The active control of 30-m ring interferometric telescope (RIT) needs edge sensing and tip sensing whenits primary mirror is composed by trapezoid-shaped segments, and the imaging performance of the RITis determined by the accuracy of these two detecting approaches. Considering the detecting accuracyavailable in current segmented telescope active control systems, the effect of these detecting approacheson the surface error of the RIT primary mirror is calculated from the point of error propagation. Thecorresponding effect on imaging performance (modulation transfer functions (MTFs) and point spreadfunctions (PSFs) at several typical wavelengths) of the RIT primary mirror is also simulated. The resultsshow that tip sensing is very important for increasing the active control quality of the RIT primary mirrorunder the present techniques. The active control of 30-m ring interferometric telescope (RIT) needs edge sensing and tip sensing when primary primary mirror is composed of trapezoid-shaped segments, and the imaging performance of the RITis determined by the accuracy of these two detection approaches. accuracyavailable in current segmented telescope active control systems, the effect of these detections approacheson the surface error of the RIT primary mirror is calculated from the point of error propagation. Thecorresponding effect on imaging performance (modulation transfer functions (MTFs) and point spreadfunctions (PSFs) at several typical wavelengths) of the RIT primary mirror is also simulated. The resultsshow that tip sensing is very important for increasing the active control quality of the RIT primary mirrorunder the present techniques.