Abstract: A method and apparatus for determining the precise location of a target on a surface by utilizing a plurality of objects that are fixed in their position proximate to the location, thereby constituting a plurality of fixed reference points, upon which the target(s) resides or is otherwise located. The plurality of fixed references points are used either in conjunction with images of the target or certain distance measurements between the target and the fixed reference points to determine the precise location of the target(s) on the surface.

Abstract: An architecture of a NAND Flash memory module interface controller (NAND-controller) provides access to data stored in an external NAND Flash memory module, and a method of booting firmware. NAND-controller automatically boots firmware from the NAND Flash memory into primary RAM of a system-on-a chip used for GNSS receivers. NAND-controller has a first external interface to connect NAND Flash memory, a second external interface to set parameters of booting firmware, and two internal interfaces: a high-speed one (system interface) and a low-speed one (control interface) to be connected to two types of SoC internal busses. Data exchange between the CPU and NAND Flash memory is implemented using a static RAM buffer which is a part of the NAND-controller and available for reading and writing via high-speed interface. Parameters of the first external interface are set and current state of data exchange process is controlled by the CPU.

Abstract: The present invention relates to processing information generated by GNSS receivers received signals such as GPS, GLONASS, etc. GNSS receivers can determine their position in space. The receivers are capable of determining both coordinates and velocity of their spatial movement. When a receiver is used in any machine control systems, velocity vector heading (in other words, velocity vector orientation) should be determined along with velocity vector's absolute value. Angle, determining velocity vector orientation, is calculated based on velocity vector projections which are computed in navigation receivers. The accuracy of velocity vector orientation calculated based on velocity vector projections strongly enough depends on velocity vector's absolute value. To enhance the accuracy, a method of smoothing primary estimates of velocity vector orientation angles using a modified Kalman filter has been proposed.

Abstract: Multipath reception by an antenna is reduced by mounting the antenna on a semi-transparent ground plane that has a controlled distribution of layer impedance over a central region and a peripheral region. The central region includes a continuous conductive segment on which the ground element of the antenna is disposed. The distribution of the layer impedance over the peripheral region is configured by multiple conductive segments electromagnetically coupled by lumped circuit elements. A semi-transparent ground plane can be fabricated by depositing a metal film on a dielectric substrate and etching grooves into the metal film to form a desired pattern of conductive segments. Lumped circuit elements can be fabricated as discrete devices, surface mount devices, and integrated circuit devices. Various semi-transparent ground planes can be configured for linearly-polarized and circularly-polarized radiation.

Abstract: A method for measuring a signal-to-noise ratio when decoding Low Density Parity Check (LDPC) codes is provided. The method includes receiving from an input of a demodulator an input code word with “strong” or “weak” solutions, decoding the input code word in a LDPC decoder using a predetermined dependence of a mean number of iterations on the signal-to-noise ratio, recording a number of iterations performed during the decoding of the input code word, averaging derived values of the number of iterations for a specified time interval, estimating a signal-to-noise ratio based on averaged derived values of the number of iterations and based on the predetermined dependence of the mean number of iterations on the signal-to-noise ratio, and generating an output decoded code word.

Abstract: The present invention proposes a digital system and method of measuring (estimating) non-energy parameters of the signal (phase, frequency and frequency rate) received in additive mixture with Gaussian noise. The first embodiment of the measuring system consists of a PLL system tracking variable signal frequency, a block of NCO full phase computation (OFPC), a block of signal phase primary estimation (SPPE) and a first type adaptive filter filtering the signal from the output of SPPE. The second embodiment of the invention has no block SPPE, and NCO full phase is fed to the input of a second type adaptive filter. The present invention can be used in receivers of various navigation systems, such as GPS, GLONASS and GALILEO, which provide precise measurements of signal phase at different rates of frequency change, as well as systems using digital PLLs for speed measurements.

Abstract: An augmented image is generated by capturing a visual image of a site with a digital camera, generating a virtual image or associated information from a digital model of the site, and superimposing the virtual image or associated information on the visual image. To register the digital model with the visual image, a sensor pole is introduced into the field of view, and a combined visual image of the site and an optical target on the sensor pole is captured. The position and orientation of the sensor pole with respect to the site reference frame are measured by sensors mounted on the sensor pole; the position and orientation of the digital camera with respect to the sensor pole are calculated from image analysis of the optical target on the sensor pole; and the position and orientation of the digital camera with respect to the site reference frame are calculated.

