JP5151872B2 - Correlation calculation processing execution method, control circuit, signal processing circuit, and positioning device - Google Patents

Description

The present invention relates to a correlation calculation processing execution method, a control circuit, a signal processing circuit, and a positioning device.

  As a positioning system using positioning signals, GPS (Global Positioning System) is widely known, and is used for positioning devices built in portable telephones, car navigation devices, and the like. In the GPS receiver, the values of four parameters including a three-dimensional coordinate value indicating the position of the own device and a clock error are determined based on information such as the positions of a plurality of GPS satellites and pseudo distances from each GPS satellite to the own device. The current position of the aircraft is measured by performing the positioning calculation obtained by

Among GPS receivers, a GPS receiver that performs intermittent positioning that repeats a positioning period in which a positioning operation is performed and a pause period in which the positioning operation is not performed is known in order to reduce power consumption. Specifically, in the pause period, the operation of the frequency converter that down-converts the received signal and converts it into an IF (Intermediate Frequency) signal, and the signal processor that performs a correlation operation between the received signal and the replica code are paused ( For example, see Patent Document 1).
JP 2001-42023 A

  Some GPS receivers have a plurality of positioning modes corresponding to reception environments such as an outdoor environment (outdoors) and an indoor environment (indoors). For example, since the signal strength is relatively strong in the outdoor environment mode, the correlation value is calculated by averaging the correlation values. In the indoor environment mode, the signal strength is weak, so the correlation value is calculated by the correlation value integration processing. Calculated. That is, when the positioning mode is different, the processing content for calculating the correlation value is different, and therefore the time (measurement time) that is the target of the measurement information to be calculated is different even if the target period is the same. When these multiple positioning modes are executed in parallel and the positioning calculation is performed using the measurement information calculated in each positioning mode, a process of correcting the measurement information in order to match different measurement times with a certain time (hereinafter referred to as the following) , A propagation process is called). However, since the measurement information is altered by the propagation process, the positioning accuracy is deteriorated. The degree of deterioration increases as the difference between the matching time and the measurement time increases.

  Furthermore, in the above-described intermittent positioning, when these multiple positioning modes are executed in parallel, it is necessary to control in consideration of the relationship between the target period of each positioning mode and the positioning / stopping period of intermittent positioning. That is, because the measurement time of measurement information for the target period changes due to the difference in the positioning / stop period included in the target period of the correlation calculation, the difference in the measurement time of the measurement information calculated in each positioning mode becomes large. As a result, the positioning error resulting from the propagation process increases. The present invention has been made in view of the above circumstances.

  According to a first aspect of the present invention, there is provided a first mode processing period as a positioning mode for performing a correlation operation between a received signal of a positioning signal spread-modulated with a spreading code and a replica signal of the spreading code. There is a first mode in which the correlation value is averaged and the correlation value is output, and a second mode in which the correlation value is integrated and output in the second mode processing period. Repetitively executing the first mode and the second mode with the intermediate time point of the mode processing period and the integration reference time point of the second mode processing period as the same timing, the first mode processing period and the A correlation calculation processing execution method including: variably setting a ratio of an ON / OFF period in at least one of the second mode processing periods.

  Further, as an eighth aspect of the invention, as a positioning mode for performing a correlation calculation process between a received signal of a positioning signal spread-modulated by a spreading code and a replica signal of the spreading code, an average of correlation values in a first mode processing period A first mode for performing correlation processing and outputting a correlation value, and a second mode for performing correlation value integration processing and outputting a correlation value in a second mode processing period, and the first mode processing period A control circuit that controls the operation of the correlation calculation processing unit that repeatedly executes the first mode and the second mode, with the intermediate point of time and the integration reference point of the second mode processing period as the same timing, A period variable setting unit that variably sets a ratio of an ON / OFF period in at least one of the first mode processing period and the second mode processing period; and the period variable setting An operation control unit for controlling the operation of the correlation operation unit in accordance with the proportion set by section, may constitute a control circuit which includes a.

  Further, as a ninth invention, as a positioning mode for performing a correlation calculation process between a received signal of a positioning signal spread-modulated with a spreading code and a replica signal of the spreading code, an average of correlation values in the first mode processing period A first mode for performing correlation processing and outputting a correlation value, and a second mode for performing correlation value integration processing and outputting a correlation value in a second mode processing period, and the first mode processing period A correlation operation processing circuit that repeatedly executes the first mode and the second mode, with the intermediate time point and the integration reference time point of the second mode processing period as the same timing, and the first mode processing period and the first mode A control circuit including a period variable setting unit that variably sets the ratio of the ON / OFF period in at least one of the two-mode processing periods. It may form.

  According to the first aspect of the invention, the first mode and the second mode are repeatedly executed with the intermediate time point of the first mode processing period and the integration reference time point of the second mode processing period as the same timing. The ratio of the ON / OFF period in at least one of the first mode processing period and the second mode processing period is variably set.

  In the first mode, a correlation value is averaged and a correlation value is output. The output correlation value is a value at an intermediate point in the first mode processing period. On the other hand, in the second mode, correlation value integration processing is performed and a correlation value is output. The output correlation value is a value at the integration reference point in the second mode processing period. The integration reference time point means a time point that is synchronized when the correlation value is integrated.

  Since the intermediate time of the first mode processing period and the integration reference time of the second mode processing period do not always coincide with each other, correlation values at different time points may be output. Therefore, the first mode processing period and the second mode processing period are shifted so that the intermediate time point of the first mode processing period and the integration reference time point of the second mode processing period have the same timing. Further, the ratio of the ON / OFF period in at least one of the first mode processing period and the second mode processing period is variably set. With this configuration, it is possible to reduce a positioning error that occurs when a plurality of positioning modes having different correlation calculation processing contents are executed in parallel while performing a power saving operation (intermittent positioning).

  The second invention is the correlation calculation processing execution method according to the first invention, wherein the execution is performed by shifting the first mode processing period and the second mode processing period by a half shift. This is a correlation calculation processing execution method.

  As a tenth aspect of the invention, in the signal processing circuit according to the ninth aspect of the invention, the correlation calculation processing circuit shifts the first mode processing period and the second mode processing period by a half shift in parallel. Thus, a signal processing circuit that is a circuit to be executed may be configured.

