JPH0572316A - Gps reception device signal processing method and device - Google Patents

Abstract

PURPOSE:To enable a time which is required for switching of a satellite for receiving signal to be reduced in a sequential GPS reception device. CONSTITUTION:A signal which is received by an antenna 1 is amplified by a low-noise amplifier 2 and is converted to a low frequency. This signal is inversely diffused by a PN code which is generated by a PN code NCO 8 and a PN code generator 7 and at the same time a distance between a satellite and a reception device is measured by a distance-measuring counter 19 and a position is calculated. When switching the reception satellite, a phase of the PN code which is generated by the PN code generator 7 is controlled by a synchronous timing generator 16, thus enabling the synchronization time to be reduced. A distance-measurement result is output from an external communication part 17.

Description

Detailed Description of the Invention

[0001]

The present invention relates to NAVSTAR / GPS
The present invention relates to a receiving device that receives a signal from a satellite and a synchronization method.

[0002]

2. Description of the Related Art The GPS (Global Positioning System) is a global radio navigation system using satellites that the US Department of Defense is constructing. The system consists of satellite system and ground system. A total of 24 satellites will be finally prepared, and if the system is completed, it will be possible to perform three-dimensional positioning worldwide 24 hours a day.

A signal transmitted from a NAVSTAR / GPS satellite is a spread spectrum modulation which has an excellent capability of being less susceptible to interference and interference, having a high signal concealment capability, capable of distance measurement, time synchronization, and code division multiple access. It is a signal. Spread spectrum modulation is a pseudo noise code (Pseudo Noise code: PN code) that is a random code that has a characteristic that the information data signal has a wider band than the frequency band of the information signal, and has high autocorrelation and low cross-correlation.
Since this is a method of transmitting the signal after being modulated by (which is referred to as PN spreading), the spread spectrum signal receiving apparatus requires the following operation. That is, a PN code having the same pattern as the PN code used for spreading the information data on the transmission side is generated inside the receiving device, and the phase of the PN code and the phase of the PN code of the received signal are matched and multiplied to demodulate. , Demodulating the transmitted information data (this is called PN despreading).

The operation will be described in detail. After the receiver is started up, the phase of the PN code included in the signal to be received and the PN code created inside the receiver coincide (PN synchronization) inside the receiver. Up to P created inside the receiver
The PN search for changing the phase of the N code is performed until the synchronization is acquired to obtain the despread signal. After the PN synchronization is established by the above operation, the vibration loop shown in, for example, Mitsuo Yokoyama, "Spread spectrum communication system" (Science and Technology Publishing Co., Ltd., 1988, PP.311-325), so that the phases of PN codes always match. The circuit controls the PN code generator (PN
Sync tracking), PN tracking.

The GPS receiver has four GPs each.
The distance between the S satellite and the receiving device is measured from the synchronized state, and at the same time, the position of the GPS satellite is analyzed from the demodulated signal, and the self position is calculated based on these data. Therefore, the type of GPS receiving device is classified according to the number of synchronizing circuits. A one-channel sequential receiving device that performs positioning by switching satellites that receive in time series using one synchronization circuit has features that the circuit configuration is simplified and the size and cost are reduced. A multi-channel receiving device that receives four or more satellite signals at the same time by four or more synchronizing circuits and performs positioning has a feature that a high-performance receiving device can be configured. In the middle of this, there is also a 2-channel sequential receiving device that performs positioning by switching two synchronization circuits in time series.

[0006]

Since the 1-channel and 2-channel sequential GPS receivers switch satellites to be received in time series, a synchronous search (PN) is performed each time.
It is necessary to perform a search) and perform synchronization tracking, and it takes time to perform PN synchronization. For example, a synchronous search speed of 100
With bit / sec, it takes an average of about 5 seconds for synchronous search to receive one satellite. Further, it takes about 20 seconds on average to receive the positioning result by receiving four satellites, and the positioning cycle becomes long.

Further, in the 1-channel and 2-channel sequential GPS receivers mounted on a mobile unit, the position change of the receiver during position measurement increases as the time required for switching the satellite to be received becomes longer, resulting in a positioning error. Will grow.

Therefore, in order to reduce the positioning error, it is necessary to switch the satellites to be received in a short period of time and synchronize with each other to perform the positioning calculation.

An object of the present invention is to reduce the time required for a sequential GPS receiver to resynchronize to satellites.

