The New Arithmetic of Force Projection

Two wars in the Gulf, eight months apart, percolated up a reality that had been forming for years: three decades of American military dominance rested on the preeminence of exquisite military technology and capability, but many of those technologies have diffused, been obviated by other technologies, or even surpassed. Middling powers can now impose both real and political costs that great powers cannot sustain, and the calculus of armed force is changing.

Part I explains one technology where the change is undeniable: satellite navigation, the quiet layer modern war runs on.

Part II: The Changing Character of War follows the consequences outward, from the battlefield to the global order built on American reach.

Northern Dipper

The navigation layer is contested.

For twelve days in June 2025, Iran and Israel fought the region’s heaviest direct missile exchange between states. Iran fired roughly 550 ballistic missiles (Fattah-1 hypersonics, Kheibar Shekans, Sejjils) and more than a thousand drones. The target list ran from Israeli airbases (Nevatim, Ramat David, Tel Nof) to Tel Aviv, Soroka Hospital in Beersheba, and the American base network from Al Udeid and Al Dhafra to Ain al-Asad. Most never arrived where they were aimed.

The interceptor batteries were the defense the cameras could see. The quieter work was electronic. American jamming aircraft over the Gulf (among them Navy EA-18G Growlers flying off the Carl Vinson) were not attacking Iranian radar; they were attacking the missiles’ sense of position, flooding the open civilian GPS frequency, the L1 band at 1575.42 MHz, with enough noise to drown the signal out. Regional reporting put the GPS-guidance failure rate on Iranian missiles above seventy percent. The weapons fell back on inertial guidance, drifted kilometers in flight, and buried themselves in open desert.

Three weeks after the ceasefire, Iran’s communications ministry confirmed what the war had suggested: some of the GPS disruption over Iran had been Tehran’s own defensive jamming, and the Islamic Republic would pursue China’s BeiDou as the alternative. The IRGC changed receivers. By the time the next war opened, Iran’s missile units were on BeiDou‘s restricted B3A channel: a Chinese military signal at 1268.52 MHz, encrypted and outside the L1 band being jammed. Access came through the 25-year China–Iran Comprehensive Strategic Partnership signed in 2021. The L1-band denial that the United States had counted on since Desert Storm (the workhorse RF attack against unencrypted GPS) no longer worked.

Eight months later they fought again, and the jamming was heavier. Within twenty-four hours of the opening strikes more than 1,100 ships across the Gulf reported their navigation scrambled; more than twenty jamming clusters were operating between the Strait of Hormuz and the Gulf of Oman. In the first war, Iranian guidance reliability (the share of missiles reaching their aimpoints within design accuracy) had collapsed. This time, even under heavier jamming, reports put it near 98 percent. The miss-distance shrank — strikes that had drifted into open desert were now reaching the bases and structures they were aimed at. On 3 March a Kheibar Shekan punched into Al Udeid, the largest American base in the region. Alain Juillet, former director of the DGSE, France’s foreign-intelligence service, said it in one phrase: Iranian strikes had become “much more accurate.”

Most of what the camera could see was unchanged: the sky, the jammers, and the airframes were similar in both wars. The most legible variable to shift was the receiver. Other things almost certainly moved too (tactics, learning, defensive posture, mission planning), but the receiver is the change a strategist can point at. Iran had stopped navigating by the American satellite system, GPS, and switched to the Chinese one, BeiDou (北斗, Běidǒu — the Northern Dipper).

The Iran-Israel exchange is not the only place this kind of contest is visible. Russian forces in Ukraine routinely defeat GPS-guided American munitions with electronic warfare; Israel has used spoofing against Iranian drones; the air war over Kashmir, six weeks earlier, ran along similar systemic lines. The Gulf in 2026 is one frame in a longer film.

These two wars are lessons in how the character of war is changing. The American military and its strategic doctrine were built around decisive battle, settled by exquisite platforms (the carrier, the stealth fighter, the precision-guided weapon) in one or two pivotal engagements. That era is closing. What is opening is sustained attrition, where the country that can produce cheap precision in volume, replace it after losses, and bind it together across weapons, sensors, and communications outlasts the country that brought the weapon that once decided wars. At the center of that integration sit the satellites the rest of it depends on. To see how a war can turn on them, begin with what they actually do.

What GPS actually is

Four signals solve for position and time.

