Abstract: A method of increasing utilization of user link bandwidth for a code division multiple access communications system is disclosed that includes the steps of selecting a set of orthogonal complex codes each having a code length that is greater than a code length of an optimum real code and less than or equal to a number of antenna elements in an antenna array of the feeder link.

Abstract: A mobile satellite payload 18 and a method for sampling communication signals 26 are provided. The mobile satellite payload 18 uses a plurality of receive radiating elements 24 within a phase array antenna 22 to convert the communication signals 26 to received signals [S(t)]. A plurality of low noise amplifiers (LNAs) 28 amplify the received signals [S(t)] to then be received by a plurality of analog-to-digital (A/D) converters 29. The A/D converters 29 transform the received signals [S(t)] into digital baseband signals [S?(t)].

Abstract: A signal processing circuit for satellite communications signal includes a first one dimensional digital beam forming circuit for forming a beam signal in a first direction and a second one dimensional digital beam forming circuit for forming a beam in a second direction. A direction filtering circuit is coupled between the first one dimensional digital beam forming circuit and the second one dimensional digital beam forming circuit. The filtering circuit determining a communications signal direction of the satellite communications signal and tunes the filter to reduce a filter bandwidth and a frequency range of said beam signal prior to processing through the second one dimensional digital beam forming circuit.

Abstract: Methods for increasing the efficiency of satellite constellation operations are disclosed. The steps of the present invention comprise calculating the maximum number of communications signals that each satellite in the satellite constellation can generate, determining an operational constraint on each satellite, the operational constraint limiting the number of communications signals that each satellite can radiate substantially simultaneously, determining an operational space for each satellite wherein the operational space is defined using the operational constraint and the calculated number of signals, and using the operational space for each satellite in the constellation to determine the operational point for the constellation.

Abstract: A modular mobile terminal for a satellite system is disclosed in which the satellite system has a ground station and a network such as a telephone network coupled to the ground station. Each of the mobile terminals has a radome layer and a support layer having a plurality of circuit traces formed thereon. An element module is coupled between the support layer and the radome layer. Each element module comprises a housing and a radiating patch having a feed therethrough. A dielectric layer is coupled adjacent to the radiating patch. A ground plane is disposed adjacent to the dielectric layer on the opposite side of the dielectric layer as the radiating patch. A plurality of circuit chips is coupled to the ground plane. The support layer of the array has a plurality of circuit traces formed thereon. A plurality of interconnections between the circuit chips and the plurality of traces connect the traces and the circuit chips.

Abstract: A signal processing circuit for satellite communications signal includes a first one dimensional digital beam forming circuit for forming a beam signal in a first direction and a second one dimensional digital beam forming circuit for forming a beam in a second direction. A direction filtering circuit is coupled between the first one dimensional digital beam forming circuit and the second one dimensional digital beam forming circuit. The filtering circuit determining a communications signal direction of the satellite communications signal and tunes the filter to reduce a filter bandwidth and a frequency range of said beam signal prior to processing through the second one dimensional digital beam forming circuit.

Abstract: A signal processing circuit for satellite communications signal includes a first one dimensional digital beam forming circuit for forming a beam signal in a first direction and a second one dimensional digital beam forming circuit for forming a beam in a second direction. A direction filtering circuit is coupled between the first one dimensional digital beam forming circuit and the second one dimensional digital beam forming circuit. The filtering circuit determining a communications signal direction of the satellite communications signal and tunes the filter to reduce a filter bandwidth and a frequency range of said beam signal prior to processing through the second one dimensional digital beam forming circuit.

Abstract: Methods for operating a satellite constellation are disclosed that utilize spatial diversity and directional gain antennas at ground terminal locations to provide multiple data rate services on a single frequency channel. One method comprises receiving a signal at a first and second satellite in the satellite constellation from a first communications device. A communications channel at a first frequency from the first satellite is used to communicate with the first communications device. A signal from a second communications device is received only at the second satellite at the first frequency, and the second satellite is used to communicate with the second communications device at the first frequency without substantially interfering with the communications with the first communications device.

Abstract: Methods for increasing the efficiency of satellite constellation operations are disclosed. The steps of the present invention comprise calculating the maximum number of communications signals that each satellite in the satellite constellation can generate, determining an operational constraint on each satellite, the operational constraint limiting the number of communications signals that each satellite can radiate substantially simultaneously, determining an operational space for each satellite wherein the operational space is defined using the operational constraint and the calculated number of signals, and using the operational space for each satellite in the constellation to determine the operational point for the constellation.

