The Communication/Navigation Outage Forecasting System (C/NOFS) satellite is scheduled for launch in June 2008 into a low inclination (13°), elliptical (~ 400 x 850 km) orbit. Models have been developed at AFRL that will ingest C/NOFS data in order to forecast ionospheric density and the presence of irregularities. The C/NOFS forecast models can be initialized using an assimilative model (e.g., GAIM), or alternatively, using a physics based model driven by the electric fields and winds that will be measured by C/NOFS (i.e., PBMOD). We present a validation study of the C/NOFS PBMOD and JPL/USC GAIM models using ground and satellite instrument data from a recent COSMIC campaign. Total electron content from ground-based GPS receivers and from the COSMIC GPS receivers are included in the GAIM assimilation. We compare the models with electron density from the Jicamarca incoherent scatter radar as well as with peak density from several equatorial ionosondes using metrics to show their strengths and limitations. We find that the assimilation of GPS TEC improves GAIM's ability to predict vertical TEC. The assimilation of COSMIC GPS TEC in particular improves the topside shape. On the other hand, assimilation tends to degrade GAIM's specification of NmF2 relative to PBMOD or to GAIM's climatology in this study. Recent changes to GAIM and the use of higher resolution are expected to enhance GAIM's specification.