  According to the second aspect of the invention, the first mode and the second mode are executed in parallel by shifting the first mode processing period and the second mode processing period by ½. For example, when the length of the first mode processing period is the same as the length of the second mode processing period, and the integration reference time point in the second mode is the start time of the second mode processing period, the first mode processing time The intermediate time point of the period and the integration reference time point of the processing period for the second mode are shifted by ½ cycle. Therefore, the correlation value at the same time point can be controlled by shifting the first mode processing period and the second mode processing period by ½.

  A third invention is the correlation calculation processing execution method according to the second invention, wherein the ratio is set to be variable in both the first mode processing period and the second mode processing period. The ON period and the OFF period of the same timing are set, and the arrival interval at the intermediate point of the set ON period becomes the processing period for the second mode, and the arrival interval of the intermediate point of the set OFF period is It is a correlation calculation process execution method used as the first mode process period.

  The eleventh invention is the signal processing circuit according to the tenth invention, wherein the variable period setting unit of the control circuit is a period of both the first mode processing period and the second mode processing period. And the correlation calculation processing circuit executes the second mode with the arrival interval at the intermediate point of the set ON period as the second mode processing period, You may comprise the signal processing circuit which performs the said 1st mode by making the arrival interval of the intermediate time of the set OFF period into the said 1st mode processing period.

  According to the third aspect of the invention, the ON period and the OFF period of the same timing are set in both the first mode processing period and the second mode processing period. Then, the arrival interval at the intermediate point of the set ON period becomes the second mode processing period, and the arrival interval at the intermediate point of the set OFF period becomes the first mode processing period.

  4th invention is the correlation calculation processing execution method of 1st invention, Comprising: Setting the said ratio variably is setting ON period and OFF period in the said 1st mode process period, In this correlation calculation processing execution method, an intermediate time point of the ON period of the first mode and an integration reference time point of the processing period for the second mode are the same timing.

  The twelfth invention is the signal processing circuit according to the ninth invention, wherein the period variable setting unit of the control circuit sets an ON period and an OFF period in the first mode processing period, and the correlation The arithmetic processing circuit is a signal processing circuit that executes the first mode and the second mode so that an intermediate time point of the ON period of the first mode and an integration reference time point of the second mode processing period have the same timing. May be configured.

  According to the fourth aspect of the invention, the ON period and the OFF period are set in the first mode processing period, and the intermediate time of the first mode ON period and the integration reference time of the second mode processing period are at the same timing. It is said.

  5th invention is the correlation calculation process execution method of 1st invention, Comprising: Setting the said ratio variably is setting ON period and OFF period in the process period for said 2nd mode, This is a correlation calculation processing execution method in which the intermediate time point of the first mode processing period and the integration reference time point of the second mode are the same timing.

  The thirteenth invention is the signal processing circuit according to the ninth invention, wherein the period variable setting unit of the control circuit sets an ON period and an OFF period in the second mode processing period, and the correlation The arithmetic processing circuit configures a signal processing circuit that executes the first mode and the second mode so that an intermediate time point of the processing period for the first mode and an integration reference time point of the second mode have the same timing. May be.

  According to the fifth aspect of the invention, the ON period and the OFF period are set in the second mode processing period, and the intermediate time point of the first mode processing period and the integration reference time point of the second mode are set to the same timing. .

  A sixth invention is the correlation calculation processing execution method according to any one of the first to fifth inventions, further comprising inputting an instruction signal related to the ratio, wherein the ratio is variably set, This is a correlation calculation processing execution method in which the ratio of the ON / OFF period is variably set based on an instruction signal.

  According to the sixth aspect of the invention, the ratio of the ON / OFF period can be variably set based on the instruction signal relating to the ratio input from the outside.

  Further, as a seventh invention, a program for causing a program executable processor for controlling the operation of the correlation calculation processing unit to execute the correlation calculation processing execution method of the first to sixth inventions may be configured.

  According to the seventh aspect, it is possible to provide a program that exhibits the same operational effects as those of the first to sixth aspects.

  According to a fourteenth aspect of the present invention, the signal processing circuit according to any one of the ninth to thirteenth aspects of the invention and a positioning arithmetic circuit that performs a positioning arithmetic operation using a correlation result of the correlation arithmetic processing circuit are provided. The circuit outputs an instruction signal related to the ratio to the control circuit of the signal processing circuit, and the operation period variable setting unit of the control circuit sets the ratio of the ON / OFF period to be variable based on the instruction signal. A positioning device may be configured.

  According to the fourteenth aspect of the invention, the instruction signal regarding the ratio is output from the positioning arithmetic circuit to the control circuit of the signal processing circuit. Then, the ratio of the ON / OFF period is variably set based on the input instruction signal by the control circuit.

  Preferred embodiments of the present invention will be described below with reference to the drawings. In the following, a case where the present invention is applied to a mobile phone that is a GPS receiver will be described, but embodiments to which the present invention can be applied are not limited thereto.

[principle]
(A) Positioning Mode In the GPS receiver of this embodiment, two types of modes, “outdoor mode (first mode)” and “indoor mode (second mode)”, can be executed as positioning modes.

  The outdoor mode is a positioning mode suitable for an environment where the intensity of the received signal is relatively strong, for example, outdoors, and the measurement information is calculated by performing the correlation value averaging process in a predetermined target period T. FIG. 1 is a diagram illustrating an example of an “outdoor mode”. In the figure, the horizontal axis indicates the system time t which is the internal time of the GPS receiver, and the measurement information calculation timing is shown based on the system time t. The unit of the system time is “millisecond (msec)”. As shown in the figure, in the outdoor mode, measurement information is calculated based on the correlation calculation result in the target period T at intervals of a predetermined target period T (for example, 1 second). The measurement information is information related to the received signal used in the positioning calculation, and includes information on the reception frequency and code phase of the received signal.

