are met by increment 2, or they will have to conduct 

additional development and testing. The Army previously identified gaps 

in increment 1 that the Air Force has either addressed in increment 1, has 

deferred to increment 2, or will need to be addressed outside of the 

MGUE increment 1 and 2 programs. Army and Navy officials also stated 

that they were concerned that any disagreements in requirements for 

increment 2 could lead to further fielding delays.

Finally, the transition from existing GPS receiver cards to M-code receiver 

cards is likely to take many years. We recently reported that transitioning 

all DOD platforms to the next generation of receiver cards will likely take 

more than a decade.18 A lengthy transition has happened before, as 

previous efforts to modernize GPS to the current receiver cards, begun in 

2003, are still underway and the older receiver cards are still being used. 

As a result, DOD anticipates that warfighters will have to operate with a 

mix of older and newer receiver cards.

DOD has begun collecting preliminary information on M-code 

requirements for individual weapon systems. In December 2016, the USD 

AT&L directed the military services, the Missile Defense Agency (MDA), 

and Special Operations Command (SOCOM) to submit implementation 

plans with M-code investment priorities across weapon systems and 

munitions, including projected costs and schedules.19 According to DOD, 

these M-code implementation plans are intended to provide DOD with a 

management and oversight tool for the fielding effort. In February 2017, 

each organization submitted its own implementation plan to USD AT&L. 

 18GAO, Space Acquisitions: DOD Continues to Face Challenges of Delayed Delivery of 

Critical Space Capabilities and Fragmented Leadership, GAO-17-619T (Washington, 

D.C.: May 17, 2017).

19The National Defense Authorization Act for Fiscal Year 2017 eliminated the position of 

USD AT&L effective February 1, 2018. The position will be divided into the Under 

Secretary of Defense for Research and Engineering and the Under Secretary for Defense 

for Acquisition and Sustainment. Pub. L. No. 114-328, § 901(a) and (b) (2016) (codified at 

10 U.S.C. §§ 133a and 133b).

DOD Has Begun Cost and 

Schedule Planning; Full 

Cost Is Unknown but 

Likely to be Many Billions 

of Dollars
Page 33 GAO-18-74 GPS Modernization

These plans were then briefed to the PNT Executive Management Board

and PNT Oversight Council in February and March, respectively.

20

However, these implementation plans are preliminary and based on 

assumptions about the Air Force’s ability to achieve MGUE increment 1 

and 2 technical requirements, the timeline required to do so, and the 

amount of development and test work that will remain for the receiver 

cards to be ready for production and fielding after the programs end. 

Since the MGUE increment 2 program has not started development, it 

has not yet finalized requirements. Once approved, the increment 2 

program office will produce an acquisition strategy, schedule, and cost 

estimate. However, after the MGUE increment 2 program ends there is no 

detailed plan for completing development, testing, and fielding of M-code 

receiver cards for weapon systems across the department.

DOD has preliminary cost and schedule estimates for some weapon 

programs, but lacks a total cost at this point because the department 

does not include all efforts initiated by programs to meet specific needs, 

including those outside the MGUE increment 1 and 2 programs. The

initial M-code implementation plans responded to what was requested but 

do not individually identify what the total cost will be for each organization 

to develop and field M-code receiver cards, so a total cost can be 

determined across DOD. Because USD AT&L required that the 

implementation plans include funding and schedule estimates for 2 to 3 

years while directing that plans be resubmitted, at a minimum, every 2 

years, weapon systems that will need M-code but were not considered an 

immediate priority were not included in the initial submissions. In addition, 

the military services, MDA, and SOCOM provided only initial cost 

estimates.21 According to military service officials, these estimates were 

based on the current MGUE increment 1 program schedule and technical 

development and include risk-based decisions to partially fund specific 

 20The PNT Executive Management Board is chaired by the DOD Chief Information Officer 

and oversees the governance process in support of the PNT Oversight Council, including 

developing topics and recommendations for PNT Oversight Council actions. The PNT 

Oversight Council is co-chaired by USD AT&L and the Vice Chairman Joint Staff. The 

Council serves as the principal unified and integrated DOD governance body that ensures 

the DOD PNT Enterprise functions meet national objectives, is consistent with national 

policy and guidance, and that the mutually supporting systems continue to evolve to 

address emerging threats.