A GPS receiver doesn’t transmit anything. It listens. Thirty-one satellites are circling the earth twenty thousand kilometers up, and each one is doing the same simple thing on a continuous loop: broadcasting the time on its onboard atomic clock and its own position in orbit. The signal is faint (by the time it reaches a ground antenna it arrives below the noise floor of the receiver), but those two pieces of information are all the receiver needs.

From the time the satellite said the signal was sent and the time the receiver heard it, the receiver knows how long the signal took to arrive. Multiply by the speed of light: that’s the distance to the satellite. Almost. The receiver’s clock is a cheap quartz oscillator, not atomic, and it drifts. Every “distance” the receiver computes carries the same clock error baked into it. The technical name for this not-quite-distance is a pseudorange.

One satellite gives you a distance, which puts you somewhere on a sphere around it. Two satellites narrow you down to the circle where their two spheres intersect. A third sphere reduces that circle to two possible points; in practice one is on Earth and the other is out in space, and the receiver picks the sensible one. That’s trilateration. The catch is that your receiver’s clock was wrong by some unknown amount, so all three “distances” are slightly off, and the three spheres don’t actually meet cleanly. A fourth satellite gives the receiver enough information to solve for the clock error and the position at the same time. Four measurements, four unknowns: three position coordinates and the clock error. They come out together. Your phone learns where it is and what the correct time is in the same instant. The cheap quartz oscillator doesn’t become atomic — it borrows atomic time from orbit.

Northern Dipper / 02

Where am I?

Scroll to find the receiver ↓

The setup

Thirty-one GPS satellites circle the earth, each one constantly broadcasting two things: the current time on its atomic clock, and its position in orbit. They don’t know who is listening. The receiver does all the math.

One satellite, one distance

A signal from one satellite arrives. The receiver knows when the satellite said it was sent and when its own clock says it arrived. The trip took about 70 milliseconds. Multiplied by the speed of light: the satellite is roughly 21,000 km away.

One distance puts you on a sphere

Knowing you’re 21,000 km from this satellite means you’re somewhere on a sphere of that radius, centered on the satellite. Anywhere on the sphere. One satellite isn’t enough to find you.

Two satellites, a circle of overlap

A second satellite gives you a second distance and a second sphere. The two spheres intersect in a circle. You’re somewhere on that circle, and two satellites aren’t yet enough to tell where on it.

Three satellites resolve the point

A third satellite, a third sphere. The third sphere cuts the circle to two points; in practice one is on Earth and the other is out in space, and the receiver picks the sensible one. Three satellites, one location. This is trilateration.

Except the clock isn’t perfect

Every distance you computed is slightly wrong, because your phone’s clock isn’t atomic — it’s quartz, and it drifts. The same clock error contaminates every measurement equally. The three circles don’t quite meet at one point: they all expand or shrink together as the clock error grows or shrinks. There’s one value of clock error that would make them meet cleanly. You don’t know what it is yet.

A fourth satellite solves for the clock too

A fourth satellite gives the receiver the missing piece. Four measurements, four unknowns: your three position coordinates and the clock error. The math solves them all at once. Your phone learns where it is and what time it is in the same instant.

That is the whole architecture: pseudoranges, geometry, four unknowns solved against four equations. GPS and BeiDou run on the same fundamentals: same math, same trilateration, same solve. Where they diverge is in everything wrapped around that shared core: where the satellites sit in orbit, how many layers each system flies, what signals each chooses to broadcast, what protections those signals carry, and which users get access to which tier.

The precision revolution

Precision moved beyond the weapon.

The capability those satellites deliver has a name: PNT, for positioning, navigation, and timing. Positioning is where you are. Navigation is how to get to where you’re going. Timing is the least obvious of the three and the most important: a single shared clock is what lets scattered units and machines act as one instead of separately. PNT is what turns a satellite signal into a guided weapon.

It is worth remembering how recent precision is. Between 1965 and 1972, American aircraft flew 871 missions against one bridge in North Vietnam, the Thanh Hoa, and lost eleven planes. The bridge stayed up. Iron bombs simply did not land where they were aimed. In April and May 1972, F-4 fighters returned with the first practical laser-guided bombs and brought the bridge down in two strikes. Laser guidance worked, but it needed clear weather and a human operator keeping the target in view. Smoke or clouds, and the bomb lost the spot.

