30 September 2023

Phasing Out GPS Reliance in U.S. Military Operations: An Imperative in the Face of Emerging Threats

Carlo J.V. Caro

The United States' military reliance on the Global Positioning System (GPS) poses significant vulnerabilities in the face of emerging threats from adversarial nations like Russia, China, and North Korea. At the moment, Europe is witnessing a conventional war between two nations. In this context, the role of technology, particularly navigation systems, has emerged as a decisive factor for military success.

Global Navigation Satellite Systems (GNSS), such as the American GPS, Europe's GALILEO, China's BEIDOU, and Russia's GLONASS, play an essential role in modern warfare. Despite their different technical specifications—like frequencies and orbits—these systems are designed to be compatible, allowing for greater positional accuracy. However, their signals are susceptible to various forms of interference, such as jamming and spoofing. While there are security measures like anti-spoofing in place, these are not foolproof.

Inaugurated during the Cold War, the Global Positioning System (GPS) was originally developed to provide the U.S. military with unparalleled navigation and timing capabilities. Over the years, this system has become deeply integrated not just into military functions but also in civilian applications. However, this ubiquitous dependency on GPS exposes the U.S. military to substantial vulnerabilities, especially given the anti-satellite capabilities and cyber warfare competencies of Russia, China, and North Korea.

In the current war in Ukraine, Russia has upped the ante by developing Anti-Satellite (ASAT) missiles capable of destroying GPS satellites. Such a move could effectively cripple NATO's long-range weaponry. Surprisingly, Russia seems unafraid of a similar attack on its own GLONASS system. This is because Russia has revitalized a pre-existing radio navigation system known as Long Range Navigation (LORAN).

Developed initially during World War II, LORAN is a hyperbolic radio navigation system. Unlike GNSS systems, LORAN calculates a receiver's position based on the time difference between signals emitted from three or more synchronized ground stations. In this setup, absolute time is less important than the differences in arrival times, a concept known as multilateration.

The origins of LORAN date back to 1940, when Alfred Lee Loomis introduced it at the U.S. Army Microwave Conference. The system originally offered an accuracy of one nautical mile within a 200-mile radius. Over time, it evolved through various iterations and names, ultimately becoming part of the MIT Radiation Laboratory under the name Project 3.

Several versions of LORAN emerged through experimentation. One such version, LF LORAN, appeared in 1945 and operated at much lower frequencies, requiring balloon antennas. After WWII, the CYCLAN and Whyn systems were created to support the navigation of American B-47 bombers. CYCLAN in particular proved successful, showing that using two frequencies instead of one resulted in better performance.

By 1952, the success of CYCLAN inspired the development of the Cytac program by Sperry. Its main objective was to operate at even lower frequencies while maintaining accuracy. Despite achieving impressive accuracies around 10 yards, the system was not widely adopted due to concerns about signal strength and interference.

Out of these experiments, LORAN B and the more successful LORAN C were developed. LORAN C became the most widespread version, operating at frequencies between 90 to 110 kHz and multiple operational chains of radio beacons worldwide. LORAN C represented a significant advancement in the speed and accuracy of obtaining positions. However, it was not without drawbacks; its technology was rooted in the 1950s, which posed limitations on the required electronic equipment.

In the late 1970s and 1980s, LORAN systems underwent significant upgrades, incorporating solid-state electronics and the first microcontrollers. Although versions D and F of LORAN were developed, their improvements were eclipsed by the emergence of GPS. The satellite-based navigation system soon made traditional radio navigation like LORAN largely obsolete. GPS became so efficient and cost-effective that maintaining LORAN systems seemed financially unjustifiable.

The ubiquitous use of Global Navigation Satellite Systems (GNSS) like GPS has led to a widespread dependence on these technologies for navigation and positioning. This mutual reliance has often been seen as a deterrent against intentional disruptions; the thinking goes, 'If we all need them, we won't sabotage them.'

Despite this reliance on GNSS, the U.S. government considered rejuvenating the LORAN system as a GPS alternative. The Obama administration allocated a budget for upgrades. However, skepticism led it to slash this budget. This decision seemed questionable, especially given the vulnerabilities of the GPS system. Consequently, LORAN has languished in obscurity, with most of its stations dismantled.

