JP4973933B2 - Calibration signal generator, GPS receiver, GPS information correction system - Google Patents

Description

The present invention relates to a calibration signal generator that generates a calibration signal having the same frequency as a carrier wave used for GPS, and a GPS receiver that uses a calibration signal to correct a propagation delay in the receiver and perform positioning.
The present invention also relates to a GPS information correction system for correcting information emitted from a GPS satellite based on a highly accurate positioning result obtained by the GPS receiver.

Conventionally, positioning by GPS includes single positioning in which positioning is performed with only a single receiver, and relative positioning in which positioning is performed in correlation with a plurality of receivers and base stations. In independent positioning, for example, there is a method of calculating a true geometric distance, that is, a geometric distance between a receiver and a positioning satellite, from a pseudo distance obtained from a C / A code or a P (Y) code. In this method, when the L wave is used for the satellite i and the receiver k, the pseudo distance Pki, the ionospheric delay Iki, the tropospheric delay Tki, the satellite clock error δi, the receiver clock error δk, and the receiver delay A _Lk The geometric distance ρ is estimated and calculated using an observation equation (equation (1)) including an error factor. Here, in Formula (1), c shows the speed of light.

In such a positioning method, ionospheric delay Iki was based on information or the like from the positioning satellites, tropospheric delay Tki, satellite clock error .delta.i, receiver clock error .delta.k, estimated geometric distance ρ by setting the receiver delay A _Lk Accuracy is affected.

  On the other hand, there are several methods for relative positioning, and one of them is a kinematic method as shown in Patent Document 1. In this method, the positioning accuracy is improved by acquiring the correction information of the positioning satellite information from the reference station separately from the information from the positioning satellite.

By the way, various methods for reducing the error factor have been devised even in the above-described single positioning method. In Non-Patent Document 1, a reference signal (calibration signal) having the same frequency as the L1 wave and L2 wave is used to transmit from a positioning satellite. A method for estimating and calculating various delay information in comparison with a signal is shown. In this method, a reference signal corresponding to the L1 wave and L2 wave and a transmission signal from a positioning satellite are received, and the propagation delay of the entire receiving system is estimated by combining the L1 waves and the L2 waves. Arithmetic.
US 5519620 Specification Andrew Cartmell, `` Considerations for Calibration of Frequency Dependent Delays ''

However, in the method of Non-Patent Document 1, the delays A _Lk of the L1 wave and L2 wave in the receiver are set to be the same although they are originally different. For this reason, at least an error corresponding to this setting occurs, and it cannot be applied to a positioning system that requires a highly accurate positioning result. Furthermore, in Non-Patent Document 1, the L1 wave and the L2 wave are generated at the same time. The calibration signal to be used cannot be generated simultaneously.

  Therefore, an object of the present invention is to consider a calibration signal generator capable of simultaneously generating a calibration signal having no delay difference between various frequencies and a propagation delay of a signal of each frequency based on an internal circuit using the calibration signal generator. An object of the present invention is to provide a GPS receiver capable of detecting an error factor with higher accuracy and performing highly accurate positioning. Another object of the present invention is to provide a GPS information correction system capable of correcting GPS position information from position information of a base station measured with high accuracy and distributing the corrected high-accuracy GPS position information. There is.

The calibration signal generator of the present invention comprises:
Code generation means for outputting a code modulation signal obtained by modulating a navigation message with a specific code uncorrelated to each code set for each positioning satellite;
Of at least three types of carrier frequencies , an addition frequency generated by adding and halving two types of carrier frequencies or a subtraction frequency generated by subtracting and halving two types of carrier frequencies A plurality of conversion signal generating means for generating at least three types of frequency conversion signals consisting of:
The frequency conversion signal output from the plurality of conversion signal generation means is combined with a code modulation signal to simultaneously generate a calibration signal for each carrier frequency.

In this configuration, a calibration signal is generated as follows.
For example, in the case of GPS, the code generation means is generated based on a base signal of a predetermined frequency with a specific pattern code uncorrelated with all of the C / A codes and P (Y) codes set for each positioning satellite. Modulate and output navigation messages.
For example, in the case of GPS, each of the plurality of conversion signal generation means is ½ times the sum frequency of the L1 wave frequency and the L2 wave frequency based on the L1 wave, L2 wave, and L5 wave carriers. The first frequency modulation signal of the frequency, the second frequency modulation signal of 1/2 frequency of the subtraction frequency of the frequency of the L1 wave and the frequency of the L5 wave, the subtraction frequency of the frequency of the L2 wave and the frequency of the L5 wave A third frequency modulation signal having a ½ frequency is generated.
The signal synthesis unit sequentially mixes the first frequency modulation signal, the second frequency modulation signal, and the third frequency modulation signal with the code modulation signal. As a result, an L1 wave frequency component, an L2 wave frequency component, and an L5 wave frequency component are formed in the calibration signal that is output after being mixed in three stages.

The calibration signal generator of the present invention is
A plurality of code generation means for outputting a code modulation signal obtained by modulating a navigation message with a specific code uncorrelated to each code set for each positioning satellite and uncorrelated with each other;
An additional frequency or two types of carrier waves , which are provided for each of the plurality of code generation means, and are generated by adding and multiplying at least three types of carrier wave frequencies by adding two different carrier frequency frequencies to each other. a plurality of conversion signal generating means for generating two frequency conversion signals consisting subtraction frequencies generated by multiplying 1/2 by subtracting a frequency between,
A plurality of signal synthesizing means for synthesizing each frequency conversion signal output from a plurality of conversion signal generating means, respectively, into a corresponding code modulation signal;
Signal adding means for adding the respective synthesized signals output from the plurality of signal synthesizing means to simultaneously generate calibration signals of the respective carrier frequencies.

