33 CFR § 62.53 - Racons.

(a) Aids to navigation may be enhanced by the use of radar beacons (racons). Racons, when triggered by a radar signal, will transmit a coded reply to the interrogating radar. This reply serves to identify the aid station by exhibiting a series of dots and dashes which appear on the radar display in a line emanating radially from just beyond the echo of the aid station. Although racons may be used on both laterally significant and non-laterally significant aids alike, the racon signal itself is for identification purposes only, and therefore carries no lateral significance.

(b) Racons are also used as bridge marks to mark the best point of passage.