JP4291083B2 - Satellite positioning system and satellite positioning method - Google Patents

Description

  The present invention relates to a satellite positioning system and a satellite positioning method for obtaining a pseudo distance between a satellite and a receiver terminal based on a signal from the satellite.

  Positioning satellites travel around the earth many times, and signals are continuously transmitted at the same carrier frequency. Each satellite is assigned a PN code (referred to as a C / A code in the case of GPS) and is different for each satellite, and is continuously transmitted from each satellite as a pseudo-noise signal. Navigation data including information such as the orbit of the satellite is transmitted from the satellite, and the polarity of the PN code is inverted with this navigation data and PSK modulated with the same carrier wave and continuously transmitted.

In the case of a GPS signal, the PN code (C / A code) is 1 msec (1 millisecond) as a 1PN frame as shown in FIG. 1, and this 1PN frame is transmitted as a periodic continuous signal.
That is, the navigation data is 1 bit {20 msec (50 bps)}, and the polarity of the C / A code is inverted according to the polarity of the navigation data. That is, if the navigation data is 1, the polarity of the C / A code remains unchanged, and if the navigation data is -1, the polarity of the C / A code is also inverted.

  An assist type GPS is known as a satellite positioning system that improves reception sensitivity (see, for example, Patent Document 1). As shown in FIG. 11, the receiving unit 104 includes an RF-to-IF converter 106 having a GPS receiving antenna 105, an A / D converter 107 for converting an analog signal from the converter 106 into a digital signal, A memory (digital snapshot memory) 108 for recording the output from the A / D converter 107 and a general-purpose programmable digital signal processing circuit (hereinafter abbreviated as a DSP circuit) 109 for processing a signal from the memory 108 are provided.

  In addition, a program EPROM (ROM, memory) 110, a frequency synthesizer 111, a power regulator circuit 112, an address writing circuit 113, a microprocessor 114, a RAM (memory) 115, an EEPROM (ROM, memory) connected to the DSP circuit 109. 116) having a modem 118 with a transceiver antenna 117 and connected to a microprocessor 114;

Next, the operation will be described. The base station 101 issues a command to the receiving unit 104 to perform the measurement via the message transmitted by the data communication link 119. The base station 101 transmits the Doppler data of the satellite information for the target satellite in this message.
The Doppler data has a frequency information format, and the message specifies the target satellite. This message is received by modem 118 which is part of receiving unit 104 and stored in memory 108 coupled to microprocessor 114. The microprocessor 114 handles the transmission of data information between the DSP circuit 109, the address writing circuit 113 and the modem 118 and controls the power management function in the receiving unit 104.

  When the receiving unit 104 receives an instruction for GPS processing and Doppler information (eg, from the base station 101), the microprocessor 114 activates the power regulator circuit 112 according to the instruction. The power regulator circuit 112 provides functions to the RF-to-IF converter 106, the A / D converter 107, the memory 108, the DSP circuit 109, and the frequency synthesizer 111 via the power lines 120a to 120e. Thereby, the signal from the GPS satellite received via the GPS receiving antenna 105 is down-converted to the IF frequency and then digitized.

The signal to be processed usually corresponds to a time of 100 msec to 1 sec (or longer). Such a continuous data set is stored in the memory 108.
The DSP circuit 109 performs sword range calculation. In addition, the DSP circuit 109 performs a number of correlation operations between the locally generated reference and the received signal quickly, thereby enabling a fast Fourier transform (FFT) that enables extremely fast computation of the sword range. ) Allows the use of algorithms. The Fast Fourier Transform algorithm searches for all such locations simultaneously in parallel, accelerating the computation process.

When the DSP circuit 109 completes the calculation of the sword range for each of the target satellites, it transmits this information to the microprocessor 114 via the interconnect bus 122. The microprocessor 114 then uses the modem 118 to transmit the sword range data to the base station 101 via the data communication link 119 for the final position calculation.
In addition to the sword data, a time lag indicating the elapsed time from the initial data collection in the memory 108 to the time of transmission of the data through the data communication link 119 can be transmitted to the base station 101 at the same time. This time lag increases the ability of base station 101 to perform position calculations. This is because GPS satellite position can be performed at the time of data collection.

  Modem 118 utilizes a separate transmit / receive antenna 117 for transmitting and receiving messages over data communication link 119. It is understood that the modem 118 includes a communication receiver and a communication transmitter, both of which are alternately coupled to the transmit / receive antenna 117. Similarly, the base station 101 can use separate transmit and receive antennas 103 to transmit and receive data link messages, and therefore, the base station 101 continuously transmits GPS signals via the GPS receive antenna 102. Can be received automatically.

The position calculation in the DSP circuit 109 is expected to take several seconds or less depending on the amount of data stored in the memory 108 and the speed of the DSP circuit 109 or some DSP circuits. As described above, the memory 108 captures records corresponding to relatively long times.
Effective processing of large blocks of data using the first convolution method contributes to the performance of processing signals at low reception levels (for example, when reception levels decrease due to significant obstruction by buildings, trees, etc.) ). All sword ranges for visible GPS satellites are calculated using this same buffered data. This has improved performance for continuously tracking GPS receivers in situations where the amplitude of the signal changes rapidly (such as an urban fault condition).

  For the signal processing performed in the DSP circuit 109, the purpose of the processing is to determine the timing of the received waveform with respect to the locally generated waveform, and to obtain higher sensitivity, a very long portion of the waveform, Usually, the part from 100msec to 1sec is processed. The received GPS signal (C / A code) is composed of 1023 bits = 1 msec repetitive sword random (PN frame).

  Therefore, the previous and next PN frames are added to each other. For example, there are 1000 PN frames per second, so the first frame is added coherently to the next second frame and the resulting is added to the third frame. Hereinafter, as shown in FIG. 12 (A) to FIG. 12 (E), they are sequentially added. As a result, a signal having a duration of 1PN frame = 1023 bits is obtained. By comparing the phase of this sequence with the local reference sequence, the relative timing between the two, that is, the sword range (pseudorange) can be determined. Signal processing performed in the DSP circuit 109 will be described with reference to FIG.

  FIG. 12 is different from an actual GPS signal, and is drawn as a pseudo explanatory diagram for explanation. In the interval (20 msec) where the navigation data is 0 (-1) or 1, 20 frames (20 C / A code periods) actually exist, but for the sake of explanation, it is shown as 4 frames. In FIG. 12A, the phase of each frame (FRAME: 1 msec) is reversed between DATA = 0 and DATA = 1. In this state, a GPS signal (C / A code signal) is input to the receiving antenna.

FIG. 12B is an explanatory diagram when a GPS signal (C / A code signal) is extracted from a rising point (data head) at which DATA becomes 0. It should be noted that this figure is captured at the timing of a special condition written for easy explanation.
That is, it is a diagram when a very special condition is established when the data is captured from the rising point where DATA becomes 0 (the leading portion of the data). The operation shown in FIG. 12 (B) starts taking a received signal (C / A code) from a certain point of time, and adds and averages the received signal (C / A code) for every four frames.

  However, it should be noted that if the received signal (C / A code) starts from the beginning of the first DATA = 0 frame 2 (FRAME 2), the result of addition and averaging is zero. Actually, it is almost impossible to successfully extract from the head of DATA when the receiver starts to acquire signals. In other words, it is actually to start taking data from the middle of the navigation data and from the middle of the frame.