In this configuration, a calibration signal is generated as follows. In the following description, a case where calibration signals corresponding to three types of carrier frequencies are generated using two types of codes will be described.
Each of the plurality of code generation units has the same configuration as that of the above-described code generation unit, and modulates and outputs a navigation message generated based on a base signal of a predetermined frequency with a specific pattern code. At this time, the codes generated by the respective code generation means are also set so as to be uncorrelated.
Each of the code generation means includes a frequency conversion signal having a frequency that is 1/2 of the addition frequency of two frequencies corresponding to two types of carrier waves out of three or more types of carrier frequencies, and subtraction of the two frequencies. Two conversion signal generating means for generating frequency conversion signals each having a frequency that is ½ the frequency are installed correspondingly. For example, in the case of GPS, with respect to a code modulation signal modulated with a first specific code, a first frequency modulation signal having a frequency ½ times the sum of the frequency of the L1 wave and the frequency of the L2 wave, A fourth frequency modulation signal having a frequency ½ times the subtraction frequency between the wave frequency and the L2 wave frequency is generated. In addition, with respect to the code modulation signal modulated with the second specific code, a fifth frequency modulation signal having a frequency that is ½ times the addition frequency of the L1 wave frequency and the L5 wave frequency, and the L1 wave frequency A second frequency modulation signal having a frequency ½ times the subtraction frequency with the frequency of the L5 wave is generated.

  Each signal synthesizing unit mixes two frequency conversion signals with the code modulation signal to generate a synthesized signal having two carrier frequency components. For example, in the GPS described above, one of the signal synthesizing means generates a synthesized signal modulated with a first specific code having an L1 wave frequency component and an L2 wave frequency component, and the other signal synthesizing means generates an L1 wave frequency component And a synthesized signal modulated with the second specific code having the L5 wave frequency component.

  The signal adding means adds these synthesized signals to generate a calibration signal having the respective frequency components. For example, in the GPS example described above, a calibration signal is generated in which the first specific code is superimposed on the L1 wave frequency and the L2 wave frequency, and the second specific code is superimposed on the L1 wave frequency and the L5 wave frequency. .

  Further, the code generation means of the calibration signal generator of the present invention is characterized in that it generates a superimposed code in which a plurality of different codes are superimposed.

  In this configuration, since the code output from the code generation means is a superimposed code of a plurality of codes, a plurality of codes used for each carrier wave are generated from one code generation means. For example, the C / A code currently used for the L1 wave and the P (Y) code used for the L2 wave are simultaneously generated by one code generation means.

The GPS receiver of the present invention is
Receiving means configured to receive the calibration signal output from the calibration signal generator installed in the vicinity of the receiver and the communication signal from the positioning satellite;
Demodulation processing means for each carrier frequency that separates the calibration signal and the communication signal for each carrier frequency and performs demodulation processing on the calibration signal and the communication signal;
Propagation delay calculating means for calculating the propagation delay between the carrier frequencies of the calibration signal, calculating the propagation delay in the receiver from the propagation delay of the calibration signal, and positioning calculation means for performing the positioning calculation using the calculation result; It is characterized by having.

In this configuration, positioning is performed as follows.
The receiving means receives the calibration signal transmitted from the calibration signal generator and the communication signal transmitted from each positioning satellite. The demodulating means separates the calibration signal and the communication signal for each carrier frequency. For example, in the GPS example described above, classification is made into an L1 wave frequency component, an L2 wave frequency component, and an L5 wave frequency component. Further, the demodulating means demodulates the calibration signal and the communication signal separated by the carrier frequency unit by different signal processing paths, and outputs the demodulated signal to the positioning calculating means.

  The propagation delay calculation means of the positioning calculation means detects a propagation delay bias between the frequency components of the calibration signal. For example, in the GPS example described above, if the code timing of the L1 wave component of the calibration signal is tL1, the code timing of the L2 wave component is tL2, and the code timing of the L5 wave component is tL5, ABS (tL1-tL2), ABS ( tL1-tL5) and ABS (tL2-tL5) are detected. Since the calibration signal generator is installed in the vicinity of the receiving means, propagation delays ABS (tL1-tL2), ABS (tL1-tL5), and ABS (tL2-tL5) between frequency components of the calibration signal are included in the receiver. This corresponds to a propagation delay bias of. The positioning calculation means uses this propagation delay bias to remove the influence of the in-receiver delay of the above observation equation and performs the positioning calculation.

  Further, the positioning calculation means of the GPS receiver according to the present invention estimates the propagation delay from the positioning satellite to the receiver using the propagation delay in the receiver, and performs the positioning calculation using the estimation calculation result. It is said.

  In this configuration, the positioning calculation means detects the propagation delay bias between the carrier frequency components of the communication signal as well as the propagation delay bias between the frequency components of the calibration signal. For example, in the GPS example described above, if the code timing of the L1 wave component of the communication signal is TL1, the code timing of the L2 wave component is TL2, and the code timing of the L5 wave component is TL5, ABS (TL1-TL2), ABS ( TL1-TL5) and ABS (TL2-TL5) are calculated.

  Then, the propagation delay ABS (TL1-TL2), ABS (TL1-TL5), ABS (TL2-TL5) between the frequency components of the communication signal calculated in this way is changed to the propagation delay ABS ( tL1-tL2), ABS (tL1-tL5), ABS (tL2-tL5), subtracting the propagation delay bias from the positioning satellite to the receiver between the frequency components of the communication signal, that is, the ionospheric delay bias and the tropospheric delay bias The total value is calculated. If the observation equation is calculated using this, the effects of ionospheric delay and tropospheric delay can be eliminated.