GPS removed both restrictions. A weapon that knows its own position can fly to a set of coordinates in any weather, day or night, without ever seeing what it hits. A 1943 B-17 landed bombs within about 1,200 feet (370 m) of where they were aimed half the time. Laser-guided bombs in the 1991 Gulf War landed within roughly 30 feet (10 m). A GPS-guided JDAM today lands within about 16 feet (5 m). PNT made that last leap, from tens of feet to a few meters. PNT is also why the leap is fragile. Jam the satellite signal and the weapon falls back on its own internal guidance, with the error growing from a few meters to tens of meters, the difference between the building and the block.

Northern Dipper / 03

The precision
revolution

370 mHalf the bombs
within this radius1991 · 10 m

District view200 mIllustrative comparison

Scroll through the five scenes ↓

1943 · the B-17

A B-17 dropping from 25,000 feet (7,600 m) landed half of its bombs within about 1,200 feet (370 m) of where it was aimed. The other half landed farther out, sometimes far enough out that they hit the next neighborhood. To destroy one factory, you had to bomb the city around it.

1965–1972 · the iron-bomb era

This is an F-105D Thunderchief over North Vietnam, with iron bombs slung beneath its wings. Over seven years, American aircraft flew 871 missions against the Thanh Hoa Bridge, lost eleven planes, and never brought it down. Unguided bombs simply did not land where they were aimed.

May 1972 · the first laser-guided bombs

This is the Thanh Hoa Bridge after F-4 fighters arrived carrying the first practical laser-guided bombs. They dropped it in a single strike. Laser guidance worked, but it depended on clear weather and a human operator keeping a laser dot on the target. Smoke or clouds, and the bomb lost the spot.

1991 · Gulf War

Laser-guided bombs landed within roughly 30 feet (10 m) of where they were aimed, when weather and visibility cooperated. The ratio reversed: one weapon could destroy one target, instead of thousands of bombs being needed to take out one factory.

Today · the GPS-guided JDAM

A modern GPS-guided JDAM lands within about 16 feet (5 m) of where it was aimed. The weapon is no longer the source of error. The error is in whatever coordinate you gave it.

The accuracy revolution did something else at the same time. It detached precision from the weapon. A guided bomb is only as accurate as the coordinate that aims it. A 16-foot bomb sent to the wrong location is a wrong-location miss. The work slid off the weapon and onto the web that finds, names, and steers it. In 1998, two American officers, Vice Admiral Arthur Cebrowski and John Garstka, gave the shift its name in the Naval Institute’s Proceedings: war was moving from platform-centric to network-centric, and the advantage would no longer live in any one machine but in how tightly all of them were wired together.

Fig. 3.1

Precision depends on every link.

1234

1 · Sensor

Finds the target

2 · Network

Passes the coordinate

3 · Navigation

Provides position
and timing

4 · Weapon

Acts on the information

We caught a glimpse of the systems competition in the open on 7 May 2025. India and Pakistan fought the largest air battle in decades. India flew the Rafale, a French jet near the top of what fighters can be, relying largely on its own sensors and missiles. Pakistan flew the J-10C, a cheaper Chinese export, inside an integrated kill chain: a Swedish Saab Erieye carrying the air picture, a Pakistani Link-17 datalink handing targets to silent-running J-10Cs, BeiDou for navigation, and the long-range PL-15 missile, which per Indian accounts after the engagement was fired from past the distance their pilots had expected to face. Some accounts claim Pakistan fired the domestic PL-15, drawn from PLA stockpiles, rather than the export-spec PL-15E it had previously bought. If true, the detail matters more than the range: China has historically armed customers only with downgraded export variants, never from its own inventory. Handing a partner the real missile on the eve of a fight would be new. At least one Rafale came down. The lesson was not about airplane quality but about the chain each side was operating inside. For most of the era since 1991, integration of that kind was something a rival could only buy from the United States, packaged whole and on American terms. What China changed is that it started selling the components (fighter, sovereign navigation, long-reach missile) at prices that let a state without American patronage wire its own chain. And several of those ‘components’ are themselves integrated systems: BeiDou alone arrives as a stack with navigation, messaging, signed signals, and layered orbits already wired together, doing much of the chain-building for the buyer.

