An official website of the United States government
Here's how you know
A .mil website belongs to an official U.S. Department of Defense organization in the United States.
A lock (lock ) or https:// means you’ve safely connected to the .mil website. Share sensitive information only on official, secure websites.

Proliferation of Global Navigation Satellite Systems: Implications for Modern Warfighting

June 1, 2020 | By apellegrino

Proliferation of Global Navigation Satellite Systems: Implications for Modern Warfighting By:


Captain Kyle P. Santarelli


Deep in the Iraqi deserts in 1991, American military forces moved through previously untraversed terrain to encircle and attack unprepared enemy forces. The Iraqi Army limited themselves to established routes and defensive positions based on the available maps and reconnaissance of their forces . The power to maneuver without ground landmarks gave American forces an exceptional upper hand in the ground campaign . Elsewhere in the conflict, precision strikes destroyed key infrastructure in the Iraqi capital, as American forces communicated freely with encrypted radio, keeping enemy forces in the dark . The availability of Positioning, Navigation, and Timing (PNT) through the Global Positioning System (GPS) enabled American forces to dominate the large Iraqi military. Over the next 20 years, the lessons of Operation Desert Storm drove considerable change in international military perspectives. American dominance in space is no longer absolute, and military reliance on GPS opens new vulnerabilities for American forces . The rise of alternate global navigation satellite systems (GNSS) complicates the modern battlefield. The implications of these new constellations are far-reaching and influence every aspect of modern warfighting. The rise of competitor GNSS degrades American dominance in global conflict through peer capability development and offers adversaries an asymmetric approach to GPS denial.


In order to examine the current GNSS environment, it is prudent to understand the history of the American GPS constellation. Following the success of the Transit and Timation satellites, the US Department of Defense authorized the first robust space-based navigation constellation in 1973 . The initial program, known as “NAVSTAR” derived its name from navigation signal timing and ranging . Due to the size of the ground receivers, this system primarily sought positioning of large naval vessels such as ships and submarines. As technology further developed in the 1970s and 1980s, the ground receivers shrank in both size and cost, enabling the use of GPS outside the naval world . This reduction in receiver size enabled application of GPS to the land component of the US military. Initial receivers were vehicle mounted and required the receiver to be stationary in order to resolve a positional fix. The US military achieved stunning operational tempo, operational reach, and battlefield success in 1991 with only 20 of the 24 GPS satellites on-orbit . As more NAVSTAR GPS satellites launched, and as computer technology miniaturized, receivers became mobile enough that individual soldiers on the battlefield now had the same positioning capability as large naval vessels . These receivers also became miniaturized enough to be attached to munitions, allowing standoff forces the ability to engage with greater precision. The presence of the NAVSTAR GPS constellation also allowed for another innovation: precise timing. The same principle that allows GPS receivers to calculate a position also allows the ground receiver to solve for atomic time . This innovation allows for the synchronous timing of communications systems enabling autonomous acquisition of encryption time for network and radio communications.


Prior to the rapid destruction of the Iraqi Army in 1991, the only other operational GNSS constellation was the GLONASS system of the USSR, with a name derived from a portmanteau of the Russian GLObalnaya NAvigatsionnaya Sputnikovaya Sistema. The constellation at the time was nearly operational and consisted of 22 satellites . Other countries took notice of the positive impact GPS had on the American military. During the 1990s, several nations began laying the groundwork for GNSS constellations similar to GPS. These constellations, when operational, had the goal of bringing nations to parity with the navigational capabilities of the United States.


During the period from 1990 to 2010, the United States took steps to bring the benefits of GPS to the civilian sector. Civilian receivers began to appear on the market, relying on the unencrypted signal from the GPS satellites. In May of 2000, President Clinton signed an executive order stating the United States would not degrade the signal to civilian receivers , and this action further integrated GPS into the civilian sector. Currently, commercial GPS receivers are available for incredibly low cost. Given the global coverage and mass production, it is now reasonable to assume that every adversary has unfettered access to the unencrypted GPS signal. Although, the US Government has preserved encryption on certain GPS signals that enables enhanced accuracy and resistance to interference for military receivers.


At the present day, the GPS constellation integrates into American military operations at a greater level than any point before. The warfighter relies on the GPS system for movement and maneuver, intelligence collection, facilitation of battle tracking, and timing synchronization, among many other purposes. It is understandable that any country would want to replicate this capability for their forces. As such, space-faring countries utilized their developing launch capabilities to build similar systems of their own design, leading to a rapid increase in the number of GNSS constellations worldwide.


In the Russian Federation, the aforementioned GLONASS system provides Russian forces with a similar capability . GLONASS functions in a manner similar; but not identically, to GPS and operates on a 24-satellite constellation. Following the fall of the Soviet Union, the constellation reached full operation in 1993, but then quickly lost a number of satellites and remained marginally operational until 2011 when the Russian Federation was able to replace the failed satellites. The Russian Federation is currently executing a modernization plan to prevent similar capability loss . Similar to the US GPS constellation, GLONASS provides an “Open Access Signal” for public receivers.


