Archaeologists have produced three-dimensional images of the horned cairns from the scans.
The stone structures are more than 60m (196ft) in length and have two projecting walls at their entrances that create small courtyard areas.
A car park and path are to be built near the cairns to allow the public to visit them.
Consultant Dr Graeme Cavers, of AOC Archaeology, said: “The Shebster area is an unusually good example of a well-preserved cluster of sites.
“They are essentially burial and ritual monuments, much like the chapels and shrines of more recent times, and each of them is likely to have been used exclusively by individual local groups or communities.”
He added: “The survey makes an invaluable contribution to the archaeological record of Caithness, and is really the first large-scale survey of its kind undertaken in Scotland.”