Topcon Positioning Systems, Inc.

Nikolay Afanasievich Vazhenin

Andrey Vladimirovich Veitsel

Vladimir Victorovich Veitsel

Fedor Borisovich Serkin

Timur G Kelin

Alexey Stanislavovich Lebedinsky

Ivan Kirianov

Ivan Andreevich Kirjanov

Dmitry Anatolyevich Rubtsov

Leonid Victorovich Purto

Dmitry A Pyatkov

Andrey V Zasorin

Igor Anatolievich Orlovsky

Navigation receiver includes antennas receiving signals from different satellite constellations, Low Noise Amplifiers, a Block of Analog Filters, a Block of Quadrature mixers (BQM) translating in phase and quadrature signals to an intermediate frequency, analog converters digitizing the in phase and quadrature signals, a Block of Digital Quadrature Mixers (BDQM) shifting the digitized signals to zero frequency, a Set Block of Digital Filters (SBDF) band-pass filtering the shifted signals, and reducing a sampling rate, and a Block of Digital Processing (BDP) calculating coordinates, all series-connected; a Block of Digital Generators (BDG) for fine control of the BDQM; and a Block of Analog Generators (BAG) that defines which signal is processed by its corresponding BQM; SBDF including Blocks of Digital Filters (BDFs), each BDF including a chain of Blocks of MultiRate Filters for antialiasing filtering/down-sampling of shifted signals, programmable commutators for controlling decimation, and FIR-filters; each BDF controlled by control block.

Block of digital filters for multisystem navigational receivers integrated with data transmission systems

An apparatus to measure signal-to-thermal noise ratio (SNR) and signal-to-pulse noise ratio (SPNR), the apparatus including a quadrature mixer, a pulse noise reduction unit, an SNR estimation unit and an offset compensation unit, connected in series, the quadrature mixer receiving the input radio signal and outputting an in-phase component and a quadrature component; a pulse noise separation unit, and an SPNR estimation unit connected series, the pulse noise reduction unit and the pulse noise separation unit inputting the in-phase and quadrature components; the SPNR estimation unit inputting a filtered in-phase component from the pulse noise reduction unit. The offset compensation unit outputs a current SNR. The SPNR estimation unit outputs a current SPNR. The pulse noise separation unit includes a first LPF, an impulse noise separator and an HPF, connected in series; and a second LPF, a pulse noise detection unit and an inverter, connected in series.

Method and apparatus for estimating the current signal-to-thermal noise ratio and signal-to-pulse noise ratio

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.

Method and apparatus for identification and compensation for inversion of input bit stream in LDPC decoding

Apparatus to measure signal-to-thermal noise ratio (SNR) and signal-to-pulse noise ratio (SPNR) includes a pulse noise reduction unit, an SNR estimation unit and an offset compensation unit; a pulse noise separation unit, and an SPNR estimation unit. Pulse noise separation unit includes (i) a first low pass filter (LPF), an impulse noise separator and a high pass filter (HPF), connected in series; and (ii) a second LPF, a pulse noise detection unit and an inverter. Pulse noise detection unit includes two channels, each with a high pass filter, an absolute value calculation unit, a low pass filter, a comparator, a pulse generator. The channels connect to OR gate, which outputs a pulse detection signal. Pulse noise reduction unit and pulse noise separation unit input in-phase and quadrature components. The SPNR estimation unit inputs a filtered in-phase component. The offset compensation unit outputs SNR, and the SPNR estimation unit outputs SPNR.

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.

Method and device for measuring the current signal-to-noise ratio when decoding LDPC codes

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.

Method and apparatus for estimating the current signal-to-noise ratio

Method and apparatus for identification and compensation for inversion of input bit stream in Ldpc decoding

A method of estimating current SNR in a sequence of symbols, including receiving a signal representing an additive mixture y(t)=s(t)+n(t) of a sequence of phase-modulated symbols with fixed length and phase modulation s(t) and including white Gaussian noise (AWGN) n(t); separating quadrature components Iand Qof the received signal in a quadrature mixer; determining a mean-squareof I; determining a mean-squareof Q; determining a square/squared value of mean absolute value (modulus); determining a square of mean value for quadrature component, where values of the quadrature component Qare averaged taking into account a sign of a symbol received in a channel; determining a current absolute value (vector length) for; determining the current SNR based on,, ||,and &#x221a;{square root over (I+Q)}; and compensating for a systematic error of the current SNR.

Navigation data processing system, comprising a navigation receiver that receives a positioning signal; a data communication subsystem comprising a plurality of data communication units for receiving correction signal and routing it to the navigation receiver, and conversion interfaces for communicating the correction data in a common format. The navigation receiver includes a navigation subsystem that generates augmented navigation data based on the positioning and correction signals. A user terminal displays the augmented data. Navigation receiver includes a profile database comprising a plurality of profiles for receiving the correction signal; a script database comprising commands for controlling a particular data communication unit. Navigation receiver sets up communication to the correction signal source, processes the positioning and correction signals and generates the augmented data based on a script and a profile of the data communication unit and the interface converter.

Method and apparatus for controlling data communication units in navigation receiver

A method of estimating signal-to-noise ratio in a Viterbi decoder comprising: setting a threshold SNR value; determining a dependence on SNR of the average decoding path length; filling branch metrics matrix, minimal path metrics matrix, path metrics matrix and paths matrix with initial values; receiving packets from a communication channel; calculating the matrices that contains paths stored during operation of Viterbi algorithm in its rows, and a minimal path metrics matrix, including calculating an estimate of a decoding path length, where all the paths converge, based on the paths matrix; calculating current SNR estimate using an estimate of a decoding path length, based on results of previous steps; setting a decoder control signal to an active state if the current estimated SNR does not exceed the threshold, and to an inactive state otherwise; if the decoder control signal is in active state, the branch metrics matrix, the minimal path metrics matrix, the paths metrics matrix and the paths matrix are filled with the initial values; generating a decoded symbol; and repeating the steps on a next packet if one is available.

Method and apparatus for signal-to-noise ratio estimation in convolutional codes (Viterbi) decoder

Antenna identification data is transferred over a regular channel that is normally used for transferring navigation signals. Modulation of the received signal is used for transferring the portable antenna parameter data. Antenna identifications and parameters are written into a portable antenna module. The antenna module is attached to a radio receiver. The antenna module and the receiver are powered up. The portable antenna module receives radio signals that are amplified in a low-noise amplifier. Then, a level of the output signal is discretely modulated in the amplitude modulator and the signal is transferred to the radio receiver. The discrete fluctuations of the level of the signal are determined in the amplitude demodulator. The fluctuation of the level of the signal carries the information about the identification parameters of the portable antenna module. An analog-to-digital conversion of the determine signal fluctuation is performed in an analog-to-digital converter. The converted digital signal is used for receiving data related to the type and parameters of the portable antenna module.

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Moscow, Russia

Nikolay Afanasievich Vazhenin