TRIMBLE NAVIGATION LIMITED

                                 THIRD AMENDMENT
                                       to
                           REVOLVING CREDIT AGREEMENT


        This THIRD AMENDMENT (the  "Amendment"),  dated as of November 12, 1996,
is among Trimble Navigation Limited (the "Borrower"), The First National Bank of
Boston  ("FNBB"),  Mellon Bank,  N.A.  ("Mellon",  and together  with FNBB,  the
"Banks"),  and The First  National  Bank of Boston as agent for  itself  and the
other Banks (the "Agent").

        WHEREAS,  the  Borrower,  the Banks and the  Agent are  parties  to that
certain  Revolving Credit  Agreement,  dated as of August 4, 1995 (as amended by
the First Amendment to Revolving Credit  Agreement,  dated as of April 30, 1996,
and the Second  Amendment to Revolving  Credit  Agreement,  dated as of June 30,
1996, the "Credit  Agreement"),  pursuant to which the Banks, upon certain terms
and  conditions,  have made  loans to and may issue  letters  of credit  for the
benefit of the Borrower; and

        WHEREAS,  the Borrower had requested that the Banks agree, and the Banks
have agreed,  on the terms and subject to the  conditions  set forth herein,  to
make certain changes to the Credit Agreement;

        NOW, THEREFORE, the parties hereto hereby agree as follows:

        Section  1.  Defined  Terms.  Capitalized  terms  which are used  herein
without  definition and which are defined in the Credit Agreement shall have the
same meanings herein as in the Credit Agreement.

        Section 2. Amendment of Credit Agreement. The Credit Agreement is hereby
amended as follows:

        (a) Section  9.1 of the Credit  Agreement  is amended by  deleting  such
Section 9.1 and restating it in its entirety as follows:

               Section 9.1. Profitable Operations.  The Borrower will not permit
               Consolidated  Net Deficit or Consolidated  Net Operating  Deficit
               for any fiscal  quarter of the  Borrower to be greater  than five
               percent (5%) of Consolidated  Tangible Net Worth as of the end of
               the fiscal  quarter  immediately  preceding  the relevant date of
               determination.

        (b) Section  9.4 of the Credit  Agreement  is amended by  deleting  such
Section 9.4 and restating it in its entirety as follows:

               Section 9.4  Consolidated  Tangible Net Worth.  The Borrower will
               not  permit  Consolidated  Tangible  Net  Worth at the end of any
               fiscal quarter of the Borrower to be less than:

                      (i) for the fiscal  quarter ended  December 31, 1996,  the
               sum of $111,000,000,  plus eighty percent (80%) of any new equity
               issuance, plus, eighty percent (80%) of positive Consolidated Net
               Income for, in each case,  the fiscal  quarter  subsequent to the
               fiscal quarter ended September 30, 1996; and

                      (ii) for the fiscal  quarter ended March 30, 1997 and each
               fiscal quarter thereafter,  the sum of $105,000,000,  plus eighty
               percent (80%) of any new equity  issuance,  plus, on a cumulative
               basis,  eighty percent (80%) of positive  Consolidated Net Income
               for each fiscal  quarter  subsequent to the fiscal  quarter ended
               December 31, 1996.

        (c) Section 9 of the Credit  Agreement is further  amended by adding the
following new Section 9.6:

               Section 9.6.  Minimum Net Cash. The Borrower will not at any time
               permit the sum of cash, plus Cash  Equivalents,  plus Investments
               of the kind  described  in  paragraphs  (a),  (b), (c) and (g) of
               Section  8.3 that  mature  within  one (1) year  from the date of
               purchase  by  the  Borrower,  minus  the  outstanding  amount  of
               Revolving  Credit  Loans as of the date of  determination,  to be
               less than $50,000,000.

        Section 3. Affirmation and Acknowledgment of the Borrower.  The Borrower
hereby  ratifies and confirms all of its  Obligations  to the Banks,  including,
without  limitation the Revolving  Credit Loans, and the Borrower hereby affirms
its absolute and unconditional  promise to pay to the Banks the Revolving Credit
Loans and all other amounts due under the Credit Agreement as amended hereby.

