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Latest Words from the Acquisition Guru of the World’s Gold Standard for PNT

September 1, 2014  - By
Col. William Cooley, Director, U.S.A.F. Global Positioning Systems Directorate.

Col. William Cooley, Director, U.S.A.F. Global Positioning Systems Directorate.

Colonel William “Wild Bill” Cooley, director of the GPS Directorate at Space and Missile Systems Center, discusses CNAV signals, GPS IIF launches, and the OCX with Defense Editor Don Jewell.

There is probably no busier United States Air Force officer than Colonel William “Wild Bill” Cooley, Ph.D., the director of the GPS Directorate at Space and Missile Systems Center (SMC), Air Force Space Command (AFSPC), Los Angeles AFB, California. He is the driving force for all things dealing with acquisition and development for GPS. Currently, he is juggling so many objects, it is amazing that he is not totally overwhelmed. Consider the issues with the Next-Generation Operational Control System (OCX), GPS IIF, GPS III, and military government user equipment (MGUE), plus a plethora of classified endeavors we can’t even discuss here. He is one busy man, but even with all that, he found time to sit down and answer a few questions in an effort to bring us all up to speed on GPS and PNT.

Don Jewell (DJ): One of the hot topics at all the symposia lately, here and abroad, has been the broadcasting of additional civilian navigation signals and messages. The U.S. Department of Transportation (DOT) originally objected and sent a strongly worded and probably unadvisable letter to General Shelton (AFSPC/CC) on the matter, but sanity prevailed, and the GPS navigation signals on L2C- and L5C-capable satellites began broadcasting with full navigation messages on April 28. However, we understand DOT still insists some restrictions be put in place for the L5C signal. Can you provide us with an update and a status on that program? Plus, what can users expect in the way of improved accuracy and signal availability?

Colonel “Wild Bill” William Cooley (WBC): As of April 28, the civil navigation message (CNAV) broadcast was implemented on all operational GPS satellites capable of transmitting the L2C and L5 signals. Currently, seven GPS IIR-M satellites broadcast L2C, and six GPS IIF satellites broadcast L2C and L5. On average, users may expect at least one L2C-broadcasting satellite to be in view at all times.

The CNAV message content now includes the minimum message set needed to support the positioning, navigation, and timing mission, namely Broadcast Message Types (MT) 10, 11, 30, and 33, which contain information about the satellites’ position, clock, health, and corrections, in lieu of the previously transmitted MT-0 placeholder or default message.

The Air Force intends to broadcast L2C messages with the health bit set healthy and L5 messages with the health bits set unhealthy until sufficient monitoring capabilities are available for the L5 signal. We expect the accuracy to be slightly less than the Legacy Navigation Message (LNAV) because we are only updating the satellites two times each week. The accuracy should improve to be slightly better than LNAV beginning this December, when we begin updating the CNAV message on each satellite daily.

DJ: The M-code (military code) and MNAV (military navigation) signals are also being broadcast on M-code-capable satellites. So, the same questions apply: what can our warfighters and government users expect as far as M-code availability and accuracy? What can you say about the multiple messaging capabilities both on the civilian and military (CNAV and MNAV) signals?

WBC: Like the civil CNAV message, the modernized military-data message MNAV will enable military users to take advantage of all of the performance improvements offered by a modernized military signal. We can expect continued accuracy improvements as newer satellites replace aging satellites.
MNAV broadcast testing will continue occasionally in support of developmental test events for the next-generation military GPS receiver cards.

DJ: I know we can get in sensitive territory here in a hurry, but since we are discussing the military signals, can you give us an update on the long-running MGUE and M-code program? When can government users expect to see an actual signal and a receiver with M-code chips and/or modules that utilize the military only signals? Plus — and here’s where we have to be careful — what can you say about the security, availability, and accuracy of the military signal?

WBC: The M-code-capable military receiver (MGUE) modules in development have successfully acquired and tracked M-code during live-sky tests, and we have many more tests scheduled. MGUE is expected to begin fielding by 2017, at which point at least 18 M-code-capable GPS satellites are expected to be on orbit, providing global four-in-view coverage of full M-code capabilities.

In the meantime, the most recent GPS IIF satellite launches have raised the total number of M-code-capable modernized GPS spacecraft to 14 (seven GPS IIR-M and seven GPS IIF). This provides four or more M-code satellites in view globally at least 50 percent of the time, and at least one M-code satellite in view continuously. This increasing M-code satellite signal coverage will enable effective, realistic, developmental and operational testing of MGUE receivers.

The new GPS III block of satellites will provide an M-code signal with greater security, and higher power, comparable availability, and accuracy when compared with the GPS IIF satellites, allowing users to operate closer to jammers and under trees, as well as with greater resistance to jamming and spoofing. Also OCX will offer significantly improved crypto protection and cyber security.

DJ: Recently, the U.S. Air Force successfully launched the fifth, sixth, and seventh SVs in the GPS IIF family of satellites in less than seven months. Quite a feat! Congratulations are in order for that milestone. However, in the past, the checkout times averaged approximately 30 days. In fact, speed in initializing the IIF SVs and declaring them operational seemed to be an unofficial goal. On GPS IIF-5, however, the rapid checkout timelines have been extended considerably. Can you enlighten us concerning the checkout program and what the government hopes to achieve?