The GPS information correction system of the present invention is
A base station including the GPS receiver described above, and including a GPS information correction unit that corrects GPS information from a positioning calculation result, and a transmission unit that transmits the corrected GPS information to a corresponding positioning satellite;
A positioning satellite including a corrected GPS information receiving unit that receives the corrected GPS information from the base station, and a GPS information updating unit that updates the GPS information included in the communication signal based on the corrected GPS information. It is characterized by that.

  In this configuration, as described above, since the influence of each error factor is removed and positioning is performed with high accuracy, the position of the GPS positioning satellite is calculated backward from the positioning information obtained by the GPS receiver of the base station. An error in the position information of the GPS positioning satellite is corrected. The base station transmits the corrected position information of the GPS positioning satellite to the corresponding positioning satellite. The GPS positioning satellite receives the corrected GPS information, updates the ephemeris information and the like emitted by itself, and transmits a communication signal including the updated information.

  According to the present invention, it is possible to realize a calibration signal generator that easily generates a calibration signal that includes three or more carrier wave components at the same time and that each carrier wave component is synchronized. Furthermore, according to the present invention, it is possible to realize a calibration signal generator that modulates and outputs a calibration signal that simultaneously includes the three or more carrier wave components with a plurality of synchronized codes.

  Further, according to the present invention, it is possible to perform highly accurate positioning calculation by detecting the delay bias in the receiver between carrier frequencies using the calibration signal output from the calibration signal generator.

  Further, according to the present invention, it is possible to perform positioning with higher accuracy by detecting the delay from the positioning satellite to the receiver using the in-receiver delay bias.

  In addition, according to the present invention, since the satellite information including the position information of the GPS positioning satellite is corrected and updated using the positioning information of the base station observed with high accuracy, the communication signal transmitted from the GPS positioning satellite is transmitted. The satellite position information included in is more accurate. Thereby, the positioning calculation result in each GPS receiver which received this satellite position information becomes more accurate. Furthermore, the accuracy of the positioning calculation result is further improved by repeating this position information correction loop.

A calibration signal generator according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a calibration signal generator according to the present embodiment.
FIG. 2 is a diagram showing signal frequencies in each transmission line. In FIG. 2, description of the reference frequency f _{0 of the} code is omitted.

  The calibration signal generator of this embodiment includes a code generator 11, a filter 12, mixers 13a to 13c, an ATT (attenuator) 14, a VCO (voltage controlled oscillator) 15, PLLs 16a to 16c, and an antenna 17.

The VCO 15 generates a reference signal having a reference frequency f ₀ and outputs the reference signal to the code generator 11 and the PLLs 16a, 16b, and 16c. This reference frequency is 10.23 MHz for GPS, for example.

The code generator 11 generates and outputs a code based on the inputted reference frequency f ₀ . Specifically, the code generated by the code generator 11 is set to a code that is uncorrelated with all the codes received by the GPS receiver described later from the positioning satellite, and is stored in a memory or the like in advance. Stored in the department. The code generator 11 reads out the code from the storage unit, codes the navigation message generated based on the reference signal of the reference frequency f ₀ , and outputs the navigation message. This code generator 11 corresponds to the “code generation means” of the present invention.
Note that the code output from the code generator 11 may be a composite code in which two codes having different bit periods and code periods are superimposed as shown in FIG.
FIG. 3 is a diagram illustrating an example of a code generated by the code generator 11. FIG. 3A shows CODE-A, FIG. 3B shows CODE-B, and FIG. 3C shows a composite code in which CODE-A and CODE-B are superimposed.
By using such a code, a single code generator can generate a plurality of codes simultaneously. If this is applied to GPS, two codes of a C / A code and a P (Y) code can be generated simultaneously by one code generator.

  The filter 12 attenuates the harmonic component of the code-modulated reference signal, and the filtered code-modulated reference signal is input to the mixer 13a.

PLL16a, based on the reference signal of the reference frequency f ₀ which is input from the VCO 15, 1/2 times the frequency of the sum frequency of the frequency f _L1 and L2 wave of frequency f _L2 of the L1 wave _{((f L1 + f L2)} / 2 ) Is generated.
PLL16b, based on the reference signal of the reference frequency f ₀ which is input from the VCO 15, L1 wave of frequency f _L1 and L5 wave subtraction frequency half the frequency of the frequency _{f L5 ((f L1 -f L5} ) / A second modulation signal consisting of 2) is generated.
The PLL 16c is based on the reference signal of the reference frequency f ₀ input from the VCO 15, and is a half frequency ((f _L2 −f _L5 ) / of the subtraction frequency of the frequency f _L2 of the L2 wave and the frequency f _{L5 of the} L5 wave. A third modulation signal consisting of 2) is generated. These PLLs 16a to 16c correspond to the “conversion signal generation means” of the present invention.
The code modulation reference signal from the code generator 11 and the first modulation signal from the PLL 16a are input to the mixer 13a. The mixer 13a mixes these signals to generate a first IF calibration signal. The frequency of the first IF calibration signal is ((f _L1 + f _L2 ) / 2).

The mixer 13b receives the first IF calibration signal from the mixer 13a and the second modulation signal from the PLL 16b. The mixer 13b mixes these signals to generate a second IF calibration signal. The second IF calibration signal is a signal in which two frequencies are superimposed, and the frequency is ((2f _L1 + f _L2 −f _L5 ) / 2) and ((f _L2 + f _L5 ) / 2).