[0010]

The time required to resynchronize with a satellite is shortened by storing the phase information of the PN code in a satellite-specific synchronized state and satisfying the phase information when the satellite is received again. It is realized by the operation of reproducing the PN code.

In order to realize this operation, the present invention creates, in the sequential GPS receiver, phase information of the PN code generated by the receiver in the PN synchronization state with each satellite, reads it, and stores it. Means and a PN code generating means for generating a PN code satisfying the phase information of the stored PN code.

In addition to the above-mentioned means, the present invention further comprises means for estimating the amount of change when the phase of the PN code changes due to Doppler shift and correcting the phase information in addition to the above means. ..

[0013]

When the satellite to be received is switched, a PN code satisfying the phase information in the synchronized state stored when previously synchronized with the satellite to be received is generated, and the stored phase information is reproduced. PN code and P transmitted from satellite
Since the synchronous search is performed with the N code, the phase difference at the start of the synchronous search is small, and the time required for the synchronous acquisition can be shortened.

Further, the stored phase information of the PN code is modified according to the Doppler shift amount, a PN code for reproducing the modified phase information is generated, and the PN code and the satellite for reproducing the modified phase information. Since the synchronous search is performed with the PN code transmitted from, even if the signal transmitted from the satellite includes the Doppler shift, the phase difference at the start of the synchronous search is small and the time required for the synchronous acquisition is short. End

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The illustrated sequential GPS receiver includes an antenna 1, a low noise amplifier 2 connected to the antenna 1,
A mixer 3 connected to the output side of the low-noise amplifier 2, a bandpass filter 5 (passband width about 2 MHz) connected to the output side of the mixer 3, and an output side of the bandpass filter 5. Mixer 6, a mixer 9 connected to the output side of the mixer 6, a low-pass filter 11 connected to the output side of the mixer 9, and an A connected to the output side of the low-pass filter 11. / D converter 12 and the A / D converter 1
A digital signal processing unit 14 connected to the output side of 2;
PN connected to the output side of the digital signal processing unit 14
A code NCO8, a PN code generator 7 and a distance measuring counter 19 connected to the output side of the PN code NCO8, and an arithmetic unit 15 connected to the output side of the distance measuring counter 19.
A reference oscillator 18, a first local oscillator 4, a second local oscillator 10, a frequency divider 13, a synchronization timing generator 16 connected to the output side of the reference oscillator 18, and the digital signal processing unit 14. An external communication unit 17 connected to the arithmetic unit 15 and the synchronization timing generator 16 via a data bus.
It is configured to include and.

The outputs of the first local oscillator 4, the PN code generator 7, the second local oscillator 10, and the frequency divider 13 are connected to the mixer 3, mixer 6, mixer 9 and A / D converter 12, respectively. PN code generator 7 and synchronization timing generator 16
Are connected to each other. The output side of the reference oscillator 18 is also connected to the input side of the PN code NCO 8. The digital signal processing unit 14, the arithmetic unit 15, the synchronization timing generator 16 and the external communication unit 17 are connected to each other via a data bus.

In the apparatus having the above structure, NAVSTAR
/ Center frequency 1575.42 transmitted from GPS satellite
The spread spectrum signal of MHz is captured by the antenna 1. Further, this signal is amplified by the low noise amplifier 2 and down-converted by the mixer 3 by the carrier wave (for example, 1509.948 MHz) created by the first local oscillator 4 whose frequency is controlled by the reference oscillator 18 to generate the first intermediate frequency signal. can get. The bandpass filter 5 removes an unnecessary out-of-band noise signal from the first intermediate frequency signal output from the mixer 3.

A PN code NCO (Numerical Controlled Oscillator) 8 generates a frequency signal of a predetermined value, and a PN code generator 7 has the same pattern as the PN code of the satellite signal of that frequency to be received. , And a PN code in phase with the received signal is generated. PN code generator 7
Simultaneously generates the epoch signal at the head position of the PN code and outputs it to the synchronization timing generator 16. The mixer 6 despreads the first intermediate frequency signal from which noise has been removed with a PN code, and demodulates a carrier signal that is two-phase phase modulated with 50 bps navigation data. Further, the second spreader which controls the frequency of the despread signal by the reference oscillator 18
A carrier wave generated by a local oscillator (for example, an oscillation frequency of 65.
472 MHz) and down-converting by the mixer 9 to obtain a second intermediate frequency signal.