Abstract: An antenna system for global navigation satellite systems includes a ground plane, an active antenna disposed above the ground plane, and a passive antenna disposed below the ground plane. The active antenna includes a conducting ring substantially parallel to the ground plane. A radiating conductor passes through substantially the center of the conducting ring; the ends of the radiating conductor are electrically connected to the conducting ring. An excitation pin is electrically connected to the radiating conductor. A set of reactive impedance elements is electrically connected between the conducting ring and the ground plane. The set of reactive impedance elements is disposed substantially orthogonal to the ground plane. The passive antenna is similar to the active antenna, except the passive antenna does not have an excitation pin. The antenna system effectively suppresses multipath reception, and its compact size and light weight make it suitable for integration with a surveying pole.

Abstract: Navigation satellite receivers have a large number of channels, where phase discriminators and loop filter of a PLL operate in phase with data bits and control of numerically controlled oscillator (NCO) carried out simultaneously on all channels. Since symbol boundaries for different satellites do not match, there is a variable time delay between the generation of control signals and NCO control time. This delay may be measured by counting a number of samples in the delay interval. A proposed system measures non-energy parameters of the BPSK-signal carrier received in additive mixture with noise when a digital loop filter of PLL controls NCO with a constant or changing in time delay. A control unit controls bandwidth and a LF order by changing transfer coefficients based on analyzing estimated signal parameters and phase tracking error at a PD output.

Abstract: A navigation receiver operably coupled to an antenna can determine location by receiving and processing radiofrequency navigation signals from global navigation satellites. The navigation receiver includes a quartz crystal oscillator that serves as a reference frequency source for a local oscillator signal that is mixed with the radiofrequency navigation signals to generate intermediate signals at intermediate frequencies lower than the radiofrequencies. In particular applications, the quartz crystal oscillator and the antenna are subjected to vibration and shock. A shift in the frequency or phase of the intermediate signals can result, and performance of phase-lock loops can degrade. Performance is improved with a phase-lock loop that processes a combination of individual channel control signals and common control signals.

Abstract: An antenna system for a global navigation satellite system reference base station is disclosed. The antenna system includes an antenna positioned above a high capacitive impedance surface (HCIS) ground plane. Over a specific range of the lateral dimension of the HCIS ground plane and the height of the antenna above the HCIS ground plane, a high level of multipath suppression and high sensitivity for low-elevated satellites can be simultaneously maintained. The HCIS ground plane can be fabricated as a flat conducting plate with an array of conducting elements such as pins, pins with expanded tips, or mushroom structures. Alternatively, the HCIS can be fabricated as a flat conducting plate with a concentric series of choke rings. The antenna system can provide a positioning accuracy of +/?1 mm, an order of magnitude improvement over previous designs.

Abstract: Dozers outfitted with manual or electric valves can be retrofitted with a control system for automatically controlling the elevation and orientation of the blade. No modification of the existing hydraulic drive system or existing hydraulic control system is needed. An arm is operably coupled to the existing joystick, whose translation controls the elevation and orientation of the blade. The arm is driven by an electrical motor assembly. Measurement units mounted on the dozer body or blade provide measurements corresponding to the elevation or orientation of the blade. A computational system receives the measurements, compares them to target reference values, and generates control signals. Drivers convert the control signals to electrical drive signals. In response to the electrical drive signals, the electrical motor assembly translates the arm, which, in turn, translates the joystick. If necessary, an operator can override the automatic control system by manually operating the joystick.

Abstract: An ultrasonic range sensor comprises at least one transducer adapted to generate an ultrasonic pulse having a first axis of transmission and detect a reflected signal that is associated with the ultrasonic pulse and propagates along the first axis of transmission. The ultrasonic range sensor also comprises a deflecting region adapted to reflect the reflected signal along a second axis different from the first axis of transmission. In one embodiment, the second axis is deflected from the first axis by a non-zero angle determined by a characteristic of the deflecting region.