The exquisite weapon still matters. But it has become the last link in a chain, and a chain is only as strong as its weakest link. To see how losing one faint satellite signal can beat a capable military, you have to look at the chain itself, and at the way modern force is composed.

The kill chain

The system gives the weapon its reach.

Every modern military runs the same kind of process: see the target, decide to hit it, hit it, check whether it worked. The American codification is linear: six discrete steps in a closed loop, easy to walk through. Other powers frame the same problem differently. The Soviets called theirs the Reconnaissance-Strike Complex. The Chinese have been formalizing a more systemic conception.

The American name is F2T2EA. First you find the target, when a satellite, a radar, or a scout notices it. Then you fix it, pinning it to coordinates a weapon can use, and track it if it moves. You target it (which weapon, what authority), then engage by firing, and finally assess whether it worked or whether you have to go again. All else being equal, the side that closes its own loop faster and breaks the other’s gains a decisive operational advantage, though attrition, geography, and morale shape much of the rest of the contest.

Running the loop takes four standing capabilities. ISR (intelligence, surveillance, reconnaissance) does the finding and the fixing. Communications carry the coordinate from the sensor to the shooter. Weapons, the precision munitions, do the engaging. Logistics keep the force fed and every unit aware of where the others are, so the chain never fires on itself.

And what holds the four together is PNT (position, navigation, and timing): not a fifth pillar in line with the others, but the substrate the four stand on. Position turns “contact” into a grid square a weapon can fly to. The shared clock lets the sensor, the network, and the shooter act on the same tick, so a track passed from radar to datalink to launcher is still the same track when the trigger is pulled. The other four are standing capabilities. PNT is the layer underneath, the foundation the rest rest on.

Interactive 4.1

What depends on PNT

Find

Swipe to explore ↔

Explore landscape ↔

Restore PNT referenceThe hardware is still working

Scroll to follow the handoff ↓

Four capabilities

ISR finds and fixes the target; communications passes the coordinate to the shooter; weapons engage; logistics keeps the force fed and aware of itself. These are the four standing capabilities that carry every step of the loop.

A common reference

One layer runs beneath all of them. Position turns “something is there” into a coordinate. The shared clock lets the sensor, the network, and the shooter act on the same instant. PNT is not one of five; it is what holds the other four together.

Without the reference

Take PNT away and the links do not weaken — they stop locking together. The sensor still sees, the network still passes data, and the weapon still flies, but none of it is the same target.

The wider world

And the dependence is not military alone: the same signal times stock exchanges, power grids, container ports, and runways.

Pull PNT out and the links do not weaken. They delaminate; the chain comes apart in layers. The sensor still sees, but its read cannot be turned into a coordinate a weapon can fly to. The network still passes data, but the data no longer lines up. The weapon still flies, toward a point that has already drifted from meters to blocks. The exquisite platform cannot buy its way out of that vulnerability. Break the weakest link and the most expensive weapon in the inventory can become a tube aimed at open ground.

The Chinese version starts from a parallel lesson. Beginning after the 1991 Gulf War, sharpened by Kosovo in 1999 and Iraq in 2003, PLA strategists drew a foundational conclusion from watching the American kill chain operate. American dominance was not primarily about platforms, it was about the system that wired the platforms together, what PLA writing would come to call zuozhan tixi (作战体系), the operational system. The aircraft, the missile, the radar were nodes. What did the actual work of war was the system linking them.

What followed in PLA literature is not a single concept but a doctrinal stack. The outermost frame is xinxihua zhanzheng (信息化战争), informationized warfare, naming the broader condition: modern war is fought through, and against, information systems. Inside that, tixi duikang (体系对抗), or systems confrontation, names the operational mode: two operational systems contend, each trying to maintain its own coherence and degrade the other’s. And inside that mode, tixi pojizhan (体系破击战), system-destruction warfare, names the specific theory of victory. You win by paralyzing the enemy’s operational system, not by annihilating fielded forces. Earlier discussions of paralysis appear in the 2001 Science of Military Strategy; the explicit system-destruction vocabulary becomes visible across the 2000s and 2010s.

