JPH11109016A - Glonass receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To calibrate signal data from a satellite in real time by generating a pilot signal with the same frequency of each frequency, constantly measuring delay time separately for each frequency, and using the delay time. SOLUTION: A pilot signal generation part 11 generates a pilot signal with the same frequency as each signal from a satellite and with a different modulation signal at the timing of a reference clock. A signal synthesizer 12 synthesizes the pilot signal with a satellite signal being inputted from an antenna part. A pilot signal delay time measurement part 7 measures a delay time for each frequency of the pilot signal being received by a reception channel part 2-2 exclusively for a pilot signal via a reception part 1 using the timing of a reference clock. The delay time information for each frequency is inputted to a calibration processing part 30 and actual satellite signal data being received are calibrated in real time, thus accurately measuring a position.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a GLONASS (G
The present invention relates to a GLONASS receiver used for a positioning device that performs positioning using a global navigation orbiting satellite system.

[0002]

BACKGROUND OF THE INVENTION As is well known, GLONAS
S: The global navigation satellite system is composed of a total of 24 satellites, eight in three different circular orbits, and the transmission frequency is L
1: 1.6GHz band, L2: 1.2GHz band, PN for both frequency bands
Although a transmission wave modulated by a C / A code (hereinafter also referred to as a PN code) and a P code is used, different frequencies are used for each satellite, and the same code is used for all satellites. This GLONASS is a GPS (Glo
val Positioning System (SA) (selective availabil
It is said that positioning using GLONASS can obtain approximately twice as high accuracy as positioning using GPS because no ity is measured.

Therefore, when configuring a high-precision positioning device,
If the configuration uses GLONASS instead of GPS, the positioning accuracy can be improved, but the problem here is that the transmission frequencies of the respective satellites are different. In other words, for positioning, a pseudorange from each satellite is obtained at each arrival time of the received transmission signal. Therefore, the transmission signal received by the reception channel unit via the reception unit of the receiver is processed by the signal processing unit. Although the arrival time is accurately measured by the antenna, the signal from the actual satellite received by the antenna is delayed by each unit in the receiver, especially the reception unit or the like, until the arrival time is measured. Here, if the transmission frequency from each satellite is the same, there is no problem because the amount of delay in the receiver is the same, but GLONASS uses a different transmission frequency for each satellite. While the signals are received and processed, a relative shift occurs in the amount of delay in each transmission signal. If the difference in amount of delay is ignored, high-precision positioning cannot be performed.

Therefore, in order to correct the deviation of the delay amount, conventionally, a GLONASS receiver is provided with a fixed correction value for each frequency, and the relative deviation of the delay amount is corrected.
Positioning is performed with the same delay amount for each frequency (the operation of setting the relative delay amount to 0 is called calibration). That is, since the frequencies used by the 24 satellites are known in advance, these frequencies generated outside the receiver are actually received by the GLONASS receiver, and the delay amount of each frequency is measured. When a correction value for each frequency is calculated to match the delay amount of one frequency and stored in a ROM table or the like in advance, and when signals are received at respective frequencies from each satellite in actual positioning,
Before the arrival time measurement or after the arrival time measurement, the delay amount of each frequency is relatively corrected.

[0005]

As described above, the conventional G
In the LONASS receiver, in order to calibrate each frequency, the relative delay amount based on the frequency difference is corrected by a fixed correction value measured in advance for each frequency. A transmission delay time of a signal inside the receiver changes due to a change in the surrounding environment (particularly, a change in temperature). In this case, there is no problem as long as the delay amount changes at the same frequency, but if the frequency is different as described above, the delay amount is shifted by each frequency, and the relative delay amount deteriorates the positioning accuracy. There was a problem.

The present invention has been made in order to solve such a problem, and performs a real-time calibration for a relative delay amount inside a receiver caused by a change in an ambient environment, thereby preventing deterioration in positioning accuracy. GLON that can be
It is intended to provide an ASS receiver.

[0007]

DISCLOSURE OF THE INVENTION The GLONASS of the present invention
The receiver receives signals from a plurality of satellites having different frequencies, calculates the arrival time, and calibrates the delay time difference in which the transmission delay of the signal generated inside the receiver differs depending on each frequency. GLON
In the ASS receiver, a pilot signal having the same frequency as each of the above-mentioned frequencies is generated inside the receiver, and the delay time of each frequency of the pilot signal is constantly measured. A means for calibrating signal data from the satellite in real time is provided. Therefore, even when the surrounding environment changes, such as a temperature change, the positioning accuracy can be kept high.