The mixer 13c receives the second IF calibration signal from the mixer 13b and the third modulation signal from the PLL 16c. The mixer 13c mixes these signals to generate a calibration signal to be transmitted. This calibration signal is a signal in which four frequencies are superimposed, and the frequencies are (f _L1 + f _L2 −f _L5 ), and f _L1 , f _L2 , and f _L5 . Here, the component of the frequency (f _L1 + f _L2 −f _L5 ) is unnecessary and is removed by a filter or the like. These mixers 13a to 13c correspond to “signal synthesis means” of the present invention.

By performing such signal processing, a calibration signal in which a frequency f _L1 component corresponding to the L1 wave, a frequency f _L2 component corresponding to the L2 wave, and a frequency f _L5 component corresponding to the L5 wave are superimposed is obtained. Can be generated. This is the same as outputting calibration signals corresponding to the L1 wave, L2 wave, and L5 wave simultaneously, that is, in synchronization.

  The ATT 14 adjusts the input calibration signal to a predetermined amplitude and outputs it to the antenna 17. And the calibration signal which contains the component of L1 wave, L2 wave, and L5 wave simultaneously from the antenna 17 is radiated | emitted.

  In this embodiment, an example in which three-stage modulation is performed on the code reference signal has been described, but modulation may be performed by setting more stages. As a result, more carrier frequency components can be generated simultaneously. Further, two-stage modulation may be performed on the code reference signal.

Next, a calibration signal generator according to a second embodiment will be described with reference to the drawings.
FIG. 4 is a block diagram showing a schematic configuration of the calibration signal generator of the present embodiment.
FIG. 5 is a diagram showing signal frequencies in each transmission line. In FIG. 5, description of the reference frequency f ₀ of the initial code is omitted.

  The calibration signal generator of this embodiment includes code generators 11a and 11b, two filters 12, mixers 13d to 13g, ATT (attenuator) 14, VCO (voltage controlled oscillator) 15, PLL 16d to 16g, antenna 17, and adder. 18 is provided.

The VCO 15 generates a reference signal having a reference frequency f ₀ and outputs the reference signal to the code generators 11a and 11b and the PLLs 16d to 16g. This reference frequency is 10.23 MHz for GPS, for example.

Code generator 11a, 11b, on the basis of the reference frequency f ₀ is input, generates and outputs a different code for each. Specifically, the codes generated by the code generators 11a and 11b are uncorrelated with all the codes received by the GPS receiver described later from the positioning satellite, and are generated by the code generators 11a and 11b. The codes are also set as uncorrelated codes, and are stored in advance in a storage unit such as a memory. The code generators 11a and 11b respectively read the codes from the storage unit, code-code the navigation messages generated based on the reference signal of the reference frequency f ₀ , and output them. These code generators 11a and 11b are synchronized based on an inputted reference signal. Here, for example, as shown in FIG. 5, CODE-A is generated by the code generator 11a, and CODE-B is generated by the code generator 11b. These code generators 11a and 11b correspond to the “code generation means” of the present invention.

By using two codes in this way, when applied to GPS, two codes of a C / A code and a P (Y) code can be generated simultaneously by individual code generators. Note that the codes output from the code generators 11a and 11b may be composite codes formed by superimposing two codes having different bit periods and code periods as described above.
The two filters 12 attenuate the harmonic components of the reference signals code-modulated by CODE-A and CODE-B, respectively, and the filtered code-modulated reference signals are input to the mixer 13d and the mixer 13f, respectively. .

The PLL 16d is based on the reference signal of the reference frequency f ₀ input from the VCO 15, and is a half frequency ((f _L1 −f _L2 ) / of the subtraction frequency of the frequency f _L1 of the L1 wave and the frequency f _{L2 of the} L2 wave. A fourth modulation signal consisting of 2) is generated.
PLL16e, based on the reference signal of the reference frequency f ₀ which is input from the VCO 15, 1/2 times the frequency of the sum frequency of the frequency f _L1 and L2 wave of frequency f _L2 of the L1 wave _{((f L1 + f L2)} / 2 ) Is generated.
PLL16f, based on the reference signal of the reference frequency f ₀ which is input from the VCO 15, L1 wave of frequency f _L1 and L5 wave subtraction frequency half the frequency of the frequency _{f L5 ((f L1 -f L5} ) / A second modulation signal consisting of 2) is generated.
PLL16g, based on the reference signal of the reference frequency f ₀ which is input from the VCO 15, 1/2 times the frequency of the sum frequency of the frequency f _L1 and L5 wave of frequency f _L5 of L1 wave _{((f L1 + f L5)} / 2 ) To generate a fifth modulation signal. Here, the PLLs 16d to 16g correspond to the “conversion signal generation means” of the present invention.
The mixer 13d receives the code modulation reference signal from the code generator 11a and the fourth modulation signal from the PLL 16d. The mixer 13d mixes these signals to generate a third IF calibration signal. The frequency of the third IF calibration signal is ((f _L1 −f _L2 ) / 2).

The mixer 13e receives the third IF calibration signal from the mixer 13d and the first modulation signal from the PLL 16e. The mixer 13d mixes these signals to generate a fourth IF calibration signal. The fourth IF calibration signal is a signal in which two frequencies are superimposed, and the frequencies are f _L1 and f _L2 .

The mixer 13f receives the code modulation reference signal from the code generator 11b and the second modulation signal from the PLL 16f. The mixer 13f mixes these signals to generate a fifth IF calibration signal. The frequency of the fifth IF calibration signal is ((f _L1 −f _L5 ) / 2).

