The new Formula 1 season gets underway at Barcelona's Circuit de Catalunya, following a busy week of launches. The home of the Spanish Grand Prix will host F1 teams over two four-day tests – the first set from February 22 to 25 and the second from March 1 to 4, 2016.

Let’s review the new 2016 challengers of the teams who have unveiled their cars so far.

Mercedes

The F1 W07 Hybrid hit the track for the first time last week, with Nico Rosberg and Lewis Hamilton clocking up just under 100km between them at Silverstone, as part of a promotional event. Despite Mercedes winning the last two constructors' championships, and with Hamilton collecting the drivers' titles the past two years, Mercedes is still aiming for perfection, according to technical executive director, Paddy Lowe.

"After a highly successful season all round in 2015, our priority has been to identify the areas in which we were weakest and to try to improve on those," said Lowe.

"We are seeking optimisation absolutely everywhere."

Ferrari

Ferrari’s SF16-H aims to push Mercedes to the wire in the 2016 championship, with the livery sporting more white than it has in recent years, predominantly on the engine cover and front wing.

In terms of making the car "properly competitive", according to technical director James Allison, Ferrari has opted for changes in a number of areas. The nose is shorter and higher, impacting positively on the aerodynamics, while after four years with a pullrod suspension, the car is now fitted with a pushrod system.

Ferrari has worked on its power unit's architecture, making it tighter and narrower, so influencing the engine cover, which again aids aero. The engine team has also improved combustion, the turbo and air intake in a bid to find more performance.

Asked as to the car's prospects, Arrivabene said: "Normally I am not setting the objectives, my boss sets the objective for the team. "I think this year, we need to push a bit more. We would like to fight until the end for the championship. I know that is not going to be easy, because our competitors are not sleeping, but we are committed to do our best."

Williams

Revealing the FW38, the Grove-based team conceded it will be "a challenge" to retain its place as the best of the rest behind Mercedes and Ferrari.

But after finishing third in the constructors' championship in 2014 and 2015, Sir Frank Williams knows it will be a tall order for a three-peat.

"Williams has started to cement our position back amongst the front-running teams after finishing third in the championship in the past two seasons," he said. "This has been a great achievement given the resources of those around us. Staying where we are will be a challenge in itself, but we are determined to keep improving because only winning will ever be good enough."