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Vision measurement, a fast and high precision measurement technology, has great application potential in aerospace applications such as on-orbit assembly and maintenance. The On-orbit Multi-view Photogrammetry System (OMPS) has insufficient known spatial reference information to assist camera orientation. To solve this problem, this paper proposes a method to realize the calibration of all Cameras External Parameters (CEP) of the OMPS using stars and scale bars. The method firstly establishes the imaging model of stars and scale bars, in which a relative position model is proposed to solve the reference camera position unconstrained problem. Subsequently, based on the constructed error equations of star imaging point, scale bar target imaging point and scale bar length, a multi-data fusion bundle adjustment algorithm is proposed to realize the high-precision calibration of CEP. The practical experiments show that the image plane errors of stars and scale bar targets are 1/7 pixel (1σ) and 1/16 pixel (1σ) respectively, and scale bar length error is 0.045 mm (1σ). Taking the measurement of V-star System (VS) as the true value, the OMPS measurement error of spatial targets in X, Y and Z directions are 0.45 mm (3σ), 0.12 mm (3σ) and 0.15 mm (3σ), respectively. This method can provide an algorithm and data reference for the calibration problem of CEP in the on-orbit application of Photogrammetry (PG).
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