A method for controlling a time of transmission and radio frequency of a plurality of signals in a non-geosynchronous satellite communication system, the system comprising a plurality of user terminals, UTs, in a beam coverage area and a gateway in communication with a non-geosynchronous satellite, the method comprising: comparing, at each UT of the plurality of UTs, a time of arrival, TOA, and a carrier frequency of a received signal, received by each UT on a forward service link between each UT and the non-geosynchronous satellite, with a local time reference and a local frequency reference of each UT respectively; computing, at each UT of the plurality of UTs, based on the comparison between the local time reference of the UT and the received signal, a pre-correction time value; computing, at each UT of the plurality of UTs, based on the comparison between the local frequency reference of the UT and the received signal, a pre-correction frequency value; applying, at each UT of the plurality of UTs, the pre-correction time value to adjust the time of transmission of a signal for transmission on a return service link between the UT and the non-geosynchronous satellite; and applying, at each UT of the plurality of UTs, the pre-correction frequency value to adjust the radio frequency of the signal for transmission on the return service link between the UT and the non-geosynchronous satellite, wherein the pre-correction time value is configured to reduce a TOA differential between a TOA of the received signal received by the UT on the forward service link between the UT and the non-geosynchronous satellite, and a TOA at the non-geosynchronous satellite of the signal for transmission on the return service link between the UT and the non-geosynchronous satellite, and wherein the pre-correction frequency value is configured to reduce a frequency offset differential between a radio frequency of the received signal received by the UT on a forward service link between the UT and the non-geosynchronous satellite, and a radio frequency of the signal for transmission on the return service link between the UT and the non-geosynchronous satellite. comparing, at each UT of the plurality of UTs, a time of arrival, TOA, and a carrier frequency of a received signal, received by each UT on a forward service link between each UT and the non-geosynchronous satellite, with a local time reference and a local frequency reference of each UT respectively; computing, at each UT of the plurality of UTs, based on the comparison between the local time reference of the UT and the received signal, a pre-correction time value; computing, at each UT of the plurality of UTs, based on the comparison between the local frequency reference of the UT and the received signal, a pre-correction frequency value; applying, at each UT of the plurality of UTs, the pre-correction time value to adjust the time of transmission of a signal for transmission on a return service link between the UT and the non-geosynchronous satellite; and applying, at each UT of the plurality of UTs, the pre-correction frequency value to adjust the radio frequency of the signal for transmission on the return service link between the UT and the non-geosynchronous satellite, wherein the pre-correction time value is configured to reduce a TOA differential between a TOA of the received signal received by the UT on the forward service link between the UT and the non-geosynchronous satellite, and a TOA at the non-geosynchronous satellite of the signal for transmission on the return service link between the UT and the non-geosynchronous satellite, and wherein the pre-correction frequency value is configured to reduce a frequency offset differential between a radio frequency of the received signal received by the UT on a forward service link between the UT and the non-geosynchronous satellite, and a radio frequency of the signal for transmission on the return service link between the UT and the non-geosynchronous satellite. wherein the pre-correction time value is configured to reduce a TOA differential between a TOA of the received signal received by the UT on the forward service link between the UT and the non-geosynchronous satellite, and a TOA at the non-geosynchronous satellite of the signal for transmission on the return service link between the UT and the non-geosynchronous satellite, and wherein the pre-correction frequency value is configured to reduce a frequency offset differential between a radio frequency of the received signal received by the UT on a forward service link between the UT and the non-geosynchronous satellite, and a radio frequency of the signal for transmission on the return service link between the UT and the non-geosynchronous satellite.