NSS astrometric models with an acceleration solution

This table contains non-single-star astrometric models for sources having a non-linear proper motion which is compatible with an acceleration solution. Several possible models are hosted within the same table and they are indicated by the field <code>nss_solution_type</code>. The description of this latter lists all possible solution types considered for this release. Only a selection of parameters hosted in this table are provided here, depending on the solution. The details of those is given in the description of field <code>bit_index</code>, which can also be used to extract the relevant elements of the correlation vector <code>corr_vec</code>.Details about the formalism used to derive the parameters in this table are given in the on-line documentation, see Chapter cu4nss.