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Adroit系统公司根据它与战略防御司令部(SDC)签定的一份合同,研制并试验基于GPS卫星信号干涉测量技术的姿态确定系统(ADS)。ADS通过测量相隔1m的一对天线之间的GPS载波相位差,可以确定天线的指向误差。若天线位置已知,则该系统只需要三颗GPS卫星就能实现姿态确定功能。利用双差分法可以消除两个天线之间的射频偏差和漂移。最初,为SDC研制的ADS采用两架天线和一条基线。为了更有效地解决整数周期的多值解问题,Adroit公司推出了一种方法,采用三架天线构成两条基线。这种修改后的系统采用一台只含两个天线输入端口的GSP接收机。由于只采用两个天线通道,接收机就不必增加第三个射频信号接收单元。三架天线构成一条短基线和一条长基线。短基线用来获得基线的粗指向矢量。然后再利用长基线测量值修正粗矢量,从而产生精确的基线矢量。Adroit ADS的第二代产品已完成设计并于1990年交付美军工程师地形测绘实验室(ETL),该产品与另两个承包商提交的另外两个ADS产品一起进行鉴定。本文发表了所有三种ADS的试验结果。Adroit的ADS可以每秒计算并修正指向信息一次。经验证,采样时间为1s时,测量精度接近10mrad,若采样时间为300s,则精度可优于1mrad。
Based on a contract it has signed with the Strategic Defense Command (SDC), Adroit Systems develops and tests attitude determination systems (ADSs) based on GPS satellite signal interferometry. ADS The antenna’s pointing error can be determined by measuring the GPS carrier phase difference between a pair of antennas 1m apart. If the antenna position is known, then the system only needs three GPS satellites to realize the attitude determination function. The use of double-difference method eliminates the RF offset and drift between the two antennas. Initially, ADS developed for SDC used two antennas and one baseline. To solve the multi-valued solution of integer cycles more effectively, Adroit introduced a method that uses three antennas to form two baselines. This modified system uses a GSP receiver with only two antenna inputs. Since only two antenna channels are used, the receiver does not need to add a third RF signal receiving unit. The three antennas form a short baseline and a long baseline. Short baselines are used to obtain the baseline coarse base vectors. The longer baseline measurements are then used to correct the coarse vectors, resulting in an accurate baseline vector. The second generation of Adroit ADS products was finalized and delivered to the US Army Terrain Mapping Laboratory (ETL) in 1990, along with two other ADS products submitted by two other contractors. This article presents the results of all three ADS tests. Adroit’s ADS calculates and corrects pointing information every second. Proven, the sampling time of 1s, the measurement accuracy close to 10mrad, if the sampling time of 300s, the accuracy can be better than 1mrad.