At present long term radio variability is not well-understood. Time-scales will be monitored from years down to a few minutes. Crucial to achieving these goals is the ability to determine the nature of the objects detected by the survey. This will be possible for observations north of . For the remaining of the survey there are no large-scale radio frequency data bases available with the sub arcmin resolution necessary to avoid confusion effects close to the Galactic Plane.
Thermal sources are relatively much stronger sources of infrared emission.
Structural morphology for extended sources can also give a strong indication of the nature of the object. For the small-diameter sources, the expected Galactic source density can be calculated by subtracting the contribution from the nearly isotropic distribution of background galaxies. As well as investigating the Galactic sources, this survey will also contain much valuable data on the population of extragalactic objects located behind the Plane. Because of the obscuring Galaxy, identification of these sources may be difficult. Large spiral galaxies will be less easy to identify as their structure is likely to be centrally peaked with diameters of only a few minutes of arc.