Observer design for descriptor systems, or systems of differential algebraic equations (DAEs) as they are also known, is well studied in the linear time invariant (LTI) case. However, those studies do not readily extend to general linear time varying (LTV) or nonlinear descriptor systems. This paper presents an alternative approach for observer design that not only works for the LTI case but also shows great potential for the design of observers for general LTV descriptor systems.