Complex sentence: After the war Yves Rocard, then director of French Navy research, impressed by Rawer's code, engaged him as "directeur scientifique" (1946--56) of his newly founded "Service de Prevision Ionospherique".
Split into simpler sentences: After the war Yves Rocard, then director of French Navy research was impressed by Rawer's code. He engaged him as "directeur scientifique" (1946--56) of his newly founded "Service de Prevision Ionospherique".