  In the GPS receiver, the received signal is sampled at a predetermined sampling interval (for example, 20 milliseconds) shorter than the target period T, and a correlation calculation is performed between each sampled data and the replica code to calculate a correlation value. In the outdoor mode, the average value of all correlation values calculated in the target period T is used as the correlation calculation result in the target period T. That is, the calculated measurement information corresponds to a value at an intermediate point in the target period T. The time corresponding to this measurement information is referred to as “measurement time (MeasTime)”. The measurement time indicates when the measurement information corresponds to the value at the time, and is not the time when the calculation is performed.

  For example, in the figure, the measurement information calculated at the time of system time t = 1000 is a value calculated based on the correlation calculation result with the period of time t = 0 to 1000 as the target period T, and the measurement time is The time t at the intermediate point of the target period T is 500. Similarly, the measurement information calculated at the next system time t = 2000 is a value with the period of time t = 1000 to 2000 as the target period T, and the measurement time is time t = 1500.

  Then, the positioning result calculated by performing the positioning calculation based on the measurement information corresponds to the value at the measurement time of the measurement information. The time corresponding to the positioning result is referred to as “positioning time (FixTime)”. This positioning time indicates when the positioning result corresponds to the value at the time, and is not the time when the calculation is performed.

  On the other hand, the “indoor mode” is a positioning mode suitable for an environment where the intensity of the received signal is weak, such as indoors, and the measurement information is calculated by performing correlation value integration processing in a predetermined target period T. FIG. 2 is a diagram illustrating an example of the “indoor mode”. As in FIG. 1, the horizontal axis indicates the system time t, and the measurement information calculation timing with the system time t as a reference is shown. As shown in FIG. 2, in the indoor mode, measurement information is calculated based on the correlation calculation result in the target period T at intervals of the predetermined target period T, as in the outdoor mode. In the indoor mode, an integrated value of all correlation values in the target period T is used as a correlation calculation result in the target period T.

  The integration of the correlation value is performed after the propagation process for correcting the correlation value at each sampling timing to the value at the integration reference time of the target period T is performed. In the present embodiment, the integration reference time is described as the start time of the target period T, but may be the end time or the intermediate time of the target period T.

In the present embodiment, the propagation process is performed as follows. That is, the phase CP corresponding to the correlation value at the sampling timing is corrected and integrated to the phase CP ′ at the start time of the target period T according to the following equation (1).
CP ′ = F / 1540 × LU × Δt / 1000 + CP (1)
In Expression (1), “Δt” is the time from the start of the target period T to the sampling timing, and “F” is the reception frequency of the received signal observed in the target period T. Further, “1540” is a value obtained by dividing the L1 band carrier frequency 1.57542 GHz of the GPS satellite signal by the modulation period of 1.023 MHz of the C / A code. “LU” is the number of divisions of one chip of the C / A code. CP and CP ′ are determined at one of the timings obtained by dividing one chip by LU. That is, the measurement time of the calculated measurement information is the start time of the target period T.

  For example, in FIG. 2, the measurement information calculated at the time of system time t = 1500 is a value calculated based on the correlation calculation result with the period of time t = 500 to 1500 as the target period T, and the measurement time Is time t = 500 at the start of the target period T. Similarly, the measurement information calculated at the next system time t = 2500 is a value with the period of time t = 1500 to 2500 as the target period T, and the measurement time is time t = 1500.

  It is also possible to execute two positioning modes (outdoor mode and indoor mode) in parallel. In this case, it is executed by shifting the target period T of each positioning mode by half. FIG. 3 is a diagram illustrating a case where the “outdoor mode” and the “indoor mode” are executed in parallel. As shown in the drawing, the outdoor mode target period To (first mode processing period) and the indoor mode target period Ti (second mode processing period) are shifted by half. That is, the measurement information for the outdoor mode and the measurement information for the indoor mode are alternately calculated at a period T / 2 that is half of the target period T. Then, at the timing when the indoor mode measurement information is calculated, positioning calculation is performed using the measurement information and the outdoor mode measurement information calculated immediately before. Here, since the target periods T of the outdoor mode and the indoor mode are shifted by half, the measurement times of the measurement information of the outdoor mode and the indoor mode used for the positioning calculation are the same.

  For example, in the same figure, measurement information for the outdoor mode is calculated at the system time t = 1000. The measurement time of this measurement information is “500”. Next, at time t = 1500, indoor mode measurement information is calculated. The measurement time of this measurement information is “500”. That is, both measurement times coincide. Then, at time t = 1500, positioning calculation based on the measurement information of the outdoor mode and the indoor mode is performed, and the positioning time of the positioning result is “500” equal to these measurement times. That is, it is not necessary to perform a propagation process for making the measurement time of the measurement information in one positioning mode coincide with the measurement time of the measurement information in the other positioning mode. For this reason, deterioration of positioning accuracy can be prevented.

  Here, the significance of setting the measurement time as a given integration reference time of the target period Ti in the indoor mode will be described. Since the indoor mode is a positioning mode suitable for an environment where the intensity of the received signal is weak, it is often difficult to determine the peak of the correlation value with a short integration time such as Δt milliseconds (for example, 20 milliseconds). Therefore, even if an average value of correlation values every Δt milliseconds in the target period Ti is calculated, there is a possibility that the detected measurement information has low accuracy. Therefore, by integrating the correlation value every Δt milliseconds over the target period Ti, the peak of the correlation value is easily discriminated.

  However, since the code phase fluctuates by F / 1540 × LU × Δt / 1000 chips during Δt milliseconds, if the correlation values for every Δt milliseconds are simply accumulated, the waveform drawn by the correlation values is As a whole, it becomes dull and it becomes difficult to detect an accurate code phase. Therefore, it is reasonable to set a certain integration reference time (integration reference time) and integrate the correlation values in synchronization with the integration reference time. Such integration is called “synchronous integration”. Although the integration reference time can be arbitrarily set, as a simple example, it is conceivable that the start time of the target period Ti is set as the integration reference time. Therefore, in the present embodiment, the measurement time in the indoor mode is set as the start time of the target period Ti.

