Abstract: Embodiments of the disclosure provide methods, apparatus, and articles allowing two nodes to communicate in a slot-based direct sequencing spreading communication system. Both a preamble sequence and a payload data spreading PN sequence are generated from the Time of Day and a given user code. Generated sequences are synchronized between two communicating nodes to allow slot-based DSSS communication to take place. Generated sequences also change dynamically from slot to slot to provide waveform security.

Abstract: A spread-spectrum preamble synchronization peak detection system performs multiple statistical tests based on instant and time-averaged channel condition measurements to identify the synchronization peak. In a normalized peak-to-average test, a peak-to-average ratio measurement is normalized by a signal-to-noise ratio measurement to form a new statistical measure which effectively eliminates the impact of the wide dynamic range of the signal-to-noise ratio of the received samples. A transition SNR test is used to eliminate potential false alarms caused by spurious PARN peaks during the transition period at the onset of preamble arrival. Code-phase aligned time-averaging is used to estimate the signal and noise levels over a sliding window. The code-phase alignment of samples effectively separates signal and noise samples in the averaging process, and resulting in more accurate signal and noise measurements.

Abstract: A spread-spectrum preamble synchronization peak detection system performs multiple statistical tests based on instant and time-averaged channel condition measurements to identify the synchronization peak. In a normalized peak-to-average test, a peak-to-average ratio measurement is normalized by a signal-to-noise ratio measurement to form a new statistical measure which effectively eliminates the impact of the wide dynamic range of the signal-to-noise ratio of the received samples. A transition SNR test is used to eliminate potential false alarms caused by spurious PARN peaks during the transition period at the onset of preamble arrival. Code-phase aligned time-averaging is used to estimate the signal and noise levels over a sliding window. The code-phase alignment of samples effectively separates signal and noise samples in the averaging process, and resulting in more accurate signal and noise measurements.

Abstract: Embodiments of the disclosure provide methods, apparatus, and articles allowing two nodes to communicate in a slot-based direct sequencing spreading communication system. Both a preamble sequence and a payload data spreading PN sequence are generated from the Time of Day and a given user code. Generated sequences are synchronized between two communicating nodes to allow slot-based DSSS communication to take place. Generated sequences also change dynamically from slot to slot to provide waveform security.

Abstract: The invention provides a combined optical sensor and communications antenna system (10). The system includes a primary reflector (12) for reflecting radiation. The primary reflector includes a centrally located core (14), which is adapted to transmit the radiation therethrough. An axis (18) centrally extending through the core forms an optical axis of the system. The system further includes a secondary reflector (16) positioned along the optical axis of the system for rereflecting and focusing the radiation reflected from the primary reflector toward the core of the primary reflector. The system still further includes a beam splitter (20) positioned adjacent the primary reflector on the opposite side from the secondary reflector, for separating and redirecting the radiation rereflected from the secondary reflector into an optical radiation component and a radiofrequency radiation component.