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: A digital system of measuring parameters of the signal (phase, frequency and frequency derivative) received in additive mixture with Gaussian noise. The system is based on the use of variables of a PLL for calculating preliminary estimates of parameters and calculating the corrections for these estimates when there is a spurt frequency caused by a receiver motion with a jerk. A jerk is determined if the low pass filtered signal of the discriminator exceeds a certain threshold. The jerk-correction decreases the dynamic errors. Another embodiment includes a tracking filter for obtaining preliminary estimates of parameters to reduce the fluctuation errors. Estimates are taken from the tracking filter when there is no jerk and from the block of jerk-corrections when there is a jerk.

Abstract: A test installation for simulating multiple reflections of GNSS signals, the installation including a top screen that is semitransparent in a radio frequency portion of the electromagnetic spectrum, wherein the top screen is substantially dome-shaped; a bottom screen that is reflective in the radio frequency portion of the electromagnetic spectrum; the top semitransparent screen over the bottom reflecting screen; and a GNSS antenna connected to a receiver and located between the top screen and the bottom screen.

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: A navigation receiver operating in a differential navigation mode can change from one solution type to another. At each epoch, primary estimates of coordinates and the solution type are received. Each solution type has a corresponding accuracy. To improve the positioning quality when the solution type changes, smoothed estimates of coordinates are generated according to a two-branch algorithm. Two conditions are evaluated. If both conditions are satisfied, the current-epoch smoothed estimates of coordinates are set equal to the current-epoch extended estimates of coordinates calculated from the sum of the previous smoothed estimates of coordinates and coordinate increments calculated from carrier phases. If at least one of the conditions is not satisfied, updated smoothed estimates of coordinates are generated based on the sum of the current-epoch extended estimates of coordinates and a correction signal.

Abstract: A method and system is provided for controlling a display in a machine operating in a work area whereby a plurality of views are displayed on a screen with each of the plurality of views corresponding to a plurality of functions and having one or more of the views independently available on another display.

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: Apparatus for estimating a current SNR of a signal, including an SNR estimator and an offset compensator connected in series, the offset compensator outputting the current SNR; the SNR estimator including (i) a first squaring unit, a summer, a square root unit, a first mean unit, a first subtractor, a scaling unit, a divider, a second subtractor and a decibel (dB)-recalculator, all connected in series, wherein an output of the second squaring unit is also connected to the divider; (ii) a third squaring unit connected to the first summer, and a second mean unit connected to an output of the summer at its input and to the subtractor at its output; and (iii) a correction calculator connected to the square root unit and to the second subtractor; the first squaring unit inputting an I component of the signal; and the second squaring unit inputting a Q component of the signal.

Abstract: Method of identification and compensation for inversion of the input bit stream when decoding LDPC codes includes obtaining a code word of the LDPC code from a demodulator output and writing the code word into a buffer memory, decoding the code word, calculating a syndrome for each iteration when decoding, making an analysis of converging the weight of the syndrome, generating an inversion feature for the input bit stream based on this analysis, continuing the decoding, if the inversion feature for the input bit stream does not give evidence of detecting inversion, resetting, if the inversion feature for the input bit stream shows inversion, the LDPC decoder and analysis parameters for the convergence of the weight of the syndrome, reading next code word from the buffer memory, and producing an inversion of this code word, and feeding the word to the decoder input to implement the next decoding operation.

Abstract: A high-linear amplifier receives, from an input bandpass filter, input signals including weak process signals and strong interference signals, amplifies the input signals, and transmits the amplified signals to an output bandpass filter. The high-linear amplifier includes a transistor and a feedback circuit that stabilizes the operating current of the transistor. The operating current includes the direct-current and low-frequency output signal currents of the transistor. The feedback circuit includes an interference detector that rectifies a portion of the high-frequency output signals of the transistor and extends the linear range of the high-linear amplifier. An interference indicator unit alerts an operator to the presence of excessively high levels of interference before the high-linear amplifier enters the non-linear mode. Amplified signals rejected by the output bandpass filter are reflected back to the high-linear amplifier stage.

Abstract: An antenna system with a sharp difference in directional pattern is intended for receiving GNSS signals. The antenna system includes at least two antenna elements located above a high-impedance capacitive ground plane, and a combining network. Antenna elements are spaced apart in vertical direction. The combining network provides subtraction of the signal reflected from the ground, the arrangement of antenna elements above the high-impedance capacitive ground plane making such subtraction efficient.