21When we refer to “funded” or “partially funded” programs, we mean programs which 

DOD has planned—in full or in part—to fund in DOD’s future years budget projections 

through fiscal year 2021, as reflected in the implementation plans.
Page 34 GAO-18-74 GPS Modernization

programs until the MGUE increment 1 program matures. According to a

USD AT&L official, the plans would both facilitate M-code implementation 

planning for the department and inform the issuance of waivers. 22 The 

official stated that as the acquisition programs critical to providing M-code 

capability mature, future implementations plans should provide more 

comprehensive estimates of cost and schedule to achieve M-code 

implementation for the department.

Our analysis of the M-code receiver card implementation plans found that 

initial funding estimates indicate a cost of over $2.5 billion to integrate and 

procure M-code receiver cards on only a small number of weapon 

systems out of the hundreds of types that need M-code receiver cards.

The full cost will be much larger—likely many billions of dollars because 

the majority of the weapon systems that need M-code receiver cards are 

not funded yet or are only partially funded, according to the M-code 

implementation plans. Specifically, the military services, MDA, and 

SOCOM identified 716 types of weapon systems in their February 2017 

implementation plans that require almost a million M-code receiver cards. 

For example, the JLTV fleet—which provides protection for passengers 

against current and future battlefield threats for multiple military 

services—is one type of weapon system that will eventually need almost 

25,000 receiver cards. Of the 716 types of weapon systems that will need 

M-code receiver cards, only 28—or less than 4 percent—are fully funded 

through fiscal year 2021. The remainder have either partially funded Mcode development and integration efforts (72 weapon systems), or do not 

yet have funding planned (616 weapon systems). Additionally, the 

preliminary estimates to develop and procure M-code receivers on 

selected weapon systems do not all include funding beyond fiscal year 

2021 that will be needed for further development, integration, and 

procurement. This means that DOD and Congress do not have visibility 

into how much additional funding could be needed to fully fund the 

remaining 96 percent of all weapon systems that need M-code receivers. 

Figure 11 shows the M-code development and integration efforts that are 

funded, partially funded, or unfunded through fiscal year 2021 across 

DOD weapon systems that will need M-code receiver cards.

 22Pub. L. No. 111-383, § 913 (the Act) provides that none of the funds authorized to be 

appropriated or otherwise made available under the Act or any other act for DOD may be 

obligated or expended to purchase GPS user equipment during the fiscal years after fiscal 

year 2017 unless the equipment is capable of receiving M-code. This limitation does not 

apply to purchases of passenger or commercial vehicles in which GPS equipment is 

installed. Additionally, the Secretary of Defense may waive this limitation under certain 

circumstances.
Page 35 GAO-18-74 GPS Modernization

Figure 11: Status of Weapon Systems That Have Determined the Cost Needed to 

Transition to M-code Receivers through Fiscal Year 2021, as of February 2017

Note: Weapon systems include all Department of Defense programs, platform systems, and 

subsystems that incorporate the Global Positioning System.

Because the implementation plans are a first step toward providing DOD 

leadership insight on this large set of acquisitions and they will be 

updated at least every 2 years by the different organizations within DOD, 

we are not making a recommendation at this time. However, we will 

continue to monitor DOD’s cost and schedule planning.

The level of development and procurement effort beyond MGUE 

increments 1 and 2 is significant and will require close coordination 

among the military services, MDA, and SOCOM. While Joint Staff officials 

stated that the DOD Chief Information Officer is working with the military 

services and Joint Staff to produce a user equipment roadmap to help 

guide that coordination, they said that these efforts are not yet complete. 

DOD has designated the Air Force to lead initial development of both 

larger and smaller test cards that other organizations will need to develop 

further to meet their individual needs. After the Air Force develops initial 

cards for both sizes, the breadth and complexity of this acquisition will 

multiply, as the offices responsible for upgrading hundreds of weapon 

systems begin their own individual efforts to further develop and test the 

cards so they work for the unique needs of their specific system. While 

some common solutions are being developed, Air Force officials said the 

military services and individual weapon systems will have the freedom to 

go to the contractors and begin their own development efforts.

