EXHIBIT 5.1


                                  May 29, 1997


     TRIMBLE NAVIGATION LIMITED
     645 North Mary Avenue
     Sunnyvale, California 94088

            RE:    REGISTRATION STATEMENT ON FORM S-8

     Ladies and Gentlemen:

     We have examined the Registration  Statement on Form S-8 to be filed by you
with the  Securities  and  Exchange  Commission  on or about  May 29,  1997 (the
"Registration  Statement"),  in  connection  with  the  registration  under  the
Securities  Act of 1933,  as amended,  of 600,000  shares of your  Common  Stock
reserved for issuance  under the 1993 Stock  Option Plan (the  "Plan").  As your
legal counsel,  we have examined the proceedings  taken and proposed to be taken
in connection  with the issuance,  sale,  and payment of  consideration  for the
shares to be issued under the Plan.

     It is our opinion that,  when issued and sold in the manner  referred to in
the Plan and pursuant to the  agreements  which  accompany the Plan,  the shares
will be legally and validly issued, fully paid, and non-assessable.

     We  consent to the use of this  opinion  as an exhibit to the  Registration
Statement and further  consent to the use of our name wherever  appearing in the
Registration Statement and any amendments thereto.

                                             Very truly yours,

                                              WILSON, SONSINI, GOODRICH & ROSATI
                                              Professional Corporation


                                              By:  /s/ John B. Goodrich
                                                   John B. Goodrich