Cycle slip detection and repair play important roles in the processing of data from dual-frequency GPS receivers onboard low-Earth orbit (LEO) satellites. To detect and repair cycle slips more comprehensively, an enhanced error method (EEM) is proposed. EEM combines single-frequency and narrow-lane carrier phase observations to construct special observations and observation equation groups. These special observations differ across time and satellite (ATS). ATS observations are constructed by three steps. The first step is differencing single-frequency and narrow-lane observations through a time difference (TD). The second step is to select a satellite as a reference satellite and other satellites as nonreference satellites. The third step is to difference the single-frequency TD observations from the reference satellite and the narrow-lane TD observations from the nonreference satellites by a satellite difference. If cycle slips occur at the reference satellite, the correction values for these ATS observations can be significantly enlarged. To process all satellites, the EEM selects each satellite as a reference satellite and builds the corresponding equation group. The EEM solves these observation equation groups according to the weighted least-squares adjustment (LSA) criterion and obtains the correction values; these correction values are then used to construct the values corresponding to different equation groups, and the EEM subsequently carries out a chi-square distribution test for these . The satellite corresponding to the maximum will be marked. Then, the EEM iteratively processes the other satellites. Cycle slips can be estimated by rounding the float solutions of changes in the ambiguities of cycle slip satellites to the nearest integer. The simulation test results show that the EEM can be used to detect special cycle slip pairs such as (1, 1) and (9, 7). The EEM needs only observation data in two adjacent epochs and is still applicable to observation epochs with continuous cycle slips.

中文翻译：

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LEO卫星双频机载GPS接收机的周跳检测和修复的增强方法

周期滑动检测和修复在处理低地球轨道（LEO）卫星上的双频GPS接收器的数据中起着重要作用。为了更全面地检测和修复周跳，提出了一种改进的误差方法（EEM）。EEM结合了单频和窄通道载波相位观测，以构造特殊观测和观测方程组。这些特殊的观测结果随时间和卫星（ATS）的不同而不同。ATS观察分为三个步骤。第一步是通过时间差（TD）区分单频和窄通道观测。第二步是选择一颗卫星作为参考卫星，选择其他卫星作为非参考卫星。第三步是通过卫星差来区别参考卫星的单频TD观测值和非参考卫星的窄道TD观测值。如果参考卫星处发生周跳，则可以显着扩大这些ATS观测值的校正值。为了处理所有卫星，EEM选择每个卫星作为参考卫星，并建立相应的方程组。EEM根据加权最小二乘平差（LSA）准则求解这些观测方程组，并获得校正值。然后将这些校正值用于构建 为了处理所有卫星，EEM选择每个卫星作为参考卫星，并建立相应的方程组。EEM根据加权最小二乘平差（LSA）准则求解这些观测方程组，并获得校正值。然后将这些校正值用于构建 为了处理所有卫星，EEM选择每个卫星作为参考卫星，并建立相应的方程组。EEM根据加权最小二乘平差（LSA）准则求解这些观测方程组，并获得校正值。然后将这些校正值用于构建值对应于不同的方程组，然后EEM对这些方程进行卡方分布测试。对应于最大值的卫星将被标记。然后，EEM迭代处理其他卫星。可以通过将周期滑动卫星的模糊度变化的浮点解约数舍入到最接近的整数来估计周期滑动。仿真测试结果表明，EEM可用于检测特殊的循环滑移对，例如（1，1）和（9，7）。EEM仅需要两个相邻时期中的观测数据，并且仍然适用于具有连续周期转差的观测时期。