The mixer 13g receives the fifth IF calibration signal from the mixer 13f and the fifth modulation signal from the PLL 16g. The mixer 13f mixes these signals to generate a sixth IF calibration signal. The sixth IF calibration signal is a signal in which two frequencies are superimposed, and the frequencies are f _L1 and f _L5 . Here, the mixers 16d to 16g correspond to the “signal synthesis means” of the present invention.

The adder 18 includes a fourth IF calibration signal that includes f _L1 and f _L2 frequency components and is modulated with CODE-A, and a sixth IF calibration signal that includes f _L1 and f _L5 frequency components and is modulated with CODE-B. Input and output a calibration signal with all these frequency components superimposed. The adder 18 corresponds to the “signal adding means” of the present invention.

By performing such signal processing, and the frequency f _L1 component corresponding to L1 wave modulated by the CODE-A, and the frequency f _L1 component corresponding to L1 wave modulated by the CODE-B, in CODE-A A calibration signal in which the frequency f _L2 component corresponding to the modulated L2 wave and the frequency f _L5 component corresponding to the L5 wave modulated by CODE-B are superimposed can be generated. This is the same as outputting calibration signals corresponding to the L1 wave, L2 wave, and L5 wave simultaneously, that is, in synchronization.

  The ATT 14 adjusts the input calibration signal to a predetermined amplitude and outputs it to the antenna 17. And the calibration signal which contains the component of L1 wave, L2 wave, and L5 wave simultaneously from the antenna 17 is radiated | emitted.

  Even with such a configuration, it is possible to easily generate a calibration signal having frequency components corresponding to a plurality of carrier frequencies. In the present embodiment, an example in which the part from the generation of the code reference signal to the signal modulation by the two-stage mixing is provided in two stages in parallel, but the number of stages is increased and three or more stages in parallel is shown. It is also possible to install and output these output signals. As a result, more carrier frequencies and codes can be generated simultaneously.

Next, a GPS receiver according to a third embodiment will be described with reference to the drawings.
FIG. 6 is a block diagram showing a schematic configuration of the GPS receiver of the present embodiment.
FIG. 7 is a block diagram showing a schematic configuration of the positioning calculation unit 25 shown in FIG.
The GPS receiver according to this embodiment includes an antenna 21, an LNA 22, IF signal processing units 24 a to 24 c, and a positioning calculation unit 25.

  The antenna 21 receives a plurality of carrier wave RF signals (communication signal and calibration signal) each having a different frequency, and outputs the received RF signal to the LNA 22. For example, an L1 wave of 1575.42 MHz, an L2 wave of 1227.60 MHz, and an L5 wave of 1176.45 MHz can be received simultaneously. In the following description, a case where an RF signal including an L1 wave, an L2 wave, and an L5 wave is received will be described. When an RF signal including a mixture of L1, L2, and L5 waves is received, the LNA 22 amplifies the RF signal and outputs the amplified RF signal to the IF processing units 24a to 24c.

  The IF processing units 24a to 24c extract an L1 wave component, an L2 wave component, and an L5 wave component from the RF signal, respectively, and convert them into IF signals. At this time, the generated IF signal is separated into an I signal corresponding to a real component and a Q signal corresponding to an imaginary component. These I and Q signals are A / D converted and output.

  Specifically, the IF processing units 24a to 24c perform IF processing on the L1 wave RF signal in the IF processing unit 24a, perform IF processing on the L2 wave RF signal in the IF processing unit 24b, and perform L5 wave processing on the IF processing unit 24c. The RF signal of IF is subjected to IF processing. These IF processing units 24a to 24c have substantially the same basic configuration except that the band characteristics of the three BPFs and the oscillation frequency settings of the respective VCOs are different. Here, these IF processing units 24a to 24c correspond to "demodulation processing means" of the present invention.

  The IF processing unit 24a includes a BPF 240a, a mixer 241a, a BPF 242a, an IQ mixer 243a, a VCO 244a, a frequency divider 245a, variable amplification LPFs 246a and 247a, and an A / D converter 248a.

The BPF 240a has a frequency pass band set so that the L1 wave frequency f _L1 exists in the pass band, and the BPF 242a provided at the subsequent stage of the mixer 241a includes the L2 wave, L5 among the RF signals received. The wave is attenuated and only the L1 wave signal is passed.

  The VCO 244a generates a conversion signal having a predetermined frequency with respect to the L1 wave frequency based on the reference frequency of 10.23 MHz, and outputs it to the mixer 241a and the frequency divider 245a. The frequency divider 245a divides the input conversion signal, generates a lower-frequency conversion signal, and outputs it to the IQ mixer 243a.

  The mixer 241a down-samples the RF signal that has passed through the BPF 240a and the conversion signal having a predetermined frequency generated by the VCO 244a to generate an IF signal. The IF signal generated by the mixer 241a is input to the BPF 242a, and the BPF 242a passes only the frequency band corresponding to the L1 wave frequency in the IF signal and attenuates other frequency bands. In this way, the L1 wave frequency of the RF signal is extracted and converted into an IF signal in two stages of BPF 240a and BPF 242a.

  The L1 wave component of the IF signal is input to the IQ mixer 243a. The IQ mixer 243a converts the L1 wave component of the IF signal to the real component I signal based on the low-frequency conversion signal input from the frequency divider 245a. Separate and output to Q signal of imaginary component.

  The variable amplification LPF 246a attenuates the harmonic of the input I signal of the L1 wave component, adjusts the gain so as to have a predetermined amplitude, and outputs it to the A / D converter 248a. Similarly, the variable amplification LPF 247a attenuates the harmonics of the input Q signal of the L1 wave component, adjusts the gain so as to have a predetermined amplitude, and outputs it to the A / D converter 248a.

