Upper limit on the amplitude of gravitational waves around 0.1Hz from the Global Positioning System

We show upper bound on the amplitude of gravitational waves around 0.1 Hz from the global posioning system (GPS). Since the atomic clocks which these satellites have are stabilized with the accuracy ∆ν/ν ≃ 10 −15 , the GPS can provide the precise navigations and enable one to calibrate the primary standard for frequency on the ground. Although the attitude of these satellites is approximetaly twenty thousand kilometers, one can stabilize one's oscillator with the accuracy ∆ν/ν ≃ 10 −12 with phase-locked loop circuits by receiving the radio wave emitted by GPS satellites for one or one hundred seconds. To take advantage of the Doppler tracking method, we have found that this it has already placed a meaningful constraint on the strain amplitude of continuous component of GWs as h c < 4.8 × 10 −12 at frequency range 10 −2 ≲ f ≲ 10 0 Hz. This work is documented in arXiv 1402.4521[1].