The unit of analysis is the enemy system. Targets are chosen at the system level, not by what is locally convenient to hit but by what would collapse the operational architecture. Sometimes that means destroying a high-value node: a command post, a comms relay, a logistics hub. Sometimes it means compromising the link between nodes: emissions, signals, satellite navigation, the trust between sensor and shooter. And for the most expensive nodes to physically reach, the link is often the cheaper attack: you don’t have to shoot down the satellite if you can degrade the signal it sends. Counter-space, electronic warfare, cyber, deception, jamming, spoofing: in the Chinese conception these are not separate tricks, they are applications of one theory.

American doctrine has its own anti-system traditions: Boyd’s OODA loop, network-centric warfare, a long lineage of attacking command-and-control. The U.S. has always thought about disrupting enemy decision cycles. But where these have generally been treated as one mode among many in American doctrine, system destruction sits at the center of the Chinese conception. That difference in centrality, more than the presence or absence of any single concept, reflects where each doctrine was written from. The United States wrote its doctrine from inside a working kill chain, and from the inside, integration is a capability to refine and extend. China wrote its doctrine watching that chain from the outside, and from the outside, integration is the leader’s most exposed surface: the first thing to sever.

Iran’s GPS shutoff during the June war and Israel’s parallel PNT struggle were system destruction at work: each side going after the signals that hold a networked force together. Kashmir showed the doctrine’s other face, systems confrontation: two operational systems contending in the open, and the better-integrated one winning.

None of the techniques is new. Jamming and spoofing and cyber and deception are old, space targeting too, and the instinct behind them is older still: Chinese strategy has long sought to exhaust an adversary rather than break him in a single decisive battle. What is new is the codification. The PLA gathered the old techniques into system-destruction warfare, a doctrine that fits the old instinct to a networked age: you win by denying the enemy the integration that binds his forces into one, and each year the exquisite parts are worth less without it.

The other new thing is diffusion. Kashmir showed the components already on the market; what has spread with them is the doctrine, so a state that buys the toolkit now gets the theory of its use as well.

And it is not only war. The same timing layer stamps stock trades, synchronizes the power grid, runs container ports, and lands aircraft. When it drops, ships appear to jump across continents and pilots reach for paper maps. The kill chain and the container port run on the same clock. A civilization has wired its existence, quietly, to a signal from twenty thousand kilometers up.

So how do you break that link without putting a weapon on the satellite? You don’t need to. The signal is faint and the band is published; jamming and spoofing are ordinary background conditions of modern conflict, and the most PNT-dependent military on earth has been paying for both. There are two ways a satellite signal can be killed.

How you break a signal

Jamming silences. Spoofing misleads.

Electronic warfare is the contest inside the spectrum: the radar returns, the radio nets, the datalinks, the satellite communications (SATCOM), the satellite-navigation signals (GNSS) militaries use to see, talk, and steer. Instead of destroying his troops directly, you wreck the band his system breathes: blind his radar, cut his radios, corrupt his navigation. In a networked force, what happens in the spectrum can decide the exchange before the first weapon arrives. The slice of EW aimed at PNT has its own name, navigation warfare, and over the last decade it has gone from specialist concern to a near-constant background condition of modern conflict. Iran shut off GPS over its own airspace during the June war. Israel ran spoofing operations against Iranian drones. Russia has blanketed the Baltic with jamming since 2022. American precision munitions in Ukraine are now routinely defeated by Russian electronic warfare.

There are two ways to defeat a satellite signal at the receiver, and they are not the same. The first is to jam it: blast noise on the signal’s frequency until the receiver can no longer pull the real signal out of the din. The second is to spoof it: broadcast a convincing counterfeit, so the receiver does not go blank but does something worse: it calmly computes a confident, precise, wrong position, one that passes every internal sanity check. There is a clean compression for the difference. Jamming silences the receiver; spoofing convinces it of the wrong thing.

Fig. 5.1

The civilian GPS signal

GPS L1 C/A

Public format

The signal carries a publicly documented code.

Faint on arrival

About −130 dBm at the phone.

What the phone hears

Background noiseGPS signal

Known pattern

The phone knows what to listen for.

Compare the patterns over time

The pattern stands out

The phone finds a match.

Different alignments of the known code

The open civilian signal everyone’s phone uses can resist neither attack. The L1 C/A broadcast arrives at the ground well below the receiver’s own noise floor, recoverable only because the receiver knows exactly which pseudorandom pattern to listen for. A jammer the size of a cigarette pack, bought on the internet for fifty dollars, drowns it across a city block. And the L1 format is fully documented, so building a convincing fake is straightforward. That combination is why jamming and spoofing are now ordinary. The mechanics divide cleanly.