        Section 4.    Representations  and  Warranties.  The Borrower  hereby 
represents  and warrants to the Banks as follows:

               (a) The execution and delivery by the Borrower of this  Amendment
        and the  performance by the Borrower of its  obligations  and agreements
        under this  Amendment and the Credit  Agreement as amended  hereby,  are
        within the corporate authority of the Borrower,  have been authorized by
        all necessary  corporate  proceedings on behalf of the Borrower,  and do
        not  and  will  not  contravene  any  provision  of  law  or  any of the
        Borrower's  charter,  other incorporation  papers,  by-laws or any stock
        provision  or any  amendment  thereof  or of any  indenture,  agreement,
        instrument or undertaking binding upon the Borrower.

               (b) This  Amendment  and the Credit  Agreement as amended  hereby
        constitute  legal,  valid  and  binding  obligations  of  the  Borrower,
        enforceable in accordance with their respective terms, except as limited
        by bankruptcy,  insolvency,  reorganization,  moratorium or similar laws
        relating to or affecting generally the enforcement of creditors' rights.

               (c) No approval or consent of, or filing with,  any  governmental
        agency or  authority  is required to make valid and legally  binding the
        execution,  delivery or performance by the Borrower of this Amendment or
        the Credit  Agreement  as amended  hereby,  or the  consummation  by the
        Borrower of the transactions among the parties  contemplated  hereby and
        thereby or referred to herein.

               (d) The representations and warranties  contained in Section 6 of
        the Credit Agreement were correct at and as of the date made.  Except to
        the extent that the facts upon which such representations and warranties
        were  based have  changed  in the  ordinary  course of  business  (which
        changes,  either singly or in the  aggregate,  have not been  materially
        adverse)  and  after  giving  effect  to  the  provisions  hereof,  such
        representations  and  warranties  also are correct at and as of the date
        hereof.

               (e) The  Borrower  has  performed  and  complied in all  material
        respects with all terms and conditions  herein  required to be performed
        or  complied  with by it prior to or at the time  hereof,  and as of the
        date hereof,  after giving effect to the provisions hereof, there exists
        no Event of Default or Default.

        Section 5.    Effectiveness.  The  effectiveness  of this  Amendment  
shall be subject to receipt by the Agent of this  Amendment  executed  by each 
of the  Borrower,  the Banks and the Agent.

        Section 6. Miscellaneous  Provisions.  (a) Except as otherwise expressly
provided by this Amendment,  all of the terms,  conditions and provisions of the
Credit Agreement shall remain the same. It is declared and agreed by each of the
parties hereto that the Credit Agreement,  as amended hereby,  shall continue in
full force and effect, and that this Amendment and the Credit Agreement shall be
read and construed as one instrument.

        (b) THIS AMENDMENT IS INTENDED TO TAKE EFFECT AS AN AGREEMENT UNDER SEAL
AND SHALL BE CONSTRUED ACCORDING TO AND GOVERNED BY THE LAWS OF THE COMMONWEALTH
OF MASSACHUSETTS.

        (c) This  Amendment may be executed in any number of  counterparts,  but
all such counterparts  shall together  constitute but one instrument.  In making
proof of this Amendment it shall not be necessary to produce or account for more
than  one  counterpart  signed  by  each  party  hereto  by  and  against  which
enforcement hereof is sought.

        (d) Pursuant to Section 15 of the Credit Agreement,  the Borrower hereby
agrees to pay to the Agent, on demand by the Agent, all reasonable out-of-pocket
costs and expenses  incurred or sustained  by the Agent in  connection  with the
preparation of this Amendment (including reasonable legal fees).




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        IN WITNESS  WHEREOF,  the parties hereto have executed this Amendment as
of the date first written above.

                                  TRIMBLE NAVIGATION LIMITED


                                  By: /s/ Dennis R. Ing
                                     Name:Dennis R. Ing
                                     Title: Vice President Finance and Chief
                                            Financial Officer


                                 THE FIRST NATIONAL BANK
                                 OF BOSTON, individually and
                                 as Agent


                                   By: /s/ Tena Lindenauer
                                      Name:Tena Lindenauer
                                      Title:Director



                                 MELLON BANK, N.A.



                                   By: /s/ Sean C. Gannon
                                      Name:Sean C. Gannon
                                      Title:Assistant Vice President





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