  The A / D converter 248a digitally samples the input I signal and Q signal at a sampling frequency set according to the frequency of the L1 wave, and L1 wave component I signal data corresponding to the I signal of the L1 wave component And L1 wave component Q signal data corresponding to the Q signal of the L1 wave component.

  The IF processing unit 24b has substantially the same configuration as the IF processing unit 24a. The IF processing unit 24b associates the set passband frequency of the BPF 240b and the BPF 242b and the frequency of the conversion signal generated by the VCO 244b with the frequency of the L2 wave. I signal data and L2 wave component Q signal data are output.

  The IF processing unit 24c has substantially the same configuration as the IF processing units 24a and 24b. The IF processing unit 24c associates the set passband frequency of the BPF 240c and the BPF 242c and the frequency of the conversion signal generated by the VCO 244c with the frequency of the L5 wave. Wave component I signal data and L5 wave component Q signal data are output.

  As described above, based on the calibration signal input from the calibration signal generator and the communication signal input from the positioning satellite, the I signal data and the Q signal data of the L1 wave component, the L2 wave component, and the L5 wave component are the positioning calculation unit. 25 is output.

  The positioning calculation unit 25 includes coding circuits 251a and 251b, a signal processing unit 252 including a CPU 250 and a propagation delay calculation unit 253, and a timing generation circuit 254. The positioning calculation unit 25 calculates a propagation delay bias IFB from the input I signal data and Q signal data of the calibration signal, and applies the calculated propagation delay bias IFB to the observation equation to receive each positioning satellite and the main GPS reception. Calculation of geometric distance from the aircraft and positioning of this GPS receiver.

  The encoding circuits 251 a and 251 b encode the I signal data and the Q signal data of the L1 wave, L2 wave, and L5 wave components, and output them to the signal processing unit 252.

  The timing generation circuit 254 outputs a correlation processing start timing signal for each calculation channel of the signal processing unit 252 based on a 1-second pulse signal input from the outside.

  In the signal processing unit 252, a calculation channel is configured for each positioning satellite. In FIG. 7, it is comprised from 24 calculation channels CH1-CH24 corresponding to 24 satellites, and the calculation signal CH25 for calibration signals. The calculation channels CH1 to CH25 store in advance a code set for each positioning satellite and a code set for the calibration signal, and are input in accordance with the correlation processing start timing signal output from the timing generation circuit 254. The encoded I signal data and the encoded Q signal data are correlated with the stored code. The CPU 250 and each of the operation channels CH1 to CH25 analyze the correlated encoded I signal data and encoded Q signal data, and if the data corresponds to the communication signal from the positioning satellite, the ephemeris information or the like Satellite position information, satellite clock information, ionospheric delay information, etc. are detected, and a pseudo distance derived from the code is calculated. If the data corresponds to the calibration signal, the code timing for the calibration signal is detected. These correlation processing, analysis, and detection are performed for each code, that is, a communication signal and a calibration signal from each positioning satellite, in each of the L1 wave, L2 wave, and L5 wave.

The CPU 250 and the propagation delay calculation unit 253 use the L1 wave, L2 wave, and L5 wave code timings acquired in the calculation channel CH25 to propagate the L1 wave and L2 wave propagation delay bias IFB _L1L2 , L1 wave and L5 wave. propagation delay bias IFB _L2L5, the propagation delay bias IFB _L1L5, L2 wave and L5 waves and calculated. This is a delay that occurs when the L1 wave, L2 wave, and L5 wave propagate through the receiver. The code timing tL1 of the code propagated by the L1 wave, the code timing tL2 of the code propagated by the L2 wave, The code timing tL5 of the code propagated by the L5 wave is detected, and these code timing shifts, that is, the code phase shifts between frequencies ABS (tL1-tL2), ABS (tL1-tL5), ABS (tL2- It is obtained by calculating tL5). The propagation delay bias calculated in this way is stored, and the calculation channel corresponding to each communication signal is read and used when estimating and calculating the geometric distance and positioning to each positioning satellite.

  The CPU 250 and the calculation channels CH1 to CH24 substitute the detected information, the pseudo distance, and the propagation delay bias IFB stored in the propagation delay calculation unit 253 into the observation equation, to the receiver and each positioning satellite. Calculating the geometric distance and positioning the receiver. At this time, calculation is performed for at least two frequencies in the entire calculation channels CH1 to CH24. That is, the geometric distance is calculated and measured by using at least any combination of the L1 wave and L2 wave, the L1 wave and L5 wave, and the L2 wave and L5 wave.

  For example, the case where the L1 wave and the L2 wave are used will be specifically described.

In general, the observation equation of the pseudo distance P _Lk ⁱ in the L wave at the receiver k and the positioning satellite i at a certain time point is that ρ is the geometric distance between the positioning satellite i and the receiver k, I is the ionospheric delay, T is a tropospheric delay, δ _k is a receiver clock error, δ ⁱ is a positioning satellite clock error, and A _Lk is an in-receiver delay.

From equation (1), the observation equation of the pseudorange P _L1k ⁱ in the L1 wave at the receiver k and the positioning satellite i is

The observation equation of the pseudorange P _L2k ⁱ in the L2 wave at the receiver k and the positioning satellite i is

It becomes. A _L1k and A _L2k are in-receiver delays of the L1 wave and L2 wave, respectively, and f _L1 and f _L2 are the frequencies of the L1 wave and L2 wave, respectively.
Here, it is assumed that the L1 wave can be received and analyzed from the positioning satellites # 1 and # 3, and the L2 wave can be received and analyzed from the positioning satellites # 2 and # 4. From equation (3), the following simultaneous equations hold.

