The 34-year-old was released by the Shrimpers in May, but has featured in three of the Shots' pre-season friendlies and has now signed a deal.
"It is a fantastic signing and I'm chuffed to have him on board," boss Terry Brown told the club website.
"Andy's leadership and ability to instruct players around him and deal with the ball itself is going to be a massive advantage for us."
quality another good singing our defence is looking good for next season!!
