中文摘要：

500 m口径球面射电望远镜（Five hundred meters aperture spherical radio telescope,FAST）是我国建成的世界第一大单口经射电望远镜,其反射面索网长度控制精度要求极其严格,误差要求控制在±1 mm以内,索长的万分之一。提出恒温持荷调索测控方法,并就钢索调索结构设计、索长稳定化措施、测量调索系统和调索操作工艺流程进行详述;对各因素导致的测量误差进行了计算和修正;通过索长测控试验,对FAST项目所用到的16种规格共抽取48根钢索的设计长度、实测长度以及长度误差进行统计分析。结果表明：钢索的长度控制精度在±1 mm以内,误差符合正态分布,满足FAST索网验收标准。

英文摘要：

The length accuracy requirement of the cables of reflector of five-hundred-meter aperture spherical radio telescope（FAST） is extremely high, which reaches up to ±1 mm and 1/10000 of cable length. The method of over tensioning and adjusting the cable length under constant temperature is put forward. The special cable structure for length adjustment, stabilization measure for cable length, measuring and control system and the technology and process for adjusting cable length are introduced in detail; and the measurement errors caused by various factors are calculated and corrected. Through the process test, design lengths, measured lengths and length errors of 48 cables selected from 16 kinds of specifications used in the FAST project were statistical analyzed and the results show that all the length errors of cable are less than ±1 mm and are conformed to the normal distribution, which meet the acceptance criteria of the cable network of FAST project.