The workshop measurement and positioning system realize coordinate measurement based on the principle of multistation observation and intersection, and the accurate calibration of the pose parameters of the measuring instrument is the premise of high-precision measurement of the system. In the process of system orientation, multiple observation equations are established based on instrumental observations and geometric constraint information to construct an orientation network, and its structural strength reflects the calibration accuracy of pose parameters. In this study, based on the mathematical model of the implicit function of the system and the orientation principle, the uncertainty of the pose parameters of is derived, and the structural strength evaluation model of the directional network is proposed. The evaluation index of the structural strength of the directional network is formed based on the structural coefficients calculated by the model. The structural strength of the directional network with different configurations is compared and verified numerically and experimentally to verify the correctness of the model. Through the analysis of the influencing factors of the structural coefficients, some guiding suggestions for the layout and structural optimization of the directional network is proposed.