Abstract: A system and method for enhanced use of voltage standing wave ratio (VSWR) tests of an avionic radio and antenna is disclosed. A signal processor/generator conducts a VSWR test of an antenna and archives the result within a database. Multiple tests are conducted spanning periods of operation of the radio. Tests may also be conducted at multiple frequencies, such as commonly used channels of communication. Results are uploaded to an external diagnostic device and analyzed to evaluate deterioration of the antenna. Analysis may including comparing test results to threshold values and analyzing test results for frequency and time dependent trends.

Abstract: A method of determining distances between communication nodes. The method includes transmitting an initial communication frame from a first node to at least one second node. The initial communication frame includes a frame preamble, first data and a first switch point. The method further includes synchronizing a local clock of the at least one second node based on the frame preamble. Switching the at least one second node to a transmitting node based on the received switch point. Transmitting a subsequent communication frame from the at least one second node to the first node. The subsequent communication frame includes a ranging preamble, second data and a second switch point. The method continues by synchronizing a local clock in the first node based on the ranging preamble from the at least one second node and determining the range between the first node and the second node based on the ranging preamble.

Abstract: A method of communicatively coupling network elements supporting multiple network protocol types comprises receiving input having multiple network protocol types from an upper-level of the protocol stack at an endpoint-flexible-interface layer in a network endpoint, mapping the input between the upper-level of a protocol stack and a common-lower-level in the protocol stack at the endpoint-flexible-interface layer, and implementing the common-lower-level protocol layer to interface the multiple network protocol types to the physical layer, so that at least two endpoints of a network are communicatively coupled.

Abstract: A method and apparatus for dealing with noise spikes in a radar system is provided. The method includes monitoring a noise channel in the radar system. Controlling gain with a control loop based at least in part on the monitored noise channel and ignoring noise spikes detected in the noise channel when controlling gain with the control loop.

Abstract: In one embodiment, a network comprises a plurality of nodes that communicate with one another. A first node included in the plurality of nodes generates a plan comprising a plurality of marker states. Each marker state comprises a value for a property associated with the first node. When the first node broadcasts information indicative of a given marker state included in the plan, at least one node other than the first node verifies the value of the property included in the given marker state.

Abstract: Systems and methods for performing vibration error suppression in a fiber optic gyro sensor. An example system includes a light source, a sensing loop assembly, a photo detector, and a processing component. The light source generates a light signal that is then modulated by the sensing loop assembly and applied to a fiber optic coil in the assembly. The photo detector receives a modulated light signal that is an output of the sensing loop assembly (coil) and generates an analog signal. The processing component converts the generated analog signal into a modulated digital signal, determines an average of the modulated digital signal, determines an intensity modulation amplitude based on the determined average of the modulated digital signal, and re-scales the modulated digital phase signal based on the determined intensity modulation amplitude.

Abstract: A wireless network comprises a plurality of nodes that communicate over wireless communication links. A virtual site is established at a primary node included in the plurality of nodes. A backup node is selected for the virtual site from the plurality of nodes. When the primary node is able to do so, the primary node performs predetermined processing for the virtual site and replicates at the backup node data related to the processing. When the primary node is unable to perform the processing, the backup node performs the processing for the virtual site using at least some of the data replicated at the backup node.

Abstract: A dead-reckoning sensory system includes a receiver unit and a transmitter unit in wireless communication with the receiver unit. The transmitter unit is operable to be mounted to a wheel of a vehicle, determine information characterizing the heading and distance traveled by the vehicle, and transmit the information to the receiver unit.

Abstract: A false lock filter circuit for a pulsed altimeter is provided. The circuit includes a low pass filter having a relatively low bandwidth (LBW LPF), a low pass filter having a relatively high bandwidth (HBW LPF) and a false lock controller. The LBW LPF has an input that is coupled to receive a detector output. The HBW LPF has an input that is coupled to receive the detector output. The false lock controller is coupled to receive outputs from the LBW LPF and HBW LPF. Moreover, the false lock controller is configured to sample an output of the HBW LPF and apply a statistical analysis on the samples to determine if a valid target has been detected.

Abstract: Methods and devices for polarizing light in a proton exchange polarizer where cross-coupling of unwanted modes of light is reduced with an integrated spatial filter. An optically transmissive substrate such as a substrate created from LiNbO3 or LiTaO3 has side surfaces, which reflect unguided TM mode light. The light originates from an input fiber. The input fiber is connected to the substrate at one end and an output fiber is connected to receive guided TE mode light at the opposite end. The spatial filter is positioned at the primary reflection position of the light with respect to the sides of the polarizer. To improve extinction further, the spatial filter can also be located at secondary reflection points in another alternate embodiment.

Abstract: A system for determining a level of angle random walk (ARW) associated with a fiber optic gyroscope (FOG) includes first and second photodiodes. The first photodiode is configured to receive a first light signal from a light source associated with the FOG. The second photodiode is configured to receive a second light signal from a fiber optic coil associated with the FOG. First and second analog-to-digital converters (ADCs) are operable to respectively convert the first and second light signals into corresponding respective first and second digital signals. A digital relative-intensity-noise (RIN) subtraction element is configured to receive the first and second digital signals and output a third signal based on the first and second digital signals. An electronic device is configured to determine a first noise level associated with the third signal, and determine the ARW level from the first noise level.

