Measuring gravity from an aircraft or a ship is essential in geodesy, geophysics, mineral and hydrocarbon exploration, and navigation. Today, only relative sensors are available for onboard gravimetry. This is a major drawback because of the calibration and drift estimation procedures which lead to important operational constraints. Atom interferometry is a promising technology to obtain onboard absolute gravimeter. But, despite high performances obtained in static condition, no precise measurements were reported in dynamic. Here, we present absolute gravity measurements from a ship with a sensor based on atom interferometry. Despite rough sea conditions, we obtained precision below 10−5 m s−2. The atom gravimeter was also compared with a commercial spring gravimeter and showed better performances. This demonstration opens the way to the next generation of inertial sensors (accelerometer, gyroscope) based on atom interferometry which should provide high-precision absolute measurements from a moving platform.

We present a cold atom gravimeter dedicated to field applications. Despite the compactness of our gravimeter, we obtain performances (sensitivity 42 µGal/Hz 1/2 , accuracy 25 µGal) close to the best gravimeters. We report gravity measurements in an elevator which led us to the determination of the Earth's gravity gradient with a precision of 4 E. These measurements in a non-laboratory environment demonstrate that our technology of gravimeter is enough compact, reliable and robust for field applications. Finally, we report gravity measurements in a moving elevator which open the way to absolute gravity measurements in an aircraft or a boat.Cold atom interferometer is a promising technology to obtain a highly sensitive and accurate absolute gravimeter. Laboratory instruments [1][2][3] have already reached the performances of the best classical absolute gravimeters [4] with a sensitivity of ∼ 10 µGal/Hz 1/2 (1 µGal = 10 −8 m/s 2 ) and an accuracy of 5 µGal. Moreover, compared to classical absolute gravimeters, atom gravimeters can achieve higher repetition rate [5] and do not have movable mechanical parts. These qualities make cold atom gravimeters more adapted to onboard applications like gravity measurements in a boat or in a plane. Cold atom gravimeters could thus be very useful in geophysics [6] or navigation [7]. In this context, cold atom sensors start to be tested on mobile platforms. An atom accelerometer has been operated in a 0 g plane [8]. An atom gradiometer has also been tested in a slow moving truck [9]. In this article, we present a compact cold atom gravimeter dedicated to field applications. First, we describe our apparatus and the technologies that we use to have a compact and reliable instrument. Then, we present the performances of the gravimeter in a laboratory environment. Finally, we report gravity measurements in a static and in a moving elevator.The principle of our cold atom gravimeter is well described in the literature [1] and we summarize in this letter only the basic elements. In an atom gravimeter, the test mass is a gas of cold atoms which is obtained by laser cooling and trapping techniques [10]. This cloud of cold atoms is released from the trap and its acceleration is measured by an atom interferometry technique. We use a Mach-Zehnder type atom interferometer consisting in a sequence of three equally spaced Raman laser pulses which drive stimulated Raman transitions between two stable states of the atoms. In the end, the proportion of atoms in the two stable states depends sinusoidally on *

We report a new experimental scheme which combines atom interferometry with Bloch oscillations to provide a new measurement of the ratio h/m Rb . By using Bloch oscillations, we impart to the atoms up to 1600 recoil momenta and thus we improve the accuracy on the recoil velocity measurement. The deduced value of h/m Rb leads to a new determination of the fine structure constant α −1 = 137.035 999 45 (62) with a relative uncertainty of 4.6 × 10 −9 . The comparison of this result with the value deduced from the measurement of the electron anomaly provides the most stringent test of QED. To test them, other determinations of α, independent of QED, are required. The most precise are deduced from the measurement of the ratio h/m between the Planck constant and the mass of an atom thanks to the relation deduced from the ionization energy of hydrogen:where m e is the electron mass. The limiting factor is the ratio h/m: the uncertainty of the Rydberg constant R ∞ is 7 × 10 −12 [5,6] and that of the mass ratio m/m e 4.8 × 10