  Here, assuming that the satellite position obtained from the satellite information is (xi, yi, zi) and the receiver position is (xk, yk, zk), from equation (4),

If IFB is calculated as described above, IFB = A _L2k −A _L1k .

It becomes. By calculating this observation equation, the error due to the delay in the receiver is reduced, so that the positioning of the receiver k can be performed with high accuracy.

  Note that the propagation delay calculation unit 253 can also calculate the propagation delay from each positioning satellite to the receiver, that is, the bias value of the combined delay of the ionosphere delay and the troposphere delay by using the propagation delay IFB.

Specifically, the propagation delay calculation unit 253 acquires the code timing for each of the L1, L2, and L5 waves detected by the calculation channels CH1 to CH24, and calculates the difference value (bias value) thereof. For example, the code timing TL1 of the L1 wave and the code timing TL2 of the L2 wave are differentiated. As a result, a communication signal propagation delay bias IFBt _L1L2 = ABS (TL1-TL2) corresponding to a propagation delay bias from the positioning satellite to the signal processing unit of the receiver is generated, and the code timing TL1 of the L1 wave is generated. The communication signal propagation delay bias IFBt _L1L5 = ABS (TL1-TL5) is generated by subtracting the L5 wave code timing TL5, and the communication signal propagation is performed by subtracting the L2 wave code timing TL2 from the L5 wave code timing TL5. Delay bias IFBt _L2L5 = ABS (TL2-TL5) is generated. Next, the propagation delay calculation unit 253 subtracts the above-described in-receiver propagation delay bias from these communication signal propagation delay biases.

That is, for the combination of L1 wave and L2 wave,
IFBt _L1L2 -IFB _L1L2 = ABS (TL1-TL2) -ABS (tL1-tL2)
For the combination of L1 wave and L5 wave,
IFBt _L1L5 -IFB _L1L5 = ABS (TL1-TL5) -ABS (tL1-tL5)
And for the combination of L2 and L5 waves,
IFBt _L2L5 -IFB _L2L5 = ABS (TL2-TL5) -ABS (tL2-tL5)
Is calculated. This calculation data corresponds to the propagation delay bias from the positioning satellite to the receiver, which corresponds to the sum of the ionospheric delay bias and the tropospheric delay bias. By performing such calculations, the current ionospheric delay and tropospheric delay can be calculated, so geometric distance and positioning can be calculated using observation equations without using ionospheric delay information and tropospheric delay information from positioning satellites. can do. Furthermore, since the bias values of the ionospheric delay and tropospheric delay calculated in this way are calculated from the delay amount of the currently received communication signal, it is possible to accurately reflect the current communication environment, that is, the ionospheric state and tropospheric state. Highly accurate ionospheric and tropospheric delays can be applied to observation equations. Thereby, positioning with higher accuracy can be performed.

  Next, a GPS information correction system according to a fourth embodiment will be described with reference to the drawings.

FIG. 8 is a block diagram showing a schematic configuration of the GPS information correction system of the present embodiment.
The GPS information correction system of the present embodiment includes a base station 5, a calibration signal generator 1, a mobile station 8, and positioning satellites 101 to 104. The number of positioning satellites is not limited to this, and may be larger than this.

  The base station 5 includes a GPS receiver 2 having the above-described configuration, a GPS information correction circuit 3, and a GPS information transmitter 4.

  The positioning satellites 101 to 104 have the same configuration, and the positioning satellite 101 includes a GPS information generation unit 111 and a GPS information transmission / reception unit 112.

  The calibration signal generator 1 has the above-described configuration, and is installed in the vicinity of the base station 5 or in the vicinity of the GPS receiver 2 of the base station 5. The calibration signal generator 1 transmits a calibration signal 200 modulated by a specific code to the outside at a frequency corresponding to the L1 wave, L2 wave, and L5 wave.

  The positioning satellite 101 generates satellite information including satellite position information such as ephemeris information, ionospheric delay information, tropospheric delay information, received clock error information, and the like in the GPS information generation unit 111, and is converted into a signal by the GPS information transmission / reception unit 112. The communication signal 201 is transmitted to the outside. Similarly, the positioning satellites 102 to 104 transmit satellite information to the outside.

  The GPS receiver 7 of the mobile station 8 and the GPS receiver 2 of the base station 5 receive this communication signal 201 and analyze each information. These GPS receivers 2 and 7 perform positioning at that time.

  At this time, the GPS receiver 2 of the base station 5 receives the calibration signal 200 and the communication signal 201 and performs its own positioning. The GPS receiver 2 performs a processing operation as described above, thereby correcting a delay in the receiver and performing positioning with high accuracy. Then, the GPS receiver 2 outputs the positioning result and correction information to the GPS information correction circuit 3.

  The GPS information correction circuit 3 calculates and inputs the position of the corresponding positioning satellite 101 based on the correction information on the positioning result and delay of the base station obtained from the GPS receiver 2 and the satellite information from the positioning satellite. An error from the satellite position information is detected. Then, correction data for the satellite position information is generated and output to the GPS information transmitter 4.

  The GPS information transmitter 4 converts the input correction data into a signal and transmits a correction communication signal 202 to the positioning satellites 101 to 104. At this time, a code is set for each positioning satellite, and the positioning satellite 101 analyzes the code to determine whether it is correction information for itself.

