The MODIS Land QA web site has information about known issues with land
products from the LANCE-MODIS system:
12.17.09 - Known Issue on the Accuracy of the LANCE-MODIS Terra
Geolocation Compared to the Standard Product
The Terra geolocation from the LANCE-MODIS system could have an average
error of 250m and, in the worst case, 500m (1 pixel) when compared to the
standard Collection 5 product as a result of differences in the correction
applied to the instrument pointing direction. In the standard system, the
attitude quaternion is used to determine the solar elevation angle
correction applied to the instrument orientation. In the LANCE-MODIS system
the attitude and ephemeris data entrained in the L0 data are used and no
quaternion is available. In this case, a fixed attitude quaternion is
determined by assuming that the satellite always has a nominal orientation.
Although the difference in pointing is very small, it is large enough to
introduce a noticeable error in geolocation. It is expected that this
problem will be fixed early in 2010.
The impact of this error on the LANCE-MODIS L2 products is very small and,
in fact, when the problem is fixed it is not expected that there will be
noticeable changes in these products. These products remain validated
without caveat. However, the Terra L2G products show visible error and user
discretion is advised.
While there are, of course, differences between the Aqua LANCE-MODIS
products and the standard products since the former uses the rate-buffered
GBAD attitude and ephemeris data from EDOS, the status of these products is
not affected by the issue noted above. All Aqua LANCE-MODIS products
(including the L2G products) remain validated without caveat.