Fig. 5.2

How jamming blocks GPS

GPS satellite

Continues to broadcast.

Nearby jammer

Adds interference near the phone.

Faint GPS signal,
unchanged throughout.Added interference
from the jammer.

Jammer offGPS available

Jammer onGPS unavailable

GPS
unavailable

The harder of the two to detect is the spoof, because the receiver does not see a glitch, it sees a clean fix. And the takeover is not a sudden swap, it is a smooth handoff. A capable spoofer starts by broadcasting a signal that matches the real one almost exactly, then slowly walks the broadcast away from truth. The receiver follows. Its perceived position decouples from its actual position by inches, then by meters, then by kilometers, with no break in the displayed precision. Researchers call this the drag-off. There is no moment when the receiver flinches.

Fig. 5.3 · Spoofing

A false position changes the course

Fig. 5.3 · Spoofing

A false position changes the course

Navigation compartment · enlarged view

Actual flight: still straight

Actual flight · regional view

01

The journey

The missile is heading toward a building inside the airfield.

Scroll to follow the explanation ↓⌄⌄

01

The journey

The missile is heading toward a building inside the airfield.

Navigation compartment · enlarged view

Actual flight: still straight

Actual flight · regional view

02

Inside the navigation

GPS helps the missile calculate its position and stay on its planned route.

Navigation compartment · enlarged view

Actual flight: still straight

Actual flight · regional view

03

It thinks it has drifted left

The false signals move its calculated position. The real missile is still on course.

Navigation compartment · enlarged view

Actual flight: still straight

Actual flight · regional view

04

It steers right to compensate

The missile gradually changes direction to correct the error shown by its navigation.

Navigation compartment · enlarged view

Actual flight: still straight

Actual flight · regional view

05

The display says it is back on course

Its calculated position returns to the route while the real flight continues to diverge.

Navigation compartment · enlarged view

Actual flight: still straight

Actual flight · regional view

06

The intended target is left behind

The missile passes clear of the target. Its navigation has led it along the wrong path.

Navigation compartment · enlarged view

Actual flight: still straight

Actual flight · regional view

The missile is on course, but false GPS signals make it think it has drifted left. It steers right to compensate, taking it away from its target.

That asymmetry, the absence of any moment when the receiver flinches, is what makes spoofing the harder problem of the two. Jamming is loud. A receiver under jamming knows it has lost the signal: it can warn the operator, fall back on inertial guidance, refuse to act on stale data. Spoofing is silent. It hands the operator a wrong answer that the receiver itself cannot tell apart from the right one. Which leaves the question: how do you defend a signal against attacks like these?

How you defend a signal

Protection begins at the signal.

There is no single thing that makes a signal hard to jam or spoof. There is a set of techniques, layered, and each system combines them its own way. The foundation, one even the open civilian signal has, is spread spectrum: every GNSS signal, civilian and military, is smeared thinly across a wide band, riding below the background noise, so a jammer cannot sit on one frequency and has to flood the whole band. That raises the price of jamming, but not by much when the signal underneath is a whisper; the cigarette-pack jammer still wins. The open civilian signal carries that first layer and nothing else.

What militarizes the signal is encryption. Key the code with a secret. Only a receiver holding that key can acquire and track the signal, and nobody without it can forge a copy the receiver will accept. That one step does much of the anti-spoofing work.

A reported moment from the 2026 war suggests what that step looks like in the field. Israeli systems tried to feed false coordinates to Iranian drones on BeiDou’s military signal, which public Chinese descriptions say is cryptographically signed at every broadcast. The receivers checked the signature, found that the fake was not signed with the right key, and rejected it. The spoof bounced off.

Fig. 6.1 · Authentication

The signed message

Fig. 6.1 · Authentication

The signed message

Navigation unit

At the trusted source

Only the source can create
this signature.

Private key · kept here

Navigation message

Satellite orbit
& clock information

Digital signatureCreated for this message

Message + signature

Navigation message

Satellite orbit

Clock information

Private key

Kept secret · creates signatures

Sign

Signed message

Navigation data

Signature

Satellite broadcast

The private key stays at the source.

