Abstract: A correlation calculating method of correlating a received code signal obtained by demodulating a received signal, which is a signal obtained by receiving a positioning satellite signal, with a replica code signal is provided which includes: correlating values of the replica code signal in a chip period with values of the received code signal at first to n-th arrival times obtained by varying an arrival time of the chip period by 1/n chip (where n is an integer equal to or greater than 2); and acquiring a correlation calculation result at a 1/n chip interval by synthesizing the correlation calculation results.

Abstract: A first correlation calculation is performed based on a first predicted frequency, with respect to received data of a GPS satellite signal. An error frequency of the first predicted frequency is estimated using a carrier phase of the GPS satellite signal based on the result of the first correlation calculation. The first predicted frequency is corrected using the error frequency, and a second predicted frequency is thus calculated. Then, a second correlation calculation is performed with respect to the same received data, based on the second predicted frequency. A navigation message carried on the GPS satellite signal is decoded using the result of the second correlation calculation.

Abstract: A correlation calculating method of correlating a received code signal obtained by demodulating a received signal, which is a signal obtained by receiving a positioning satellite signal, with a replica code signal is provided which includes: correlating values of the replica code signal in a chip period with values of the received code signal at first to n-th arrival times obtained by varying an arrival time of the chip period by 1/n chip (where n is an integer equal to or greater than 2); and acquiring a correlation calculation result at a 1/n chip interval by synthesizing the correlation calculation results.

Abstract: A code phase is detected on the basis of a signal received by an RF receiving circuit unit which is a receiving unit that receives a GPS satellite signal. When the code phase is within a predetermined edge of a PRN code, a control of suppressing intermittent driving of the RF receiving circuit unit is performed.

Abstract: An RF receiving circuit unit that receives a GPS satellite signal from a GPS satellite is intermittently driven by a first driving control of intermittently driving the RF receiving circuit unit with a first intermittent driving pattern and a multistage driving control of intermittently driving the RF receiving circuit unit with a multistage intermittent driving pattern in which a driving period in the first intermittent driving pattern is set to a second intermittent driving pattern of which an intermittent cycle is shorter than that of the first intermittent driving pattern.

Abstract: A received signal determination method includes: receiving a positioning signal; performing correlation calculations on the received positioning signal using a code replica of one spreading code among the plurality of spreading codes; selecting a total peak value and a remote peak value, the total peak value being a first maximum correlation value among correlation values obtained by the correlation calculations, and the remote peak value being a second maximum correlation value among correlation values apart from a phase of the total peak value by a phase equal to or greater than a given phase; changing a threshold value condition for the total peak value based on the remote peak value; and determining whether or not the received positioning signal is spread-modulated with the one spreading code by determining whether or not the total peak value satisfies the threshold value condition.

Abstract: A positioning method includes: executing a first correlation accumulation process on a received signal, a positioning signal spread-modulated with a spread code, and a replica code of the spread code while shifting a phase of the replica code in a first phase search range, setting a second phase search range narrower than the first range based on an accumulated correlation value at a first timing in the first correlation accumulation process, executing a second correlation accumulation process on the received signal and the replica code while shifting the phase of the replica code in the second phase search range, determining appropriateness of the second phase search range based on the accumulated correlation value at the first timing and an accumulated correlation value at a second timing in the first correlation accumulation process, and positioning using a result of the second correlation accumulation process, if the second phase search range is determined appropriate.

Abstract: A bit change determination method includes performing a correlation operation of a signal received from a satellite and a replica code, segmenting the signal using a bit transition timing of navigation message data and performing a first calculation to calculate the result of the correlation operation for a first period having N (N?1) continuous unit periods with a bit period of navigation message data as a unit period, performing a second calculation to calculate the result of the correlation operation for a second period having M (M>1) continuous unit periods adjacent to the first period, and determining whether a bit value changes or not at a boundary between the first period and the second period using the first and second calculation results.

Abstract: A correlation calculating method of correlating a received code signal obtained by demodulating a received signal, which is a signal obtained by receiving a positioning satellite signal, with a replica code signal is provided which includes: correlating values of the replica code signal in a chip period with values of the received code signal at first to n-th arrival times obtained by varying an arrival time of the chip period by 1/n chip (where n is an integer equal to or greater than 2); and acquiring a correlation calculation result at a 1/n chip interval by synthesizing the correlation calculation results.

Abstract: A capture frequency decision method of deciding a capture frequency by executing a frequency search in which a correlation operation on a received signal, which is a CDMA (Code Division Multiple Access) signal, is performed at a plurality of search frequencies, includes: executing a first frequency search; setting a frequency for a side lobe check on the basis of a correlation integration time used in the first frequency search; selecting a plurality of search frequencies including the frequency for a side lobe check on the basis of a result of the first frequency search; executing a second frequency search of performing the correlation operation at the plurality of selected search frequencies; and deciding a capture frequency by executing a third frequency search using a result of the second frequency search.

Abstract: A pseudorange calculation method for calculating a pseudorange in a position calculation device includes: passing a received signal received from a satellite for position calculation through a first filter; passing the received signal through a second filter having a different phase characteristic from that of the first filter; calculating a first pseudorange on the basis of a signal acquired by passing through the first filter; calculating a second pseudorange on the basis of a signal acquired by passing through the second filter; and calculating a third pseudorange to be used for position calculation, on the basis of the first pseudorange and the second pseudorange.