DOD Risks Duplication of 

Effort Integrating and 

Testing M-code Receiver 

Cards
Page 36 GAO-18-74 GPS Modernization

DOD does not have a developed plan in place to help ensure that 

common design solutions are employed and that DOD avoids duplication 

of effort as multiple entities separately mature receiver cards. We 

previously found that duplication occurs when two or more agencies or 

programs are engaged in the same activities.23 In this case, because the 

individual organizations and program offices are likely to be pursuing 

individual and uncoordinated receiver card programs at different times 

with different contractors, DOD is at risk for significant duplication of 

effort. We previously found that establishing formal mechanisms for 

coordination and information sharing across DOD programs reduces the 

risk of gaps and results in more efficient and more effective use of 

resources.24 Internal control standards also state that establishing clear 

responsibilities and roles in achieving objectives is key for effective 

management.25 Further, DOD previously reported clear leadership 

ensures that programs and stakeholders are aligned with common 

goals.26

According to MGUE program officials, the MGUE increment 1 program is 

already capturing all issues observed in receiver test card risk reduction 

testing and sharing this information through a joint reporting system. 

However, while non-lead platforms may also report deficiencies in this 

system, there is no requirement that they do so, nor is there an entity 

responsible for ensuring data from testing, design, and development is 

shared between programs. We previously found that the absence of a 

formal process for coordination results in the potential for duplication, 

overlap, and fragmentation.27 DOD therefore risks paying to repeatedly 

find design solutions to solve common problems because each program 

office is likely to undertake its own uncoordinated development effort. 

Some duplicated effort may already be occurring. Air Force officials have 

expressed concern that work is already being duplicated across the 

military services in developing embedded GPS systems to be integrated 

 23GAO, 2017 Annual Report: Additional Opportunities to Reduce Fragmentation, Overlap, 

and Duplication and Achieve Other Financial Benefits, GAO-17-491SP, (Washington, 

D.C.: Apr. 26, 2017).

24GAO-17-491SP.

25GAO, Standards for Internal Control in the Federal Government, GAO-14-704G, 

(Washington, D.C.: Sept. 2014).

26Defense Science Board, Creating a DOD Strategic Acquisition Platform, April 2009.

27GAO-17-491SP.
Page 37 GAO-18-74 GPS Modernization

into aircraft. According to multiple DOT&E assessments, the absence of a 

plan across the wide variety of intended interfaces leaves significant risk 

in integrating the receiver cards, and therefore fielding cost and schedule 

risk for DOD.

GPS is a national asset for civilians and the military service members who 

depend upon it each day. Any disruption to the system would have severe 

economic and military consequences. In keeping the system sustained 

and modernizing it with additional capabilities, DOD has spent billions of 

dollars more than planned developing five interdependent GPS programs. 

Developing these technologies is complex work with the collective effort 

already years behind initial estimates to provide the warfighter with a 

means to counter known threats, such as jamming, to the current system. 

It will be many years before M-code receiver cards are fielded at a cost 

that remains unknown but that will be substantially higher than the 

estimated $2.5 billion already identified through fiscal year 2021. In the 

short term, it is unclear when there will be a receiver card ready for 

production after the end of operational testing, and in the long term DOD 

risks wasting resources duplicating development efforts on weapon 

systems with similar requirements. Without better coordination of this 

effort, DOD risks unnecessary cost increases and schedule delays 

because there is no established process or place for collecting and 

sharing development and integration practices and solutions between 

programs.

We are making the following recommendation to DOD:

The Secretary of Defense should ensure that the Under Secretary of 

Defense for Acquisition, Technology, and Logistics, as part of M-code 

receiver card acquisition planning, assign an organization with 

responsibility for systematically collecting integration test data, lessons 

learned, and design solutions and making them available to all programs 

expected to integrate M-code receiver cards.

