Former world champions Williams have targeted next month's Spanish Grand Prix for a significant step forward with their car after failing to score a point in the first two races of the Formula One season.
Williams won at Barcelona's Circuit de Catalunya, the first race of the European season, last year with Venezuelan Pastor Maldonado. This year's race is on May 12.
In a preview of Sunday's Chinese Grand Prix, which is followed next week by the Bahrain Grand Prix, technical director Mike Coughlan said the team had been going through the data to try and understand where they needed to improve.
"We feel we have a better understanding of where we are and the whole team has been working hard to improve our competitiveness going into the next few races," he said.
"Ultimately we are looking at a significant upgrade for the Spanish Grand Prix."
Coughlan said the conditions in China, with cooler temperatures, should suit the Williams team better than in Australia and Malaysia although the circuit surface was quite hard on tyres.