Abstract: A system and method for providing location information using a long baseline accelerometer/GNSS system. A first set of accelerometers is operatively associated with the first GNSS antenna while a second set of accelerometers is operatively associated with a second (or more) GNSS antenna. The multiple assemblies are separated by predefined distances and held rigid to each other. Accelerometer data is combined with the GNSS data to provide improved navigation and location information.

Abstract: A compact, low profile dipole antenna assembly includes first and second linear radiating elements that form the positive and negative sides of the dipole antenna, and a balun that extends in parallel with the second radiating element, i.e., the negative side of the dipole antenna. The second radiating element is connected to ground at one end and is an open circuit at an opposite end. A main feed line, which is part of the balun, also connects to a common ground with the second radiating element. The balun and the connection to ground act as an impedance transformer, and the second radiating element acts as the negative side of the dipole antenna as well as a ground plane for the balun. The balun and the second radiating element share a volume with the second radiating element electrically shielding the balun, and the main feed probe connecting to ground within the shared volume.

Abstract: A GNSS/INS navigation system includes an INS filter that uses relative yaw values as an observable for attitude updates. The system calculates the relative yaw values based on carrier phase measurements, e.g., phase windup measurements, of GNSS signals received at a system GNSS antenna. The use of the relative yaw values as an observable in the INS filter allows the system to improve estimates of associated biases, and also to continue to estimate the associated biases in low dynamic environments.

Abstract: The system includes a reconfigurable GNSS antenna subsystem that dynamically reconfigures one or more antenna parameters to change one or more operating characteristics of an antenna based on environmental conditions and/or the presence of interfering signals to improve the quality of GNSS satellite signal reception. The system analyzes the received signals to determine if the GNSS satellite signals are sufficiently above received noise, if interfering signals are present, and/or if multipath signals are adversely impacting position calculations. Based on the analysis, the reconfigurable antenna subsystem selectively and dynamically reconfigures one or more parameters to change one or more operating characteristics of the antenna. As the conditions change, the reconfigurable antenna subsystem may dynamically reconfigure one or more of the antenna parameters accordingly.

Abstract: A system and method to determine the location of an interfering signal source within a few meters. Three or more networked GNSS receivers are located at known locations and used to simultaneously collect and time-stamp data samples at L1 and L2. The data samples are passed over the network to a server which identifies samples associated with an interfering signal, cross correlates associated samples from pairs of receivers, and applies a discriminator function to significantly improve the accuracy of a computed time difference of arrival (TDOA) for the interfering signal, thereby significantly improving the accuracy of the location determination.

Abstract: A carrier phase correction sub-system for use with a GNSS receiver that utilizes an active null and beam steering controlled radiation pattern antenna (CRPA) determines carrier phase corrections that compensate for antenna phase center movements in the carrier phase measurements taken from the CRPA filtered signal. The carrier phase sub-system utilizes measured radiation patterns, angles of incidence of the satellite signals at the CRPA, and the applied weights to determine carrier phase corrections to be applied to the CRPA filtered signals from which the carrier phase measurements are later taken or to the carrier phase measurements depending on the dynamics of the jamming signal. With the carrier phase corrected, the GNSS receiver may utilize known RTK techniques to resolve carrier cycle ambiguities.

Abstract: A system detects, identifies, and optically tracks a jammer by calculating position and velocity information associated with the jammer based on jamming signals received at one or more antennas, and utilizing the position and velocity information to control one or more cameras. The cameras capture a series of images that include the calculated location, the expected movement of the jammer, or both. The system analyzes the images to extract motion information associated with one or more objects identified in the images. The system utilizes the calculated position and velocity information and the extracted motion information to determine which of the identified object in the images is the jammer. Further, the jammer motion information extracted from the images may be utilized to update the calculated position and velocity information associated with the jammer, to improve the overall accuracy of the tracking of the jammer.

Abstract: The inventive technique calculates lever arm values associated with a GNSS/INS system photogrammetrically. A calibrated camera on a device captures a plurality of images of the GNSS/INS system with the inclusion of a target, having known attributes and a plurality of control points. Thereafter, an application, executing on the device determines the lever arm values from the images of the GNSS/INS system utilizing the known attributes and the control points of the target. The INS may utilize the calculated lever arm values to combine information received from a GNSS receiver, of the GNSS/INS system, with information provided by sensors of the INS to compute updated positions, velocities, and/or orientations.

Abstract: A system and method for augmenting a GNSS/INS system by using a vision system is provided. The GNSS system generates GNSS location information and the INS system generates inertial location information. The vision system further generates vision system location information that is used as an input to an error correction module. The error correction module outputs inertial location adjustment information that is used to update the inertial system's location information.

Abstract: A system and method for a wide-band low loss quadrature phase antenna feed system is provided. A 180° phase shifter is configured to generate a 0° and 180° phase output. The phase shifter's outputs are fed into a 90° hybrid coupler to generate 0°, 90°, 180° and 270° outputs for used to feed a quadrature phase antenna.

Abstract: A dual band antenna having a directive element and a reflective element is disclosed. A first and second antennas are arranged substantially parallel to each other and spaced between approximately 0.5-0.8 times the wavelength of the first antenna. The dual band antenna provides high gain at the zenith and at the horizon and enable v variation in the antenna beam shape as well as a reduction in cross polarization.