Russia has been actively upgrading its radio navigation system, known as CHAYKA ('seagull' in Russian), which is similar to LORAN. Initially developed to address GPS's limitations in Russia—a problem later resolved with their GNSS system, GLONASS—CHAYKA has nonetheless remained in active service. Russia has not only modernized CHAYKA but has also expanded its operational scope to include areas of geopolitical interest, like Ukraine. This robust backup to satellite-based systems allows Russia to credibly threaten the disruption of global GNSS systems, knowing they have a reliable alternative for navigation.

Technological innovations don't exist in a vacuum; they often reshape military doctrines and strategies. For example, the precision and real-time capabilities introduced by GNSS have redefined modern engagement forms, from drone warfare to real-time data analytics for situational awareness. However, the robust and less vulnerable nature of LORAN-like systems lends itself well to scenarios where satellite communications can be compromised. This co-evolution of technology and strategy necessitates a reevaluation of both the tactical and geopolitical landscapes.

The military's use of the Global Positioning System (GPS) for navigation and precision targeting is a double-edged sword. While the system offers unparalleled advantages in command and control, its inherent flaws pose substantial risks that could be exploited by adversaries like Russia, China, and North Korea.

The first layer of vulnerability is grounded in the technical limitations of GPS. Signal strength and propagation present immediate concerns; GPS signals must travel vast distances through Earth's atmosphere to reach surface receivers. Their strength can be weakened not only by natural factors such as weather conditions but also by intentional jamming. In a military context, this vulnerability could be seized upon by an adversary using focused signal disruption tactics to degrade operational efficiency. Equally alarming is the issue of spectrum congestion. The L-band in which GPS operates is becoming increasingly crowded. This escalating congestion elevates the risk of unintentional signal interference, which can further be exploited intentionally through high-power transmissions in the same band.

While modern military GPS applications often feature encrypted signals for better security, legacy systems and interoperability requirements occasionally force the use of civilian GPS signals. These unencrypted signals become low-hanging fruits for spoofing attacks. A well-executed spoofing operation can mislead a GPS receiver into calculating a false position, leading military assets astray or into traps. Moreover, the central control infrastructure—the Ground Control Segment—becomes a single point of failure. Despite redundancies and hardened facilities, its centralized nature remains a chink in the armor, vulnerable to both kinetic and cyber-attacks.

The technical limitations manifest into operational constraints that further complicate the military's heavy reliance on GPS. The Time-to-First-Fix (TTFF), which is the duration a GPS receiver takes to obtain an initial position, can induce delays. In high-stakes, time-sensitive operations, such delays can prove fatal.

Operational planning becomes a herculean task when considering potential GPS failures. The necessity for alternative navigation strategies adds layers of complexity to missions, which traditionally rely on the predictability and accuracy of GPS. This burden extends to tactical behavior. Over-reliance on GPS can induce predictable patterns, such as using certain well-navigated routes, thus exposing military assets to enemy observation and potential ambushes.

The ripple effects of GPS vulnerabilities reach far beyond immediate operational timelines. Should a mission need to be aborted due to GPS failure, the larger strategic goals could be compromised. In addition to the immediate tactical impact, the economic and logistical burdens of equipping military assets with redundant systems and countermeasures are not insignificant. These entail not only economic costs but also added weight and power requirements that could limit mission duration and mobility.

Perhaps the most insidious impact is the skill atrophy among military personnel who have become overly reliant on GPS for navigation. The erosion of traditional navigation skills, such as map reading and celestial navigation, could severely impede operational effectiveness in GPS-denied environments.

Given these interconnected technical and operational vulnerabilities, it is imperative for the U.S. military to reconsider its GPS-centric strategy. The adoption of multi-modal redundancies, the revival of traditional navigation skills, and long-term investments in quantum navigation are not just options but necessities. By doing so, the military can mitigate these risks and preserve its operational effectiveness in increasingly contested and complex battlefields.

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