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White Paper - SX12 Tracking and Target Separation 10 https://geospatial.trimble.com 10 To calculate the minimum separation angle for two targets at different distances, use the average of the minimum separation angle for the two sizes. For example, calculate the minimum separation for two 25 mm diameter prisms: one at 10 m range, and one at 100 m range: First, look up the minimum separation in Figure 10: At 10 m range, a 25 mm prism requires 0.244° separation from a prism the same size At 100 m range, a 25 mm prism requires 0.049° separation from a prism the same size Next, average the two to calculate the required separation: (0.244°+0.049°) ÷2 = 0.147° Answer: One 25 mm diameter prism at 10 m range, and one 25 mm prism at 100 m range require 0.147 degrees of separation from center-to-center Relation to Trimble S Series All Trimble S series total stations include the ability to find, track, and lock onto prisms using Trimble Autolock technology. Trimble FineLock® is available on Trimble S7, S9 and S9HP instruments, which allows for a smaller prism separation than the other S series instruments. FineLock uses only the inner fine detector of the tracker receiver which has a very narrow field of view, removing the interfering reflections from other prisms and allowing the instrument to center on a single prism. The SX12 tracking abilities are also attributed to Autolock technology, though the implementation is slightly different since the SX12 uses a camera based tracking system. For the SX12, narrowing the field of view would not affect minimum separation needed, and so something like FineLock is not needed for the SX12. Comparing the S series and SX12, at distances farther than 40 m, the SX12 requires smaller target separation than the S Series. Minimum Target Separation between Two Prisms of 25 mm Diameter Distance to Target [m] SX Series [mm] S Series FineLock Monitoring Installations [mm] S Series FineLock General Survey Workflows [mm] 10 43 16 40 25 52 40 100 50 64 80 200 100 85 150 400 200 114 300 800 Figure 13. The table above shows the minimum separation where the instrument can still distinguish two prisms as separate targets. The separation values refer to center-to-center distance between prisms. In other words, at long distances the SX12 requires 10x smaller prism separation than the S series using FineLock.

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