| CPC G01S 19/258 (2013.01) [H04B 7/043 (2013.01); H04W 64/003 (2013.01)] | 20 Claims |

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1. A user terminal (UT) comprising:
a receiver connected to an electronically steerable phased array antenna (“antenna”); and
a first set of one or more processors executing instructions to:
determine, at a first time, first data comprising a current time and a geolocation of the UT;
determine first ephemeris data that is acquired prior to the first time and is outdated, wherein the first ephemeris data is associated with one or more satellites of a constellation of non-geostationary satellites;
determine, based on the first data and the first ephemeris data, a first predicted direction of a first satellite of the constellation relative to the UT;
determine parameter data indicative of receive antenna gain of the antenna;
responsive to determining the first predicted direction of the first satellite and the parameter data, determine a first set of sample directions relative to the first predicted direction; and
responsive to determining the first set of sample directions:
operate the antenna to direct a respective receive beam toward each of the first set of sample directions;
operate the receiver to determine second data indicative of a received signal strength of a signal received from each of the first set of sample directions; and
determine, using the parameter data and the second data, a second estimated direction of the first satellite relative to the UT using a least-square estimation algorithm.
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