No world files involved.
This is what I do (OTB-6.6.0-Linux64):
gdalinfo multi.tif
gdalinfo KAISER2-3000S0_PAN2.tif
otbcli_BundleToPerfectSensor -inp KAISER2-3000S0_PAN2.tif -inxs multi.tif -out KAISER2-3001S0_REFpansharpOTB.tif
gdalinfo KAISER2-3001S0_REFpansharpOTB.tif
gdalinfo for input images:
Corner Coordinates:
Upper Left ( 0.0000000, 0.0000000) ( 1d29’19.48"W, 0d 0’ 0.01"N)
Lower Left ( 0.000, -1000.000) ( 1d29’19.48"W, 0d 0’32.47"S)
Upper Right ( 1000.000, 0.000) ( 1d28’47.23"W, 0d 0’ 0.01"N)
Lower Right ( 1000.000, -1000.000) ( 1d28’47.23"W, 0d 0’32.47"S)
Center ( 500.000, -500.000) ( 1d29’ 3.35"W, 0d 0’16.23"S)
gdalinfo for output:
Corner Coordinates:
Upper Left ( 0.0, 0.0)
Lower Left ( 0.0, 1000.0)
Upper Right ( 1000.0, 0.0)
Lower Right ( 1000.0, 1000.0)
Center ( 500.0, 500.0)
Note that input and output images are displayed in the same region by QGIS, but not by Monteverdi and R