(Recommendation 1)

Conclusions

Recommendations for 

Executive Action
Page 38 GAO-18-74 GPS Modernization

We provided a draft of this report to the Department of Defense for review 

and comment. In its written comments, reproduced in appendix II, DOD 

concurred with the recommendation. DOD also provided technical 

comments, which we incorporated as appropriate.

We are sending copies of this report to the appropriate congressional 

committees, the Secretary of Defense, the Secretary of the Air Force, and 

other interested parties. In addition, the report is available at no charge on 

the GAO website at http://www.gao.gov.

If you or your staff have any questions concerning this report, please 

contact me at (202) 512-4841 or by email at chaplainc@gao.gov. Contact 

points for our Offices of Congressional Relations and Public Affairs may 

be found on the last page of this report. Key contributors to this report are 

listed in appendix IV.

Cristina T. Chaplain

Director, Acquisition and Sourcing Management

Agency Comments 

and Our Evaluation
Page 39 GAO-18-74 GPS Modernization

List of Committees

The Honorable John McCain

Chairman

The Honorable Jack Reed

Ranking Member

Committee on Armed Services

United States Senate

The Honorable Thad Cochran

Chairman

The Honorable Richard J. Durbin

Ranking Member

Subcommittee on Defense

Committee on Appropriations

United States Senate

The Honorable Mac Thornberry

Chairman

The Honorable Adam Smith

Ranking Member

Committee on Armed Services

House of Representatives

The Honorable Kay Granger

Chairwoman

The Honorable Pete Visclosky

Ranking Member

Subcommittee on Defense

House of Representatives
Appendix I: Objectives, Scope, and 

Methodology

Page 40 GAO-18-74 GPS Modernization

To determine the extent to which there are acquisition risks to sustaining 

the Global Positioning System (GPS) satellite constellation, we reviewed 

the Air Force GPS quarterly reports, program acquisition baselines, 

integrated master schedules, acquisition strategies, software 

development plans, test plans, and other documents to the extent they 

existed for GPS III, Next Generation Operational Control System (OCX), 

and Contingency Operations (COps) programs. We also interviewed 

officials from the GPS III, OCX, and COps programs; the Air Force Space 

and Missile Systems Center’s (SMC) GPS Enterprise Integrator office; the 

prime contractors from all three programs; the Defense Contract 

Management Agency; the Office of Cost Assessment and Program 

Evaluation; and the Office of the Director, Operational Test and 

Evaluation (DOT&E). We also reviewed briefings and other documents 

from each to evaluate program progress in development. We assessed 

the status of the currently operational GPS satellite constellation, 

interviewing officials from the Air Force SMC GPS program office and Air 

Force Space Command.

To assess the risks that a delay in the acquisition and fielding of GPS III 

satellites could result in the GPS constellation falling below the 24 

satellites required by the standard positioning service and precise 

positioning service performance standards, we employed a methodology 

very similar to the one we had used to assess constellation performance 

in 2009, 2010, and 2015.1 We obtained information dated May 2016 from 

the Air Force predicting the reliability for 63 GPS satellites—each of the 

31 current (on-orbit as of July 2017) and 32 future GPS satellites—as a 

function of time. Each satellite’s total reliability curve defines the 

probability that the satellite will still be operational at a given time in the 

future. It is generated from the product of two reliability curves—a wearout reliability curve defined by the cumulative normal distribution, and a 

random reliability curve defined by the cumulative Weibull distribution.2

For each of the 63 satellites, we obtained the two parameters defining the 

cumulative normal distribution, and the two parameters defining the 

 1

GAO, Global Positioning System: Significant Challenges in Sustaining and Upgrading 

Widely Used Capabilities, GAO-09-325 (Washington, D.C.: Apr. 30, 2009); Global 

Positioning System: Challenges in Sustaining and Upgrading Capabilities Persist,

GAO-10-636 (Washington, D.C.: Sept. 15, 2010); and GPS: Actions Needed to Address 

Ground System Development Problems and User Equipment Production Readiness, 

GAO-15-657 (Washington, D.C.: Sept. 9, 2015).