Abstract: An architecture of a NAND Flash memory module interface controller (NAND-controller) provides access to data stored in an external NAND Flash memory module, and a method of booting firmware. NAND-controller automatically boots firmware from the NAND Flash memory into primary RAM of a system-on-a chip used for GNSS receivers. NAND-controller has a first external interface to connect NAND Flash memory, a second external interface to set parameters of booting firmware, and two internal interfaces: a high-speed one (system interface) and a low-speed one (control interface) to be connected to two types of SoC internal busses. Data exchange between the CPU and NAND Flash memory is implemented using a static RAM buffer which is a part of the NAND-controller and available for reading and writing via high-speed interface. Parameters of the first external interface are set and current state of data exchange process is controlled by the CPU.

Abstract: Navigation satellite receivers have a large number of channels, where phase discriminators and loop filter of a PLL operate in phase, with data bits and control of numerically controlled oscillator (NCO) carried out simultaneously on all channels. Since symbol boundaries for different satellites do not match, there is a variable time delay between the generation of control signals and NCO control time. This delay may be measured by counting a number of samples in the delay interval. A proposed system measures non-energy parameters of the BPSK signal carrier received in additive mixture with noise when a digital loop filter of PLL controls NCO with a constant or changing in time delay. A control unit controls bandwidth and a LF order by changing transfer coefficients based on analyzing estimated signal parameters and phase tracking error at a PD output.

Abstract: A patch antenna system with improved multipath resistance includes a top antenna assembly and a bottom antenna assembly. Each antenna assembly includes a radiator patch and a ground plane separated by a dielectric medium. The radiator patch on the top antenna assembly is excited by an exciter and an excitation circuit. The bottom antenna assembly is electromagnetically coupled to the top antenna assembly. The resonant frequency of the bottom antenna assembly is approximately equal to the resonant frequency of the top antenna assembly. Electromagnetic fields induced in the bottom antenna assembly are in opposite phase to the electromagnetic fields excited in the top antenna assembly. Amplitudes of electromagnetic fields induced in the bottom antenna assembly are subtracted from amplitudes of electromagnetic fields excited in the top antenna assembly, and multipath signals are suppressed. Single band and dual band antenna systems suitable for global navigation satellite systems can be implemented.

Abstract: A global navigation system includes a first navigation receiver located in a rover and a second navigation receiver located in a base station. Single differences of measurements of satellite signals received at the two receivers are calculated and compared to single differences derived from an observation model. Anomalous measurements are detected and removed prior to performing computations for determining the output position of the rover and resolving integer ambiguities. Detection criteria are based on the residuals between the calculated and the derived single differences. For resolving integer ambiguities, computations based on Cholesky information Kalman filters and Householder transformations are advantageously applied. Changes in the state of the satellite constellation from one epoch to another are included in the computations.

Abstract: The present invention relates to processing information generated by GNSS receivers received signals such as GPS, GLONASS, etc. GNSS receivers can determine their position in space. The receivers are capable of determining both coordinates and velocity of their spatial movement. When a receiver is used in any machine control systems, velocity vector heading (in other words, velocity vector orientation) should be determined along with velocity vector's absolute value. Angle, determining velocity vector orientation, is calculated based on velocity vector projections which are computed in navigation receivers. The accuracy of velocity vector orientation calculated based on velocity vector projections strongly enough depends on velocity vector's absolute value. To enhance the accuracy, a method of smoothing primary estimates of velocity vector orientation angles using a modified Kalman filter has been proposed.

Abstract: A method and system for signal reception and processing, and more particularly for reducing the effects of random additive impulse interference is provided.

Abstract: Disclosed is a technique for generating a three dimensional terrain map of a geographic area. Mobile units are equipped with satellite receivers (e.g., GPS receivers) for generating location data. A map generator uses the location data to generate a three dimensional terrain map. In one embodiment, the mobile units have primary uses other than mapping, and are traversing the geographic area to be mapped in connection with their primary function. The map generation process may be performed iteratively over time, as additional location data becomes available. During a time period when location data is unavailable for a portion of the three dimensional terrain map, the map generator may estimate the missing portion of the map using the available data. The estimated portion may later be updated with actual data as that data becomes available. The map may also contain enhancements based on enhancement data received by the map generator.