As a specific configuration, a pilot signal generator for generating a pilot signal having the same frequency and a different modulation code as each signal from a satellite at a reference clock timing, and a pilot signal generated by the pilot signal generator are provided. A signal combiner for combining with a real satellite signal input from an antenna unit, a pilot signal for measuring a delay time for each frequency of a pilot signal received by a pilot signal receiving channel unit via a receiving unit using the reference clock timing. A delay processing unit that inputs delay time information for each frequency measured by the delay time measurement unit and the pilot signal delay time measurement unit to the calibration processing unit and calibrates real satellite signal data being received in real time is provided. It is characterized by having.

Further, when each signal from the satellite is subjected to a Doppler frequency shift, a pilot signal having the same frequency shift is used as the pilot signal. The measurement of the delay time of each frequency of the pilot signal is performed by a rotation method for each frequency of the pilot signal. Also, a PN code for GPS is used as a modulation code of the pilot signal.

[0010] The present invention is characterized in that a constant delay filter is used for the BPF provided in the antenna unit. With such a configuration, the relative delay amount of a portion that cannot be corrected by the pilot signal can be reduced.

Further, the invention is characterized in that the pilot signal generator and the signal combiner are connected by a strip line. With such a configuration, it is possible to prevent an error from occurring in a portion unrelated to a signal from a satellite.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention. In the figure, 1 is a transmission frequency of 1602.5625 MHz to 1615.5 MHz used by the GLONASS satellite.
G that converts the frequency of the signal of about 14 MHz band into an IF signal
The lonass receiving section 2-1 receives a real satellite signal from the IF signal output from the receiving section 1 and a satellite signal receiving channel section for tracking the signal, and the section 3 sets a frequency according to a satellite to be received. Frequency setting section for reception, 4
Is a real satellite signal processing unit for processing signals from satellites, 5 is a calibration processing unit 30 for calibrating the signal processed by the real satellite signal processing unit 4, executes positioning calculation, and controls the entire apparatus. These are the same as the conventional GLONASS receiver.

Here, reception and tracking of an actual satellite signal performed by the satellite signal reception channel unit 2-1 will be described.
The satellite signal receiving channel unit 2-1 has 24 GLONA
It consists of 12 channels, which is the maximum number of SS satellites that can receive the signal at the same time. The IF signal input to the carrier correlator is correlated with the carrier generated by the carrier generator, and the carrier frequency and its phase An error is detected. Similarly, the code correlator correlates with the code generated by the code generator, detects a code phase error, and sends the detected code phase error, carrier frequency and its phase error to the actual satellite signal processing unit 4. The signal is processed here, converted into operation information, and sent to the CPU 5. In the CPU 5, a code generator,
The control amount of the carrier generator is calculated, and the difference between the code phase, the carrier frequency, and the phase of the input IF signal and the code phase, the carrier frequency, and the phase generated by the code generator and the carrier generator are zero. So that
The reception frequency setting unit 3 tracks a signal from a satellite while controlling the carrier generator and the code generator. Therefore, even if the signal from the satellite fluctuates in frequency due to Doppler frequency shift or the like, the signal from the satellite can be continuously tracked.

2-2 is the I output from the receiver 1.
A dedicated pilot signal receiving channel section for receiving a pilot signal from the F signal exclusively; 6 a pilot signal processing section for processing the pilot signal; 7 a detection time of the pilot signal detected by the pilot signal processing section and a pilot signal. A pilot signal delay time measuring unit for measuring the delay time of the pilot signal at the time when the pilot signal is generated, 8 a pilot signal frequency setting unit for setting the frequency of the pilot signal, and 9 a pilot signal generation timing for controlling the timing of generating the pilot signal. A control unit 10 is a reference clock generation unit for synchronizing each unit of the receiver, 11 is a pilot signal generation unit, and 12 is a signal synthesizer that synthesizes a satellite signal from an antenna and a pilot signal generated by the pilot signal generation unit 11. These are the parts that are newly provided in the present embodiment. That.

Next, the operation will be described. As described above, in GLONASS, the transmission frequency of the signal from each satellite is different, but since this frequency is known in advance, the pilot signal generator 11 generates a pilot signal which is a pseudo signal having the same frequency as these frequencies. Let it. Since this pilot signal must be distinguished from the real signal from the satellite, a code (for example, G
A signal modulated with a PN code for PS) is used. Therefore, the pilot signal generator 11 basically needs to generate a pilot signal of the GPS PN code of each frequency of the satellite 24, but the actual signal from the satellite receives the Doppler frequency shift. Therefore, it is necessary to consider this Doppler frequency shift in order to execute a highly accurate calibration. Accordingly, the CPU 5 measures and holds the Doppler frequency shift of the satellite calculated in the previous positioning, and the pilot signal frequency setting unit 8 performs pilot control in consideration of the frequency shift information sent from the CPU 5. The frequency of the pilot signal generated by the signal generator 11 can be set.

