GPS Directorate: Receivers Will Operate in Environments Impossible Today
By Col. Bernie Gruber
I believe the future of global navigation satellite systems (GNSS) and particularly GPS will only be limited by our ingenuity and imagination. In terms of economic benefit, GPS contributes $60 billion to our economy, and that’s no stretch considering the positive and real advantages GPS affords us every day through fuel savings, transportation optimization, banking transactions, recreational activities, and certainly the defense of our great nation.
GPS consists of three segments — space, ground and user equipment — all contributing synchronistically to provide the world positioning, navigation, and timing (PNT). Having joined the GPS program office (for the first time) in 1992, I was privileged to lead the very first Foreign Military Sales contracts and the development of the Selective Availability Anti-Spoofing module (SAASM) — both focused within the realm of user equipment. As program director of GPS reflecting back on the monumental change of the past 20 years, I am encouraged and look forward to seeing the fruition of the projects and plans we have already set in motion for the next 20. This is why:
Space Segment. The launch and handover of the third GPS IIF satellite on October 4 proves once again our commitment to mission success. We have exceeded our published worldwide accuracy standard since 1993, and the NavStar GPS constellation remains robust with 31 satellites currently available.
In regards to the satellite systems, next-generation Block IIF and III satellites are in various states of test, integration, or production in an effort to improve the average user range error (URE) from 0.9 meters, achieved and maintained for the last 3 years, to a root-mean-squared URE of 0.5 meters by 2016. Along with increased civil and military signals, I also envision digital waveform generation (that is, the ability to change on-orbit signals in space via software) as an integral part of our architecture. Digital waveform generation coupled with an augmentation of the GPS III constellation for affordability and resiliency will pave our way to the future.
Ground Segment. Along with a host of additional satellite capabilities and signals, we will correspondingly modernize our ground segment. Our Next-Generation Operational Control System (OCX) is designed to command and control our modernized secondary civil signal L2C, safety-of-life signal L5, and the internationally compatible signal L1C. In fact, users such as John Deere and NavCom are already accessing the currently broadcast L1 C/A and L2C (with a default code) for dual-frequency ionospheric correction to improve upon accuracy. As the modernized signals become operational, users will see faster signal acquisition, enhanced reliability, and a greater operating range. The information assurance, expandability, and service-oriented architecture will afford users and operators with security and information they simply don’t have today.
User Segment. All that said, I am thrilled to look at the future of user equipment. We need to take advantage of the use of civil GPS. Apple and Android have shown the way to interface with and use applications, displays, and packaging; Google Map overlays, smart phone apps, time-to-first-fix augmentations from cell towers, and multi-GNSS international coverage are already in use, with the growth of apps, users will only get smarter and more sophisticated in their GPS expectations.
To that end, the Air Force is augmenting its pilots with digital maps and starting to integrate GPS with the digi-maps beginning with the C-130J. The Army is paving the way with an app store for military use and beginning to integrate GPS with its equipment, such as the use of a GPS integrated wind app for calibrating bullet trajectories.
Security, authentication, integrity, and the ability to operate in almost any environment is vital to our warfighters. The Department of Defense is posturing to operate in an anti-access area denial (A2AD) environment. Make no mistake; the list of potential adversaries also includes a list of known attacks on GPS — along with use of GPS and other GNSS systems against us. For that purpose, the modernized GPS is working on better and improved items like key management, M-Code power and cryptography, and Blue Force Electronic Attack (BFEA). In this area too, I see the commercial market burgeoning with new ideas to protect the calculation of GPS PNT solutions.
In the selective-availability anti-spoofing module, we introduced positive control and resiliency to the military GPS receivers. Now with M-Code we are taking it one step further. M-code will leverage the National Security Agency (NSA) Key Management Infrastructure and augment it with more tools to ensure only authorized users have access to M-Code. This provides greater protection from spoofing, ensures that keys are readily available to the United States and her Coalition partners, and that security cost drives for our user equipment are minimized.
With more signal power, almost every aspect of GPS is better. While the 6–10 dB of additional power in GPS III will not in itself defeat known threats, more power complements anti-jam techniques as well as improves operation under foliage and in the presence of pervasive unintentional interference. We’re going to see receivers that operate in navwar environments that would be impossible today. Similarly, I see us having the flexibility to operate with other GNSS systems in benign environments, but the ability to also operate in hostile or contested environments.
Blue Force Electronic Attack was always a principle driver for GPS modernization. It is embodied in the White House Directives and Title 10 U.S.C [Title 10 of the United States Code outlines the role of armed forces in the U.S. Code, a compilation and codification of the general and permanent federal laws of the United States — Ed.] Today’s Block II systems do not have enough spectral separation for effective BFEA. As M-Code becomes readily available, along with the additional filtering available in military GPS user equipment (MGUE), we are providing Joint Task Force Commanders with options to deny GPS; options that they don’t have today.
The future of GPS is bright indeed! From the originators of GPS to present day men and women who work tirelessly to deliver and operate it, we are all striving to improve and enhance this magnificent capability. The economic benefits of a system that, in reality, pays for itself guarantees the world’s desire to see improvements and growth in the overall GPS system. The Air Force is a proud steward of the GPS system, but it is our collective job to proliferate new ideas to use it and secure it.
Colonel Bernie J. Gruber is director, Global Positioning Systems (GPS) Directorate, Space and Missile Systems Center, Air Force Space Command, Los Angeles Air Force Base, California. He is responsible for a multiservice, multinational systems directorate which conducts development, acquisition, fielding and sustainment of all GPS space segment, satellite command and control (ground) and military user equipment. The $32 billion GPS program, with a $1 billion annual budget, maintains the largest satellite constellation and the largest avionics integration and installation program in the Department of Defense. He has served in key positions at Major Command, Air Staff, Joint Staff and Defense Agency levels. Prior to assuming his current position, Colonel Gruber was Chief, Space Superiority and Global Integrated Intelligence, Surveillance and Reconnaissance Division, Directorate of Programs, Deputy Chief of Staff, Strategic Plans and Programs, Headquarters, United States Air Force, Washington, D.C.