SAR interferometric DEM quality assessment

The aptitude of SAR interferometric acquisition for relief mapping has been demonstrated, and illustrated on a few test sites. Unfortunately, the validation of this mapping technique is still very limited, for three main reasons : First, the quality assessment of each interferometric DEM is generally performed using questionable data sets, i.e. either a small number of ground control points with limited statistical representativity, or a so-called reference DEM (obtained from a SPOT stereo pair or from an official data base) which is often less accurate than the interferometric DEM itself. Second, very few experiments have been carried out completely, i.e. including height computation and DEM geocoding. Therefore, it is difficult to predict the performances of SAR interferometry in general terms without taking into account the influence of a particular landscape (vegetation, atmosphere, slope...) or particular acquisition conditions (sensor parameters, baseline...). Third, DEM quality assessment is often limited to a single criterion, namely, elevation standard deviation, which is very easy to evaluate, This criterion is very relevant for orthorectification but not for most DEM applications, in particular geoscientific applications. Therefore, user needs have to be expressed more clearly before a user-oriented quality assessment can be undertaken. These limitations will be analysed in our presentation. We will propose solutions for overcoming them, based on a simulation-based concept already published (Polidori & Armand 1995) and we will present some preliminary results.