  Next, the necessity of matching the measurement time between the outdoor mode and the indoor mode will be described. Consider a case where the measurement time in the outdoor mode is t = 2000 and the measurement time in the indoor mode is t = 1500. That is, the measurement time does not match between the outdoor mode and the indoor mode. In this case, if the time at which the positioning calculation is performed is t = 2000, the measurement information at t = 1500 in the indoor mode cannot be used as it is. Therefore, the above-described propagation process is performed, and the measurement information at t = 2000. It is necessary to ask.

Specifically, in the indoor mode, if the code phase and reception frequency detected at t = 1500 are CP0 and F0, respectively, the code phase CP1 at t = 2000 is calculated according to the following equation (2).
CP1 = F0 / 1540 × LU × 500/1000 + CP0 (2)

  As can be seen from Equation (2), the code phase (CP1) obtained by the propagation process depends on the accuracy of the reception frequency (F0) detected at the measurement time. Therefore, as long as the accuracy of the reception frequency is not 0, the error included in the positioning result is smaller when the positioning calculation is performed using the code phase for which the propagation process is not performed. Therefore, it is necessary to set the target period so that the measurement times match in the outdoor mode and the indoor mode.

(B) Power saving operation In addition, the GPS receiver according to the present embodiment performs a power saving operation (intermittent positioning) that repeats the execution / stop (pause) of the correlation calculation process at a predetermined cycle in order to reduce power consumption. FIG. 4 is a diagram for explaining the power saving operation. In the figure, the horizontal axis indicates the system time t, and the period for executing the correlation calculation process (ON period) and the period for stopping (OFF period) are shown. As shown in the figure, in the power saving operation, the ON period and the OFF period are repeated with a period having a length equal to the measurement information calculation target period T as an operation period. For example, in the case of the 60% power saving operation mode, an ON period of 600 msec corresponding to 60% and an OFF period of 400 msec corresponding to 40% are repeatedly executed in one second as an operation cycle. The

  And FIG. 5 is a figure which shows the case where two positioning modes are performed in parallel and a power saving operation is performed. In the figure, the horizontal axis indicates the system time t, and the ON / OFF period of the power saving operation and the calculation timing of the measurement information in each positioning mode are shown. As shown in the figure, the intermediate point in the ON period of the power saving operation coincides with the start point / end point of the target period Ti in the indoor mode. That is, the period from the intermediate point of the ON period to the intermediate point of the next ON period coincides with the target period Ti of the indoor mode. Therefore, since the start time of the target period Ti in the indoor mode is the ON period, the measurement time of the measurement information in the indoor mode is the start time of the target period Ti.

  In addition, the intermediate point in the OFF period of the power saving operation coincides with the start point / end point of the outdoor period target period To. That is, the period from the intermediate point of the OFF period to the intermediate point of the next OFF period coincides with the target period To of the outdoor mode. Since the distribution of the ON period and the OFF period in the target period To in the outdoor mode is symmetrical in the time direction with respect to the intermediate time point of the target period To, the measurement time of the measurement information in the outdoor mode is the middle of the target period To It is time.

  As described above, the measurement time in the indoor mode is the start time of the target period Ti, and the measurement time in the outdoor mode is an intermediate time of the target period To. Further, the target period Ti and the target period To are shifted by a half cycle. Therefore, even when the power saving operation is performed, the measurement times of the measurement information in the indoor mode and the outdoor mode match.

  Further, the ratio X between the ON period and the OFF period of the power saving operation is variable, and in this embodiment, a plurality of power saving operation modes having different ratios X are defined. Specifically, there are five types of modes A to E. FIG. 6 is a diagram illustrating an example of the power saving operation mode. This figure shows the relationship between the power saving operation ON / OFF period and the target period T of the positioning mode (outdoor / indoor mode) for each power saving operation mode with the horizontal axis as the common system time t. Yes. The power saving operation modes are, in order from the top in the figure, mode A with an ON period of 20%, mode B with 40%, mode C with 50%, mode D with 60%, and mode E with 80%. is there. In any power saving operation mode, the interval at the intermediate point in the ON period matches the target period Ti in the indoor mode, and the interval at the intermediate point in the OFF period matches the target period To in the outdoor mode.

[Constitution]
FIG. 7 is a block diagram showing an internal configuration of the mobile phone 1 that is a GPS receiver. According to the figure, the mobile phone 1 includes a GPS antenna 10, a GPS receiving unit 20, a host CPU (Central Processing Unit) 51, an operation unit 52, a display unit 53, and a ROM (Read Only Memory) 54. , A RAM (Random Access Memory) 55, a portable wireless communication circuit unit 60, and a portable antenna 70.

  The GPS antenna 10 is an antenna that receives an RF (Radio Frequency) signal including a GPS satellite signal transmitted from a GPS satellite. The GPS satellite signal is a signal that is spectrum-modulated by a C / A code that is a PRN code, and is superimposed on an L1 band carrier wave having a carrier frequency of 1.57542 [GHz].

  The GPS receiving unit 20 captures and extracts a GPS satellite signal from the RF signal received by the GPS antenna 10, and performs a positioning calculation based on a navigation message or the like extracted from the GPS satellite signal to calculate a current position. The GPS receiving unit 20 includes an RF receiving circuit unit 30 and a baseband processing circuit unit 40.

  The RF receiving circuit unit 30 includes a SAW (Surface Acoustic Wave) filter 31, an LNA (Low Noise Amplifier) 32, a local oscillation signal generation unit 33, a multiplication unit 34, an amplification unit 35, and an A / D conversion unit 36. And performs signal reception by a so-called superheterodyne method.

  The SAW filter 31 is a band-pass filter, passes a signal in a predetermined band with respect to the RF signal input from the GPS antenna 10, and blocks and outputs a frequency component outside the band. The LNA 32 is a low noise amplifier, and amplifies the signal input from the SAW filter 31 and outputs the amplified signal. The local oscillation signal generation unit 33 is configured by an oscillator such as an LO (Local Oscillator) and generates a local oscillation signal. The multiplication unit 34 is configured to include a multiplier that synthesizes a plurality of signals, and multiplies (synthesizes) the RF signal input from the LNA 32 by the local oscillation signal generated by the local oscillation signal generation unit 33 to generate an intermediate frequency. Down-converted to a signal (IF signal). The amplification unit 35 amplifies the IF signal input from the multiplication unit 34 with a predetermined amplification factor. The A / D converter 36 converts the signal (analog signal) input from the amplifier 35 into a digital signal.