Abstract: Disclosed is a method for mapping network identifiers to a set of sensor modules that measure a three-dimensional action vector and that are sensitive to orientation in three-dimensional space. Each sensor module is mounted at a different position on a machine such that the orientation of each sensor module is different. The method includes one or two stages. In the first stage, the machine is placed in a stationary state, and measurements of a static action vector from a sensor module identified by a network identifier are correlated with expected measurements from a sensor module having a corresponding orientation and corresponding position. In the second stage, the machine is placed in a dynamic state, and measurements of a dynamic action vector from a sensor module identified by a network identifier are correlated with expected measurements from a sensor module having a corresponding orientation and corresponding position.

Abstract: A digital system of measuring parameters of the signal (phase, frequency and frequency derivative) received in additive mixture with Gaussian noise. The system is based on the use of variables of a PLL for calculating preliminary estimates of parameters and calculating the corrections for these estimates when there is a spurt frequency caused by a receiver motion with a jerk. A jerk is determined if the low pass filtered signal of the discriminator exceeds a certain threshold. The jerk-correction decreases the dynamic errors. Another embodiment includes a tracking filter for obtaining preliminary estimates of parameters to reduce the fluctuation errors. Estimates are taken from the tracking filter when there is no jerk and from the block of jerk-corrections when there is a jerk.

Abstract: A method and apparatus for filtering point cloud data obtained using a plurality of sensors generates data representative of a surface and for use with a specific type of sensor. The filtering allows certain machines and sensor types to be used to acquire point cloud data and different sensor types to be used during surface construction and modification. The method can be utilized with various types of machine controls and surface construction methods.

Abstract: A method of movement mode determination comprising measurement of vehicle's position and orientation and calculation of movement parameters, a compass on the vehicle, is azimuthally oriented along the prevailing and is mostly used movement direction (“forward” direction), a movement vector measurement unit, is used for measuring the azimuth of movement vector. A calculation unit being used for measuring an angle between vehicle movement vector azimuth measured by the movement vector measurement unit and vehicle azimuth measured by the compass fixed on the vehicle; movement is regarded as “backward” if the calculated angle is greater than 90 degrees, and “forward” if the calculated angle is smaller than 90 degrees. Also, an apparatus for movement direction determination includes a compass and a computation unit and further comprises a movement vector measurement unit for determining vehicle movement azimuth and connected through a signal connection to the computation unit.

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: A method and system utilizing one or more agricultural drones in combination with agricultural equipment, e.g., an agricultural boom sprayer, to evaluate the crops being farmed, and to improve the real-time delivery and dispensing of liquid from the sprayer including monitoring and verifying that the liquid is being dispensed correctly and/or in accordance with a desired distribution pattern or level.

Abstract: A method of movement mode determination comprising measurement of vehicle's position and orientation and calculation of movement parameters, a compass on the vehicle, is azimuthally oriented along the prevailing and is mostly used movement direction (“forward” direction), a movement vector measurement unit, is used for measuring the azimuth of movement vector. A calculation unit being used for measuring an angle between vehicle movement vector azimuth measured by the movement vector measurement unit and vehicle azimuth measured by the compass fixed on the vehicle; movement is regarded as ‘backward” if the calculated angle is greater than 90 degrees, and “forward” if the calculated angle is smaller than 90 degrees. Also, an apparatus for movement direction determination includes a compass and a computation unit and further comprises a movement vector measurement unit for determining vehicle movement azimuth and connected through a signal connection to the computation unit.

Abstract: A navigation receiver operating in a differential navigation mode transmits primary estimates of coordinates with an accuracy estimate that can vary during operation. To improve the positioning quality when the accuracy estimate changes, smoothed estimates of coordinates are generated according to a two-branch algorithm. The current-epoch accuracy estimate is compared to a current-epoch value of threshold accuracy. Upon determining that the current-epoch accuracy estimate is greater than or equal to the current-epoch value of threshold accuracy, the current-epoch smoothed estimates of coordinates are set equal to the current-epoch extended estimates of coordinates calculated from the sum of the previous smoothed estimates of coordinates and coordinate increments calculated from carrier phases.

Abstract: Disclosed is a dual-band Global Navigation Satellite System antenna with a hollow core. The antenna includes a conductive cylindrical tube with a longitudinal axis. A ground plane, a low-frequency radiator, and a high-frequency radiator are annuli orthogonal to the longitudinal axis. The inner peripheries of the ground plane and the low-frequency radiator are electrically connected to the outer surface of the cylindrical tube. The outer periphery of the high-frequency radiator is electrically connected to the low-frequency radiator. A vertical low-frequency radiating gap is configured between the ground plane and the outer periphery of the low-frequency radiator. A horizontal high-frequency radiating gap is configured between the inner periphery of the high-frequency radiator and the outer surface of the cylindrical tube. In an embodiment, the inner diameter of the cylindrical tube has a value from about 27 mm to about 102 mm, permitting insertion of a post or pole.