The capabilities provided by this system impact the warfighter in a number of ways. First, the peer military of the Russian Federation has the same capacity to accurately determine the position of their forces. The dominance seen over the Iraqi military by US forces is unlikely against a peer threat. Next, this capability extends to all forces fully supported by the Russian Federation. In any theater, the GLONASS availability coupled with commercial GPS will enable a relatively undeveloped country to determine similar positional accuracy as US forces in the area. The precision munitions available to the Russian Federation will likely proliferate to these conflict zones. Therefore, it is critical to assume precision guided munitions are now a threat in any conflict where the Russian Federation markets or supplies arms. Finally, the timing available to both the Russian Federation and their supported militaries gives an adversary the ability to synchronize and encrypt communications in a manner similar to the United States.


Another peer capability is growing in the People’s Republic of China (PRC). Their constellation of satellites: BeiDou Navigation Satellite System (BeiDou) takes a different approach to providing PNT . Unlike GLONASS and GPS, the constellation currently uses specific orbits to provide continuous unbroken coverage over the PRC and much of East Asia. The constellation intends to provide global coverage upon maturity and will contain up to 35 satellites. This different approach allows for regional usage of the constellation prior to the full constellation-reaching orbit in late 2020 . BeiDou provides a military signal and a civil signal similar to GPS and GLONASS. BeiDou has also incorporated the additional benefit of a short message service (SMS) between receivers, a capability that is not available on other GNSS constellations.


Future conflicts in East Asia must account for this alternate GNSS constellation. Military forces on the ground must assume that any PRC forces will have access to a precise navigation and timing signal, as well as redundant SMS communications. The PRC has previously provided access to the military signal to the Pakistani armed forces , this implies that any forces that ally with PRC in a conflict will also have access to the precise and resistant military BeiDou signal. BeiDou will also enable adversary long-range precision munitions such as rocket and air forces. This munition accuracy places friendly forces operating in any theater at risk. With the availability of the BeiDou system, the PRC and other adversaries will be more likely to attempt to jam the GPS signal; this places US forces reliant on such signals at a significant disadvantage in any conflict.


Beyond traditional adversaries, some smaller countries and regions have endeavored in recent years to augment or develop independent PNT capabilities. The largest of these supplemental capabilities is the Galileo constellation. Launched as a joint effort of European countries, this is a civil-focused GNSS with a stated goal to reduce the reliance of European countries on GPS and GLONASS.


The proliferation of this constellation provides another signal to civil and government users. Galileo is a globally focused constellation that reached full operational capability in 2020. Beyond global constellations are regional augmentations, notably those of India and Japan that seek to increase accuracy in a specific country or area. The repercussions of these new systems align with the issues identified with the BeiDou and GLONASS systems. A cheap receiver may be able to draw on multiple constellations to determine a location. The availability of GPS, Galileo, GLONASS and BeiDou makes it difficult for electronic attack assets to fully deny all GNSS signals in a theater. This ease of access allows unconventional forces similar access to positioning data as US forces. Regional augmentation in India and Japan also assists local forces with accuracy of positioning without reliance on the encrypted code of GPS. The proliferation of GNSS complicates the battlefield for all parties in a conflict. For adversary forces facing a coalition, the denial of GPS must now be accompanied by the denial of other GNSS systems. To accomplish this effort, the adversary must now jam a series of signals at high power instead of just GPS frequencies . A broad-spectrum electromagnetic (EM) jammer may also have collateral effects on the adversary’s own systems, resulting in unintentional consequences for their own forces. Yet, the advantage the adversary gains through GPS jamming is unmistakable and the number of GPS jammers in operation by peer nations continues to climb.


With independent systems, adversaries are now at liberty to deny American GPS frequencies through significant jamming. The effects of this jamming are far-reaching, and influence all of the warfighting functions. Command and control (C2) systems rely heavily on the timing signal from the GPS constellation. Denial of the GPS signal places a significant burden on the warfighter. After a few days in a denied environment, the timing of systems may have degraded enough to force a switch to unencrypted methods. American forces attempting to move and maneuver in a denied environment must contend with increased uncertainty of friendly forces’ situation, disposition, and strength. The force may have difficulty determining their position in relation to one another, and the warfighting equipment may not operate as effectively without precise location or timing.

Some intelligence collection systems, such as unmanned aerial vehicles (UAVs) rely on GPS signals for navigation in the course of their activities. Denial of GPS may prevent many of these systems from extended operation in jamming environment. GPS jamming inhibits accurate tagging of adversary capabilities for targeting, complicating the intelligence picture of the battlefield. Longer range fires systems, when in a GPS denied environment, will take additional time to set up and accurately execute missions. Precision Guided Munitions (PGMs), many of which have GPS receivers, may fail to perform as precisely as intended. The warfighter must be prepared to operate in this denied environment to remain successful.


GPS jamming also impacts planning and sustainment of forces. Forward deployed forces must endeavor to accurately describe their location, without the aid of GPS. Sustainment elements may struggle with communication and navigation during their transit of the battlefield and advanced sustainment delivery systems may become denied in this environment. Planners must account for the GPS denied environment throughout every stage of the planning process. They must consider alternate methods of navigation, communication, and coordination, as all are essential to success on the modern battlefield.