  In FIG. 12 (B), the continuous reception signals captured from a certain point in time are synchronously added every four periods (four C / A codes) and averaged. Next, FIG. 12C shows the correlation calculation result of the replica PN code (replica C / A code) inside the receiver and the result of FIG. The polarity of the peak value of the correlation calculation is positive if the polarity of the result of synchronous addition in FIG. 12B and the polarity of the replica PN code in the receiver match, and negative if they are different.

  FIG. 12 (D) shows a diagram of the absolute value of the correlation result of FIG. 12 (C). That is, the absolute value of each correlation calculation is taken in FIG. In FIG. 12E, each correlation calculation obtained with an absolute value is synchronously added. The sensitivity (S / N) is improved by adding the PN (C / A code) signal, which is a periodic signal, many times by the above synchronous addition and correlation calculation.

Other conventional satellite positioning systems include the following.
The C / A code of the GPS reception signal is temporarily stored in a memory for a certain period of time by an A / D converter. This C / A code signal has a place where the polarity is inverted by GPS navigation data. In this patent, the C / A code signal buried in noise is obtained from the external navigation data in order to emerge from the noise, and the synchronous addition and correlation calculation are performed with the C / A code signal having the same polarity. To perform high-sensitivity reception.

  In this system, navigation data is received from a server of an external base station into a receiver terminal via a communication line and received at the receiver terminal, and the phase of the navigation data and the C / A code signal in the received signal of the receiver terminal are added. The phase of the C / A code signal is completely matched, and the polarity of the received PN code is changed with this navigation data to make all the C / A code signals have the same polarity. Is gaining super sensitivity by making it appear in the noise.

  In this system, the phase of the C / A code signal in the received signal received by the server of the external base station and the receiver terminal and the phase of the navigation data obtained by incorporating the navigation data from the server of the external base station into the receiver via the communication line. Does not match. The reason is that there are variations and delays in communication time in the communication line.

For this purpose, the GPS terminal of the GPS positioning system sends its own time signal to a time server that outputs an accurate time signal, and receives the time signal from this time server so as to know the communication time to the time server. .
By knowing this communication time, the phase difference of the navigation data taken from the server of the external base station to the receiver via the communication line is reduced as much as possible, and the navigation data from the outside is scanned to determine the phase difference. They are completely matched (for example, see Patent Document 2).
US Pat. No. 5,663,734 US Pat. No. 6,329,946

The conventional GPS positioning system is configured as described above. However, the phase of the PN signal included in the GPS received signal is inverted in the navigation data section and polarity depending on the content of the navigation data.
For this reason, in such processing, the polarity of the PN signal changes depending on the navigation data. Therefore, when synchronous addition is performed according to the polarity of the PN signal, the signal components cancel each other out in the process of FIG. N) There was a drawback that it was not sufficient for improvement. In other words, the boundary of polarity reversal of navigation data was not detected. Therefore, there is a problem that the improvement in sensitivity (S / N) is insufficient.
Also, taking the absolute value of the correlation calculation value in the process of FIG. 12 (D) and FIG. 12 (E) and performing synchronous addition does not lead to the reduction of white noise itself, so the sensitivity (S / N) is not improved. There is a problem that it is sufficient.

  Further, in the conventional GPS positioning system (Patent Document 2), when synchronous addition is performed, signal components cancel each other out in the process of FIG. 12B due to the polarity of the PN signal, which is not sufficient for improving the sensitivity (S / N). The problem of not being solved. Specifically, in order to make the polarity of the received signal (PN signal) the same, the navigation data is received from the base station, and the received signal (PN signal) is multiplied to make the polarity the same. Then, by performing synchronous addition, an ideal noise reduction effect is obtained.

  However, it has the following problems. In this case, the communication time from the base station to the receiver terminal is not zero. When the communication line is the Internet or packet communication, etc., the communication time also varies considerably and the phase error becomes extremely large, so the scan time also increases, and therefore the delay variation in the communication line becomes the position measurement response time. It will be greatly involved. That is, in order to realize high-sensitivity positioning, there is a serious drawback that the receiver cannot be measured with a practical response time unless strict requirements are imposed on the communication time standard in the communication line.

  Accordingly, the present invention provides a satellite positioning system and satellite positioning that can receive a signal from a satellite in a building or the like, that is, an attenuated satellite reception signal, and can know the reception position with high sensitivity and good response. A method is provided.

The satellite positioning system according to the present invention is a satellite positioning system in which a receiver terminal receives a signal from a satellite, and the receiver terminal obtains a pseudorange with the satellite by the received satellite reception signal. the receiver terminal includes a pseudo pattern portion previously stored to generate a plurality of types of pseudo patterns for polarity changes for changing shifting the polarity of the PN signal by 1msec containing carrier component of 20msec the satellite received signal, said A storage unit for storing a replica PN code including a carrier wave component for demodulating the satellite reception signal, and a plurality of types of pseudo patterns acting on the same satellite reception signal of 20 msec to change the polarity of the PN signal including the carrier wave component in the satellite reception signal a first arithmetic unit for obtaining a plurality of polarity changing PN signal is varied by shifting by 1 msec, and a second arithmetic unit for adding each synchronization for each polarity changing PN signal A third arithmetic unit that performs correlation calculation between the respective synchronous addition PN signal and the replica PN code synchronous addition, detection by the delay and the delay value corresponding to the correlation peak value and a correlation peak value from results of correlation calculations And a pseudo distance detecting device for obtaining the pseudo distance from the value.

Also, the receiver terminal is one that is configured to process as a value obtained by discretizing at a predetermined sample interval the PN signal including carrier components of one frame.

The satellite positioning method according to the present invention is a satellite positioning method in which a receiver terminal receives a signal from a satellite, and the receiver terminal obtains a pseudorange with the satellite based on the received satellite reception signal. The receiver terminal applies a plurality of types of pseudo patterns for polarity change prepared in advance by the receiver terminal to the same satellite received signal of 20 msec to change the polarity of the PN signal including the carrier component in the satellite received signal. obtaining a plurality of polarity changing PN signal is changed by shifting by 1 msec, respectively synchronously adding for each polarity changing PN signal replica including a carrier wave components each synchronous addition PN signal and said receiver terminal obtained by adding synchronization is prepared in advance Correlation calculation is performed with the PN code, a correlation peak value and a delay value corresponding to the correlation peak value are detected from the result of the correlation calculation, and the pseudo distance is obtained from the delay value.

Also, the receiver terminal is treated as a value obtained by discretizing the PN signal at a predetermined sample interval containing a carrier component for one frame.

According to the present invention, the polarity of the received PN signal including the carrier component is made identical by the pseudo pattern inside the receiver terminal, so that the sensitivity (signal-to-noise ratio) can be significantly improved by synchronous addition and correlation calculation.
As in the prior art, GPS navigation data from an external base station is not required to detect the phase inversion boundary of the C / A code signal based on the navigation data, and the navigation data of the signal received inside the receiver terminal Since it is not necessary, a PN signal including a carrier wave component buried in noise can be detected with significantly improved S / N.
In other words, the PN signal can be efficiently raised from the noise, and the pseudorange with the satellite can be accurately and responsive even in places where GPS signals (GPS radio waves) are significantly attenuated, such as in buildings or buildings. Measure well.