  The baseband processing circuit section 40 captures and tracks a GPS satellite signal from the IF signal input from the RF receiving circuit section 30, and calculates a pseudo distance based on a navigation message, time information, and the like obtained by decoding the data. And positioning calculation. FIG. 8 shows a circuit configuration of the baseband processing circuit unit 40. As shown in the figure, the baseband processing circuit unit 40 includes a correlation processing unit 41 and a positioning calculation CPU 42.

  The correlation processing unit 41 captures and tracks a GPS satellite signal from the IF signal input from the RF receiving circuit unit 30, and calculates measurement information for positioning calculation. The correlation processing unit 41 includes a memory 411, a correlation calculation unit 412, an accumulation unit 414, a correlation processing CPU 416, a ROM 417, and a RAM 418.

  The memory 411 stores IF signal data input from the RF receiving circuit unit 30.

  The correlation calculation unit 412 has n correlators 413. The correlator 413 performs a correlation operation between the IF signal data stored in the memory 411 and the replica code generated by a replica code generation unit (not shown) while shifting the phase of the replica code. The replica code generation unit generates a replica code simulating the C / A code of the GPS satellite to be captured under the control of the correlation processing CPU 416.

  The accumulating unit 414 includes n accumulators 415 that are associated with the correlators 413 on a one-to-one basis. The accumulator 415 accumulates the correlation values input from the preceding correlator 413 under the control of the correlation processing CPU 416.

  The correlated correlator 413 and accumulator 415 constitute n sets of reception channels. For each of these reception channels, the positioning mode (outdoor / indoor) and the GPS satellite to be captured can be controlled independently.

  The correlation processing CPU 416 comprehensively controls each unit of the correlation processing unit 41, and performs measurement information calculation processing for calculating measurement information while controlling the power saving operation. In this measurement information processing, ON (execution) / OFF (stop) of the operations of the correlation calculation unit 412 and the RF reception circuit unit 30 are controlled according to the current power saving operation mode according to the power saving operation control table 4172.

  The current power saving operation mode is stored in the power saving operation mode data 4181. FIG. 9 shows an example of the data configuration of the power saving operation mode data 4181. According to the figure, the power saving operation mode data 4181 stores the current power saving operation mode. This power saving operation mode is appropriately switched by, for example, a switching instruction signal from the positioning calculation CPU 42.

  The power saving operation control table 4172 is a data table that defines the control timing of the ON / OFF operation of the power saving operation. FIG. 10 shows an example of the data configuration of the power saving operation control table 4172. According to the figure, the power saving operation control table 4172 has an ON period ratio 4172b, an ON period start timing (ON timing) 4172c, and an OFF period start timing (OFF timing) for each power saving operation mode 4172a. 4172d is stored in association with each other. The value of the start timing of the ON / OFF period in the power saving operation control table 4172 is determined as follows.

  FIG. 11 is a diagram illustrating the setting of the ON / OFF timing of the power saving operation mode. As shown in the figure, the intermediate time point of the OFF period is defined as the reference time t0, and the intermediate time point of the next OFF period is defined as the time t4. In other words, the period from the reference time t0 to the time t4 corresponds to the target period To in the outdoor mode, and its length is equal to any target period T in the outdoor / indoor mode. Further, the ratio of the ON period to the period T is “X”. However, 0 <X <1.

Then, the time t1 at the start of the ON period is given by the following equation (3).
t1 = t0 + (T × (1-X) / 2) (3)
Further, the time t2 at the intermediate time point of the ON period corresponds to the intermediate time point of the cycle T and is given by the following equation (4).
t2 = t0 + T / 2 (4)
The time t3 at the start of the OFF period is given by the following equation (5).
t3 = t0 + (T × (1−X) / 2) + (T × X) (5)
That is, time t1 is the ON timing and time t3 is the OFF timing.

  In the power saving operation control table 4172, the ON / OFF timing is determined as times t1 and t3 when the reference time t0 = 0, that is, the elapsed time from the reference time t0. However, FIG. 10 shows a case where the operation cycle Tp is “1000”.

  Further, the correlation processing CPU 416 calculates measurement information based on the correlation calculation result of each reception channel according to the current power saving operation mode according to the correlation operation control table 4173.

  The correlation operation control table 4173 is a data table that defines the control timing for measurement information calculation. FIG. 12 shows an example of the data configuration of the correlation operation control table 4173. According to the figure, the correlation operation control table 4173 includes a measurement information calculation timing 4173b and an integration reset timing 4173c for resetting the integration value (that is, the correlation calculation result) of the integrator 415 for each power saving operation mode 4173a. Are stored in association with each other. Calculation timing 4173b and integrated reset timing 4173c are stored for each of the indoor mode and the outdoor mode.

  The timing value in the correlation operation control table 4173 is determined by the elapsed time from the reference time t0, similarly to the ON / OFF timing of the power saving operation mode shown in FIG. That is, in the figure, times t0 and t4 coincide with the start / end times of the target period To in the outdoor mode. That is, times t0 and t4 are the calculation timing of the outdoor mode measurement information and the integration reset timing. The latter half of the outdoor period target period To is an OFF period. For this reason, the calculation timing of the measurement information in the indoor mode may be the time t3 that is the end point of the ON period, instead of the above-described time t4.

  Further, the positioning mode of each reception channel is defined in positioning mode data 4182. In FIG. 13, an example of a data structure of the positioning mode data 4182 is shown. According to the figure, the positioning mode data 4182 stores the current positioning mode 4182b and the capture target satellite 4182c in association with each reception channel 4182a. Note that the positioning mode and the acquisition target satellite determined for each reception channel are appropriately switched by, for example, a switching instruction signal from the positioning calculation CPU 42.

  The measurement information calculated by the correlation processing CPU 416 is output to the subsequent positioning calculation CPU 42 together with data such as the measurement time, the positioning mode, and the capture target satellite.

