Metroid Dread’s Planet ZDR is full of alien tech for Samus Aran to harness for her own use. This includes the Phantom Cloak, which allows her to go invisible and hide from enemies. The Pulse Radar is almost the inverse of that, letting you scan for hidden objects in the vicinity. But first you need to find it.
This requires that you kill the EMMI patrolling the Ghavoran region first, as you’ll need its Ice Missile ability to reach the Pulse Radar. Once you have that, head to the southern Save Station in the area – the next ability is due north from there, past the flooded chamber and Morph Ball tunnels. From those tunnels, climb up to find an Enky at the end of the passage and use an Ice Missile to destroy it. Now start climbing the series of tunnels via the Morph Ball and its Bombs. When you emerge in a room to the northwest, head to the lower left corner. Tuck into a ball to roll over some breakaway blocks and find yourself in a large room. In here is the Chozo Statue which holds the Pulse Radar ability.
Like the Phantom Cloak, this ability uses your yellow energy meter. Holding right on the D-pad charges up the scan; once released, it’ll burst out and analyze your surroundings, revealing any hidden blocks. In fact, you’ll need to do this right away to actually escape the room where the Pulse Radar was found. Just note that a scan consumes your entire meter, which will recharge automatically after a moment.