The approach to GPS jamming is different in American and adversary doctrine. Through the executive order of President Clinton, the United States will not utilize the “Selective Availability” feature of GPS that reduces positional accuracy of the unencrypted GPS signal. Current US policy is to “prevent the use of GPS though localized denial that does not unduly disrupt civil and commercial GPS access outside the battlefield.” Many adversaries do not operate in the same manner; their broad-spectrum denial of GNSS signals at high power is a component of their electronic attack doctrine. This broad spectrum jamming provides the adversaries an upper hand in the prosecution of a conflict. Additionally, if adversaries are able to incorporate the civilian signals of many of the aforementioned alternate GNSS sources, they may endeavor to deny GPS frequencies and garner an upper hand against American forces in a theater.

Some may contend that the logical answer to jamming of GPS frequencies is the incorporation of multi-GNSS receivers by the US Military. However, the current US policy prohibits the use of GLONASS and BeiDou receivers in military hardware. Ignoring the astronomical cost associated with replacing all current GPS receivers, introduction of multi-GNSS receivers introduces additional risk and vulnerability to operations. The GLONASS and BeiDou signals are provided to the world free by their respective owners. Russia and the PRC have not guaranteed access to the civil signal in time of conflict, therefore incorporation of multi-GNSS receivers may not solve the jamming problem. A more effective response to the proliferation of GNSS starts at the service level. The US military needs to expand their focus on Navigation Warfare (NAVWAR). An increase in US EW capability will allow friendly forces to level the battlefield, effectively jamming the adversary GNSS and forcing a conflict on equal terms. This increase in EW capability must be accompanied by an increase in training and education of US military leaders. Leaders and planners must learn the impacts of GPS jamming, the effects on their systems, and the methods of mitigation. Armed with increased knowledge, US forces will continue to fight and win on the modern battlefield.


Ultimately, the continued global proliferation of GNSS continues to complicate the battlefield for the warfighter. The Russian Federation and the GLONASS constellation provides an alternate PNT source for adversaries. The continued proliferation of this system to third parties enables Russian supported militaries and generates an incentive to deny GPS. The PRC and the BeiDou constellation provides a global alternative to GPS. The availability of alternate PNT enables an adversary to target the GPS signal without significant impact to their own navigation. Alternate GNSS constellations give rise to global positioning for all participants on the battlefield. The proliferation of alternate systems increases the likelihood of GPS frequency targeting. The warfighter must contend with the reality of GNSS on the current battlefield. The future success of US military forces requires leaders to expend considerable planning efforts to understand and operate within the new paradigm.


Author bio: CPT Kyle P. Santarelli is a space operations officer serving with the 1st Space Battalion, 1st Space Brigade, USASMDC.




Frank Wicks, "Where on Earth?" Mechanical Engineering 124 (7): 34


Ibid. 34.


Whitcomb, Darrel. 2012. "FLYING THE FIRST MISSION OF DESERT STORM." Air Power History, Spring, 5.


"The Spreading GPS Virus." 2001.Air Safety Week 15 (30): 1.


White, James. 1993. "GPS in the Driver's Seat." Satellite Communications 17 (9): 2.


Sturdevant, Rick W. “NAVSTAR, The Global Positioning System: A sampling of it’s Military, Civil, and Commercial Impact.” Societal Impact of Spaceflight. 331.

Yang, Guohai. 2013. "Principle of Satellite Navigation Orbit and Positioning." International Journal of Education and Management Engineering 3 (2): 43.

Williams, David R. 2020. “NAVSTAR 2A-01” retrieved from: Retrieved on April 26, 2020


Ibid. 42.


Grant, A., Williams, P., Ward, N., & Basker, S. (2009). GPS Jamming and the Impact on Maritime Navigation. The Journal of Navigation, 62(2), 177.


Urlichich, Yuri, Valery Subbotin, Grigory Stupak, Vyacheslav Dvorkin, Alexander Povalyaev, Sergey Karutin, and Rudolf Bakitko. 2011. “GLONASS Modernization.” GPS World 22 (11): 35.


Lawler, Andrew. 2000. "Scientists Gain Access to Sharper GPS Signal." Science 288 (5467): 783.

Ibid. 783.

Urlichich, Yuri Ibid. 36.

Ibid. 37.

Curriden, Christian. 2018. "Why Beidou could Help Protect GPS." Georgetown Journal of International Affairs 19: 92.

Ibid. 94.

Lele, Ajey. 2014. "Autonomy in Satellite Navigation Systems: The Indian Programme." Indian Foreign Affairs Journal 9 (3): 251.

Ibid. 243.

Sahmoudi, & Amin. (2009). Robust tracking of weak GPS signals in multipath and jamming environments. Signal Processing, 89(7), 1326.

Ibid. 1328.


Ibid. 42.

Ibid. 40.

“United States Policy, Denying Hostile Use” retrieved from: Retrieved on April 26, 2020