手持式GPS坐标转换参数解算方法(整理).ppt

单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,GPS,坐标转换参数计算方法,2012,年,2,月,15,日,参数计算的必要性,手持式,GPS,单点定位的坐标属于,WGS-84,大地坐标系,而在实际测量和定位工作中常常采用的是,1954,年北京坐标系或,1980,西安坐标系,.,由于坐标系统的不同,使得同一点在不同的坐标系下有不同的坐标值,只有对,GPS,导航定位成果进行转换,才能满足实际工作的要求。,解算原理,常用的坐标转换方法有七参数法和五参数法。七参数法一般用于转换精度要求较高的计算。手持式,GPS,接收机的设置包括,5,个参数,(D,X,、,D,Y,、,D,Z,、,D,A,、,D,F,),适用五参数法,.,其中,D,A,和,D,F,只与,2,个待转换的坐标系统有关,在研究中皆为常数,也称此法三参数法,.,三参数法空间直角坐标系的转换是假设两坐标系各轴相互平行,坐标原点不相重合,.,因此,两坐标系之间的坐标转换公式为,:,计算步骤,1,、数据获取,1.1,获取已知测量控制点数据,1.2,将,GPS,设置在,WGS-84,坐标下，读取控制点的坐标,(,经纬度,),读数,然后将,GPS,接收机放在控制点上,持续观测,每隔一段时间读数一次,X,Y,h,4745057.26,537568.07,517.0,4742024.68,530533.81,545.8,4744277.82,530960.10,494.5,4741682.76,534252.73,247.8,控制点西安,80,坐标,1,、国家级测量控制点,2,、工作区内已有的测量控制点,3,、选取的控制点尽量在工作区内均匀分布,B,L,h,1,4250239,12927396,5200,4250242,12927395,5140,4250232,12927390,5160,4250243,12927394,5180,2,4248466,12922292,5470,4248470,12922291,5450,4248467,12922290,5430,4248453,12922289,5460,3,4244355,12922462,4950,4244357,12922464,4930,4244356,12922461,4960,4244354,12922463,4920,4,4248351,12925128,2500,4248350,12925127,2450,4248354,12925126,2470,4248354,12925125,2480,实测,WGS-84,坐标,计算步骤,2,、计算过程,2.1,高斯投影的反算,根据地面一点在高斯平面上的坐标,(x,y),计算该点在椭球面上的大地坐标,(B,、,L),称为高斯投影反算。大地坐标的求解采用直接法。,B,L,h1,425024.23690,1292734.32833,517,2,424847.09098,1292223.98691,545.8,3,424435.98543,1292241.22193,494.5,4,424835.44483,129257.601412,247.8,计算步骤,2.2,大地坐标与空间直角坐标的转换,X=(N+h)cosBcosL,Y=(N+h)cosBsinL,Z=N(1-e,2,)+hsinB,N,为卯酉圈曲率半径,N=a/(1-e,2,sin,2,B),1/2,h,为大地高,X,、,Y,、,Z,为大地坐标系中的三维直角坐标,a,为相应大地坐标系对应椭球之长半轴,e为相应大地坐标系对应第一偏心率。,a,b,f,e,2,西安,80,6378140,6356755.288,1/298.257,0.006694385,北京,54,6378245,6356863.019,1/298.3,0.006693422,WGS-84,6378137,6356752.314,1/298.257223563,0.00669438,1,-2977209.661,3616657.021,4314836.65,-2977201.11,3616650.208,4314839.36,-2977206.611,3616674.758,4314818.09,-2977199.887,3616652.296,4314844.34,2,-2973071.209,3622726.402,4312652.74,-2973063.2,3622720.224,4312660.43,-2973064.504,3622725.395,4312652.28,-2973082.771,3622751.235,4312622.63,3,-2976684.598,3626519.827,4306929.7,-2976684.524,3626512.567,4306932.87,-2976681.975,3626520.219,4306932.65,-2976686.287,3626518.3,4306925.39,4,-2975958.454,3620385.156,4312190.55,-2975955.701,3620385.385,4312184.89,-2975949.551,3620381.481,4312195.31,-2975948.261,3620383.491,4312195.99,X,Y,Z,1,-2977112.739,3616727.66,4314844.249,2,-2972973.959,3622794.609,4312665.052,3,-2976591.793,3626585.233,4306942.372,4,-2975862.99,3620455.029,4312198.877,计算结果,DX=-92649,DY=-6788,DZ=-11779,DA=-3,DF=0,DA,是椭球长半轴的差,;DF,为椭球扁率的,差,东西偏差为,500 000 m,南北偏差为,0,北京,54,坐标参数,参数中的常数：,DA=-108,DF=0.0000005,其他参数计算方法同西安,80,坐标参数的计算。,总结,使用已知的国家级控制点,通过坐标转换求出了地心空间直角坐标系与参心空间直角坐标系之间的,3,个转换参数,有效地提高了手持式,GPS,的单点定位精度,对于使用手持式,GPS,进行相关研究和生产具有重要的现实意义,.,