  The ROM 417 stores a system program for the correlation processing CPU 416 to control each unit of the baseband processing circuit unit 40 and the RF receiving circuit unit 30, various programs and data for realizing various processes including baseband processing, and the like. doing. FIG. 14 shows the configuration of the ROM 417. According to the figure, the ROM 417 stores a measurement information calculation program 4171 as a program, and stores a power saving operation control table 4172 and a correlation operation control table 4173 as data.

  The RAM 418 is used as a work area of the correlation processing CPU 416, and temporarily stores programs and data read from the ROM 417, calculation results executed by the correlation processing CPU 416 according to various programs, and the like. FIG. 15 shows the configuration of the RAM 418. According to the figure, the RAM 418 stores power saving operation mode data 4181 and positioning mode data 4182.

  The positioning calculation CPU 42 performs positioning calculation for calculating the current position of the mobile phone 1 based on the measurement information calculated by the correlation processing CPU 416. Specifically, for example, the positioning calculation is performed using the measurement information in each positioning mode input from the correlation processing CPU 416 at the timing after the measurement information in the indoor mode is calculated. In this case, as shown in FIG. 3, the measurement times of the measurement information in the indoor / outdoor modes are the same, and the positioning time is the measurement time. The positioning result (current position) calculated by the positioning calculation CPU 42 is output to the host CPU 51 at the subsequent stage.

  Returning to FIG. 7, the host CPU 51 comprehensively controls each unit of the mobile phone 1 in accordance with various programs such as a system program stored in the ROM 54. Specifically, the telephone function as a telephone is mainly realized, and a navigation screen in which the current position of the mobile phone 1 input from the baseband processing circuit unit 40 is plotted on a map is displayed on the display unit 53. Processing for realizing various functions including a navigation function is performed.

  The operation unit 52 is an input device including operation keys, button switches, and the like, and outputs an operation signal corresponding to an operation by a user to the host CPU 51. By operating the operation unit 52, various instructions such as a positioning start / end instruction are input. The display unit 53 is a display device configured by an LCD (Liquid Crystal Display) or the like, and displays a display screen (for example, a navigation screen or time information) based on a display signal input from the host CPU 51.

  The ROM 54 stores a system program for the host CPU 51 to control the mobile phone 1 and various programs and data for realizing a navigation function. The RAM 55 is used as a work area of the host CPU 51, and temporarily stores programs and data read from the ROM 54, data input from the operation unit 52, calculation results executed by the host CPU 51 according to various programs, and the like.

  The portable wireless communication circuit unit 60 is a mobile phone communication circuit unit configured by an RF conversion circuit, a baseband processing circuit, and the like, and transmits and receives wireless signals under the control of the host CPU 51. The portable antenna 70 is an antenna that transmits and receives wireless signals for mobile phones to and from a wireless base station installed by a communication service provider of the mobile phone 1.

[Process flow]
FIG. 16 is a flowchart for explaining the flow of measurement information calculation processing performed by the correlation processing CPU 416. According to the figure, the correlation processing CPU 416, for example, if a power saving operation mode switching instruction is input from the positioning calculation CPU 42 (step S1: YES), the power saving operation mode is set according to this switching instruction. Switching (step S3). If a positioning mode switching instruction is input (step S5: YES), the positioning mode of each reception channel is switched according to the switching instruction (step S7). If a capture target satellite switching instruction is input (step S9: YES), the capture target satellite of each reception channel is switched according to the switch instruction (step S11).

  Subsequently, the correlation processing CPU 416 sets, for example, the current system time as the reference time t0 (step S13). Then, with reference to the power saving operation control table 4172 and the correlation operation control table 4173, it is determined whether the elapsed time from the reference time t0 has reached the time corresponding to the current power saving operation mode set at each timing. It is determined whether or not the timing has been reached, and processing corresponding to the timing determined to have been reached is performed.

  That is, when the ON timing of the power saving operation is reached (step S15: YES), the operations of the correlation calculation unit 412 and the RF reception circuit unit 30 are started (ON) (step S17). When the power saving operation OFF timing is reached (step S19: YES), the operations of the correlation calculation unit 412 and the RF reception circuit unit 30 are stopped (OFF) (step S21).

  If the calculation timing of the indoor mode measurement information is reached (step S23: YES), the measurement information is calculated based on the correlation calculation result for each reception channel whose positioning mode is set to the indoor mode, The data is output to the positioning calculation CPU 42 (step S25). If the calculation timing of the outdoor mode measurement information is reached (step S27: YES), the measurement information is calculated based on the correlation calculation result for each reception channel whose positioning mode is set to the outdoor mode, It outputs to CPU42 for positioning calculation (step S29).

  If the outdoor mode integration reset timing is reached (step S31: YES), the integrated value of the reception channel whose positioning mode is set to the outdoor mode is reset (step S33). If the indoor mode integration reset timing is reached (step S35: YES), the integrated value of the reception channel whose positioning mode is set to the indoor mode is reset (step S37).

  Next, it is determined whether a predetermined period T has elapsed from the reference time t0. If it has not elapsed (step S39: NO), the process returns to step S13. If the predetermined period T has elapsed (step S39: YES), it is subsequently determined whether or not the measurement information calculation is to be ended depending on whether, for example, an instruction to end the measurement information calculation is input. If the calculation of the measurement information is not finished (step S41: NO), the process returns to step S1, and if finished (step S41: YES), the measurement information calculation process is finished.

[Modification]
Needless to say, the applicable embodiments of the present invention are not limited to the above-described embodiments, and can be appropriately changed without departing from the spirit of the present invention.

(1) Switching of power saving operation mode For example, in the above-described embodiment, a plurality of power saving operation modes (modes A to E) are determined and switched in advance. The ratio X may be arbitrarily set within the range of “0 to 1.0”. In this case, every time the ratio X is switched, as described with reference to FIG. 11, the power saving operation ON / OFF timing, the measurement information calculation timing and the integrated value reset timing in each positioning mode, and the like. Each timing may be calculated and set.

(2) Variable setting of the target period In the above-described embodiment, the correlation calculation process is described with the target period To of the outdoor mode and the target period Ti of the indoor mode set to “1 second (1000 milliseconds)”. The target period may be variably set between the outdoor mode and the indoor mode. Hereinafter, the cases will be described separately.