Abstract: A terminal device searches for a satellite signal by performing a correlation process over a predetermined first accumulation time within a predetermined frequency range in units of search frequencies at specific intervals. When the terminal device has failed in searching for the satellite signal, the terminal device searches for the satellite signal by performing the correlation process over a predetermined second accumulation time longer than the first accumulation time at the search frequency and frequencies differing from the search frequency by a specific frequency which is less than the interval of the search frequencies and specified based on a drift of a reference oscillator of the terminal device within the second accumulation time. The terminal device determines a search result of the satellite signal based on a search result at the search frequency and search results at the frequencies differing from the search frequency by the specific frequency.

Abstract: A positioning method includes: executing a first correlation accumulation process on a received signal, a positioning signal spread-modulated with a spread code, and a replica code of the spread code while shifting a phase of the replica code in a first phase search range, setting a second phase search range narrower than the first range based on an accumulated correlation value at a first timing in the first correlation accumulation process, executing a second correlation accumulation process on the received signal and the replica code while shifting the phase of the replica code in the second phase search range, determining appropriateness of the second phase search range based on the accumulated correlation value at the first timing and an accumulated correlation value at a second timing in the first correlation accumulation process, and positioning using a result of the second correlation accumulation process, if the second phase search range is determined appropriate.

Abstract: A pseudorange calculation method for calculating a pseudorange in a position calculation device includes: passing a received signal received from a satellite for position calculation through a first filter; passing the received signal through a second filter having a different phase characteristic from that of the first filter; calculating a first pseudorange on the basis of a signal acquired by passing through the first filter; calculating a second pseudorange on the basis of a signal acquired by passing through the second filter; and calculating a third pseudorange to be used for position calculation, on the basis of the first pseudorange and the second pseudorange.

Abstract: A terminal device searches for a satellite signal by performing a correlation process over a predetermined first accumulation time within a predetermined frequency range in units of search frequencies at specific intervals. When the terminal device has failed in searching for the satellite signal, the terminal device searches for the satellite signal by performing the correlation process over a predetermined second accumulation time longer than the first accumulation time at the search frequency and frequencies differing from the search frequency by a specific frequency which is less than the interval of the search frequencies and specified based on a drift of a reference oscillator of the terminal device within the second accumulation time. The terminal device determines a search result of the satellite signal based on a search result at the search frequency and search results at the frequencies differing from the search frequency by the specific frequency.

Abstract: A positioning apparatus for positioning a current position based on satellite signals from positioning satellites includes: positioning time unit information estimating means for estimating positioning time unit information which is the unit information received at positioning time based on the satellite orbit information and the time information; polarity reversal rate information generating means for generating polarity reversal rate information which indicates a rate of reversal of the polarity of a positioning standard code put on the satellite signals based on the positioning time unit information; positioning standard code polarity adjusting means for keeping or reversing the polarity of the positioning standard code based on the polarity reversal rate information.

Abstract: A terminal device searches for a satellite signal by performing a correlation process over a predetermined first accumulation time within a predetermined frequency range in units of search frequencies at specific intervals. When the terminal device has failed in searching for the satellite signal, the terminal device searches for the satellite signal by performing the correlation process over a predetermined second accumulation time longer than the first accumulation time at the search frequency and frequencies differing from the search frequency by a specific frequency which is less than the interval of the search frequencies and specified based on a drift of a reference oscillator of the terminal device within the second accumulation time. The terminal device determines a search result of the satellite signal based on a search result at the search frequency and search results at the frequencies differing from the search frequency by the specific frequency.

Abstract: A correlation calculation process execution method utilizes a first mode and a second mode as a positioning mode that performs a correlation calculation process on a received signal of a positioning signal that is spread-modulated by a spreading code and a signal replica of the spreading code, the first mode being a mode in which correlation values are averaged in a first mode process period to output a correlation value, and the second mode being a mode in which correlation values are integrated in a second mode process period to output a correlation value, the method including repeating the first mode and the second mode while setting an intermediate time of the first mode process period to be the same as an integration reference time of the second mode process period, and variably setting a ratio of an ON/OFF period in at least one period of the first mode process period and the second mode process period.

Abstract: A received signal determination method includes: receiving a positioning signal; performing correlation calculations on the received positioning signal using a code replica of one spreading code among the plurality of spreading codes; selecting a total peak value and a remote peak value, the total peak value being a first maximum correlation value among correlation values obtained by the correlation calculations, and the remote peak value being a second maximum correlation value among correlation values apart from a phase of the total peak value by a phase equal to or greater than a given phase; changing a threshold value condition for the total peak value based on the remote peak value; and determining whether or not the received positioning signal is spread-modulated with the one spreading code by determining whether or not the total peak value satisfies the threshold value condition.

Abstract: A positioning apparatus 100 includes: a satellite selection indicator information generating device 121 that generates satellite selection indicator information based on satellite location information 131 of SPS to select SPS to be used for positioning; a positioning device 111 that acquires positioning information 135 using the SPS selected based on the satellite selection indicator information; and an outputting device 102 that outputs the positioning information. The positioning apparatus includes: a reception environment indicator information generating device 123 that generates reception environment indicator information 134 for the SPS to compare to the satellite selection indicator information with respect to positioning precision, and calculated based on reception environment information contained in electric waves from the SPS; and a positioning information evaluation device 120 that determines whether the positioning information is to be output to the outputting device or not.