The low-pass filter 11 halves the sampling frequency of the A / D converter 12 from the second intermediate frequency signal.
The noise signal composed of the above frequency components is removed. Here, the cutoff frequency of the low-pass filter 11 is the NAV to be received.
Considering that the STAR / GPS signal fluctuates about ± 4 kHz Doppler frequency on the ground and the reference oscillator 18 also fluctuates in frequency, about 5 to 7 kHz may be selected.

Further, this signal is converted from analog to digital by the A / D converter 12. As for the sampling frequency, if the oscillation frequency of the reference oscillator 18 is divided by 2 to the Nth power, the configuration is simplified. For example, if the frequency division ratio of the frequency divider 13 is 4
It is preferable to divide by 096 and obtain a sampling frequency of 15.948375 kHz from the reference frequency of 65.472 MHz.

The digital signal processing unit 14 performs processing such as PN synchronization search, PN synchronization acquisition, tracking, demodulation of navigation data signal, and measurement of Doppler frequency. The PN synchronization search (hereinafter referred to as a synchronization search) is an operation for matching (synchronizing) the phases of the PN code sent from the satellite and the PN code generated inside the GPS receiver, and this operation is completed by the PN synchronization acquisition. To do. The PN synchronization tracking is an operation of controlling the phase of the PN code generated inside the GPS receiver so that the phases of the PN codes always match after capturing the PN synchronization. Here, as a means for changing the phase of the PN code, the chip rate frequency of the PN code generated by the PN code NCO 8 is slightly changed with respect to the chip rate frequency of the PN code sent from the satellite, so that the PN code is equivalently changed. A means for changing the phase of is used. The digital signal processing unit 14 sends a feedback signal to the PN code NCO 8 to change the phase of the PN code generated by the PN code generator 7 with respect to the phase of the PN code transmitted from the satellite. For example, the PN code chip rate frequency of the satellite signal is 1.023 MHz, and the PN code chip rate frequency generated inside the GPS receiver is 1.0232 MH.
If z, the phase change rate of the PN code is 200 bits / second. Also sent from the satellite by two-phase modulation 50
The bps navigation data signal is demodulated by a TAN format demodulator or the like to obtain navigation data. The Doppler frequency is measured from the phase change of the carrier.

The calculation unit 15 edits the demodulated navigation data signal to obtain almanac data (overall position information of NAVSTAR / GPS satellites) and eformeris data (detailed position information of NAVSTAR / GPS satellites) necessary for positioning and speed calculation. ). Further, the self position is calculated using the pseudo distance data between the satellite and the GPS receiver antenna measured by the distance measurement counter 19 and the ephemeris data. Three
Two-dimensional positioning is possible when one satellite can be received, and three-dimensional positioning is possible when four satellites can be received. The positioning result is output via the external communication unit 17. The arithmetic unit 15 also reads and stores the synchronization shortening timing data from the synchronization timing generator 16 and outputs the synchronization shortening timing data to the synchronization timing generator 16.

The synchronization timing generator 16 generates a PN code sent from a NAVSTAR / GPS satellite and a P generated inside the GPS receiver when the receiving satellite is switched.
A timing signal (synchronization shortening timing data) for synchronizing with the N code at high speed and for synchronizing in a short time is generated.

Next, the structure of the synchronization timing generator 16, which is a feature of the present invention, will be described with reference to FIG. The synchronization timing generator 16 is a 1023 binary synchronization counter 2
0, a latch 21 connected to the 1023 binary synchronization counter 20, a latch 22 connected to the latch 21 via a data bus, an exclusive NOR 23 connected to the latch 22 and the 1023 binary synchronization counter 20, and NAND connected to the output side of exclusive NOR 23
It is composed of 24.

The 1023 binary synchronization counter 20 outputs the result of counting the 1.023 MHz clock generated by the reference oscillator 18. Here, the clock frequency is 1.0
The processing can be simplified by selecting a multiple of 23 MHz. Further, the counter may be an asynchronous type.

The count result is always latched in the latch 21 by an epoch signal having a cycle of about 1 millisecond indicating the start position of the PN code. The latched count result becomes synchronization shortening timing data of the PN code transmitted by the NAVSTAR / GPS satellite being received at that time, and this data is sent to the arithmetic unit 15 via the data bus.

