How to disallow space using ng-pattern

Question

I have belopw ng-pattern set in one of my form field. It gives validation error on field if user enters non numeric value. If i just put empty string and validate, it doesnot show any validation error on field. How can i check if my field is empty using ng-pattern below.

ng-pattern="/^(\+|-)?(?:180(?:(?:\.0{1,6})?)|(?:[0-9]|[1-9][0-9]|1[0-7][0-9])(?:(?:\.[0-9]{1,6})?))$/"