FIG. 1 is an explanatory diagram illustrating a PN signal (C / A code) structure in a GPS satellite reception signal, and FIG. 2 is a block diagram illustrating an overview of a satellite positioning system.
In the present invention, the received PN signal is described as a carrier wave superimposed. That is, in the following, the PN signal is a PN signal including a carrier wave component.

The present invention is a satellite positioning system and method in which a signal from a satellite S is received by a receiver terminal 11 and the receiver terminal 11 obtains a pseudorange between the satellite S and the received satellite received signal.
In FIG. 2, S ₁ , S ₂ , S ₃ , and S ₄ are target positioning satellites that travel around the earth, and 1 is a base station. The base station 1 includes a receiving antenna 2 installed in an environment with a good view, and a GPS signal is received by a GPS reference signal server receiver 3.

  The GPS reference signal server receiver 3 extracts Doppler information 4 from the received satellite reception signal (GPS signal). Further, the base station position, each satellite position, and the pseudo distance between each satellite and the receiving antenna 2 position are extracted. These pieces of information are transmitted to the receiver terminal 11 by the transmitter 5 via the communication means L. This transmission is generally performed by broadcasting. The communication means L may be a mobile phone line, terrestrial broadcast, or satellite broadcast. Or you can use the internet line, and all possible means (by electromagnetic means) are covered.

11 is a GPS receiver terminal. The Doppler information 4 and information on the base station position, each satellite position, and the pseudo distance 6 between each satellite and the base station are received by the receiving unit 12 of the GPS receiver terminal 11 from the base station 1.
If the frequency of the broadcast radio wave is a frequency band near the GPS radio wave (signal), the receiving unit 12 may be shared with the GPS receiving unit 13. In the present invention, it is assumed that many terminals 11 receive simultaneously by means of communication means L (line, broadcast, mobile phone, Internet, etc.). FIG. 2 shows one GPS receiver terminal 11.

Reference numeral 14 denotes an antenna unit of the GPS receiver terminal 11. The location of the GPS receiver terminal 11 (antenna unit 14) is not only where the satellite S can be directly seen, but also the strength of GPS radio waves, such as in the shade of trees (inside outdoor reception) and in buildings. We assume weak places.
The reception unit 13 is an A / D conversion portion that converts an analog signal of a GPS reception signal --- a PN signal including a carrier wave component--to a digital signal. The PN signal including the digitized carrier wave component is stored in a memory (RAM) 15---GPS signal storage unit-.
The above configuration is widely used in general with conventional GPS technology, and detailed description thereof is omitted.

The receiver terminal 11 included in the satellite positioning system of the present invention includes a first calculation unit 8 that applies the pseudo pattern A to the satellite reception signal to change the polarity of the PN signal including the carrier wave component in the satellite reception signal, and the polarity. A second arithmetic unit 9 for synchronously adding the changed PN signal; a third arithmetic unit 10 for performing a correlation calculation with the synchronously added PN signal and the replica PN code including the carrier wave component; A pseudo distance detecting device 19 for detecting a peak value and a delay value corresponding to the correlation peak value and obtaining a pseudo distance from the delay value.
Hereinafter, the first calculation unit 8 is referred to as a polarity changing device 17, and the second calculation unit 9 and the third calculation unit 10 are referred to as a synchronous addition / correlation calculation device 18.

And the Example in the case of accumulating the GPS signal of a 20 msec area is demonstrated. As will be described later, the present invention can be applied to any accumulation time.
Of the signals from successive satellites S, the 20 msec section has the same time as the 1-bit section of the navigation data.
In FIG. 2, reference numeral 21 denotes a signal processing unit included in the receiver terminal 11. Among them, the Doppler correction unit 16, the polarity change device 17, the synchronous addition / correlation calculation device 18, and the pseudo distance detection device 19 indicate functional blocks, and the signal processing unit 21 stores the polarity of the accumulated PN signal for 20 msec (+ − ) Are all made identical, and the pseudo-range is obtained by performing synchronous addition and correlation calculation.

  The PN code polarity changing device 17 is a 20 msec satellite reception signal that is stored in the memory 15 with 20 types of pseudo patterns A for changing the polarity of the satellite reception signal prepared (stored) in the pseudo pattern section 22. It is a device that acts on a PN signal that contains components, changes the polarity of the signal, and changes the polarity of the accumulated signal. That is, as will be described later, the polarity of the PN signal including the carrier wave component accumulated in the memory 15 by the PN code polarity changing device 17 is changed in each of the 20 types of pseudo patterns A.

  Then, the synchronous addition / correlation calculation device 18 performs synchronous addition and correlation calculation on the PN signal including the respective carrier components. Thereafter, the pseudorange detection device 19 detects the pseudorange between the receiver terminal 11 and the satellite S by detecting a value (delay value τ) at which the correlation calculation peak value becomes the maximum value. The detected delay value τ is equal to the result of synchronous addition and correlation calculation using 20 msec data in which the polarities of the PN signals are all the same.

With the PN signal having the same polarity within 20 msec, noise reduction by synchronous addition and correlation calculation is maximally improved. The pseudo distance detection device 19 detects the pseudo distance in a state in which the noise reduction is improved to the maximum by making the polarity of the PN signal within 20 msec the same.
The position calculation device 20 can know the self-position of the receiver terminal 11 based on the pseudo distance obtained here and the information on the base station position from the receiving unit 12, each satellite position, and the pseudo distance between the base station and each satellite. it can.

FIG. 3 is a detailed hardware block diagram of the GPS receiver terminal 11. The code | symbol of each block of FIG. 2 respond | corresponds with the code | symbol of the block of FIG. The Doppler correction unit 16, the polarity changing device 17, the synchronous addition / correlation calculation device 18, the pseudo distance detection device 19, and the position calculation device 20 in FIG. 2 are functional blocks.
The means for configuring the functional block may be a hardware configuration, a software configuration, or a mixed configuration. The signal processing unit 21 shows a hardware configuration for executing software processing, which is means for configuring this functional block.

  In FIG. 3, 14 is a receiving antenna unit, 13 is a GPS receiving unit, a high frequency amplification unit 32, a frequency conversion unit 33 that down-converts the frequency, a frequency synthesizer unit 34, an I signal conversion unit 35, a Q signal conversion unit 36, 90 degree phase shifter 37, A / D converters 38 and 39, 15 a memory (RAM) for temporarily storing information, 21 a signal processing unit, DSP unit 41, CPU unit 42, a pseudo pattern portion (ROM) 22 for storing or generating a pseudo pattern A, a DSP ROM 44, a RAM 45, and a ROM 46 of the DSP portion 41, and a storage portion 7 connected to the CPU portion 42. Reference numeral 12 denotes a receiving unit for obtaining information from the base station 1 of FIG. Further, the memory arrangement in the RAM 45 of the signal processing unit 21 is shown in FIG.