The pilot signal generated by the pilot signal generator 11 according to a command from the pilot signal generation timing controller 9 is applied to a signal synthesizer 12 at the clock timing from the reference clock generator 10, where the signal from the satellite is transmitted. Signal and GLONASS receiving unit 2
Is input to The pilot signal converted into an IF signal together with the signal from the satellite by the GLONASS receiving unit 2 is tracked by the signal received by the dedicated receiving channel unit for pilot signal 2-2 and received in the same manner as the signal from the actual satellite. Done. Here, the reason why the tracking of the pilot signal is performed is to prevent the deviation due to the frequency fluctuation of the oscillator that generates the pilot signal and to delay the delay generated in the receiver in the same manner as the real signal from the satellite. . Then, the pilot signal processing unit 6 performs the same signal processing as that of the real satellite signal processing unit 4 and sends the signal to the pilot signal delay time measuring unit 7 to measure the reception time of the pilot signal by the reference clock. The pilot signal delay time measuring section 7 includes a pilot signal generation timing control section 9.
The information on the time when the pilot signal was generated is input from the CPU. The delay time of the pilot signal generated inside the receiver is measured based on the generation time and the reception time. This information is input to the CPU 5 and the calibration of the CPU 5 is performed. The processing unit performs a calibration process of the actual signal from the satellite. The pilot signal generator 11 generates a required number (frequency) of pilot signals for each frequency by a rotation method, and measures the delay time for each frequency by a rotation method for each frequency.

FIG. 2 is a diagram for explaining a calibration process performed by the calibration processing unit 30 of the CPU 5. For example, as shown in FIG. 2A, when the delay times in the receiver of the 12 pilot frequencies are respectively the delay times indicated by black points, the delay time of a certain frequency (for example, a1) is changed to the delay time of all other frequencies. , The relative delay amount can be made zero. Therefore, as shown in FIG. 2 (B), a correction value for reducing the delay time is calculated for a frequency with a delay time longer than a1 (+ side) at other frequencies, and a frequency with a delay time shorter than a1 increases the delay time. Is calculated, a correction value is calculated such that all frequencies have the same delay time as a1, and time correction is performed on the arrival time of the signal frequency from the actual satellite (this is correction of the measurement time). + And-can be easily corrected,
Alternatively, the delay time of each frequency may be made to match the delay time of the frequency having the largest delay time.)

That is, the calibration performed in the present embodiment is the same as the satellite signal inside the receiver (if the actual satellite signal contains a Doppler frequency shift, it is shifted similarly).
A plurality of pilot signals of a frequency are constantly flowed by a rotation method, a delay amount for each frequency is appropriately measured, and a correction value that makes the delay amount the same at all frequencies is appropriately calculated. Is appropriately corrected with this correction value for the same frequency,
Real-time calibration can be performed, and even if there is a change in the receiver environment such as a temperature change, calibration corresponding to the change can be performed.

In the present embodiment, the calibration is performed as described above, but a configuration in which more accurate calibration can be performed may be adopted. In other words, the signal from the actual satellite is slightly delayed from the antenna unit to the signal combiner because the transmission signal is delayed, so that the delay amount is shifted. In the pilot signal, the pilot signal generation unit 11 and the pilot signal Since the delay in the transmission path from the signal generator 11 to the signal combiner 12 also varies,
If the configuration is such that the relative delay amounts of these portions are suppressed as much as possible, more accurate calibration can be performed.

FIG. 3 is a diagram showing an embodiment of the configuration from the antenna to the signal combiner 12, wherein reference numeral 31 denotes an antenna,
32 and 34 are amplifiers, and 33 is a B using a constant delay filter.
PF (band pass filter), 35 is a coaxial cable. It is known that the signal delay in this portion mainly occurs in the BPF 33. Therefore, by using a configuration as shown in FIG. 3 using a constant delay filter for the BPF, the relative delay amount can be reduced to 1 nsec or less. can do.

FIG. 4 is a block diagram showing an embodiment of the configuration of the pilot signal generator 11, wherein 40 is a pilot signal carrier oscillator, 41 is an LPF (low-pass filter), and 42, 44, and 46 are signals. A synthesizer, 43 is a BPF, 45 and 47 are frequency dividers, 48 is a voltage controlled oscillator,
Reference numeral 49 denotes a pilot signal code generator.

