To get the full map with ARB you need to patch the SH3.exe with The special Tycho patch.
Main thread:
https://www.subsim.com/radioroom/sho...37&postcount=1
From read me:
How to install:
!!! FIRST MAKE A BACKUP OF SH3.EXE FILE IN THE GAME FOLDER !!!
1. Copy files in the folder ARB WideGui 1920x1080 into the game folder.
2. Copy files in the folder TychoSh3Patch_v3 into the game folder.
3. Run the TychoSh3Patch.bat
TychoSh3Patch - expand Nav and Attack maps render limit from 1024x1024 to 2048x2048.
http://www.subsim.com/radioroom/showthread.php?t=231140