Received signal determination method, positioning device, and electronic instrument

A method for a positioning device, comprising:

• receiving a positioning signal;
• performing correlation calculations on the received positioning signal using a code replica of one spreading code among a 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,
• the performing of the correlation calculations including integrating correlation values while changing an integration time;
• the method further comprising:
• determining a type of the remote peak value with respect to the integration time when performing the correlation calculations from a plurality of types that are defined in advance as types of change in correlation value corresponding to the integration time during the correlation calculations;
• wherein
• the changing of the threshold value condition including changing the threshold value condition using a threshold value condition change policy corresponding to the determined type among a plurality of threshold value condition change policies defined in advance corresponding to the plurality of types.

A positioning device comprising:

• a receiver section that receives a positioning signal;
• a correlation calculation section that performs correlation calculations on the received positioning signal using a code replica of one spreading code among the plurality of spreading codes;
• a selection section that selects 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;
• a threshold value condition change section that changes a threshold value condition for the total peak value based on the remote peak value;
• a signal determination section that determines 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;
• and
• a positioning section that calculates a position using the determined positioning signal by the signal determination section,
• the spreading code including a predetermined number N of chips, N being an integer;
• the correlation calculation section dividing the spreading code into M cells, M being an integer greater than or equal to N, and performing the correlation calculations while shifting a phase in cell units;
• and
• the selection section selecting a maximum correlation value among correlation values corresponding to cells that are included in the M cells and apart from the phase of the total peak value by M/N or more cells as the remote peak value.

A positioning device comprising:

• a receiver section that receives a positioning signal;
• a correlation calculation section that performs correlation calculations on the received positioning signal using a code replica of one spreading code among a plurality of spreading codes;
• a selection section that selects 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;
• a threshold value condition change section that changes a threshold value condition for the total peak value based on the remote peak value;
• a signal determination section that determines 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;
• and
• a positioning section that calculates a position using the determined positioning signal by the signal determination section,
• the correlation calculation section integrating calculated correlation values while changing an integration time;
• the positioning device further comprising:
• a correlation value type determination section that determines a type of the remote peak value with respect to the integration time during the correlation calculations performed by the correlation calculation section from a plurality of types that are defined in advance as types of change in correlation value corresponding to the integration time during the correlation calculations;
• wherein
• the threshold value condition change section changing the threshold value condition using a threshold value condition change policy corresponding to the type determined by the correlation value type determination section among a plurality of threshold value condition change policies defined in advance corresponding to the plurality of types.