(2-1) When To <Ti FIG. 17 shows the indoor mode when the target period To in the outdoor mode is “500 milliseconds” and the target period Ti in the indoor mode is “1000 milliseconds” (To <Ti). It is explanatory drawing of operation | movement in the outdoor mode. In the drawing, a period corresponding to the ON period of the power saving operation mode is indicated by an arrow. The period in which the arrow is not shown is a period corresponding to the OFF period of the power saving operation mode.

  In the outdoor mode, for example, the correlation value is calculated with the period from time t = 0 to 500 as the target period To, and the average value of the correlation values in the 500 millisecond period is used as the correlation calculation result in the target period. Then, at time t = 500, the outdoor mode measurement information is calculated. The measurement time of the measurement information in the outdoor mode is “250” that is an intermediate point in the target period To of t = 0 to 500.

  In the indoor mode, the correlation calculation process is started at time t = 250, which is shifted by 250 milliseconds, which is a half of the target period To from the start time of the outdoor mode, and the period of t = 250 to 1250 is set to the target period Ti. As a result, the correlation value is integrated. At time t = 1250, indoor mode measurement information is calculated. The measurement time of the measurement information in the indoor mode is “250” at the start time which is the integration reference time of the target period Ti of t = 250 to 1250.

  Then, at time t = 1250, positioning calculation based on the measurement information of the outdoor mode and indoor mode is performed, and the positioning time of the positioning result is “250” equal to these measurement times. During the period from t = 500 to 1000, the outdoor mode is set to the OFF period, and only the processing in the indoor mode is performed. At time t = 1000, the outdoor mode becomes the ON period again. In the indoor mode, after the measurement information is calculated at t = 1250, the correlation value accumulation process is performed with the period of t = 1250 to 2250 as the target period Ti. Therefore, the indoor mode is always in the ON period.

  Thereafter, outdoor mode measurement information is calculated at time t = 1500, and indoor mode measurement information is calculated at time t = 2250. The measurement time in this case is “1250” in both the outdoor mode and the indoor mode. Then, at time t = 1250, positioning calculation based on the measurement information of the outdoor mode and indoor mode is performed, and the positioning time of the positioning result is “1250” equal to these measurement times.

  FIG. 18 is an explanatory diagram of the power saving operation mode in this case. As described above, the indoor mode is always in the ON period (100% ON). In the outdoor mode, the ON period and the OFF period are repeated with the length of the period equal to the target period To as the operation period. In the outdoor mode A (20% ON), a period of 100 milliseconds of t = 200 to 300 is set as the ON period with a start time t = 250, which is the integration reference time of the indoor mode.

  Similarly, in the outdoor mode B (40% ON), a period of 200 milliseconds from t = 150 to 350, and in the outdoor mode C (60% ON), a period of 300 milliseconds from t = 100 to 400 is used. In (80% ON), a 400 ms period of t = 50 to 450 is set as an ON period, and in an outdoor mode E (100% ON), a 500 ms period of t = 0 to 500 is set as an ON period. In any mode, the intermediate time point of the outdoor mode ON period coincides with the start time / end time of the indoor period target period Ti.

(2-2) When To> Ti FIG. 19 shows the indoor mode when the target period To in the outdoor mode is “1000 milliseconds” and the target period Ti in the indoor mode is “500 milliseconds” (To> Ti). It is explanatory drawing of operation | movement in the outdoor mode. In the drawing, a period corresponding to the ON period of the power saving operation mode is indicated by an arrow. The period in which the arrow is not shown is the OFF period.

  In the outdoor mode, for example, the correlation value is calculated with the period from time t = 0 to 1000 as the target period To, and the average value of the correlation values in the 1000 millisecond period is used as the correlation calculation result in the target period. At time t = 1000, outdoor mode measurement information is calculated. The measurement time of the measurement information in the outdoor mode is “500” that is an intermediate point in the target period To of t = 0 to 1000.

  In the indoor mode, the correlation calculation process is started at time t = 500, which is shifted by 500 milliseconds, which is a half of the target period To from the start time of the outdoor mode, and the period of t = 500 to 1000 is set to the target period Ti. As a result, the correlation value is integrated. At time t = 1000, indoor mode measurement information is calculated. The measurement time of the measurement information in the indoor mode is “500” at the start time which is the integration reference time of the target period Ti of t = 500 to 1000.

  Then, at time t = 1000, positioning calculation based on the measurement information of the outdoor mode and indoor mode is performed, and the positioning time of the positioning result is “500” equal to these measurement times. During the period from t = 1000 to 1500, the indoor mode is set to the OFF period, and only the processing in the outdoor mode is performed. Then, at time t = 1500, the indoor mode becomes the ON period again. In the outdoor mode, after the measurement information is calculated at t = 1000, the correlation value is subjected to integration processing with the period of t = 1000 to 2000 as the target period To. Therefore, the outdoor mode is always in the ON period.

  Thereafter, at time t = 2000, measurement information for the outdoor mode and the indoor mode is calculated. In this case, the measurement time is “1500” in both the outdoor mode and the indoor mode. Then, at time t = 2000, a positioning calculation based on the measurement information of the outdoor mode and the indoor mode is performed, and the positioning time of the positioning result is “1500” which is equal to these measurement times.

  FIG. 20 is an explanatory diagram of the power saving operation mode in this case. As described above, the outdoor mode is always in the ON period (100% ON). In the indoor mode, the ON period and the OFF period are repeated with the length of the period equal to the target period Ti as an operation period. In the indoor mode A (20% ON), a period of 100 milliseconds of t = 500 to 600 is set as an ON period, with t = 500 being an intermediate time point in the outdoor mode being a start time point being an integration reference time point.

  Similarly, in indoor mode B (40% ON), a period of 200 milliseconds of t = 500 to 700 is used, and in indoor mode C (60% ON), a period of 300 milliseconds of t = 500 to 800 is used. In (80% ON), a 400-millisecond period from t = 500 to 900 is set as the ON period, and in indoor mode E (100% ON), a 500-millisecond period from t = 500 to 1000 is set as the ON period. In any mode, the intermediate point in the outdoor mode coincides with the start point of the target period Ti that is the integration reference point in the indoor mode.