WBC: There are three key dates with regard to checkout timelines: completion of on-orbit checkout, the transfer of Satellite Control Authority (SCA), and the Operational Acceptance of the vehicle. Measured from launch, the nominal on-orbit checkout timeline is 21 days. The nominal checkout for SCA transfer is 28 days. For the IIF-5 mission, the on-orbit checkout occurred in six days and the SCA in 11 days, a record for the IIF program!

The operational acceptance was completed 60 days later, following an on-orbit observation validating a requirement to see if the vehicle works as expected without receiving any commands from the ground segment in that time period.

This may explain the perceived extended checkout, which is in reality a delayed operational acceptance.
The average time to SCA transfer for the first four vehicles is 42 days. The average is inflated due to a long checkout of the first GPS IIF space vehicle, which took 88 days. From IIF-2 to the present, the average SCA transfer time has been 21 days.

Using SCA transfer time makes the most sense, because that is the time it took the SPO to go through the entire process (to include meetings and documentation) to hand over the vehicle.

DJ: Can you give us a status update on the entire GPS IIF family of satellites? How are the SVs faring in orbit, and are the clocks proving to be as stable and accurate as forecast?

WBC: The first seven of 12 GPS IIF satellites are currently on-orbit and meeting all mission requirements. Of the remaining satellites, one is being prepared for launch in October 2014, one is being prepared for shipment to Cape Canaveral AFS, two are in storage, and one is completing production. The oldest satellite is now four years old. The legacy GPS satellites have remained operational well past their design lives, demonstrating the high-quality engineering and mission-assurance practices used on this program. The clocks are improving the overall accuracy of the constellation with the best-ever day (measured in Signal-in-Space User Range Error) in June 2013 of 46.6 centimeters and the best week in April 2014 of 64.6 centimeters.

DJ: What exactly do the IIFs mean to the GPS modernization program, for the average user and for the GPS constellation and program as a whole?

WBC: The 12 Boeing-built GPS IIF satellites will provide improved signals that will enhance the precise global positioning, navigation, and timing (PNT) services supporting both the warfighter and the growing civilian needs of our global economy. The next-generation satellites will provide improved accuracy through advanced atomic clocks, a longer design life than previous GPS satellites, and a new operational third civil signal (L5) that benefits commercial aviation and safety-of-life applications. It will also continue to deploy the modernized capabilities that began with the modernized GPS IIR satellites, including a more robust military signal.

The anomalies that we have seen on orbit have been resolved either through rework at the factory or through modifications in flight software.


GPS IIF Launch. The seventh of the follow-on generation, rising August 1.

DJ: Bill, that’s comforting, but what about the clocks on the IIF SVs? There were serious problems with the Cesium clocks on the first couple of launches. Are the operators now able to utilize or activate either the Rubidium or the Cesium atomic reference systems?

WBC: Don, the answer is yes. The system has triple redundancy with two Rubidium frequency standard clocks and one Cesium frequency standard.

DJ: What about signal strength and stability on the IIF birds?

WBC: In addition to an increased number of signals, GPS IIF provides more than the legacy power levels, and all signals on GPS IIF meet stability requirements. For reference, the GPS IIR-M series introduced one new L1 and two new L2 signals, while GPS IIF introduced the new L5 signal. All of these signals are part of the GPS IIF navigation payload and provide information including GPS date and time, satellite health, satellite ephemeris (for individual satellite positioning), and almanac information (for information on other satellites in the constellation).

The L1 frequency carries the L1 C/A code for civil users, and the L1 P (Y) code and L1 M-code for military users. The L2 frequency carries the first modernized civil signal, L2C, and the L2 P (Y) code and L2 M-code for military users. Finally, the L5 frequency carries the newest modernized civil signal.

Modernized GPS civil signals provide dual-frequency signals to all GPS users, enabling ionospheric corrections that greatly improve the accuracy. The new L5 signal will be used for safety-of-life applications, including aviation. In addition to an increased number of signals, GPS IIF provides more than the legacy power levels, and all signals on GPS IIF meet stability requirements.

DJ: Let’s move to the ground segment. OCX, the next-generation GPS Command and Control (C2) system, has literally moved to the right on the schedule timeline for every month it has been in existence since it was awarded in 2010. The end date just keeps getting farther and farther away. OCX is also currently exceeding the original contract budget by a large margin.

What’s the problem? Is OCX more difficult or complicated than originally planned? Is there any good news to report to users on OCX? What can users expect in the future?

Just so our readers know, just what is it that OCX brings to the GPS arena that cannot be provided by the current Architecture Evolution Plan (AEP) C2 system? Why do we need OCX? And in your opinion is it still a viable option? Are there contingency plans?

My apologies — that is about eight questions in one, but hopefully you can bring us up to speed on OCX.

