Topcon Positioning Systems, Inc.

Alexey Stanislavovich Lebedinsky

Andrey Vladimirovich Veitsel

Mark Isaakovich Zhodzishsky

Victor Andreevich Prasolov

Ilya Vladimirovich Ivantsov

Nikolay Afanasievich Vazhenin

Vladimir Victorovich Veitsel

Leonid Victorovich Purto

Dmitry Markovich Zhodzishsky

Dmitry Anatolievich Rubtsov

Ivan Andreevich Kirjanov

Nikolay Nikolaevich Vasilyuk

Alexandr Vladimirovich Doronin

Sergey Ivanovich Tychinskiy

Daniel Milyutin

Vladimir Victorovich Beloglazov

Roman Valerievich Kurynin

Konstantin Viktorovich Ebauer

GNSS timing receiver with synchronization of raw GNSS measurements to an external timescale. Synchronization is achieved by using a hardware Time Interval Measurement Unit (TIMU). The TIMU measures time intervals between two pulse signals and makes additional processing of these measurements. The first pulse signal is generated inside the GNSS receiver. The second pulse signal is the external pulse signal generated by an external time reference device. This time interval is used to control the time instant when the output GNSS measurement will be taken. In the first embodiment all actual GNSS measurements are physically taken at time instants indicated by external pulse signal. These measurements are used as output GNSS measurements. In another embodiment all actual GNSS measurements are taken at their default time instants indicated by internal pulse signal. But output GNSS measurements are calculated at the time instants indicated by the external pulse signal.

GNSS receiver with synchronization to external timescale

A method and apparatus are provided for processing navigation signals with improved stability in a multi-frequency, multi-system environment. Satellite signals, which are transmitted by a plurality of satellites from a plurality of different global navigation satellite systems, are received on a common radio path and processed in separate digital satellite channels, with each of the separate digital satellite channels corresponding to a respective satellite signal. A common quartz-locked-loop (QLL) discriminator signal is generated based on correlation signals from each of the separate digital satellite channels. Based on the common QLL discriminator signal, guiding signals are generated, with each of the guiding signals corresponding to a respective one of the separate digital satellite channels, for reducing phase-related tracking errors in the respective satellite signal processed in its corresponding digital satellite channel.

Method and apparatus for building vibrostable GNSS receivers to receive and process navigation signals from multiple navigation systems

GNSS receiver includes first type correlators and a maximum selecting unit selecting an output from the first type correlators, and with a common control of all the correlators in code delay, carrier phase and carrier frequency; second type correlators with individual control in code delay of each correlator or each sub-group of second type correlators and with common control of all second type correlators in carrier phase and frequency; and a processor. The first type correlators can convolve one quadrature only, and demodulates CSK symbols, the second type correlators calculate discriminator values for CSK-modulated signal DLL, the demodulated data then is used by the processor to produce improved position and velocity.

Method and system for demodulating and tracking of CSK-modulated signals

A method for demodulating and tracking of CSK-modulated signals comprising the steps of receiving a CSK-modulated signal at a plurality of correlators, the CSK-modulated signal including a transmitted symbol; convolving the CSK-modulated signal with a preset reference replica of the CSK-modulated signal for N shifts (D. . . D) of a PRN code relative to an internal receiver clock corresponding to N possible code shifts in the transmitted symbol, and M other code shifts (T. . . T), where M&#x3c;N, that satisfies D&#x2212;&#x394;T&#x2264;T&#x2264;D+&#x394;T for all Tfrom (T. . . T); selecting one of the N shifts (D) where the convolution is a maximum; adjusting a CSK-signal Delay Locked Loop (DLL) based on a ratio of convolution values for the shifts Dand Tfor all Tfor which a modulus |D&#x2212;T| is smaller than a predefined threshold; and determining a value of the transmitted symbol based on D.

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

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

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.

Digital system and method of estimating quasi-harmonic signal non-energy parameters using a digital Phase Locked Loop

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.

Digital system and method of estimating non-energy parameters of signal carrier

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.

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Moscow, Russia

Alexey Stanislavovich Lebedinsky