Establishment and Accuracy Analysis of Measurement Control Network Based on Length–Angle Mixed Intersection Adjustment Model

To achieve high-precision measurements of target points on long straight tracks, a multi-level measurement method based on length–angle mixed intersection techniques was explored. Firstly, a control network with graded measurement levels was proposed, based on the spatial error characteristics of different measuring devices and the principle of nonlinear least squares, and a method for adjustment calculation based on length–angle mixed intersection was studied. Secondly, numerical simulation was conducted to assess the impact of instrument placement on measurement accuracy, and the results indicated that central positioning within the measurement range can effectively minimize the overall point location errors. Finally, the methodology was validated in a practical setting at a rocket sled test site. Experimental results demonstrated that, within a measurement range of approximately 669 m, when target points were located on one side of the track and distance measurements were used as benchmark values, the measurement control network achieved a distance standard deviation of 0.20 mm. The range of distance deviations was between −0.85 mm and 0.98 mm. This approach offers substantial reference value for high-precision coordinate measurements over extended distances.