GPS Accurate to a Centimeter

How to find peace, love, and joy in the midst of the storms ahead in all that we do:

I have chosen to include God in all that I do, and that has made all the difference in my life.  I have learned that as we ask, seek, and knock (Matt. 7:7), God will put thoughts into our minds and inspire our doings.  I believe my master’s thesis, which gave birth to the Allan variance (AVAR), was inspired by God: Allan Variance – Spirit of Revelation | It’s About Time (  Similar experiences have occurred over my professional career, and I give God the glory.  As an example, before I retired from the lab in Boulder, I was pondering on the problem of the inaccuracies in determining the positions of the GPS satellites; the vertical error component is the largest.  And the idea came into my mind that Kepler’s Third Law could solve this problem.  I asked my good friend, Professor Neil Ashby, to help me do the simulations.  We got some impressive results and presented a paper in the UK and later at an Institute of Navigation GPS conference in 2001 in Salt Lake City, UT: A New Paradigm for High Accuracy Orbit Determination at the Centimeter Level (
Along with help from wonderful colleagues, I believe the Lord helped me in writing the AT-1 algorithm for optimally combining the readings of atomic clocks for the generation of official time for the USA back in 1968.  With improvements by colleagues, that algorithm, AT-1, is still ticking today to produce UTC(NIST).  When Dr. Elizabeth Donley, the Division Chief of the Time and Frequency Division of NIST came to our home 5-6 November 2018 to conduct an ORAL HISTORY of my life for the IEEE/UFFC, she asked me to describe AT-1 in layman’s terms and made a  six-minute video as part of my oral history, which you can see here: Oral-History: David W. Allan – Engineering and Technology History Wiki (  You will also find my witness of God’s love and the precious gift of His Beloved Son as well.

Recently, I was asked by the GPS leadership to make some suggestions for improvements, which I sent off to them.  One can understand GPS in simple terms: Everyone Can Understand GPS | It’s About Time (  But one needs some math and engineering skills to appreciate these seven recommendations – one of which could lead to GPS being accurate at the centimeter level: Seven Improvement Suggestions for GPS (  The atomic clock statistical tools needed to better appreciate these suggestions are in an IEEE tutorial: 190426_David_Allan_Lecture_FINAL.pdf (

All kinds of fascinating questions arise at the centimeter level of accuracy.  Solid earth tides are at the several centimeter levels.  Is the big “G” gravitational constant really constant?  Our UFT research shows that it is not mass, but energy density that is most important for the attraction of bodies: Unified Field Theory with New Model for Gravity (  There are data that indicate that Kepler’s Third Law may not apply perfectly for all the planets.  Is it because of variations in big “G?”  Are there dimensions beyond Einstein’s four dimensions of relativity?  Our UFT experiments indicate a fifth dimension – called the eternity domain, where God and His angels do their magnificent work, as explained in chapters 21-25 of my book: Purchase “It’s About Time” | It’s About Time (

I believe there are some exciting science insights ahead.  Let’s hope that we can use them to best serve humanity and preserve our liberty: The Transparent Truth Shall Set You Free | It’s About Time (  Jesus said, “He that abideth in me, and I in him, the same bringeth forth much fruit: for without me ye can do nothing.” (John 15:5)  In so doing, the Holy Ghost will give us guidance and we will enjoy peace, love, and joy in the midst of the storms ahead, as we anticipate His glorious Second Coming.

David W Allan