Abstract: In accordance with one or more embodiments of the present invention, a quadrifilar helix antenna can be formed to accommodate multiple frequencies using a single microstrip feed system, illustratively comprising an infinite balun in combination with interspersed antenna conductors tuned for effective resonance at the desired frequencies around the single feed system. Accordingly, as an additional aspect, the present invention also combines the multiple frequency antenna elements and the single feed system into a unitary assembly of cylindrical geometry that is generally reduced in size, with the interspersed arrangement of the multiple (e.g., resonating) antenna conductors wrapped into a short cylindrical surface. Through the use of the single hybrid feed system and resonating antenna conductors for multiple frequencies, the need for complex feed networks having multiple circuits (hybrid circuits, transformers, etc.) is alleviated, while still maintaining acceptable levels of performance.

Abstract: A system and method for augmenting a GNSS/INS system by using a vision system is provided. The GNSS system generates GNSS location information and the INS system generates inertial location information. The vision system further generates vision system location information including horizon, plumb lines and distance traveled. The GNSS information, INS information and vision system are combined in a Kalman filter to produce improved location information.

Abstract: A camera image processing subsystem processes image data corresponding to observations taken through a lens of focal point f using a spherical pin-hole model that maps the image data through a perspective center of a pin-hole prospective plane located within the lens onto a model sphere that is a focal length f in diameter and has its center at the perspective center of the pin-hole prospective plane. The subsystem models systematic distortion as rotation about coordinate axis of the pin-hole prospective plane, and maps all of the data, over the entire field of view of the lens, to corresponding spherical coordinates.

Abstract: A navigation system for use with moving vehicles includes target points proximate to a rendezvous site located on a first moving vehicle. One or more transmitters broadcast target point positioning information. A navigation unit on a second moving vehicle utilizes a camera to capture images that include the target points or a detector system that emits one or more beams to the target points. The navigation unit determines the relative position and orientation of the rendezvous site at the second vehicle. The navigation unit utilizes the relative position and orientation and an absolute position and orientation of the rendezvous site calculated from the target position information and calculates an absolute position and orientation corresponding to the second vehicle. The navigation unit then initializes its component inertial subsystem using a local position and orientation that are based on the calculated absolute position and orientation of the second vehicle.

Abstract: A system for performing post processing of GNSS and INS measurement data and image data to provide highly accurate location information for a camera, an INS measurement unit or both performs first processing operations using the GNSS and INS measurement data, to determine position, velocity and attitude solutions. The system then analyzes the solutions to determine which measurement data provide sufficiently reliable solutions from which to determine the precise position, velocity and attitude of the camera, and thus, which measurement data do not provide sufficiently reliable solutions. The system and method then performs more time consuming and processing intensive processing operations using the measurement data and camera image data that are associated with solutions that are not sufficiently reliable.

Abstract: A GNSS receiver and antenna system transmits signals from an antenna structure to a remote GNSS receiver and includes a digital communications subsystem that utilizes a high speed digital communications conductor. The transmissions are digital signals that preserve GNSS satellite signal frequency and/or carrier and code phase information. The system may transmit digital signals corresponding to GNSS signals such as GPS, GLONAS, Galileo and Compass satellite signals. In addition, the system may transmit, over the same digital communications conductor in appropriately formatted digital signals, ranging signals from ground-based transmitters or other satellites, differential GNSS correction signals from beacons or base GPS receivers, and/or signals from transmitting or co-located sensors, such as inertial sensors, temperature sensors and so forth.

Abstract: The invention relates to a method for correcting a distortion in an aerial photograph caused by a flight movement in the forward direction. The aerial photograph is captured by a surface sensor, the sensor lines of which sensor are exposed at different, successive exposure times, so that each individual sensor line senses a strip of terrain of the terrain flow over at the different exposure times. A relative flight altitude above the strips of terrain captured by the respective sensor line is assigned to the individual sensor lines. Furthermore, a compensation factor is separately determined for each of the individual sensor lines, wherein the factor depends on an air speed of the flying object, a focal length of the aerial camera and the relative flight altitude assigned to the respective sensor line, and corrects the distortion in the aerial photograph for the lines based on the respective compensation factor.

Abstract: A system for determining precise position includes a chirp receiver that processes broadcast chirp signals in the frequency domain to distinguish direct path signals from multipath signals. The chirp receiver processes the received chirp signals, which consist of respective pulsed frequency sweeps, by combining a received chirp signal with a synchronized locally generated chirp signal and phase adjusting and concatenating the results over multiple sweeps, based on estimated clock phase errors and expected phase rotations of the direct path signals, to produce a sine wave. The phase adjustment and concatenation allows the use of longer Fast Fourier Transforms (FFTs) that, in turn, provide increased accuracy of frequency estimation and separate component signals that are very close in frequency.

Abstract: A system detects, identifies, and optically tracks a jammer by calculating position and velocity information associated with the jammer based on jamming signals received at one or more antennas, and utilizing the position and velocity information to control one or more cameras. The cameras capture a series of images that include the calculated location, the expected movement of the jammer, or both. The system analyzes the images to extract motion information associated with one or more objects identified in the images. The system utilizes the calculated position and velocity information and the extracted motion information to determine which of the identified object in the images is the jammer. Further, the jammer motion information extracted from the images may be utilized to update the calculated position and velocity information associated with the jammer, to improve the overall accuracy of the tracking of the jammer.