  When the positioning satellite 101 receives the corrected communication signal 202 by the GPS information transmission / reception unit 112, the GPS information generation unit 111 analyzes the detection satellite 101 to detect correction information for itself, and stores each information stored in advance as the correction information. Update. Then, the positioning satellite 101 generates satellite information by the GPS information generation unit 111 based on the new information, converts it into a signal by the GPS information transmission / reception unit 112, and transmits it as the communication signal 203 to the outside. The GPS receiver 2 of the base station 5 and the GPS receiver 7 of the mobile station 8 receive this newly corrected communication signal 203 and analyze the information. These GPS receivers 2 and 7 perform positioning at that time. Also at this time, the GPS receiver 2 of the base station 5 performs positioning by correcting the in-receiver delay, ionospheric delay, and tropospheric delay using the calibration signal 200, so that positioning can be performed with higher accuracy than the previous time. Can do. At this time, correction information of the GPS satellite is generated from the generated correction information by the GPS information correction circuit 3 as described above, and fed back to the positioning satellites 101 to 104 via the GPS information transmitter 4.

  Thus, by using the GPS information correction system of the present embodiment, highly accurate satellite position information and delay information can always be acquired. Thereby, it is possible to perform positioning with higher accuracy than conventional ones in any GPS receiver, not limited to base stations and mobile stations.

  In addition, although each above-mentioned embodiment demonstrated GPS as an example, other systems (GRONASS, Galileo, etc.) utilized as a GNSS system are applicable.

1 is a block diagram showing a schematic configuration of a calibration signal generator according to a first embodiment. The figure which shows the signal frequency in each transmission line shown in FIG. The figure which shows an example of the code | cord | chord which the code generator 11 shown in FIG. 1 produces | generates The block diagram which shows schematic structure of the calibration signal generator of 2nd Embodiment The figure which shows the signal frequency in each transmission line shown in FIG. The block diagram which shows schematic structure of the GPS receiver of 3rd Embodiment. The block diagram which shows schematic structure of the positioning calculating part 25 shown in FIG. The block diagram which shows schematic structure of the GPS information correction system of 4th Embodiment

Explanation of symbols

1-calibration signal generator, 2,7-GPS receiver, 3-GPS information correction circuit, 4-GPS information transmitter, 5-base station, 8-mobile station, 101-104 positioning satellite, 111-GPS information Generator, 112-GPS information transmitter / receiver, 11, 11a, 11b-code generator, 12-filter, 13a-13g, 241a-241c-mixer, 14-ATT, 15,244a-244c-VCO, 16a-16g- PLL, 17, 21-antenna, 18-adder, 22-LNA, 24a-24c-IF processing unit, 240a-240c, 242a-242c-BPF, 243a-243c-IQ mixer, 245a-245c-frequency divider, 246a to 246c, 247a to 247c-variable amplitude LPF, 248a to 248c-A / D converter 25-positioning calculation unit, 250- PU, 251a, 251b- encoding circuit, 25 2-signal processing unit, 253- propagation delay calculation unit, 254- timing generator

Claims (6)

Code generation means for outputting a code modulation signal obtained by modulating a navigation message with a specific code uncorrelated to each code set for each positioning satellite;
Of at least three types of carrier frequencies , an addition frequency generated by adding and halving two types of carrier frequencies or a subtraction frequency generated by subtracting and halving two types of carrier frequencies A plurality of conversion signal generating means for generating at least three types of frequency conversion signals consisting of:
Signal synthesizing means for synthesizing the frequency conversion signals output from the plurality of conversion signal generating means with the code modulation signal to simultaneously generate calibration signals of the respective carrier frequencies. Calibration signal generator. A plurality of code generation means for outputting a code modulation signal obtained by modulating a navigation message with a specific code uncorrelated to each code set for each positioning satellite and uncorrelated with each other;
Provided for each of the plurality of code generation means, and at least three types of carrier frequencies , an addition frequency generated by adding two types of carrier frequencies of different combinations to each other and multiplying by half, or two types of carriers a plurality of conversion signal generating means for generating two frequency conversion signals consisting subtraction frequencies generated by multiplying 1/2 by subtracting a frequency between,
A plurality of signal synthesizing means for synthesizing each frequency conversion signal output from each of the plurality of conversion signal generating means into a corresponding code modulation base signal;
A calibration signal generator comprising: signal addition means for adding together each synthesized signal output from a plurality of signal synthesis means to simultaneously generate a calibration signal for each carrier frequency.   The calibration signal generation device according to claim 1, wherein the code generation unit generates a superimposed code in which a plurality of different codes are superimposed. Receiving means configured to receive a calibration signal output from a calibration signal generator installed in the vicinity of a receiver and a communication signal from a positioning satellite. When,
Demodulating means for each carrier frequency for separating the calibration signal and the communication signal for each carrier frequency, and performing demodulation processing on the calibration signal and the communication signal;
Propagation delay calculating means for calculating a propagation delay between carrier frequencies of the calibration signal, positioning calculation means for calculating a propagation delay in the receiver from the propagation delay of the calibration signal and performing a positioning calculation using the calculation result And a GPS receiver.   5. The GPS receiver according to claim 4, wherein the positioning calculation means estimates a propagation delay from a positioning satellite to the receiver using a propagation delay in the receiver, and performs a positioning calculation using the estimation calculation result. A GPS information correction unit that includes the GPS receiver according to claim 4 or 5 and that corrects GPS information from a result of the positioning calculation, and a transmission unit that transmits the corrected GPS information to a corresponding positioning satellite; , Including base stations,
The positioning satellite including: a corrected GPS information receiving unit that receives corrected GPS information from the base station; and a GPS information updating unit that updates GPS information included in a communication signal based on the corrected GPS information. GPS information correction system provided.

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