Next, an outline of the operation in FIG. 3 will be described.
A 1.5 GHz _Z band GPS signal that has been subjected to spread spectrum modulation with a PN signal is received by the high frequency amplifier 32 from the receiving antenna unit 14. The signal is down-converted by the frequency synthesizer unit 34 and the frequency conversion unit 33 and converted into, for example, a frequency region of 70 MHz band. The frequency synthesizer unit 34 and the 90-degree phase shifter 37 multiply by the carrier of 70 MHz having a phase difference of 90 degrees, that is, the I and Q PNs orthogonal to each other in the I signal conversion unit 35 and the Q signal conversion unit 36. The code is extracted.
This operation is shown in FIG. FIG. 5 is a diagram showing an outline of operations of the I signal conversion unit 35 and the Q signal conversion unit 36. In FIG. 5, the I signal conversion unit 35, the Q signal conversion unit 36, the phase shifter 37, the A / D converter 38, A The / D converter 39 and the memory 15 correspond to the reference numerals in FIG.
47 and 48 are multipliers. 49 and 50 are band filters (band pass filters).

  The GPS reception signal down-converted to the 70 MHz band by the frequency conversion unit 33 is represented by PN.cos ((w + Δw) t + Φ). Δw is the Doppler frequency. Δw is a combination of the Doppler frequency fluctuation of the satellite signal captured by the antenna unit 14 and the frequency fluctuation of the frequency synthesizer 34. Here, the description will be made assuming that there is no frequency variation of the frequency synthesizer 34. In this case, Δw is only the Doppler frequency fluctuation of the satellite signal captured by the antenna unit 14.

The signals from the frequency synthesizer unit 34 in FIG. 3 and signals having a phase difference of 90 degrees in the 90-degree phase shifter 37 are carrier waves cos (w ₁ t) that are orthogonal to each other when the angular frequency from the frequency synthesizer unit 34 is w _1. , Sin (w ₁ t). When these orthogonal signals and the signal PN.cos ((w + Δw) t + Φ) from the frequency converting unit 33 are multiplied by multipliers 47 and 48 and passed through bandpass filters 49 and 50, PN.cos ((w + w ₁ + Δw) t + Φ), −PN.sin ((w + w ₁ + Δw) t + Φ) is obtained. These conversions are generally used as I and Q converters.

  These orthogonal signals (analog signals) are converted from analog signals into digitized discretized signals by A / D converters 38 and 39, respectively. These two signals are stored in the memory (RAM) 15 for 20 msec (the length of the navigation data 1-bit section). Each of the high frequency amplification unit 32, frequency conversion unit 33, synthesizer unit 34, I signal conversion unit 35, Q signal conversion unit 36, phase shifter 37, A / D converter 38, and A / D converter 39 described above is as follows. It is general purpose and generally used widely.

  The (digital) signal processing unit 21 in FIG. 3 has a CPU unit 42 connected to the receiving unit 12, a memory (RAM) 45 connected thereto, and a memory (ROM) in order to take in the data obtained through the receiving unit 12. 46, a DSP unit 41 connected to a memory (RAM) 45, a memory (ROM) 44 connected to the DSP unit 41, and a pseudo pattern unit 22. The pseudo pattern portion 22 is a storage portion (ROM) of a pseudo pattern stored in advance. The CPU unit 42 and the DSP unit 41 are connected to each other. The CPU unit 42, the RAM 45, and the ROM 46 operate as a microprocessor.

  The ROM 46 is a part that also stores a digital signal processing execution program, and the configuration of the hardware part of the digital signal processing unit 21, that is, the DSP unit 41, the CPU unit 42, the RAM 45, the ROM 46, and the ROM 44 is a conventional CPU, A general-purpose digital signal processing configuration using a DSP and a memory (RAM, ROM) is widely used and known.

  Then, the digital signal processing unit 21 causes the functional blocks of the Doppler correction unit 16, the polarity changing device 17, the synchronous addition / correlation calculation device 18, the pseudo distance detection device 19, and the position calculation device 20 shown in FIG. A case where this functional block is executed by digital signal processing by software will be described.

FIG. 8 is a diagram for explaining functional block operations of the polarity changing device 17, the synchronous addition / correlation calculating device 18, and the pseudo distance detecting device 19 in FIG.
The pseudo pattern A of the pseudo pattern portion 22 is a set of 20 patterns from A ₁ to A ₂₀ in FIG. This pseudo pattern A is a 20-bit pattern composed of a combination of a continuous 0 data string such as [0000...] And a continuous 1 data string such as [1111. The sum of 1 and 1 consists of 20 bits. That is, A ₁ to A ₂₀ are pseudo patterns A each consisting of 20 bits.

An example of the pseudo pattern A will be described below with respect to A ₁ to A _{20 in} FIG. A ₁ is _one 0 and the other 19 bits are a continuous data string [0111... 1]. A ₂ is a continuous data string of 2 bits, and the other 18 bits are a continuous data string of 1 [0011... 1]. That is, if k is any integer from 1 to 20, Ak is a data string of 0 with k bits continuous and a data string of 1 with (20−k) bits continuous. As another example, these pseudo patterns A may be 1 instead of 0 and -1 instead of 1.

Next, the operation of the digital signal processing unit 21 will be described.
FIG. 7 shows a flowchart for executing the functional blocks of the digital signal processing unit 21 in FIG. 2 by software. In FIG. 7, the Doppler correction unit 16, the polarity changing device 17, the synchronous addition / correlation calculation device 18, the pseudorange detection device 19, and the position calculation device 20, which are functional blocks, correspond to the functional blocks in the digital signal processing unit 21 in FIG. 2. is doing.
F ₁ to F _{10 in} FIG. 7 are software blocks (processes) processed by the respective functional blocks.

First, a received signal of 20 msec is fetched from the memory 15 (process F ₁ ). Digital data 0.5PN.cos ((w + Δw + w ₁ ) t + Φ), −0.5PN.sin ((w + Δw) stored in the memory 15 from the A / D converters 38 and 39 in FIG. + w ₁ ) t + Φ) contains the Doppler component. Next, the Doppler frequency Δw is taken from the outside (base station 1) (step F ₂ ).
The Doppler frequency Δw can be obtained from the base station 1 (server) in FIG. 2 by the receiving unit 12 of the GPS receiver terminal 11. This Δw is received by the CPU unit 42 and stored in the RAM 45.

Next, Doppler correction is performed by the following algorithm (step F ₃ ). Digital data of discretized I and Q signals stored in the memory 15 with Doppler correction information Δw 0.5PN.cos ((w + Δw + w ₁ ) t + Φ), −0.5PN.sin ((w + Δw + w FIG. 6 shows an operation for performing Doppler correction on ₁ ) t + Φ.
FIG. 6 is a functional block diagram performed by a program. 26, 27, 28, and 29 are multipliers, 30 is an adder, and 31 is a subtractor. t is a discretized value and is t = 0: Δt: W × T, and t is a value discretized from 0 to W × T at a sample interval Δt. Sampling frequency is fKHz. Here, f = N will be described. T = 1 msec; W = 20. The sampling interval Δt is Δt = 1 / f.

