Exhibit 23.3
CONSENT
OF INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM
We have
issued our report dated March 17, 2008 with respect to the consolidated
financial statements of ATS Corporation and subsidiary included in the Annual
Report of ATS Corporation on Form 10-K for the year ended December 31, 2007
which are incorporated by reference in this Registration Statement. We
consent to the incorporation by reference in the Registration Statement of the
aforementioned report.
/s/ GRANT
THORNTON LLP
McLean,
Virginia
February
27, 2009