Radar

"That's Miwa and Izumi. Tōma's wearing Bagworm so we can't tell."

- Ken Satori

Radar (レーダー) is a Standard Equipment Trigger so it can be used by all A and B-rank Border combatants.

Appearance
Radar is projected by Border agents as a flat, round hologram of a in which equidistant, concentric circles intersect two perpendicular lines. The lines, every fifth circle and all intersections are more pronounced than the other rings. Trion signatures appear as dots that leave a trail as they move. If their altitude differs from Radar's user's, an underscored caption reading "high" or "low" in capital letters appears next to the signature.

Overview
It is unknown when Border created this Trigger. Since some Neighbor countries use a similar Trigger, it might be part of the technology that Border acquired in the Neighborhood. An enhanced version was also developed at some point which is used by Asumi Amakura

Abilities
Radar detects the signatures emitted by trion bodies, allowing the user to know the position and numbers of Trigger users within range. Compass points are also displayed as well as the elevation of other trion signatures relatively to the user's position ("high" or "low"). This information can be cross-referenced with the topographical data available to Operators for greater accuracy: trion signatures detected by Radar can be superimposed on a map of the area, as well as tagged so their owners can be told apart. A Radar user can also increase its precision without an Operator's assistance, zooming in on the trion signatures to get a better sense of their direction, distance and speed in return for an increase in trion consumption.

Radar is able to detect agents who turn invisible with Chameleon, but not the ones utilizing Bagworm or other stealth Triggers designed to hide the user's trion signature. Since it is not placed in either the Main or the Sub, it can be activated even when one Trigger from each column is already active. However, an enhanced version also exists which does occupy a Trigger slot. Its effects are currently unknown.

Aftokrator
Hyuse owns a device which, among others, has a function identical to Radar's, with the trion signatures appearing on a grid instead of a C-scope. Despite the signatures appearing as mere dots, he was able to recognize them as belonging to Idras. This could be because of their movements and/or his knowledge of Rhodokhroun.

Rabbit ears work much like Radar, further suggesting that, even though no Neighbor seemingly used it during the Second Large-Scale Invasion, Aftokrator indeed possesses this technology.

Galopoula
The first model is not unlike Border's standard version that sports a grid instead of a C-scope and might be able to reproduce a layout of the user's surroundings without the Operator's topographical data. It is unable to tell a human's trion signature apart from those left by Switchbox. The signatures it detects can be projected on what the user sees.

The second model has a square display, which hovers over the user's wrist or palm. It is seemingly much more advanced than the other version or Border's, as not only humans in trion bodies and the various types of Trion Soldiers have each their own distinctive icon, it is also capable of bypassing Bagworm's cloaking effect and to display the trajectory of bullets as well as an approximation of their size, making it possible to tell Sniper and Gunner Triggers apart, in addition to arrows pointing towards the direction groups of enemies are moving.

Users
As a Standard Equipment Trigger, Radar is included in the Trigger sets of all A and B-rank agents, for a total of approximately 130 users. Asumi Amakura is the only known user of its enhanced variant. C-rank trainees are given access to Radar during training.

Trivia

 * This Trigger is based on real-life s.
 * Radar was originally supposed to be unable to reveal elevation, although it was consistently shown to be able to do so from Chapter 163. It is unknown if this is an in-universe update, a retcon or a mistake.
 * Radar is similar in function to Echo, one of the seals of Yūma's Black Trigger, although it provides far less information.
 * If Radar and Echo share the same mechanics, it would mean that Radar works by emitting a faint wave of trion much like a would sound.