Michael Schumacher has shrugged off speculation about his future after a poor Turkish Grand Prix by insisting he is still "motivated" to succeed.

The German legend admitted after finishing 12th in Istanbul that "the big joy is not there right now".

But in a Mercedes preview to the Spanish Grand Prix he said: "I was not happy with my weekend in Turkey.

"But there have been clear signs of improvements for the team, which push and re-boost my motivation even more."

The seven-time world champion has been out-qualified by Nico Rosberg in 15 of their 23 races as team-mates and was more a than a second off the qualifying pace of his German compatriot.

While Rosberg has collected 20 points this season, Schumacher has six in what has been a disappointing season for the German team.

quote It will be interesting to see the effect of Kers, the DRS and the Pirelli tyres on a track where overtaking is always difficult

But the 42-year-old's optimism has been renewed by a aerodynamic update, along with a suspension adjustment, for the WGP-02 car ahead of the Spanish Grand Prix on 22 May.

The Circuit de Catalunya in Barcelona is one of Schumacher's favourites, where he has won six of his record 91 grands prix victories.

"The Spanish Grand Prix is traditionally where it really feels like the European season gets underway and holds a lot of good memories for me," he added.

"Of course, we know the Circuit de Catalunya very well from testing, but it will be interesting to see the effect of Kers, the DRS and the Pirelli tyres on a track where overtaking is always difficult."

Team principal Ross Brawn said the new updates should improve the car's consistency and bring it closer to the standard expected by the German giants.

"The last two races in Turkey and China have proved that we can be quick in certain conditions but we need to focus on achieving that level of performance consistently over the entire race weekend," said the Englishman.

"The Circuit de Catalunya is such a familiar venue to the teams that we should be able to maximise our practice time to focus on this, and I hope to see another step forward and a positive weekend."

Although Rosberg suggested Mercedes still need to develop their race configuration, the 25-year-old said he is expecting good results in Barcelona.

"I'm excited to see how it works," he said.

"We showed a good level of performance at the final winter test on this circuit, and hopefully we can translate that into a strong result this weekend."