The discretized I signal and Q signal (data) stored in the memory 15 in FIG. 5 are input signals 0.5PN.cos ((w + Δw + w ₁ ) t + Φ), − as shown in FIG. 0.5PN.sin ((w + Δw + w ₁ ) t + Φ)
These signals are multiplied by cos (Δwt) and sin (Δwt) from the Doppler frequency Δw obtained from the receiving unit 12 by the multipliers 26, 27, 28, and 29, and then passed through the adder 30 and the subtractor 31. And −0.25PN.sin ((w + w ₁ ) t + Φ) and 0.25PN.cos ((w + w ₁ ) t + Φ) are obtained.

The multipliers 26, 27, 28, 29, the adder 30, and the subtractor 31 can be easily realized by a program (calculation means). That is, the following calculation is performed.
The digital signal PN.cos ((w + Δw + w ₁ ) t + Φ), −PN.sin ((w + Δw + w ₁ ) t + Φ) of the I and Q signals is converted to SIin = −0.5PN.sin (( w + Δw + w ₁ ) t + Φ), SQin = 0.5 PN.cos ((w + Δw + w ₁ ) t + Φ), −SIin × cos (Δwt) + SQin × sin (Δwt), SQin × cos (Δwt) Calculate −SIin × sin (Δwt). Then, the calculation result as _{-0.25PN.sin ((w + w 1)} t + Φ), 0.25PN.cos ((w + w 1) t + Φ) is obtained.
The thus obtained I and Q PN signals orthogonal to each other are stored in the memory units 51 and 61 of FIG. 4 (step F ₄ ). This accumulated data does not include the Doppler component Δw.

  FIG. 9 shows an example of data in which one of the I and Q signals is accumulated. FIG. 9 consists of a matrix of 20 rows and N columns. In this figure, one row and N column on the horizontal axis corresponds to one cycle of the PN signal for one row of N because one cycle (1 msec) of the PN signal (C / A code) is sampled at NKHz. That is, one row is one period of the PN signal (corresponding to one frame). And since 20msec data is collected, it shows that it consists of 20 lines.

These matrixes will be described below by defining the matrix with the following expression. D (M1: M2, N1: N2) is defined as a matrix from the M1st row to the M2th row and from the N1th column to the N2th column. NI: N2 is described as indicating a natural number from N1 to N2. D (A, B: C) indicates columns B to C in row A. Therefore, the matrix in FIG. 9 can be expressed as D (1: 20,1: N) (FIG. 9 indicates N = 204600). ).
The operation of obtaining the results of synchronous addition and correlation calculation by making the PN polarities the same for the discretized I and Q PN signals (data) of 20 rows and N columns will be described below. The synchronous addition and the correlation calculation are performed on a PN signal including a carrier component (carrier).
That is, the operation of the polarity changing device 17, the synchronous addition / correlation calculating device 18, and the pseudo distance detecting means 19 in the flowchart of FIG.

This operation will be described with reference to FIG. Although the blocks in FIG. 8 are actually the same blocks for the I signal and Q signal, and the operations are the same, only one of the signals will be described here.
In FIG. 8, 22 is a pseudo pattern portion. A ₁ , A ₂ ,..., A ₂₀ are a set of 20 pseudo patterns, and A ₁ to A ₂₀ are pseudo patterns consisting of data obtained by shifting 0 one by one from the left as shown in the figure. .
6 outputs −0.25PN.sin ((w + w ₁ ) t + Φ) and 0.25PN.cos ((w + w ₁ ) t + Φ) are stored in the memory units 51 and 61 (FIG. 4). ing. The following _{0.25PN.cos ((w + w 1)} t + Φ) signals will be described _{(-0.25PN.sin ((w + w 1} ) t + Φ) operate for the same).

P ₁ to P ₂₀ are multiplications for multiplying each row of the PN signal (here, 0.25PN.cos ((w + w ₁ ) t + Φ)) as an input signal by a set of pseudo patterns A ₁ to A ₂₀ respectively. It is a vessel. However, the value of 0 of the data of each pseudo pattern A ₁ ... A ₂₀ is multiplied by −1 and multiplied in the multiplication. In other words, the pseudo patterns A ₁ to A ₂₀ are multiplied by D (1: 20,1: N) in FIG. 9 (20 rows in total). The multiplication will be described below. The value 0 is replaced with -1. Multiplying by -1 means that the polarity of the PN signal (code) is inverted because the sign is inverted. When multiplying by 1, it means that the polarity does not change.

The pseudo patterns A ₁ to A ₂₀ are represented by A ₁ (1: N), A ₂ (1: N), A ₃ (1: N),... A ₂₀ (1: N), respectively. The multiplier P ₁ multiplies each row of D (1: 20,1: N) in FIG. 9 by the _first pseudo pattern A ₁ . That D: A ₁ in (1,1 N) (1) = 0, D (2,1: N) to _{A 1 (2) = 1,} D (3,1: N) to A ₁ (3) = 1 ... D (20,1: N) is multiplied by A ₁ (20) = 1. As a result, D1 (1:20, 1: N) is stored in the memory unit R ₁ (FIG. 10).

The multiplier P ₂ multiplies each row of D (1: 20,1: N) by the following pseudo pattern A ₂ . That the D: _{(1,1 N) A 2 (1} ) = 0, D (2,1: N) to the _{A 2 (2) = 0,} D (3,1: N) to the A ₂ (3) = 1 ... D (20,1: N) is multiplied by A ₂ (20) = 1. As a result, D2 (1:20, 1: N) is stored in the memory unit R ₂ (FIG. 10).
Similarly, the same calculation is repeated, and the multiplier P ₁₉ multiplies each row of D (1: 20,1: N) by the pseudo pattern A ₁₉ . That D (1,1: N) to the _{A 19 (1) = 0,} D (2,1: N) to the _{A 19 (2) = 0,} D (3,1: N) to A ₁₉ (3) = 0,... D (20,1: N) is multiplied by A ₁₉ (20) = 1. Consequently D19 (1: 20,1: N) to be stored in the memory unit R _19.

The multiplier P ₂₀ multiplies each row of D (1: 20,1: N) by the pseudo pattern A ₂₀ . That _{D: A 20 (1) =} 0 in (1,1 N), D: the _{(2,1 N) A 20 (2} ) = 0, D (3,1: N) to A ₂₀ (3) = Multiply 0,... D (20,1: N) by A ₂₀ (20) = 0. Consequently D20 (1: 20,1: N) to be stored in the memory unit R _20.
As shown in FIG. 10, the multiplication results are as shown in FIG. 10. Each of the 20 rows and N columns of data D1 (1: 20,1: N), D2 (1: 20,1: N), D3 (1: 20,1 : N),... D20 ( _1:20 , ₁ : N) are stored in the memory units 52 and 62 in FIG. 4 as memory units R ₁ , R ₂ ... R ₁₉ and R ₂₀ (step F ₅ ).

  Next, synchronous addition is performed for each of these 20 rows and N columns of data. In general, synchronous addition is widely known as a method for reducing noise in a periodic signal in a digital signal processing circuit. To describe this calculation, in general, when one cycle of a periodic signal is sampled with s sampling pulses and data for m cycles is obtained, data of D (1: m, 1: s) can be obtained ( s is the number of samples, m is the number of additions). At this time, the synchronous addition average result of the Mth row is expressed by the equation (1).