  In this way, the target period To and the target period Ti are shifted by setting the intermediate time point of the target period To and the start time point, which is the integration reference time point of the target period Ti, to be the same in the target period with the shorter period. By setting the ratio of the ON / OFF period to be variable, it is possible to make adjustment so that the measurement time is the same in the outdoor mode and the indoor mode, and the measurement information at the same time is calculated.

(3) Host CPU
In the embodiment described above, the positioning calculation CPU 42 provided in the baseband processing circuit unit 40 has been described as performing the positioning calculation, but the host CPU 51 may perform the positioning calculation. In the above-described embodiment, the correlation processing unit 41 performs correlation calculation processing to capture and track GPS satellite signals. However, the host CPU 51 performs correlation calculation processing to capture and track GPS satellite signals. It is also possible to adopt a configuration.

Explanatory drawing of outdoor mode. Explanatory drawing of indoor mode. Explanatory drawing in the case of performing outdoor mode and indoor mode in parallel. Explanatory drawing of a power saving operation | movement. Explanatory drawing in the case of performing outdoor / indoor mode in parallel with power saving operation. The figure which shows an example of a power saving operation mode. The block diagram of a mobile telephone. The block diagram of a baseband process circuit part. The data structural example of power saving operation mode data. The data structural example of a power saving operation control table. Explanatory drawing of the setting of each timing of a power saving operation and positioning mode. The data structural example of a correlation operation | movement control table. The data structural example of positioning mode data. The block diagram of ROM. The block diagram of RAM. The flowchart of a measurement information calculation process. Explanatory drawing of parallel execution of outdoor / indoor mode in a modification. The figure which shows an example of the power saving operation mode in a modification. Explanatory drawing of parallel execution of outdoor / indoor mode in a modification. The figure which shows an example of the power saving operation mode in a modification.

Explanation of symbols

1 mobile phone, 10 GPS antenna, 20 GPS receiver,
30 RF receiving circuit section, 40 baseband processing circuit section, 41 correlation processing section,
411 memory, 412 correlation calculation unit, 413 correlator, 414 integration unit,
415 integrator, 416 CPU for correlation processing, 417 ROM,
4171 measurement information calculation program, 4172 power saving operation control table, 4173 correlation operation control table, 418 RAM,
4181 power-saving operation mode data, 4182 positioning mode data,
42 Positioning calculation CPU, 51 Host CPU, 52 Operation section, 53 Display section,
54 ROM, 55 RAM, 60 Portable wireless communication circuit unit,
70 Portable antenna

Claims (9)

As a positioning mode for performing a correlation calculation process between a received signal of a positioning signal spread-modulated with a spreading code and a replica signal of the spreading code, a correlation value is averaged during a first mode processing period to obtain a correlation value. There is a first mode for outputting, and a second mode for outputting the correlation value by performing correlation value integration processing in the processing period for the second mode,
Repetitively executing the first mode and the second mode with the intermediate time point of the first mode processing period and the integration reference time point of the second mode processing period as the same timing;
Variably setting the ratio of the ON / OFF period in at least one of the first mode processing period and the second mode processing period;
A correlation calculation processing execution method including   2. The correlation calculation processing execution method according to claim 1, wherein the execution is that the first mode processing period and the second mode processing period are shifted in parallel by ½. To set the ratio variably is to set the ON period and OFF period of the same timing in both the first mode processing period and the second mode processing period,
The arrival interval at the intermediate time point of the set ON period is the second mode processing period, and the arrival interval at the intermediate time point of the set OFF period is the first mode processing period. Correlation operation execution method. Setting the ratio variably is setting an ON period and an OFF period in the processing period for the first mode,
The correlation calculation processing execution method according to claim 1, wherein an intermediate time point of the ON period of the first mode and an integration reference time point of the processing period for the second mode are the same timing. Setting the ratio variably is setting an ON period and an OFF period in the processing period for the second mode,
The correlation calculation processing execution method according to claim 1, wherein an intermediate time of the first mode processing period and an integration reference time of the second mode are the same timing. Further comprising inputting an instruction signal relating to the ratio;
Setting the ratio variably is setting the ratio of the ON / OFF period variably based on the instruction signal.
The correlation calculation processing execution method according to any one of claims 1 to 5. As a positioning mode for performing a correlation calculation process between a received signal of a positioning signal spread-modulated with a spreading code and a replica signal of the spreading code, a correlation value is averaged during a first mode processing period to obtain a correlation value. A first mode to be output, and a second mode to output a correlation value by performing correlation value integration processing in the second mode processing period, and an intermediate time point in the first mode processing period and the second mode A control circuit that controls the operation of the correlation calculation processing unit that repeatedly executes the first mode and the second mode, with the integration reference time point of the processing period as the same timing,
A period variable setting unit that variably sets a ratio of an ON / OFF period in at least one of the first mode processing period and the second mode processing period;
An operation control unit for controlling the operation of the correlation calculation processing unit according to the ratio set by the period variable setting unit;
Control circuit with. As a positioning mode for performing a correlation calculation process between a received signal of a positioning signal spread-modulated with a spreading code and a replica signal of the spreading code, a correlation value is averaged during a first mode processing period to obtain a correlation value. A first mode to be output, and a second mode to output a correlation value by performing correlation value integration processing in the second mode processing period, and an intermediate time point in the first mode processing period and the second mode A correlation calculation processing circuit that repeatedly executes the first mode and the second mode, with the integration reference point of the processing period as the same timing;
A control circuit comprising a period variable setting unit that variably sets a ratio of an ON / OFF period in at least one of the first mode processing period and the second mode processing period;
A signal processing circuit comprising: A signal processing circuit according to claim 8 ;
A positioning calculation circuit that performs a positioning calculation using the correlation result of the correlation calculation processing circuit;
With
The positioning calculation circuit outputs an instruction signal related to the ratio to the control circuit of the signal processing circuit,
The operation period variable setting unit of the control circuit sets the ratio of the ON / OFF period to be variable based on the instruction signal.
Positioning device.

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