As mrz says, the SATS results are to check progress 5 years later in GCSE and are aggregated up to give a guide to the performance of the school.
However, I think it depends on the secondary school on whether they are used before then for setting by subject or even end-of-year target setting.
Many schools use CATS for initially setting the children in year 7 and also for deciding on their targets for the end of year 7. Cats tests are like the 11+ tests with verbal reasoning etc. They look a lot like IQ tests to me.
The CATS tests are supposed to measure ability rather than attainment, so they aren't supposed to be something that can be coached for (unlike SATS), but I see a lot of children going to private tutors for a year before they take the 11+, so I am not sure how true that is.
It depends on the school when the CATS are given (if at all). Some will do them at an induction day this term, whilst others will wait until September. Some won't do them at all.
The secondary schools try to keep the CATS low key and not alarm the children, and they often don't share the results with the parents.
Some secondaries don't even bother setting in year 7, so I guess they may not bother to do CATS tests at all.