  Assuming that the noise superimposed on the signal is Gaussian with a statistical property, the noise component is known to be reduced to 1 / √m by m additions. In the embodiment of the present invention, m = 20. Therefore, noise reduction by the synchronous addition of the present invention is 1 / √20.

The results of synchronous addition are stored in the memory units R ₁ , R ₂ ... R _{20 in} FIG. Further, the synchronous addition result memory unit R ₁ U _1: as (1, 1 N), the synchronous addition result memory unit _{R 2 U 2 (2,1: N} ) as, ... synchronous adding memory unit R ₂₀ The result is stored as U ₂₀ (20, 1: N) as a whole in the memory units 53 and 63 in FIG. 4 (step F ₆ ).
Then, the correlation calculation is performed between each of the 20 sets of data of each 1 row and N column and the replica PN code including the carrier wave component that the receiver terminal 11 of FIG. 8 has in advance. The replica PN code and the correlation calculation are widely known contents, but will be briefly described below.

In general, a plurality of GPS satellites S travel around the earth, and each satellite S performs a spread spectrum modulation using a 1575.42 MHz carrier wave with a PN signal (also called a C / A code) corresponding to each individual satellite S. Sending on earth.
For example, it is assumed that 1575.42 MHz is transmitted with spectrum spread modulation by satellite S _{1 using} PN signal a and satellite S _{2 using} PN signal b. In order to take out (demodulate) the signal of the satellite S ₁ at the receiver terminal 11, the receiver terminal 11 side stores in advance the PN signal a 'identical to the PN signal a, and the PN signal a' is used to store the satellite. In S ₁ , the receiver terminal 11 demodulates the PN signal a.

In order to receive the satellite S ₂ , the same PN signal b ′ as the PN signal b must be stored in advance on the receiver terminal 11 side. Therefore, if the receiver terminal 11 does not have all the PN signals corresponding to each satellite S emitted from each satellite S in advance, the signal of each satellite S cannot be received. In the present invention, the PN signal prepared in advance is used as a replica PN code including a carrier wave component.
Each replica PN code corresponding to each GPS satellite S (which demodulates the satellite reception signal) is stored in advance in the ROM 46 of the signal processing unit 21 provided in the GPS receiver terminal 11. Yes.

  In general, when data X is x (n) (where n = 0: N), data Y is h (n) (where n = 0: N), k is an integer, and 0 ≦ k ≦ N, Equation 2 It is expressed as

  Then, y (1), y (2), y (3)... Y (N) is calculated. Here, in the calculation of y (k), the number of data additions is N. Accordingly, it is known that the noise component is reduced to 1 / √N by adding N times if the noise superimposed on the signal at this time is Gaussian with a statistical property. Therefore, the noise reduction by this calculation is 1 / √N. This calculation is called correlation calculation. (Equivalent correlation calculation is a well-known method that uses FFT as a high-speed operation. Here, a general calculation method is shown for explaining the principle.)

If y (1), y (2), y (3) ... y (N) are the absolute values of y (nn), the absolute value of y (nn) Is a correlation peak value (where 0 ≦ nn ≦ N). Nn at this time is called a delay amount τ. Further, obtaining the delay amount τ and the peak value y (nn) is called obtaining the correlation peak.
If the data X is x (n) obtained by synchronously adding a signal m times, the noise reduction amount is expressed by the equation (3) by this correlation calculation.

In the present invention, the PN signal is x (n), the replica PN code is h (n), m is the number of synchronous additions, N is the number of samples for one period of the PN signal, and m = 20, N = 204600 as an embodiment. Is assumed.
Therefore, only by acquiring GPS data of 20 msec, the noise reduction amount can bring about the effect of the result of the above equation (3). That is, the delay amount τ can be obtained even for a very weak signal that is muddy by noise.

As a result of synchronous addition, 20 sets of data of U ₁ (1,1: N), U ₂ (2,1: N), U ₃ (3,1: N)… U ₂₀ (20,1: N) are Are stored in the memory units 53 and 63, and the correlation calculation unit C performs correlation calculation using each of the 20 sets of data in each of the 1 row and N columns and the replica PN code having the carrier wave component of FIG. . That is, the correlation calculation unit C ₁ calculates the correlation between the synchronous addition result U ₁ (1,1: N) of the synchronous addition unit U and the replica PN code. Then, 1-row N-column data C ₁ (1,1: N), which is a result of the correlation calculation in the correlation calculation unit C ₁ , is stored. Similarly, the correlation calculation result C ₂ (2,1: N) of the correlation calculation unit C ₂ is stored, this is sequentially repeated, and the correlation calculation result C ₂₀ (20,1: N) of the correlation calculation unit C ₂₀ is repeated. Remember.
Although the correlation calculation of the I signal is performed, the same calculation is performed for the Q signal.

The correlation calculation result of the I signal is stored in the memory unit 54 (FIG. 4), and the stored data is expressed as C-I (1:20, 1: N).
Further, the correlation calculation result of the Q signal is stored in the memory unit 64 (FIG. 4), and the stored data is expressed as CQ (1:20, 1: N).
Next, I signal and Q signal are synthesized. A matrix of C-IQ (1:20, 1: N) synthesized from C-I (1:20, 1: N) and C-Q (1:20, 1: N) is created.
That is, the data in the terms of the x-th row and the z-th column of C-I (1:20, 1: N) and C-Q (1:20, 1: N) [{C-I (x, z)} ² + {CQ (x, z)} ² ] ^0.5 is calculated, and the result is calculated as the data in the x-th column and the z-th column of C-IQ (1: 20,1: N). To do.
The results of the same calculation for x = 1: 20 and z = 1: N are set as C-IQ (1:20, 1: N) and stored in the memory unit 70 (FIG. 4).

The operation of the pseudo distance detection device 19 in FIG. 8 will be described. Pseudorange detecting device 19 C-IQ stored in it memory unit 70 a result obtained by the correlation calculation section _{C 1, C 2 ... C 20} (1: 20,1: N) , and 20 rows N Searches for data with the maximum absolute value in the column data. That is, if the absolute value of C-IQ (z, τ) is maximum, the absolute value of the correlation peak value C-IQ (z, τ) obtained in C-IQ (z, 1: N) and the delay The quantity τ is the detection result.

If this delay amount τ is obtained, a pseudo distance (a distance between the satellite S and the GPS receiver terminal 11) can be obtained from the delay amount τ. The means for obtaining the pseudo distance from the delay amount τ is generally well known and can be easily realized.
Thereafter, in the block of the position calculation device 20 in FIG. 2, information on the base station position from the base station 1, each satellite position, and the pseudorange between each satellite and the base station is acquired by the receiver 12 of the receiver terminal 11. Self-position is determined. In addition, the position calculation device 20 is generally well known and can be easily realized from the pseudorange obtained here, the base station position, each satellite position, and the pseudorange between each satellite and the base station. .

  In the above operation, in order to obtain the delay amount τ, synchronous addition and correlation calculation are performed with the PN polarity being made identical to the maximum for a discrete GPS reception signal (PN code) of 20 rows and N columns. This is equivalent to obtaining the delay amount τ. As an example, m = 20 and N = 204600, which is equivalent to obtaining the delay amount τ with the same PN polarity only by acquiring a GPS signal of 20 msec (corresponding to the time of 1 bit of navigation data). Therefore, the noise reduction amount can produce an effect close to the result of the equation (4). That is, the delay amount τ can be obtained even for a very weak signal that is muddy by noise. Therefore, position measurement is possible even with a very weak signal.

