© BBCThe survey built on the previous studies carried out by English Heritage
The discovery has been made as part of an underground archaeological survey of the Stanton Drew stone circles.
The complex is the second biggest in Europe and dates back to the late Neolithic and early Bronze Age.
An earlier study in 2009 concluded the site was 1,000 years older than previously thought after an underground burial chamber was found.
'Sacred objects'
The studies, which took place in 2009 and 2010, were made by Bath and North East Somerset Council and Bath and Camerton Archaeological Society (BACAS) in a joint project.
The geophysical studies build on previous work by English Heritage in 1997.
Team leader John Oswin, from BACAS, said: "The main set of rings are even more complex than English Heritage thought with the work they did.
"We've also found some form of occupation using the rings - not treating them as sacred objects but by using them as a farmstead.
"We found an extra entrance through into the main ring, and there was a bank and ditch around the stone circle but that is now totally invisible."
Further work in the south-west section of the circle also showed that the stones in the south-southwest circle sat on a deliberately-levelled surface - which "seemed to be deliberate" and "quite impressive" according to Mr Oswin.
The stone circle complex is made up of the Cove, which are three stones, a main stone circle and two smaller circles as well as two avenues which link together the main circle and north-east circle.
A second avenue also comes off the north-east circle.
In 2009 archaeologists confirmed the existence of a long barrow - or underground burial chamber - underneath the Cove, about 1,000 years older than the stones themselves.
The archaeologists now hope to extend their work to nearby stone monuments such as the Tyning Stones, Hautville's Quoit to understand more about the purpose of the Stanton Drew complex.
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