When the next satellite to be received is switched,
The synchronization shortening timing data of the PN code of the satellite to be received next, which is collected by the above method, is sent from the arithmetic unit 15 to the latch 22 as a chip select signal. Exclusive NOR23 and NAND24 are latch 2
When the data stored in 2 and the output data of the 1023 binary synchronization counter 20 match, the PN code is reset P
The N code reset signal is output to the PN code generator 7. P
Upon receiving the N code reset signal, the PN code generator 7 generates a PN code having that time as a start time, and the digital signal processing unit 14 starts the synchronous search. That is, since the PN code is generated at substantially the same timing as the timing of the PN code generated on the receiving device side, which was synchronized when the PN code from the satellite was received last time, the satellite at the start of the synchronous search The phase difference between the PN code from and the PN code generated on the receiving device side becomes small,
The time to PN synchronization is shortened. Further, the output data of the 1023 binary synchronization counter 20 changes from 0 to 1022 within 1 millisecond, and the data set in the latch 22 is a number between 0 and 1022.
And the output data of the 1023 binary synchronization counter 20 become the same once in about 1 millisecond.

Next, the operation principle of the synchronization timing generator will be described with reference to FIG.

P transmitted by the NAVSTAR / GPS satellite
The N code is a Gold code having a repetition period of 1023 bits and a chip rate frequency of 1.023 MHz. Therefore, although the PN code generated inside the GPS receiver has the same configuration, it is further configured to repeatedly output an epoch signal indicating the start position of the PN code. Here, the period θ of the epoch signal is 1 millisecond.

When the phase of the PN code from the satellite and the phase of the PN code generated by the receiving apparatus are synchronized, the value of the synchronization counter is always latched by the epoch signal and the synchronization shortening timing data is obtained. This data has an arbitrary value from 0 to 1022 in the configuration shown in FIG. Computing unit 15
Always reads the synchronization shortening timing data and stores it in the memory when switching the satellite to be received.

When the satellite to be received is switched and a signal from a new satellite (however, the synchronization shortening timing data has been collected before) is received, the arithmetic unit 15 reads the synchronization shortening timing data of the satellite to be received from the memory. , Latch 22 in the synchronization timing generator 16. The PN code generator 7 is reset at the timing when the count value of the internal 1023 binary sync counter and the value of the synchronization shortening timing data latched by the latch 22 match, and the PN code whose starting point is the PN code generator is the PN code generator. 7
And the chip rate frequency of the PN code NCO 8 is controlled by the feedback signal from the digital signal processing unit 14 to rapidly find the synchronization point. If there is no disturbance such as Doppler shift in the signal from the satellite, the sync point is found within 1 millisecond, and the sync search is completed.
If there is a disturbance such as Doppler shift in the signal from the satellite, the phase of the PN code from the satellite is out of phase with that when the synchronization shortening timing data was sampled first, so immediately when the PN code reset signal is output. The synchronization is not acquired, and the synchronization search starts from that point. However, even in that case, since the phase shift is small, the time required for the synchronous search is shortened.

Next, a GP equipped with a synchronous timing generator
The operating principle of the S receiver will be described with reference to FIG.

First, the arithmetic unit 15 obtains a combination of four satellites whose self position can be calculated most accurately from the almanac data and the time (three satellites are sufficient for two-dimensional positioning). After the combination is determined, the synchronization shortening timing data for shortening the synchronization acquisition time is set in the synchronization timing generator 16, and the digital signal processing unit 14 starts the synchronization search. However, in the first sync search, since there is no sync shortening timing data, the sync shortening timing data is not set. The sync search continues until a PN sync is sought. After the synchronization is acquired, synchronization tracking is performed by the digital signal processing unit 14 so that the PN synchronization is not deviated, and the calculation unit 15 collects distance data (ranging data) between the satellite and the own position and navigation data. However, the navigation data can be collected only once at the first time after launch, and can be omitted after the second time.

Further, the calculation unit performs positioning calculation using the ephemeris data included in the distance measurement data and navigation data, and outputs the positioning data to the outside. Further, before switching the satellite to be received, the above-mentioned synchronization shortening timing data is collected and stored in the memory.

The same process is performed while switching the satellites to be received and the positioning is continued.

When the signal from the satellite has a frequency change such as Doppler shift, the synchronization is not immediately acquired when the PN code reset signal is output, and the synchronization search starts from that point. In this case, the time required for the synchronization search can be shortened by correcting the synchronization shortening timing data. Hereinafter, a method of correcting the synchronization shortening timing data when there is a frequency change such as Doppler shift will be described with reference to FIG.