In a GPS positioning system, in the past, it was almost impossible to determine its own position in a building or the like. However, according to the present invention, the sensitivity that can be received by the GPS receiver terminal 11 has been referred to as impossible in the past. Even if the signal is very weak, such as in a building, the sensitivity can be dramatically improved and position measurement is possible.
In addition, ultra-high sensitivity is realized only by acquiring GPS data of 20 msec (corresponding to 1-bit time of navigation data) basically. In the acquired GPS data of 20 msec (corresponding to the time of 1 bit of navigation data), 20 pseudo patterns A are prepared in advance, and this is applied to the GPS received signal, so that the delay amount τ with the same PN polarity. Is equivalent to That is, according to the present invention, it is possible to measure the position by GPS even if it is a very weak signal such as in a building.

Furthermore, since the polarity of the PN signal varies depending on the navigation data as in the past, the signal components are canceled out when synchronous addition is performed according to the polarity of the PN signal, eliminating the disadvantage that the sensitivity (S / N) is not improved sufficiently. There is an effect that can be done.
In this embodiment, this operation was explained with the data of the PN signal D (1: 20,1: N). However, by changing the sampling frequency of the D / A converter, m of D (1: 20,1: m) is changed. It may be changed. The correlation calculation unit can improve sensitivity (S / N) by increasing m.

Next, another embodiment of the present invention will be described. The functional blocks of the parts of the Doppler correction unit 16, the polarity changing device 17, the synchronous addition / correlation calculation device 18, and the pseudo-range detection device 19 in FIG. 2 have been described with the algorithm by software, but the Doppler correction unit 16 and FIG. For the six functional blocks, multipliers 26, 27, 28, 29, adder 30, and subtractor 31, the functional blocks of the multipliers P _{1 to} P ₂₀ and the correlation calculators C _{1 to} C ₂₀ in FIG. It may be configured.
Moreover, you may comprise by mixing software and hardware.

In FIG. 8, the pseudo patterns A ₁ , A ₂ ... A ₂₀ are prepared in the ROM 46 in advance, but a pattern may be generated by an equivalent method by a program. For example, all 20 data such as 1 or 0 in 1 row and 20 columns may be generated by left-shifting or right-shifting to generate a pattern equivalent to that described above.
In addition, although 20 patterns of pseudo patterns A ₁ , A ₂ ... A ₂₀ are prepared, A ₂₀ in FIG. 8 is all 0 patterns, and this is synchronized by changing all the polarities in the calculation of the multiplier P _20. Since the addition and correlation calculation are performed to obtain the absolute value of the correlation peak value, the pseudo pattern A ₂₀ and the multiplier P ₂₀ are omitted and 19 pseudo patterns A ₁ , A ₂ ... A are omitted. ₁₉ is also acceptable.
Further, in FIG. 8, the pseudo pattern A may be changed to 0 instead of 0 and 0 instead of 1. Again, the pseudo-pattern A ₂₀ are all 1 pattern, pseudo pattern A _20, yet good as a multiplier P ₂₀ is omitted and 19 types of pseudo random pattern _{A 1, A 2 ... A 19} .

In other words, the positioning method according to a satellite positioning system of the present invention, the receiver terminal 11, PN signal including carrier components in the receiver terminal 11 to the satellite received signal by applying a pseudo pattern A to prepare in advance the satellite received signal The PN signal with the changed polarity is synchronously added, and the correlation calculation is performed by the synchronous addition PN signal obtained by synchronous addition and the replica PN code including the carrier wave component prepared in advance by the receiver terminal 11. From the result, the correlation peak value and the delay value corresponding to the correlation peak value are detected, and the pseudo distance is obtained from the delay value.
Then, the receiver terminal 11 performs processing on the satellite reception signal in the 1-bit section of the navigation data in the navigation data of the signal from the satellite S, and also processes one frame of the satellite reception signal in the 1-bit section. As a unit, the polarity of the PN signal including a carrier component in a 1-bit section is changed.

Thereby, the present invention solves the conventional problem, the same polarity of the received signal (PN signal) with the code prepared in advance in the receiver terminal 11, the synchronous addition and correlation calculation, Alternatively, by performing synchronous addition, it is completely eliminated that signal components cancel each other out in synchronous addition and the sensitivity (S / N) improvement is deteriorated.
That is, the sensitivity (S / N) can be dramatically improved by performing synchronous addition and correlation calculation with the same polarity of the received signal (PN signal) using a pseudo pattern prepared in advance in the receiver terminal 11. A high-sensitivity satellite positioning means (method) capable of stable positioning can be obtained even in a plan, in a house, behind a building, or inside a building.

  Further, the present invention is different from the method of taking navigation data from an external base station as in the prior art in order to make the polarity of the satellite reception signal (PN signal) the same, and therefore can be released from the external base station. . In other words, the information of the external base station is unnecessary in order to make the polarity of the satellite reception signal (PN signal) the same, and the polarity of the reception signal (PN signal) is made the same and then the synchronous addition is performed. The noise can be reduced effectively.

That is, even if the navigation data is not received from the external base station by the communication means L, for example, from the received signal received by the receiver terminal 11 existing in the building, the navigation data of the satellite S from the external base station is used. The receiver terminal 11 itself synchronizes and adds all the polarities of the PN signal. Therefore, without depending on the navigation data from the outside by the communication means L, all the polarities of the PN signal are made the same, and the PN signal buried in the noise emerges from the noise by synchronous addition and correlation calculation. Get super high sensitivity.
In the present invention, the sensitivity (S / N ratio) is remarkably improved in the correlation calculation by increasing the number of samplings in the A / D converters 38 and 39 only by receiving a short continuous signal of 20 msec. The pseudo-range with the satellite S can be detected accurately and quickly even in a building.
The PN signal can also be applied to a GPS reception PN signal, a Gallileo reception PN signal, or the like.

As described above, according to the present invention, there is provided a satellite positioning system in which the receiver terminal 11 receives a signal from the satellite S and the receiver terminal 11 obtains a pseudorange between the satellite S and the received satellite reception signal. In this case, the receiver terminal 11 stores a pseudo pattern unit 22 for storing or generating a pseudo pattern A for changing the polarity of the satellite reception signal, and a storage unit 7 for storing a replica PN code including a carrier wave component for demodulating the satellite reception signal. A first calculation unit 8 that changes the polarity of the PN signal including the carrier wave component in the satellite reception signal by applying the pseudo pattern A to the satellite reception signal, and a second calculation unit 9 that synchronously adds the PN signal having the changed polarity. And a third arithmetic unit 10 for performing a correlation calculation using the synchronously added synchronous PN signal and the replica PN code, and detecting a delay from the correlation calculation result and a correlation peak value and a delay value corresponding to the correlation peak value To provide a pseudo distance detecting device 19 for determining the pseudo-distances from the value, and the receiver terminal 11 inside the pseudo pattern A, in order to equal the polarity of the received PN signal, by the synchronous addition and correlation calculation sensitivity (signal-to (Noise ratio) can be significantly improved.
In addition, since processing is performed on a PN signal including a carrier wave, noise can be reduced and sensitivity can be improved by increasing the number of samplings.