WBC: Actually, the primary drivers of schedule delays for OCX are related to:

  • issues with the integration and testing of Block 0 on the cyber-hardened infrastructure; and
  • the concurrent systems engineering approach for Block 1 and Block 2, which drove a high rate of rework and inefficient staffing.

The OCX program is a pathfinder for many of the U.S. Air Force’s and Department of Defense’s most rigorous Information Assurance (IA) and Cyber Security requirements, which have turned out to be more complex to implement than anticipated.

OCX is a challenged program, but there is progress to report. Raytheon completed a hardware compatibility and integration test with the non-flight test bed of the Lockheed Martin GPS III space vehicle. This test validated the network infrastructure’s ability to communicate between the Lockheed Martin Launch and Checkout Capability and the Raytheon Launch and Checkout System, sending commands to the full-sized, functional satellite prototype test bed.

In addition, Raytheon and Lockheed Martin completed the third of five planned launch and early orbit exercises to demonstrate launch readiness. This exercise used new installments of the Raytheon OCX software and network infrastructure to demonstrate space-ground communications for initial acquisition, orbit-raising maneuver planning and execution, and basic anomaly detection and resolution.

Another recent accomplishment was the merging of the Cyber Security hardware and software baseline with the Block 0, Launch and Checkout System, mission applications. The completion of this merge allowed the program to enter formal integration and test activities, which are ongoing.

The full capabilities of OCX provide more than a dozen new capabilities for the GPS mission. OCX enables the full capabilities of the modernized navigation signals: adding L2C and L5 for civil users, M-code secure signal for military users, an internationally compatible L1C, as well as worldwide monitoring of these modern signals for quality and integrity.

OCX enables operation of the new GPS III satellites. As we discussed previously, OCX will provide the USAF’s most rigorous cyber-security capabilities, built in from the OCX foundation.

Raytheon just completed implementation of a program re-plan, which implemented lessons learned to date to correct many of the development challenges encountered, and created a lower risk schedule for delivery. With these changes, the program remains a viable and important component of the modernized GPS enterprise.

DJ: With that in mind, when do you currently plan on having the first GPS III OCX-controlled launch? Original schedules called for a late 2014 date, then it was 2015, and now we are hearing 2016 or as late as 2018 for OCX. Are there viable alternatives, and if so, can you tell us what they are and if they are being pursued?

WBC: OCX and GPS III are synchronized to support launch of the first vehicle in the second half of 2016, conditioned upon launch manifest availability. Contingency plans are being developed, but will only be implemented if warranted by the risk.

DJ: Now, Bill, I am not asking you to blow your own horn here, but frankly we have heard nothing but good reports from SMC and the GPS Directorate since you arrived about 14 months ago. That is a short period of time, but evidently you have made your presence felt and have had a major impact on the GPS program overall. What have you done differently that seems to work so well? To what do you ascribe your success so far?

WBC: Thank you, Don. I’m very happy to hear the reports are positive, but the credit goes to the men and women of the GPS Directorate, our federally funded Research and Development Center personnel, and our contractors. My job is to continually assess the challenges and barriers that slow modernization. I help resolve the challenges or get additional resources if needed to enable the team to accomplish their important mission.

I am incredibly fortunate in that the GPS team is passionate about our mission to maintain the Gold Standard for position, navigation, and timing (PNT) for the world. The entire directorate understands the critical role we play for civilian and military users worldwide, and that knowledge motivates and energizes us every day!

I’m the luckiest colonel in the Air Force because I get to work alongside this terrific team of government and contractor professionals on one of the most important missions in the U.S. Air Force.

DJ: Obviously you are proud of your team, and you know what it means to be a great leader. In closing, do you have any final comments?

WBC: Don, just that the GPS Directorate and our contractor team, along with our partners at the 2nd Space Operations Squadron (2SOPS) who fly the GPS constellation 24/7, take our job seriously and understand the important mission we have: to provide reliable and precise position, navigation, and timing services for America’s warfighters, our allies, and civilian users around the globe. GPS is the Gold Standard for space-based PNT today, and we are modernizing to ensure GPS is the Gold Standard for the future.

About the Author: Don Jewell

Don Jewell served 30 years in the United States Air Force, as an aviator and a space subject-matter expert. Don’s involvement with GPS and other critical space systems began with their inception, either as a test system evaluator or user. He served two command assignments at Schriever AFB, the home of GPS, and retired as Deputy Chief Scientist for Air Force Space Command. Don also served as a Politico Military Affairs Officer during the Reagan administration, working with 32 foreign embassies and serving as a Foreign Disclosure Officer making critical export control decisions concerning sophisticated military hardware and software. After retiring from the USAF, Don served seven years as the senior space marketer and subject-matter expert for two of the largest government contractors dealing in space software and hardware. Don currently serves on two independent GPS review teams he helped found, and on three independent assessment teams at the Institute for Defense Analyses, dealing with critical issues for the U.S. government. Don has served on numerous Air Force and Defense Scientific Advisory Boards. He writes and speaks extensively on technical issues concerning the U.S. government. Don earned his Bachelor’s degree and MBA; the Ph.D. is in progress.