星载激光测高系统亚毫弧量级的发散角和冰层表面几乎没有穿透效应的优势使其非常适于监测南北极冰盖变化。利用GLAS激光测高卫星的高程数据，通过交叉和重复点方法分析2003~2009年3月格陵兰2 000 m以上区域冰盖高程变化，并改进了交叉点计算方法，使其适合纬度跨度较大的格陵兰地区。经过粗差剔除和时序解算，研究结果表明，该区域7年间冰盖高程年均变化+3.80 cm/年，中误差0.91 cm，呈缓慢增长趋势；交叉点和重复点方法所得结果趋势一致，重复点数量为交叉点数量的4~15倍，但位置分布不均匀，使用星载激光测高数据分析极地冰盖变化时，较大区域适合使用交叉点方法，较小区域适合使用重复点方法。

The spaceborne laser altimeter has the advantages of divergence angle of milli arc magnitude and no penetration effect on ice surface, which are suitable for monitoring the icesheet changing of polar region. Using elevation data of GLAS laser altimeter, the ice sheet changing of the region above 2 000 m of Greenland was obtained and analyzed through the crossing and repeat pairs over the time span of March 2003 to March 2009. The novel method was developed and applied to calculate crossing pairs in the entire Greenland where the latitudinal span was very large. After coarse error elimination and time series analysis, a positive elevation change rate of 3.80 cm/year, and a standard deviation of 0.91 cm were obtained, and change trends from the crossing and repeat pairs were agreed. The number of repeat pairs was much larger than that of cross pairs, approximately 4-15 times, while its spatial distribution was very non-uniform. The conclusion is that on elevation change monitoring in Greenland’s ice sheet,the crossing pairs is more fit for large zone, while the repeat ones suitable for small area.