| DefaultCoordSystem | AstroCoordSystem | DefaultCoordSystem | |
| EndDate | datetime | The end time of this external survey | |
| Epoch | float | The epoch of the reference frame if applicable (EQUATORIAL and ECLIPTIC) | |
| FileName | str | The file name of this Reference Ground Based Survey. | |
| NObservations | int | NObservations | |
| NPatches | int | NPatches | |
| NPointings | int | The total number of pointings contained in this foreseen ground based survey | |
| ProductId | str | ProductId | |
| SoftwareName | str | SoftwareName | |
| SoftwareVersion | str | SoftwareVersion | |
| StartDate | datetime | The start time of this external survey | |
| Title | str | The title of this GroundBased survey: KIDS/LSST/DES/CFIS/.... could use the extSurvey data type from ext sim package | |
