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We have observed three near-Earth objects(NEOs), 2017VR12, Camillo, and Midasduring the year 2018. The observations were made by the 1-m telescope of YunnanObservatory over 2 nights. Their precise astrometric positions are derived from989 CCD observations. The theoretical positions of asteroids are retrieved fromthe Jet Propulsion Laboratory (JPL) Horizons System and Institut deM\'{e}canique C\'{e}leste et de Calcul des \'{E}ph\'{e}m\'{e}rides (IMCCE). Thepositions of three asteroids are measured with respect to the stars in Gaia DR2star catalogue. For 2017 VR12, the mean (O-C) of right ascension anddeclination are -0.090$^{''}$ and -0.623$^{''}$ based on the ephemeris ofpublished JPL, but the mean (O-C) are 3.122$^{''}$ and -0.636$^{''}$ based onthe ephemeris of published IMCCE. The great difference in declination could beexplained by several factors. (1)The degenerated CCD images caused by the highapparent motion speed of the object leads to the reduction of positioningaccuracy. (2)The poor timing system may bring the system error, especially inthe high speed direction. (3)The asteroid may be perturbed by the earth when itapproaches the earth too closely. The astrometric results show that thecentroid centring method can reduce the dispersion of the non-Gaussian imagescompared with the PSF model method. For Camillo and Midas, the astrometricresults are consistent based on two ephemerides. High-precision timing system,some astronomical effects and geometric distortion of CCD images should becarefully considered in the future works.

CCD astrometric observations of 2017 VR12,Camillo and Midas