Further, unlike the prior art, GPS navigation data from an external base station is not required to detect the phase inversion boundary of the C / A code signal based on the navigation data, and the signal received inside the receiver terminal 11 Since navigation data is not required, a PN signal buried in noise can be detected with significantly improved S / N.
That is, the PN signal can be efficiently raised from the noise, and the pseudo-range with the satellite S can be accurately and even in a place where the GPS signal (GPS radio wave) is significantly attenuated, such as in a building or a building. Measure with good response.

Further, since the receiver terminal 11 processes the satellite reception signal in the 1-bit section of the navigation data among the navigation data of the signal from the satellite S, the necessary satellite reception signal can be shortened and depends on the reception time. There is no waiting time, and responsiveness is extremely improved.
Further, since the receiver terminal 11 is configured to change the polarity of the PN signal including the carrier component of the 1-bit section in units of one frame of the satellite reception signal of the 1-bit section, noise can be reduced and the sensitivity can be improved. I can plan.

  Further, since the receiver terminal 11 is configured to process a PN signal including a carrier component of one frame as a value discretized at a predetermined sample interval, noise can be further reduced, accuracy can be improved, and sensitivity can be improved. can do.

Further, the present invention relates to a satellite positioning method in which a receiver terminal 11 receives a signal from a satellite S, and the receiver terminal 11 obtains a pseudo distance from the satellite S based on the received satellite received signal. The terminal 11 applies the pseudo pattern A prepared in advance by the receiver terminal 11 to the satellite reception signal to change the polarity of the PN signal including the carrier wave component in the satellite reception signal, and synchronously adds the PN signal whose polarity has been changed. The correlation addition is performed using the synchronous addition PN signal that has been synchronously added and the replica PN code including the carrier wave component prepared in advance by the receiver terminal 11, and the correlation peak value and the delay value corresponding to the correlation peak value are obtained from the result of the correlation calculation. In order to detect and obtain the pseudo distance from the delay value, in order to make the polarity of the received PN signal identical by the pseudo pattern A inside the receiver terminal 11, sensitivity (signal to noise ratio) is obtained by synchronous addition and correlation calculation. The can be significantly improved.
In addition, since processing is performed on a PN signal including a carrier wave, noise can be reduced and sensitivity can be improved by increasing the number of samplings.

Further, unlike the prior art, GPS navigation data from an external base station is not required to detect the phase inversion boundary of the C / A code signal based on the navigation data, and the signal received inside the receiver terminal 11 Since navigation data is not required, a PN signal buried in noise can be detected with significantly improved S / N.
That is, the PN signal can be efficiently raised from the noise, and the pseudo-range with the satellite S can be accurately and even in a place where the GPS signal (GPS radio wave) is significantly attenuated, such as in a building or a building. Measure with good response.

Further, since the receiver terminal 11 processes the satellite reception signal in the 1-bit section of the navigation data among the navigation data of the signal from the satellite S, the necessary satellite reception signal can be shortened and depends on the reception time. There is no waiting time, and responsiveness is extremely improved.
In addition, since the receiver terminal 11 changes the polarity of the PN signal including the carrier component in the 1-bit section in units of one frame of the satellite reception signal in the 1-bit section, noise can be reduced and sensitivity can be improved.

  In addition, since the receiver terminal 11 processes a PN signal including a carrier component of one frame as a value obtained by discretizing at a predetermined sample interval, noise can be further reduced, accuracy can be improved, and sensitivity can be improved. Can do.

It is explanatory drawing explaining the PN signal in a GPS received signal. It is a block diagram which shows the outline | summary of one Embodiment of this invention. It is a block diagram which shows the structure of a GPS receiver terminal. It is explanatory drawing which shows the memory content of a memory part. It is operation | movement explanatory drawing of the memory part which memorize | stores the I * Q signal conversion part, an A / D converter, and its output. It is operation | movement explanatory drawing which performs a Doppler correction | amendment from I and Q signal, and obtains a PN signal. It is a flowchart from receiving a GPS signal to obtaining a pseudorange. It is explanatory drawing explaining the operation | movement which makes a pseudo pattern act on a PN signal, and obtains a correlation calculation result. It is a memory | storage state figure of the memory part which memorize | stored the result obtained by sampling a signal. It is explanatory drawing which shows the memory pattern of RAM when an input PN signal is multiplied by a pseudo pattern. It is a block diagram which shows the conventional GPS positioning system. It is explanatory drawing explaining the conventional GPS positioning system.

Explanation of symbols

7 Storage Unit 8 First Calculation Unit 9 Second Calculation Unit
10 Third operation section
11 Receiver terminal
19 Pseudo distance detector
22 Pseudo-pattern part A Pseudo-pattern S Satellite

Claims (4)

In a satellite positioning system, a receiver terminal (11) receives a signal from a satellite (S), and the receiver terminal (11) obtains a pseudorange with the satellite (S) based on the received satellite received signal. Te, the receiver terminal (11), a plurality of types of pre-stored pseudo pattern (a) for polarity changing for changing shifting the polarity of the PN signal by 1msec containing carrier component of 20msec the satellite signals received Or a pseudo pattern part (22) to be generated, a storage part (7) for storing a replica PN code including a carrier wave component for demodulating the satellite reception signal, and the above-mentioned plural types of pseudo patterns (A) for the same satellite reception of 20 msec. first arithmetic unit for obtaining a plurality of polarity changing PN signal the polarity of the PN signal including a carrier component in the satellite received signal is applied to the signal is changed in shifted by 1msec and (8), which for each polarity changing PN signal The A second arithmetic unit for adding synchronization (9), a third arithmetic unit that performs correlation calculation between the respective synchronous addition PN signal and the replica PN code synchronously adding (10), the correlation peak value from results of correlation calculations A satellite positioning system comprising: a pseudo-range detection device (19) that detects a delay value corresponding to the correlation peak value and obtains the pseudo-range from the delay value. The satellite positioning system according to claim 1, wherein the receiver terminal (11) is configured to process the PN signal including a carrier component of one frame as a value discretized at a predetermined sample interval . In a satellite positioning method, a receiver terminal (11) receives a signal from a satellite (S), and the receiver terminal (11) obtains a pseudorange with the satellite (S) based on the received satellite received signal. Then, the receiver terminal (11) causes the satellite reception signal to act by applying a plurality of types of pseudo patterns (A) for polarity change prepared in advance by the receiver terminal (11) to the same satellite reception signal of 20 msec. The polarity of the PN signal including the carrier wave component is shifted and changed by 1 msec to obtain a plurality of polarity-change PN signals, and each polarity-change PN signal is synchronously added, and each synchronous addition PN signal that is synchronously added and the receiver The terminal (11) performs a correlation calculation with a replica PN code including a carrier wave component prepared in advance, and detects a correlation peak value and a delay value corresponding to the correlation peak value from the result of the correlation calculation. Find the pseudorange Satellite positioning method according to claim Rukoto. Said receiver terminal (11), 請 Motomeko 3 satellite positioning method according that handles the PN signal as a value obtained by discretizing at a predetermined sample interval containing a carrier component for one frame.

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