Ellipse fitting is a useful tool to obtain the differential signal of two atom interference gravimeters. The quality standard of ellipse fitting should be the deviation between the true phase and the fitting phase of ...Ellipse fitting is a useful tool to obtain the differential signal of two atom interference gravimeters. The quality standard of ellipse fitting should be the deviation between the true phase and the fitting phase of the interference fringe. In this paper, we present a new algorithm to fit the ellipse. The algorithm is to minimize the differential noise of two interference gravimeters and obtain a more accurate value of the gravity gradient. We have theoretically derived the expression of the differential-mode noise and implemented the ellipse fitting in the program. This new algorithm is also compared with the classical methods.展开更多
The first Asia-Pacific Comparison of Absolute Gravimeters(APMP.M.G-K1) was organized by the National Institute of Metrology(NIM) of China from December 21, 2015 to March 25, 2016 in Changping, Beijing. Our compact col...The first Asia-Pacific Comparison of Absolute Gravimeters(APMP.M.G-K1) was organized by the National Institute of Metrology(NIM) of China from December 21, 2015 to March 25, 2016 in Changping, Beijing. Our compact cold atom gravimeter(CCAG) was transported from Hangzhou to Beijing with a long distance of about1200 km to participate in this comparison. The CCAG is the only one, to the best of our knowledge, that is based on the principle of atom interferometry among all the instruments. Absolute gravity in the indicated three test sites has been measured as requested by the organizer. The sensitivity of our CCAG is estimated to be90 μGal∕Hz p, even when the measurements are carried out without any vibration isolation. Besides, the accuracy of this gravimeter has been evaluated to be about 19 μGal by considering the significant system errors.Our results show a good agreement with the given reference value.展开更多
For most atom interferometers, the vibration isolation unit is applied to reduce vibration noise. In our experiment, instead of isolation, the vibration signals are monitored, and combining with the sensitive function...For most atom interferometers, the vibration isolation unit is applied to reduce vibration noise. In our experiment, instead of isolation, the vibration signals are monitored, and combining with the sensitive function, the compensation phase shift for the atom interferometer is obtained. We focus on the correction over a wide spectrum rather than on "monochromatic" frequencies. The sensitivity of the atom gravimeter can be upgraded by a factor of more than two. Furthermore, we demonstrate that the atom interferometer can still produce a good measurement result without passive vibration isolation in extremely noisy environments by using vibration compensation.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFC0601602)the Fundamental Research Funds for the Central Universities,China(Grant Nos.2017FZA3005 and 2018FZA3005)
文摘Ellipse fitting is a useful tool to obtain the differential signal of two atom interference gravimeters. The quality standard of ellipse fitting should be the deviation between the true phase and the fitting phase of the interference fringe. In this paper, we present a new algorithm to fit the ellipse. The algorithm is to minimize the differential noise of two interference gravimeters and obtain a more accurate value of the gravity gradient. We have theoretically derived the expression of the differential-mode noise and implemented the ellipse fitting in the program. This new algorithm is also compared with the classical methods.
基金supported by the National Key Research and Development Program of China(Nos.2017YFC0601602 and 2016YFF0200206)the National Natural Science Foundation of China(Nos.61727821,61475139,11604296,and 11174249)
文摘The first Asia-Pacific Comparison of Absolute Gravimeters(APMP.M.G-K1) was organized by the National Institute of Metrology(NIM) of China from December 21, 2015 to March 25, 2016 in Changping, Beijing. Our compact cold atom gravimeter(CCAG) was transported from Hangzhou to Beijing with a long distance of about1200 km to participate in this comparison. The CCAG is the only one, to the best of our knowledge, that is based on the principle of atom interferometry among all the instruments. Absolute gravity in the indicated three test sites has been measured as requested by the organizer. The sensitivity of our CCAG is estimated to be90 μGal∕Hz p, even when the measurements are carried out without any vibration isolation. Besides, the accuracy of this gravimeter has been evaluated to be about 19 μGal by considering the significant system errors.Our results show a good agreement with the given reference value.
基金supported by the National Key Research and Development Program of China (No. 2017YFC0601602)the Fundamental Research Funds for the Central Universities, China (No. 2018FZA3005)
文摘For most atom interferometers, the vibration isolation unit is applied to reduce vibration noise. In our experiment, instead of isolation, the vibration signals are monitored, and combining with the sensitive function, the compensation phase shift for the atom interferometer is obtained. We focus on the correction over a wide spectrum rather than on "monochromatic" frequencies. The sensitivity of the atom gravimeter can be upgraded by a factor of more than two. Furthermore, we demonstrate that the atom interferometer can still produce a good measurement result without passive vibration isolation in extremely noisy environments by using vibration compensation.