Navigation message

Satellite orbit

Clock information

Altered data

Signature

Signature valid

Public key

Trusted copy · checks signatures

Verify

VerifiedUse this message

The check binds the signature to this message.

01

The source signs the message

The source uses its private key to sign the navigation data. The signature travels with the message so the navigation unit can check it.

Scroll to follow the message ↓

01

The source signs the message

The source uses its private key to sign the navigation data. The signature travels with the message so the navigation unit can check it.

Navigation unit

At the trusted source

Only the source can create
this signature.

Private key · kept here

Navigation message

Satellite orbit
& clock information

Digital signatureCreated for this message

Message + signature

02

The message travels with its signature

The source signs the navigation data before broadcast. The message and signature travel together; the private key stays behind.

Navigation unit

Navigation message

Satellite orbit

Clock information

Private key

Kept secret · creates signatures

Sign

Signed message

Navigation data

Signature

Satellite broadcast

The private key stays at the source.

03

The navigation unit checks the message

Using a trusted copy of the public key, the unit verifies the signature for the message it received.

Navigation unit

Navigation message

Satellite orbit

Clock information

Altered data

Signature

Signature valid

Public key

Trusted copy · checks signatures

Verify

VerifiedUse this message

The check binds the signature to this message.

04

An altered message fails the check

Changing the message invalidates the signature attached to it. Without the private key, the sender cannot create a valid replacement.

Navigation unit

Navigation message

Satellite orbit

Clock information

Altered data

Signature

Signature invalid

Public key

Trusted copy · checks signatures

Verify

RejectedMessage not used

The check binds the signature to this message.

A signature lets the navigation unit check who sent a message and whether its contents have changed.

Beyond encryption, the two superpower constellations diverge. America’s M-code, broadcast since the modernized GPS satellites began launching, but still waiting on user equipment and ground systems to deploy at scale, leans on power, and on aiming it. A focused spot beam can concentrate the hardened signal up to roughly a hundred times stronger over a chosen region for a chosen time. BeiDou’s military signals reportedly add what M-code does not: frequency hopping, where the signal jumps across frequencies on a schedule a jammer cannot follow, and navigation message authentication, a cryptographic signature on every broadcast. And where M-code bets on aimed power, BeiDou’s bet runs toward breadth: a low-orbit layer planned for later this decade would raise the strength of the whole signal everywhere at once, since a satellite six hundred kilometers up is far closer, and far louder, than one at twenty thousand. Europe’s Galileo runs an encrypted Public Regulated Service that resembles M-code most closely, and Russia’s GLONASS keeps its own military protections on an aging constellation, but neither fields the reach or the layering to contest the tier the two superpowers are fighting over.

The difference in the two wars was cruder than any of this. The weapons of 2025 were on the open civilian signal, which carries none of these protections; the weapons of 2026 were on the hardened B3A tier, and the same jamming failed. That tier cannot be bought off a shelf: the keys, the receivers, and the integration come only from the power that owns the constellation, and Iran’s came from Beijing.

Beijing’s tier is not merely different; by the American government’s own assessment, it is better. In November 2022 the National Space-Based PNT Advisory Board warned that GPS is “now substantially inferior” to BeiDou. The words carry a qualifier worth keeping: the inferiority lies in what is fielded today, in jam resistance and in functions beyond navigation, not in the underlying signal design. The fix exists: the next generation of GPS satellites carries Regional Military Protection, the hundred-times spot beam, but the program has slipped repeatedly and the first satellite carrying it is not expected before 2027. Some of that gap is schedule, and that part will close as the new satellites reach orbit. But where BeiDou is furthest ahead, in what its satellites themselves do beyond navigation, there is no announced American answer at all. That contest will not be settled this decade.

Spread spectrum, encryption, power, hopping, authentication — all of these are moves at the signal layer. And they all serve one function: keeping guidance reliable under attack, so a weapon arrives where it was aimed. That is what the two wars turned on. But there is a deeper difference between GPS and BeiDou, not in their signals but in their architecture: where the satellites orbit, and how much more than navigation a constellation can be built to do.

Continued in Part II: The Changing Character of War picks up there and finishes the technical story first: the architecture of the two constellations, and the kill webs assembled on top of them. Then it turns to the consequences: what the new arithmetic does to force projection, to the powers built on it, and to the global order predicated on that power.