At the 2026 World Cup, referees on the field and officials on the sidelines will have access to an unprecedented array of technology to call penalties, spot offside violations, and make other consequential decisions. The video assistant referee system (VAR) and semi-automated offside technology (SAOT) have been used in soccer for years, but the setup at this summer’s tournament represents some of the most advanced implementations of adjudication tech ever deployed in high-level sports.

How the System Works

During each match, the pitch will be saturated with sensors, cameras, and cutting-edge computer vision software. A standout advancement this year is the use of digital twins. Every player in the World Cup has undergone a full-body scan by computer. These digital twins—precisely matching each athlete’s height, limb length, and shoe size—can be dropped into a virtual simulation of the game to determine their exact position relative to the ball, boundary lines, and other players. Officials then use this data to help spot infractions, determine penalties, and sharpen the accuracy of the beautiful game.

Though these systems can scrutinize the action far more closely than human eyes, flesh-and-blood referees remain integral to the game. However, when officials make mistakes—and they do, ask any fan—they can turn to the technology to correct errors, replacing subjective calls with objective truths. The primary purpose is to catch major errors, such as checking if a player was offside during a play that decides a game-winning goal. Teams can also request reviews of even inconsequential plays, sparking debate about the system’s true value: bringing an impartial eye to pivotal moments or allowing leagues to adjudicate tiny infractions measured in inches.

The Eyes Have It

FIFA and other worldwide soccer agencies have made their stance clear: they want to eliminate big errors, but those inches matter. Elements of this year’s setup resemble the 2022 World Cup but with upgrades. Hawk-Eye remains the optical tracking provider, with its computer vision system capturing over two dozen skeletal points on each player at all times. The tracking system now uses 16 high-resolution cameras, up from 12 in 2022, according to FIFA director of innovation Johannes Holzmüller.

As in 2022, optical data is combined with advanced sensors inside the ball. Kinexon, a leader in sports wearables, again provides the match ball’s digital brain. This time it includes an ultrawide-band and IMU sensor setup (incorporating both an accelerometer and gyroscope, the latter crucial for tracking ball spin) that records the ball’s precise location and any distinct touches 500 times per second.

The 2022 version of the ball sensor was suspended in the center of the ball’s interior by a string-based sling made by Adidas, which also manufactures the ball. Now, Adidas has created a small bladder to hold the sensor along the inside wall of the ball. “It’s vulcanized inside the bladder with a little plastic pouch,” says Maximillian Schmidt, Kinexon’s cofounder and managing director. “That vulcanization is just way more stable than those strings, which had hooks that could break easier.” Placing the sensor along the wall instead of the center requires counterbalancing to prevent wobbling. Schmidt notes the entire setup weighs just 13 grams, but his team calibrated everything to ensure even tracking of every touch or movement. Because the sensor now sits where it can be kicked directly, robust impact testing was essential.

Combined, these optical and in-ball tracking systems will capture every nuance of all 104 World Cup games. However, it’s the high-tech assist borrowed from virtual reality that makes them even more accurate.

Digital Twins

In the lead-up to the tournament, all 2026 World Cup players underwent a 360-degree high-resolution scan from FIFA’s tech partner, Lenovo. These scans are ingested into the Hawk-Eye system, replacing generic avatars used previously for offside and other VAR applications. Art Hu, Lenovo’s global chief innovation officer, says these scans define the body’s shape, muscle tone, and even shoe size with an accuracy of 1 to 2 millimeters. “That’s an order of magnitude improvement on an ordinary avatar,” Hu explains. The real technical challenge lies in using a single static scan and applying that digital twin to Hawk-Eye’s skeletal pose data during active gameplay—when players are running, jumping, or sliding. Achieving those few extra inches of precision requires enormous computing power and algorithmic tuning.

FIFA tested the new setup at the Club World Cup and Intercontinental Cup in 2025, as well as various youth tournaments over the past 18 months, according to Holzmüller. Previous versions of the digital twin tech had already assisted in VAR decisions for all goals and penalty kicks. The new version also helps review red-card penalties and incidents where an on-field official accidentally penalizes the wrong player. VAR technicians can now overturn corner kick decisions if the system detects an error and alerts the referees via headset without delaying the game. (Some calls take longer to calculate and would slow down the game, so VAR won’t be used for those.)

To further reduce wasted time, VAR now sends immediate alerts to sideline officials for obvious, promptly detectable offside decisions, stopping play right away. This differs from past arrangements where play continued after a violation, only stopping later if a notable event like a goal or penalty occurred. Holzmüller says his team is confident the upgrades will yield the correct call more often, even on nuanced decisions like “when there’s only one toe offside.”

Keeper Peeper

While the vast majority of offside plays can be spotted by watching slowed-down broadcast footage, a handful of infractions (or non-infractions) occur at the precise moment between video frames. Despite the rarity, FIFA is committed to solving this: Holzmüller says a combination of 3D scans and ball-tracking data—capturing positions 500 times per second, surpassing video’s 60 frames per second—will supplement the footage to provide the most complete picture possible.

Perhaps the most intriguing feature of the digital twin tech is a “3D goalkeeper view” within VAR. This visualizer shows the goalkeeper’s point of view and, using the system’s digital inputs, determines if an attacking player in an offside position interfered with the keeper. Such interference has long been illegal in soccer, but the number of players and field size made it hard to call accurately. Hu points out wide-ranging possible uses for digital twin technologies across sports, from officiating to athlete health and performance. As models become more powerful and computing costs drop, they will only improve.

It’s fair to question if the juice is worth the squeeze for gaining an inch or two of resolution on certain rare calls. Holzmüller readily admits these advances, with all the technical and financial legwork they require, might change only a few calls throughout the entire tournament. From FIFA’s perspective, however, for arguably the world’s biggest sporting event, the value is unquestionable. “We have to bring the best technology to the World Cup,” he says. “That’s our goal.”

This system represents a quantum leap in how soccer is officiated, blending human judgment with machine precision. The integration of digital twins, advanced ball sensors, and high-resolution cameras ensures that every call is backed by data, reducing controversy and enhancing fairness. As the technology evolves, it may set a new standard for sports adjudication worldwide, not just in soccer but across all competitive athletics.

Source: Ars Technica News