An adaptive subspace echogram locates the Ansata base on Rutia
An adaptive subspace echogram, also known as a magnetosphere echogram, was a method developed by the crew of the USS Enterprise-D in 2366 to track the movements of Ansata terrorists, who traveled interdimensionally through use of a device called an inverter.
The crew was able to utilize the echogram to track the subspace reflections that occurred as a side effect of using the inverter. Using this technology, they were able to locate the Ansata base on Rutia IV and rescue their crewmembers, who had been kidnapped by the Ansata for use as bargaining chips to leverage Federation involvement in their conflict with the Rutians. (TNG: "The High Ground")