Abstract: A frequency hopping Global Positioning System (GPS) system comprises an on-orbit reprogrammable digital waveform generator configured to generate a GPS signal comprising a resilient frequency-hopping spread spectrum GPS signal that hops at a hop rate between two or more GPS channels. The GPS signal further comprises a legacy direct-sequence spread spectrum signal for at least two of the two or more GPS channels. Further, a receiver is configured to receive the GPS signal, wherein the receiver is further configured to decode the GPS signal.

Abstract: A system for generating a frequency hopping Global Positioning System (GPS) system includes: an on-orbit reprogrammable digital waveform generator (ORDWG) configured to generate a GPS signal comprising a resilient frequency-hopping spread spectrum GPS signal that hops at a hop rate between two or more GPS channels, the GPS signal further comprising a legacy direct-sequence spread spectrum signal for at least two of the two or more GPS channels; and a receiver configured to receive the GPS signal, the radio further configured to decode the GPS signal.

Abstract: An exemplary satellite in a communication system supports communications among earth stations and has a first receiver that receiving a first RF signal transmitted from a first earth station that is down converted to a first electrical IF signal. An up converter converts a second electrical IF signal, from a second earth station carrying information for the first earth station, to a second RF signal and transmits it to the first earth station. A switch switches remotely reconfigurable electrical IF communication circuits between pairs of ports. Signals carrying information to be communicated between the first and second earth stations are linked together by the switch.

Abstract: An apparatus includes: a Global Positioning System (GPS) phased array comprising a plurality of digital beam forming elements (DBFEs), wherein at least one of the DBFEs includes: an antenna configured to transmit a GPS signal; a radio frequency (RF) electronics section operably connected to the antenna and digital electronics sections; and a digital electronics section operably connected to the RF electronics section. An apparatus includes: a GPS phased array comprising a plurality of DBFEs, wherein at least one of the DBFEs includes: an antenna configured to transmit a GPS signal; an RF electronics section operably connected to the antenna and digital electronics sections; and a digital electronics section operably connected an RF electronic section; a navigation encoder and frequency generator (NEFU) unit operably connected to the GPS phased array; and an atomic frequency standard operably connected to the NEFU unit.

Abstract: An apparatus includes: a Global Positioning System (GPS) phased array comprising a plurality of digital beam forming elements (DBFEs), wherein at least one of the DBFEs includes: an antenna configured to transmit a GPS signal; a radio frequency (RF) electronics section operably connected to the antenna and digital electronics sections; and a digital electronics section operably connected to the RF electronics section. An apparatus includes: a GPS phased array comprising a plurality of DBFEs, wherein at least one of the DBFEs includes: an antenna configured to transmit a GPS signal; an RF electronics section operably connected to the antenna and digital electronics sections; and a digital electronics section operably connected an RF electronic section; a navigation encoder and frequency generator (NEFU) unit operably connected to the GPS phased array; and an atomic frequency standard operably connected to the NEFU unit.

Abstract: An optical communication system (20) is provided for transmitting a multi-rate data signal between a transmitter (22) and a receiver (24) in a power efficient manner. The optical communication system (20) includes an optical source (32) that supplies an optical carrier signal; an encoder (44) that receives and encodes a data signal; an external phase modulator (42) that modulates the optical carrier signal with the encoded data signal, such that the modulator (42) varies the duty factor of the modulated optical signal based on the encoded data signal; and an optically saturated erbium doped fiber amplifier (36) that amplifies the modulated optical signal prior to transmission by the transmitter (22). In accordance with the present invention, the modulation scheme of the optical communication system (20) varies the duty cycle of the modulation to attain power efficiency during periods of low data demand.