Abstract: A modular mobile terminal for a satellite system is disclosed in which the satellite system has a ground station and a network such as a telephone network coupled to the ground station. Each of the mobile terminals has a radome layer and a support layer having a plurality of circuit traces formed thereon. An element module is coupled between the support layer and the radome layer. Each element module comprises a housing and a radiating patch having a feed therethrough. A dielectric layer is coupled adjacent to the radiating patch. A ground plane is disposed adjacent to the dielectric layer on the opposite side of the dielectric layer as the radiating patch. A plurality of circuit chips is coupled to the ground plane. The support layer of the array has a plurality of circuit traces formed thereon. A plurality of interconnections between the circuit chips and the plurality of traces connect the traces and the circuit chips.

Abstract: Methods for increasing the efficiency of satellite constellation operations are disclosed. The steps of the present invention comprise calculating the maximum number of communications signals that each satellite in the satellite constellation can generate, determining an operational constraint on each satellite, the operational constraint limiting the number of communications signals that each satellite can radiate substantially simultaneously, determining an operational space for each satellite wherein the operational space is defined using the operational constraint and the calculated number of signals, and using the operational space for each satellite in the constellation to determine the operational point for the constellation.

Abstract: Methods for increasing the efficiency of satellite constellation operations are disclosed. The steps of the present invention comprise calculating the maximum number of communications signals that each satellite in the satellite constellation can generate, determining an operational constraint on each satellite, the operational constraint limiting the number of communications signals that each satellite can radiate substantially simultaneously, determining an operational space for each satellite wherein the operational space is defined using the operational constraint and the calculated number of signals, and using the operational space for each satellite in the constellation to determine the operational point for the constellation.

Abstract: A modular mobile terminal for a satellite system is disclosed in which the satellite system has a ground station and a network such as a telephone network coupled to the ground station. Each of the mobile terminals has a radome layer and a support layer having a plurality of circuit traces formed thereon. An element module is coupled between the support layer and the radome layer. Each element module comprises a housing and a radiating patch having a feed therethrough. A dielectric layer is coupled adjacent to the radiating patch. A ground plane is disposed adjacent to the dielectric layer on the opposite side of the dielectric layer as the radiating patch. A plurality of circuit chips is coupled to the ground plane. The support layer of the array has a plurality of circuit traces formed thereon. A plurality of interconnections between the circuit chips and the plurality of traces connect the traces and the circuit chips.

Abstract: A method of increasing utilization of user link bandwidth for a code division multiple access communications system is disclosed that includes the steps of selecting a set of orthogonal complex codes each having a code length that is greater than a code length of an optimum real code and less than or equal to a number of antenna elements in an antenna array of the feeder link.

Abstract: A mobile satellite payload 18 and a method for sampling communication signals 26 are provided. The mobile satellite payload 18 uses a plurality of receive radiating elements 24 within a phase array antenna 22 to convert the communication signals 26 to received signals [S(t)]. A plurality of low noise amplifiers (LNAs) 28 amplify the received signals [S(t)] to then be received by a plurality of analog-to-digital (A/D) converters 29. The A/D converters 29 transform the received signals [S(t)] into digital baseband signals [S″(t)].

Abstract: A communication system transmitting messages includes two-way ranging by communicating between a target vehicle and a traffic controller station through a plurality of satellites. A set of the plurality of satellites may be used simultaneously or sequentially to transmit and receive signals from the ground station to a target vehicle, preferably an aircraft in the preferred embodiment. Each aircraft includes a particular ranging code combined with a message signal to selectively process the ranging data supplied to each vehicle. The ranging determination may be used in conjunction with alternative ranging devices, such as a global positioning system, in order to improve the accuracy of the estimations provided by the ranging processing. Nevertheless, the method and apparatus of the present invention provide relatively accurate state vectors without the need for precisely accurate timing synchronization at each of the stations connected by communication links.

Abstract: A method permitting beam forming at a ground station for providing a coherent and stable uplink signal to a satellite system employing multiple spot beams by combining orthogonal synchronous code division multiplex codes and pseudo-random spreading codes with an information signal to implement a satellite feeder uplink.

Abstract: A receiver is disclosed for acquiring and tracking a data signal in a highly stressed environment. The receiver comprises first and second I.F. sections, a mixer for translation from the first I.F. frequency to the second I.F. frequency, a 2 KHz bandpass filter at the second I.F. frequency, signal translator for synchronous translation of the signal at the second I.F. frequency to baseband, a digitizer for complex sampling operation on the baseband signal, a microprocessor for processing the digital samples, and a numerically controlled oscillator coupled to the mixer and controlled by the microprocessor. The microprocessor formulates matched digital discrete Fourier Transform filters which drive frequency, phase and symbol lock loops at the symbol rate. Each of the loop filters is formed by symbol-rate recursive, first-order equations.