Sir Frank Williams believes his team can turn themselves back into credible front-line contenders in 2006.
The team, who dominated most of the 1990s, had a disappointing 2005 and have to pay for Cosworth engines this year after splitting with partner BMW.
Unveiling the team's new car, Williams said: "We are as ambitious as anyone but we are also cautious.
"I'd like to win every race but being realistic if we finish in the top three in the constructors that will be good."
Williams agreed that losing BMW was a blow but hoped their new-found independence would work to their advantage.
"We tend to be more impressed with brain power than budget power," said Williams.
"Not having a manufacturer is a disadvantage. You can just get more done and more quickly by means of having more people and spending more money.
"But there is still room for being nimble and agile, being able to recognise problems ahead of other people, and maybe that is what we can demonstrate we can do."
Technical director Sam Michael is the man in charge of ensuring the new car is capable of challenging the best.
"The car has a lot resting on it - it must re-establish Williams at the sharp end.
"There are many good F1 teams; beating them is simple - design a faster car," he said.
Australian Mark Webber is the team's lead driver and he will have the added pressure of helping 20-year-old newcomer Nico Rosberg adjust to the challenges of Formula One.
Williams said: "I'd love to win a race this year otherwise I will be called Tim Henman.
"I want to be a consistent operator and performing at the front.
"I'm very conifdent in terms of the work that has been put in. We will find out how good it is in Valencia when we test next weekend."