The pilot signal generator 11 is configured as shown in FIG. 4 and modulated using a 1.6 GHz band as a carrier wave, and a strip line is used for a transmission line between the pilot signal generator 11 and the signal combiner 10. Thereby, the relative delay amount can be made 0.5 nsec or less. With such a configuration, the error in the positioning accuracy based on the incomplete difference in calibration can be set to several tens cm or less, and a positioning device capable of high-accuracy positioning can be obtained.

In the embodiment shown in FIG. 1, the reception channel section 2-2 dedicated to the pilot signal is provided separately. However, the apparatus configuration shown in FIG. 1 is one embodiment.
For example, since the pilot signal receiving channel section 2-2 and the satellite signal receiving channel section 2-1 have the same configuration hardware, the pilot signal is received and tracked using an empty channel of the satellite signal receiving channel section 2-1. Needless to say, the present invention is not limited to the device configuration shown in FIG. Further, the calibration may be performed at the stage of measuring the arrival time of the signal from the satellite or at the stage of calculating the positioning data.

[0024]

As described above, the GLONA of the present invention is described.
The SS receiver can calibrate in real time the deviation of the delay amount based on the difference in frequency generated in the receiver due to changes in the surrounding environment, and can obtain a positioning device capable of performing high-accuracy positioning using GLONASS. There is.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a calibration process.

FIG. 3 is a diagram illustrating an embodiment from an antenna to a signal combiner.

FIG. 4 is a diagram illustrating an embodiment of a pilot signal generator.

[Explanation of symbols]

 Reference Signs List 1 GLONASS receiving section 2-1 Satellite signal receiving channel section 2-2 Satellite signal receiving channel section 3 Receiving frequency setting section 4 Real satellite signal processing section 5 CPU 6 Pilot signal processing section 7 Pilot signal delay time measuring section 8 Pilot signal Frequency setting unit 9 Pilot signal generation timing control unit 10 Reference clock generation unit 11 Pilot signal generation unit 12 Signal combiner 30 Calibration processing unit 31 Antenna 32, 34 Amplifier 33 Constant delay BPF 35 Coaxial cable 40 Pilot signal carrier generator 41 LPFs 42, 44, 46 Signal synthesizer 43 BPF 45, 47 Divider 48 Voltage controlled oscillator 49 Code generator for pilot signal

Claims (7)

[Claims] 1. A method for receiving signals from a plurality of satellites having different frequencies, calculating arrival times thereof, and calibrating a delay time difference in which a transmission delay of a signal generated inside the receiver differs depending on each frequency. GL
In the ONASS receiver, a pilot signal having the same frequency as each of the above-mentioned frequencies is generated inside the receiver, and the delay time of each frequency of the pilot signal is constantly measured. A GLONASS receiver comprising means for calibrating signal data from the satellite in real time. 2. Receiving signals of different frequencies from a plurality of satellites input from an antenna unit for each frequency, measuring the arrival time of the received signals from the satellites, and generating the signals inside the receiver. In a GLONASS receiver for calibrating in a calibration processing unit a delay in a transmission delay of a signal to be transmitted which varies depending on each frequency, a pilot signal having the same frequency as each signal from the satellite and having a different modulation code is used as a reference clock timing. A pilot signal generation unit generated by the pilot signal generation unit; a signal synthesizer that synthesizes the pilot signal generated by the pilot signal generation unit with a real satellite signal input from the antenna unit; and a pilot signal reception channel unit via a reception unit. The delay time for each frequency of the pilot signal is referred to as the reference clock timer. A pilot signal delay time measuring unit that measures by using an imaging, delay time information for each frequency measured by the pilot signal delay time measuring unit is input to the calibration processing unit, and real satellite signal data being received is processed in real time. A GLONASS receiver, comprising: a calibration processing unit for performing calibration on the GLASS. 3. The pilot signal according to claim 1, wherein, when each signal from a satellite is subjected to a Doppler frequency shift, a pilot signal having the same frequency shift is used as the pilot signal. A GLONASS receiver as described. 4. The method according to claim 1, wherein the delay time of each frequency of the pilot signal is measured by a rotation method for each frequency of the pilot signal.
A GLONASS receiver as described. 5. The modulation code of the pilot signal includes:
3. The GLONASS receiver according to claim 2, wherein a PN code for GPS is used. 6. A BPF provided in the antenna unit,
6. The GLONASS receiver according to claim 2, wherein a constant delay filter is used. 7. The GLONA according to claim 2, wherein a strip line is connected between the pilot signal generator and the signal combiner.
SS receiver.