usd = (usdjpy/100 + usdcad + 1/gbpusd + 1/eurusd + usdchf + 1/audusd + 1/nzdusd)/7
DXY is hard to compare against other indices because of it's weightening. Secondly it does not compare against all majors and includes SEK which is not a major currency. Source: Wikipedia.
In this chart it becomes more clear why GU is in an uptrend. From April 25th USD has been consolidating against the basket of majors while GBP has gained in strength against the same basket.
gbp = ( gbpusd + gbpjpy/100 + gbpcad + 1/eurgbp + gbpchf + gbpaud + gbpnzd )/7