2

The Weibull distribution is a common two-parameter continuous probability distribution; it 

is used to model the random failures of GPS satellites. 

Appendix I: Objectives, Scope, and 

Methodology
Appendix I: Objectives, Scope, and 

Methodology

Page 41 GAO-18-74 GPS Modernization

cumulative Weibull distribution. For each of the 32 unlaunched satellites 

we included in our model, we also obtained a parameter defining its 

probability of successful launch, and its current scheduled launch date. 

The 32 unlaunched satellites include 10 GPS III satellites currently under 

contract and 22 GPS III satellites planned for contract award in late 2018; 

launch of the final GPS III satellite we included in our model is scheduled 

for October 2031. Using this information, we generated overall reliability 

curves for each of the 63 GPS satellites. We discussed with Air Force and 

Aerospace Corporation representatives, in general terms, how each 

satellite’s normal and Weibull parameters were calculated. However, we 

did not analyze any of the data used to calculate these Air Force provided 

parameters.

Using the reliability curves for each of the 63 GPS satellites, we 

developed a Monte Carlo simulation to predict the probability that at least 

a given number of satellites would be operational as a function of time, 

based on the GPS launch schedule as of May 2016. We conducted 

several runs of our simulation—each run consisting of 10,000 trials—and 

generated “sawtoothed” curves depicting the probability that at least 24 

satellites would still be operational as a function of time.3 We then used 

our Monte Carlo simulation model to examine the effect of delays to the 

operational induction of the GPS III satellites into the constellation. We 

reran the model based on month/year delay scenarios, calculating new 

probabilities that at least 24 satellites would still be operational as a 

function of time, determining in terms of month/year the point at which a 

satellite would be required to enter operations to maintain an 

uninterrupted maintenance of the 95 percent probability of 24 satellites in 

operation. The Air Force satellite parameters we used for the Monte Carlo 

simulation pre-dated the Air Force investigation into navigation payload 

capacitors and the subsequent decision to launch the first satellite “as is” 

with questionable parts. Therefore, the reliability parameters for this 

satellite were not informed by any possible subsequent Air Force 

consideration of the decision to launch the first GPS III satellite “as is” 

with these parts.

 3

Monte Carlo simulation refers to a computer-based analysis that uses probability 

distributions for key variables, selects random values from each of the distributions 

simultaneously, and repeats the random selection over and over. Rather than presenting a 

single outcome—such as the mostly likely or average scenario—Monte Carlo simulations 

produce a distribution of outcomes that reflect the probability distributions of modeled 

uncertain variables.
Appendix I: Objectives, Scope, and 

Methodology

Page 42 GAO-18-74 GPS Modernization

To determine the extent to which the Department of Defense (DOD) faces 

acquisition challenges developing a new ground system to control the 

broadcast of a modernized GPS signal, we reviewed Air Force program 

plans and documentation related to cost, schedule, acquisition strategies, 

technology development, and major challenges to delivering M-code 

Early Use (MCEU) and OCX blocks 1 and 2. We interviewed officials from 

the MCEU and OCX program offices, SMC GPS Enterprise Integrator 

office, DOT&E, and the prime contractors for the two programs. For OCX, 

we also reviewed quarterly reviews, monthly program assessments, and 

slides provided by Raytheon on topics of our request. We also 

interviewed Office of Performance Assessments and Root Cause 

Analyses officials regarding root causes of the OCX program’s cost and 

schedule baseline breach and Defense Contract Management Agency 

officials charged with oversight of the OCX contractor regarding cost and 

schedule issues facing the program’s development efforts, major program 

risks, and technical challenges. 

