> For the complete documentation index, see [llms.txt](https://docs.ceruleansonar.com/c/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ceruleansonar.com/c/rov-locator/multi-unit-operation-swarms/multi-unit-1-2.md). # Multi-Unit 1:2 The Multi-Unit 1:2 case has two independent transmitters on ROVs or divers, with each transmitter on a different channel. A single receiver tracks both transmitters. The position of each transmitter is updated once per second. If a topside GPS is associated with the receiver, the absolute (latitude/longitude) position of each transmitter can be known. The Mk II Autosync model is the only ROVL model that can operate on two channels (and thus the only model that supports this version of 1:2). In order to maintain clock synchronization, all three units must surface and re-acquire the GPS signal periodically (every hour or two). {% hint style="info" %} The 1:2 case is partially supported by CeruleanTracker and CeruleanMap software (one unit is fully supported and the second unit's position can be simultaneously plotted on CeruleanMap). Additionally, users can write their own software to make use of the positional information created. {% endhint %}