Abstract: A system is provided for reducing latency data collection from space-based sensor satellites. A mobile vehicle platform includes a sensor module configured to monitor certain conditions, circumstances, environments and situations occurring on or around, or associated with, the Earth, and to generate sensor data resulting from the monitoring. A relay satellite terminal is configured to execute data communications via a communications channel of a first satellite beam, wherein the data communications are configured to relay the sensor data, via satellites, to respective gateways for forwarding to a central processing facility for one or more of aggregation, processing, analysis and dissemination of the data. The relay satellite terminal is further configured to switch the data communications from the communications channel of the first satellite beam to a communications channel of a second satellite beam based on a position of the relay satellite terminal relative to the first and second satellite beams.

Abstract: A method and a satellite terminal are provided. The satellite terminal may range over multiple frequencies and may receive, from a satellite gateway, a signal quality indicator with respect to each of the ranged multiple frequencies. Noise and interference for a corresponding frequency are estimated based on at least one of the received signal quality indicators for the corresponding frequency. Path loss is estimated based on multiple received signal quality indicators, each of which is received in response to the satellite terminal transmitting a signal while not performing the ranging process. A transmit power level of the satellite terminal is adjusted for the corresponding frequency based on the estimated path loss and the estimated noise and interference for the corresponding frequency.

Abstract: An apparatus and method for synchronizing communication between systems having different clock rates, is described. The apparatus includes a communication unit, a synchronization unit, and an interface unit. The communication unit receives upstream information and generates a first sample stream representative of the upstream information based on a first clock rate. The synchronization unit converts the first sample stream to a second sample stream based on a second clock rate and in accordance with a predetermined burst plan. The interface unit receives the second sample stream at the second clock rate and outputs it based on the predetermined burst plan.

Abstract: A system is provided for reducing latency data collection from space-based sensor satellites. A mobile vehicle platform, configured to travel around the Earth, includes a sensor module and a relay satellite terminal. The sensor module monitors certain conditions, circumstances, environments and/or situations occurring on or around, or associated with, the Earth, and generates sensor data resulting from the monitoring. The relay satellite terminal executes data communications with a first of a plurality of satellites while the mobile vehicle platform is in a first area within a communications range of the first satellite, and, upon moving to a second area within a communications range of a second of the plurality of satellites, the relay satellite terminal switches the data communications to the second satellite. The data communications relay the sensor data, via the satellites, to a central processing facility for aggregation, processing, analysis and/or dissemination of the data.

Abstract: Approaches for efficient, dynamic and continuous handover processes, which encompass selection of an optimal path (consisting of a satellite, a satellite beam and carrier frequency set) over which a mobile user terminal (UT) communicates with the radio access network in a mobile satellite communications system, are provided. A set of path factors are determined regarding each of a plurality of communications paths for the UT. A path selection metric (PSM) for each communications path is determined, wherein the PSM for each communications path is determined via a weighted calculation based on the respective set of path factors for the communications path. A decision is made as to whether to perform a handover of the UT from a first of the communications paths to a second of the communications paths, wherein the determination is based on an evaluation performed based at least in part on the PSM.

Abstract: A synchronization approach is provided that compensates for the large Doppler offset of the satellites in a LEO satellite system by exploiting the predictable and deterministic nature of the Doppler component, and thereby simplifies the delay and the Doppler domain uncertainty ranges that the physical layer receivers have to resolve. The compensation is based on the known ephemeris information of the LEO satellite and the known positions of the gateway (GW) and the user terminal (UT) on the ground. Utilizing the deterministic component of the LEO Doppler, the synchronization process continually tracks and compensates for the time-varying offsets between the GW and UT frame timing, frame numbering (FN), symbol timings, and Doppler-induced scaling of center frequency and the signal bandwidth.

Abstract: A method for iterative estimation of a set of unknown channel parameters in a beamforming network including determining a first order estimate of offsets at measurement nodes and an estimate of the confidence in the initial estimate of the measurement nodes' offsets, and iterating, until a desired estimation accuracy is obtained, determining an improved estimate of a parameter set, and the confidence in the estimates, using the prior estimate of the offsets at the measurement nodes and determining an improved estimate of the offsets at the measurement nodes and the associated confidence values using the prior estimate of the parameter set and the corresponding confidence values.

Abstract: An approach provides for conversion of global positioning system (GPS) data. A user terminal receives positioning data from a base station, wherein the positioning data is received in a second format, and wherein the second format was derived from ephemeris data broadcast via a global positioning system (GPS) in a first format. The user terminal converts the positioning data from the second format into a third format that is compatible with a protocol of the GPS system, and determines a first fix using the third format of the positioning data.

Abstract: A system is provided for reducing latency data collection from space-based sensor satellites. A mobile vehicle platform includes a sensor module configured to monitor certain conditions, circumstances, environments and situations occurring on or around, or associated with, the Earth, and to generate sensor data resulting from the monitoring. A relay satellite terminal is configured to execute data communications via a communications channel of a first satellite beam, wherein the data communications are configured to relay the sensor data, via satellites, to respective gateways for forwarding to a central processing facility for one or more of aggregation, processing, analysis and dissemination of the data. The relay satellite terminal is further configured to switch the data communications from the communications channel of the first satellite beam to a communications channel of a second satellite beam based on a position of the relay satellite terminal relative to the first and second satellite beams.

Abstract: A method for iterative estimation of a set of unknown channel parameters in a beamforming network including determining a first order estimate of offsets at measurement nodes and an estimate of the confidence in the initial estimate of the measurement nodes' offsets, and iterating, until a desired estimation accuracy is obtained, determining an improved estimate of a parameter set, and the confidence in the estimates, using the prior estimate of the offsets at the measurement nodes and determining an improved estimate of the offsets at the measurement nodes and the associated confidence values using the prior estimate of the parameter set and the corresponding confidence values.

Abstract: A method for iterative estimation of a set of unknown channel parameters in a beamforming network including determining a first order estimate of offsets at measurement nodes and an estimate of the confidence in the initial estimate of the measurement nodes' offsets, and iterating, until a desired estimation accuracy is obtained, determining an improved estimate of a parameter set, and the confidence in the estimates, using the prior estimate of the offsets at the measurement nodes and determining an improved estimate of the offsets at the measurement nodes and the associated confidence values using the prior estimate of the parameter set and the corresponding confidence values.

Abstract: An approach provides for conversion of global positioning system (GPS) data. A user terminal receives positioning data from a base station, wherein the positioning data is received in a second format, and wherein the second format was derived from ephemeris data broadcast via a global positioning system (GPS) in a first format. The user terminal converts the positioning data from the second format into a third format that is compatible with a protocol of the GPS system, and determines a first fix using the third format of the positioning data.

Abstract: A message format and associated method for estimating the frequency and timing offset of a reference burst of a random access channel in a time-division multiple access communications system. A signal structure in which the continuous wave segment is split into two parts separated by some portion of the content of the random access channel burst is used to provide more precise frequency estimation. Iteration of separate frequency and timing estimation procedures is used to refine both estimates, as the individual estimation processes are more accurate when there is less error in the other parameter. Multiple hypothesis testing is used, in which more than one initial frequency estimate is carried through the iteration process, with thresholding to identify the best frequency offset. Reliable rejection of false ambiguities is achieved because the degradation in timing estimation, due to large frequency offsets, can be detected with thresholding.