I assume your mesh is perfectly centered at the 3d space, you could first use <kbd>Shift</kbd><kbd>S</kbd> --> Cursor to center to make sure the 3d cursor is at the center of the 3d space.

Then (with the mouse pointer pointing to the 3d window) you can make the center of scaling (pivot point) to be exactly the same as the 3d cursor by:

 - Pressing <kbd>.</kbd> on the keyboard

or

 - Select it from the menu
![enter image description here][1]

By icon of coordinates I think you mean the red, green, blue arrows, sticking out of the 


  [1]: https://i.sstatic.net/UfeQG.png