First, the synchronization shortening timing data stored in the memory is loaded.

Next, the rate of change Δf (Hz) of the Doppler frequency in the PN code per unit time is obtained. There are two methods for obtaining this: the method of obtaining the measured value and the method of obtaining the calculated value. The method of measurement is based on the fact that the time change of the carrier frequency measured by the digital signal processing unit 14 and the change of the Doppler frequency in the PN code are in a proportional relationship. In the calculation method, the rate of change Δf of the Doppler frequency in the PN code is calculated from the satellite orbit calculated from the almanac data and its own approximate position.

Further, the synchronization shortening timing data is collected from the latch 21, and the time t (second) until the value is set in the latch 22 is obtained. The phase shift amount of the PN code is
It can be calculated from the following formula.

[0040]

## EQU00001 ## .DELTA.f.times.t (bit) Therefore, the corrected synchronization shortening timing data X can be expressed by the following equation, where the synchronization shortening timing data before correction is X '.

[0041]

## EQU00002 ## X = X '+. DELTA.f.times.t Latch 2 for the sync shortening timing data X calculated above.
Set to 2 and start the synchronous search. However, since the rate of change of the Doppler frequency changes depending on the time and the amount of movement of the mobile body equipped with the GPS receiver, it is advisable to provide the synchronization shortening timing data with a slight margin. The above method enables high-speed, synchronous search without malfunction.

Next, a simplified method of correcting the synchronization shortening timing data will be described.

The maximum value fmax (Hz / sec) of the Doppler frequency change rate can be calculated according to the use of the GPS receiver. Further, from the cycle of switching the satellites, the time t (seconds) until the synchronization shortening timing data is collected from the latch 21 and the value is set in the latch 22 can be obtained. Therefore, the synchronization shortening timing data X can be expressed by the following expression when the synchronization shortening timing data X ′ before correction is used.

[0044]

## EQU3 ## X = X '± fmax × t However, the code is determined in the direction of advancing the phase of the PN code. According to this method, the synchronous search time is slightly longer than that of the above-mentioned method, but the synchronous search can be performed without malfunction.

FIG. 6 shows an example in which some circuits of the GPS receiver are integrated. PN code generator 7, PN code NCO
8, the frequency divider 13, the digital signal processing unit 14, the synchronization timing generator 16, and the distance measuring counter 19 can be configured by a digital circuit, so that one gate array and a custom I
The signal processing integrated circuit 25 such as C can be integrated. By integrating these circuits, downsizing, cost reduction, and low power consumption of the GPS receiver can be realized.

According to the above embodiment, the phase information of the PN code when the PN code is synchronized is stored for each satellite, and the PN code is stored by using the phase information stored when the signal from the same satellite is received next time. Since the start time of the code is set,
The time required for the synchronous search is shortened, and the cycle for switching the satellite to be received is shortened, so that the positioning cycle can be shortened.
Furthermore, since the cycle of switching the satellites to be received is shortened, the positioning accuracy of the GPS receiving device applied to a moving object is improved.

Since the above functions can be realized by adding a few circuits to the conventional 1-channel or 2-channel sequential GPS receiver, the configuration is simplified, downsizing and cost reduction are made compared with the multi-channel sequential GPS receiver. Be converted.

Next, a configuration example in which the GPS receiving apparatus to which the present invention is applied is applied to a mobile navigation apparatus is shown in FIG.
Shown in. The mobile navigation device shown in the figure is a main operation that controls a sensor and an input device to collect data, calculates a traveling position based on these data, controls an output device such as a display, and outputs a result. A unit 26, a memory 27 configured by a ROM and a RAM for storing programs of the main calculation unit, a display unit 28 for displaying a map and various information, and a voice output unit 29 for outputting route guidance and various guidance by voice. , A man-machine interface unit 30 for a user to input information, a CD-ROM device 31 for reading a recorded map and accompanying attribute information, a running distance detecting unit 32 for measuring a running distance, and a running direction. Running direction detection unit 33 and GPS receiver 34 to which the above-described invention is applied
And a data bus interconnecting these devices.

According to the mobile body navigation device having the above-mentioned structure, the GPS receiving device is used for determining the traveling position, so that the traveling position determining accuracy can be improved.

