在正四棱台 ABCD−A1B1C1D1{ABCD} - {A}_{1}{B}_{1}{C}_{1}{D}_{1}ABCD−A1B1C1D1 中, AB=2,A1B1=1,AA1=2{AB} = 2,{A}_{1}{B}_{1} = 1,{A{A}_{1}} = \sqrt{2}AB=2,A1B1=1,AA1=2 ,则该棱台的体积为___.