Topcon Positioning Systems, Inc.

Leonid Victorovich Purto

Andrey Vladimirovich Veitsel

Dmitry Anatolyevich Rubtsov

Sergey Sayarovich Bogoutdinov

Alexey Stanislavovich Lebedinsky

Dmitry Anatolievich Rubtsov

Victor Andreevich Prasolov

Nikolay Afanasievich Vazhenin

Vladimir Victorovich Veitsel

Fedor Borisovich Serkin

Igor Anatolievich Orlovsky

A method and apparatus for fast searching GNSS signals performed on a GNSS receiver includes the steps of receiving a signal having a known pseudo random noise code. State information of a code generator is stored when a pseudo random noise code is generated. Several NCO, including a Doppler NCO are used to search GNSS signal for several supposed Doppler's simultaneously. A search window associated with the received signal is reviewed a first time to identify a source of the received signal. After it is determined if a source of the received signal can be identified, the state information is loaded into the code generator prior to reviewing the search window a second time etc. Search windows is shifting by all length PRN Code. The loading of state information allows sequential review of the search window without re-adjustment of a fast search module which speeds the process of analyzing the received signals.

Method and apparatus for fast searching global navigation satellite system signals

Method of demodulation of M-CPFSK signal, includes receiving the M-CPFSK radio signal; moving it to zero frequency; sampling at no less than double a frequency of symbols; storing the samples with their amplitude and phase for at least L4 symbols; demodulating the sampled signal in three stages, wherein each stage includes iterating over symbol values within a block of symbols, of length is L1, L2 and then L3; in the first stage, N1 symbol sequences out of all possible symbol sequences are iterated over, at the second stage, N2 symbol sequences out of all possible symbol sequences are iterated over, and at the third stage, N3 symbol sequences out of all possible symbol sequences are iterated over, to obtain final symbol values; symbol values obtained at previous stage is used in a next stage to reduce a number of symbol sequences; and determining encoded bits based on final symbol values.

Method and apparatus for receiving FSK signals

An apparatus for forming wideband pseudo random noise signals includes a set of channels each comprising an NCO having a controlled frequency and phase and a PRN code generator, the NCO generating a strobe that is output to the PRN code generator. The PRN code generator forms a new sequence element of +1 or −1 in response to the strobe. The apparatus also comprises a first modulator having a plurality of weight coefficients, a plurality of multipliers each multiplying one of the weight coefficients, an adder outputting a sum of the plurality of multipliers output signals, and a mixer with a quadrature output signal multiplying the adder's output by sine and cosine of a low intermediate frequency. The apparatus also includes a processor controlling the set of channels, a transceiver module to receive and/or transmit quadrature signals, and an interface connecting the output of the mixer and the transceiver module.

Method and apparatus for forming wideband PRN signals

A method of receiving two chip-by-chip multiplexed CSK signals (e.g., GNSS signals) and searching for a non-CSK signal with optimal performance at a given digit capacity of a sampling memory resided in parallel correlators. For CSK signals Prompt, Early and Late results for each of possible code shift are calculated as different sums of four punctured convolutions. Depending on configuration, the method allows to receive both multiplexed CSK signals with lesser quality or one of the CSK signals with better quality. The method can be implemented as an apparatus with four punctured correlators, a set of multipliers by 1 or 2, another set of multipliers by 1 or 0, summers of four input to one result, a RAM, searchers of maximum, and conditional commutators.

Method and apparatus for receiving chip-by-chip multiplexed csk signals

Method and apparatus for receiving chip-by-chip multiplexed CSK signals

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

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.

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Moscow, Russia

Leonid Victorovich Purto