Abstract: Systems and methods for performing self calibration of a radar altimeter. An example system includes a first component that generates a simulated return signal based on one or more range values. A transmitter generates a transmission radar signal and a receiver processes the simulated return signal based on the transmission radar signal. A second component determines one or more calibration factors based on the processed simulated return signal and ideal return signal characteristics. The transmission radar signal is a fixed frequency signal and the first component includes a programmable frequency divider that creates at least on sideband of a known signal. A third component determines if the radar system is in at least one of a calibration mode or normal mode of operation. If the radar system is determined to be in a normal mode of operation, a fourth component applies the determined calibration factors to actual radar return signals.

Abstract: A navigation system used by a user includes a navigation unit and a portable device. The navigation unit generates navigation-related output. The navigation unit transmits the navigation-related output to the portable device over a wireless communication link. The portable device receives the navigation-related output and uses at least a portion of the navigation-related output for processing performed thereby. In one embodiment, the portable device includes an input interface to receive user input from a user of the portable device. In such an embodiment, the portable device transmits the navigation-related input to the navigation unit over the wireless communication link, and the navigation unit uses at least a portion of the navigation-related input to generate the navigation-related output.

Abstract: A two-axes rate sensing MEMS system. The system includes two proof masses, two drive components, two drive sense components, two orthogonal sets of substrate electrodes, and a processing device. The processing device is in signal communication with the two proof masses, the two sense components, or the two sets of substrate electrodes. The processing device determines the rate of rotation about two orthogonal axes based on signals received from the two proof masses, the two sense components, or the two substrate electrodes. Rotation about one axis will induce proofmass motion in the plane of the substrate. Rotation about an orthogonal axis will induce proofmass motion out-of-plane of the proofmasses. The sensing scheme independently detects these proof mass motion, which can infer rate of rotation.

Abstract: Methods and systems for selecting modulation in an orthogonal frequency division multiplexing system are provided. In one embodiment, a method for a remote unit of an OFDM multipoint-to-point communications system comprises: establishing communication between a first remote unit and a host unit, the first remote unit and a plurality of remote units communicatively coupled to the host unit in a multipoint-to-point configuration; transmitting a plurality of tones from the first remote unit such that tones from the first remote unit and at least one other remote unit are simultaneously received at the host unit, the plurality of tones modulated with upstream information using OFDM; modulating up to a plurality of tones using a first modulation scheme when transmitting a first type of upstream information; and modulating up to a plurality of tones using a second modulation scheme when transmitting a second type of upstream information.

Abstract: A multiplexing apparatus comprising at least one band pass filter, a receiver filter, and a transmitter filter is disclosed. The receiver filter, the transmitter filter and each band pass filter are communicatively coupled to a cable so that the receiver filter is configured to pass signals in a first spectral region from the cable to a first-band base transceiver station, the transmitter filter is configured to pass signals in the first spectral region from the first-band base transceiver station to the cable, and each band pass filter is configured to filter and bi-directionally pass signals in a second spectral region between the cable and at least one other base transceiver station.

Abstract: A sensing apparatus for determining the pressure of a fluid includes first and second support members. The first and second support members are configured to define at least one sealed chamber. A flexible diaphragm is disposed between the first and second support members. The diaphragm includes first and second opposing surfaces. The first opposing surface is in fluid communication with a first fluid-flow circuit, and the second opposing surface is in fluid communication with a second fluid-flow circuit. A first electronic circuit is disposed within the at least one chamber and coupled to the diaphragm for sensing a first differential pressure associated with the first and second flow circuits. The first electronic circuit is configured to produce at least one electrical signal proportional to a magnitude of the first differential pressure.

Abstract: A received RF signal can include data information intended for transmission over a wireless communication link. The data information of the signal can be processed at a node to produce overhead bits supporting a serial transmission of the data information over a communication medium to another node. For example, the data information of the received signal and overhead bits can be combined or framed according to a serial transport protocol for transmission over the communication medium. This technique of mapping or framing the data information into a serial transport protocol is used to more efficiently transmit the data over the communication medium to a target receiver, where the original RF signal can be reconstructed.

Abstract: Optical systems for sensing chemicals. An example system includes a light source, a light sensor, a processing device in signal communication with the light source and the light sensor, and a fiber optic cable that receives light from the light source and delivers light to the light sensor. The fiber optic cable includes a cladding material that is permeable to a predefined substance and an optical fiber core surrounded by the cladding material. The optical fiber core is a single mode optical fiber having a diameter greater than 30 ?m. The optical fiber core includes a hollow center having a diameter between 1-50 ?m. The optical fiber core includes a plurality of lengthwise holes positioned to provide single mode light propagation properties. The plurality of lengthwise holes have a diameter between 0.2-4 ?m.

Abstract: A method for controlling start-up of a network is provided. The method includes receiving a message from one node of a plurality of nodes at a hub while the network is in an unsynchronized state, relaying the message to the other nodes of the plurality of nodes of the network independent of the content of the message, and blocking all messages from the one node of the plurality of nodes until a relaying condition is met.