To determine the extent to which DOD faces acquisition challenges 

developing and fielding modernized receiver cards across the 

department, we reviewed Air Force program plans and documentation 

related to M-code GPS User Equipment (MGUE) increment 1 cost, 

schedule, acquisition strategy, and technology development. We 

interviewed officials at the Air Force SMC GPS program office, MGUE 

program office, DOT&E, and the three MGUE increment 1 contractors—

L3 Technologies, Raytheon, and Rockwell Collins. To identify the military 

services’ respective development efforts and challenges in integrating 

MGUE with their lead platforms, we interviewed officials from the lead 

program offices for the Army’s Defense Advanced GPS Receiver 

Distributed Device/Stryker, Air Force’s B-2 aircraft, Navy’s DDG-51 

Arleigh Burke class destroyer, and Marine Corps Joint Light Tactical 

Vehicle. Additionally, to understand the extent to which DOD has a plan 

for implementing M-code for the warfighter, we analyzed DOD 

Positioning, Navigation, and Timing (PNT) plans and other DOD 

memorandum on GPS receiver cards. We also held discussions with and 

received information from officials at Office of the Undersecretary of 

Defense for Acquisition, Technology, and Logistics; Joint Staff / J-6 

Space Branch; and military service officials from the offices responsible 

for developing M-code receiver card implementation plans.

We conducted this performance audit from February 2016 to December 

2017 in accordance with generally accepted government auditing 

standards. Those standards require that we plan and perform the audit to 

obtain sufficient, appropriate evidence to provide a reasonable basis for 
Appendix I: Objectives, Scope, and 

Methodology

Page 43 GAO-18-74 GPS Modernization

our findings and conclusions based on our audit objectives. We believe 

that the evidence obtained provides a reasonable basis for our findings 

and conclusions based on our audit objectives.
Appendix II: Comments from the Department 

of Defense

Page 44 GAO-18-74 GPS Modernization

Appendix II: Comments from the Department 

of Defense
Appendix II: Comments from the Department 

of Defense

Page 45 GAO-18-74 GPS Modernization
Appendix III: GPS Modernization Cost 

Increases, Original Baseline vs. Current 

Estimate

Page 46 GAO-18-74 GPS Modernization

Table 5: GPS Modernization Costs

Program Original Baselinea

(fiscal year 2017

dollars, in millions) 

Current Estimate 

(fiscal year 2017 

dollars, in millions)

Percentage 

Increase

GPS IIIb 4,275.2 5,834.1 36

Next Generation Operational Control System 

(OCX)

3,591.8 5,498.4 53

Military GPS User Equipment (MGUE)

Increment 1

1,505.7 1,505.7 0

Contingency Operations (COps) 0.0 161.7 N/A

M-Code Early Use (MCEU) 0.0 119.5 N/A

Totalc 9,372.7 13,119.4 40

Source: GAO analysis of Department of Defense data. | GAO-18-74

a

Dates for original baselines are: GPS III–May 2008, OCX–November 2012, and MGUE–January 

2017.

b

The original GPS III baseline was for eight satellites. The current baseline is for 10 satellites. The 

cost per satellite has increased from $534 million to $583 million, or approximately 9 percent.

c

The total cost does not include the cost for the GPS Enterprise Integrator which integrates, 

synchronizes, tests, and verifies the GPS programs but is not a baselined program of record. The 

fiscal year 2018 budget request projects total GPS Enterprise Integrator expenditures across 

numerous fiscal years as $801.9 million. The table also omits future potential development for GPS III 

satellites or their procurement (up to 22 in total), the planned MGUE increment 2 program, or the 

costs to operationally test, integrate, and procure receiver cards across the Department of Defense. 

The table also does not include costs to operate and maintain any of the programs once operational.

Appendix III: GPS Modernization Cost 

Increases, Original Baseline vs. Current 

Estimate
Appendix IV: GAO Contact and Staff 

Acknowledgments

Page 47 GAO-18-74 GPS Modernization

Cristina T. Chaplain (202) 512-4841 or chaplainc@gao.gov

In addition to the contact named above, David Best, Assistant Director; 

Jay Tallon, Assistant Director; Karen Richey, Assistant Director; Pete 

Anderson; Andrew Berglund; Brandon Booth; Brian Bothwell; Patrick 

Breiding; Erin Carson; Connor Kincaid; Jonathan Mulcare; Sean 

Sannwaldt; Alyssa Weir; Robin Wilson and Marie P. Ahearn made key 

contributions to this report.

Appendix IV: GAO Contact and Staff 

Acknowledgments

GAO Contact

Staff 

Acknowledgments

(100643)
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