[0050]

According to the present invention, the phase information of the PN code when the PN code is synchronized is stored for each satellite, and the phase information stored when the signal from the same satellite is received next is used. Since the start time of the PN code is set, the time required for the synchronous search is shortened, and the cycle for switching the satellite to be received is shortened, so that the positioning cycle can be shortened.

Furthermore, since the cycle of switching the satellites to be received is shortened, the positioning accuracy of the GPS receiving apparatus applied to a mobile body is improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a system diagram showing a configuration of a synchronization timing generator that is a part of an embodiment of the present invention.

FIG. 3 is an explanatory diagram of an operation principle of the synchronization timing generator shown in FIG.

FIG. 4 is an operation algorithm diagram of a GPS receiving device equipped with a synchronization timing generator.

FIG. 5 is a diagram showing a correction algorithm of synchronization shortening timing data.

FIG. 6 is a configuration diagram in the case where some circuits of the GPS receiving device according to the embodiment of the present invention are integrated.

FIG. 7 is a block diagram showing another embodiment of the present invention.

[Explanation of symbols]

 1 Antenna 2 Low Noise Amplifier 3, 6, 9 Mixer 4 1st Local Oscillator 5 Bandpass Filter 7 PN Code Generator 8 PN Code NCO 10 2nd Local Oscillator 11 Lowpass Filter 12 A / D Converter 13 Divider 14 Digital Signal Processing Unit 15 Computing Unit 16 Synchronous Timing Generator 17 External Communication Unit 18 Reference Oscillator 19 Distance Measuring Counter 20 1023 Binary Synchronous Counter 21,22 Latch 23 Exclusive NOR 24 NAND 25 Signal Processing Integrated Circuit 26 Main Computing Unit 27 ROM, RAM memory 28 Display unit 29 Voice output unit 30 Man-machine interface unit 31 CD-ROM device 32 Running distance detection unit 33 Running position detection unit 34 GPS receiver

Claims (9)

[Claims] 1. A GPS receiver signal processing method for receiving a signal from a plurality of GPS satellites to determine a current position of a mobile body, wherein a PN code generated by a receiver in a PN code synchronization state is generated for each satellite. Phase information is collected and stored, and the start time of the PN code generated by the receiving device is set based on the phase information, and P having the set start time is set.
A GP characterized by performing synchronous search, synchronous acquisition, and positioning while changing the phase of the N code as a starting point and changing the phase.
S receiver signal processing method. 2. The phase information of the PN code is corrected in accordance with the Doppler frequency fluctuation, and synchronization is acquired based on the phase information,
The GPS receiver signal processing method according to claim 1, wherein positioning is performed. 3. The GPS receiving apparatus signal according to claim 2, wherein the phase information of the PN code is corrected according to the measured Doppler frequency fluctuation, and synchronous acquisition is performed based on the phase information to perform positioning. Processing method. 4. The position information is corrected by correcting the phase information of the PN code according to the Doppler frequency fluctuation calculated from the orbital data of GPS satellites and the approximate value of the self-position, and synchronously capturing based on the phase information to perform positioning. The GPS receiver signal processing method according to claim 1 or 2. 5. The maximum value data of Doppler frequency fluctuation is P
The GPS receiver signal processing method according to claim 2, wherein the phase information of the N code is corrected, the phase is acquired synchronously based on the phase information, and positioning is performed. 6. A GPS receiving apparatus for receiving a signal from a plurality of GPS satellites to obtain a current position of a mobile body, the PN code transmitted from each of the plurality of satellites,
A GPS comprising: a unit for detecting and storing phase information of the PN code transmitted from the receiving device in a synchronized state; and a unit for setting the phase of the PN code generated by the receiving device based on the phase information. Receiver 7. A means for detecting phase information of a PN code,
The GPS receiver according to claim 6, further comprising a counter that counts pulses of the reference frequency. 8. A GPS receiving apparatus for receiving a signal from a GPS satellite to obtain the current position of a moving body, a signal processing circuit, a circuit for generating a PN code and a circuit for detecting and setting phase information of the PN code. GPS provided for one integrated circuit and including the integrated circuit
Receiver. 9. A GPS receiving apparatus comprising means for detecting phase information of a PN code transmitted by a receiving apparatus with respect to a PN code transmitted from each satellite, and means for setting a phase of the PN code based on the phase information. A mobile navigation device comprising: