JP3557024B2 - Positioning device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a positioning device using a GPS satellite.
[0002]
[Prior art]
FIG. 2 is a diagram for explaining a positioning device using a conventional GPS satellite. In the drawing, reference numeral 1 denotes a GPS satellite, 2 denotes a GPS antenna, 3 denotes a GPS receiving unit, and 4 denotes a GPS positioning calculating unit.
The operation of a positioning device using a GPS satellite as shown in FIG. 2 is well known, but a radio wave from a GPS satellite 1 is received by a GPS antenna 2, and a satellite / positioning device called a pseudo-range is received by a GPS receiver 3. Information on the distance between the two, and information on the Doppler velocity between the satellite and the positioning device caused by the movement of the positioning device (a moving object equipped with the positioning device) are output, and the GPS positioning calculation unit 4 outputs four or more satellites. The absolute position and the moving speed of the positioning device (the moving body on which the positioning device is mounted) can be obtained by calculation from the pseudo distance from and the Doppler speed.
A method of obtaining the absolute position and velocity of a moving object using the GPS satellites is well known, but is described in, for example, "Precision Positioning System Using GPS-Artificial Satellites" published by the Japan Geodetic Society and edited by the Geodetic Society of Japan. I have.
[0003]
[Problems to be solved by the invention]
As described above, in the conventional positioning device using a GPS satellite, since the position and the speed are obtained only by the radio wave from the GPS satellite, the accuracy and reliability of the obtained information are limited.
As described above, the conventional positioning device using GPS satellites performs positioning based on pseudoranges obtained from four or more satellites, but outputs a completely wrong position due to the reception state of radio waves from the satellites and the like. Therefore, some positioning devices of this type include a calculation for outputting accurate positioning information by limiting a range that can be located at that time from the relationship between the measured speed and time, for example, speed. The calculation is performed by using a differential equation constituting a Kalman filter using information as an observation value of a non-stationary signal, and the position information is output. Because the Doppler velocity measured in the above is used, its reliability is limited.
[0004]
Further, for example, in the case of a car navigation device or the like, the positioning information is output by switching to dead reckoning while the radio wave from the satellite cannot be received, but in this case, the conventional positioning device cannot obtain any information from outside. Therefore, the positioning accuracy and the reliability are reduced.
[0005]
The present invention has been made in order to solve such a problem, and it is possible to obtain information from other sources than satellites at all times, and to obtain highly reliable information while receiving radio waves from satellites and performing dead reckoning navigation. It is an object of the present invention to provide a positioning device capable of obtaining highly accurate positioning information.
[0006]
[Means for Solving the Problems]
The positioning device according to the present invention includes means for measuring a radio frequency Doppler speed of a terrestrial radio signal such as an FM broadcast, a TV broadcast, a mobile phone base station signal, and a PHS base station signal. By using it as one of the calculation factors, the accuracy and reliability of the position and velocity information obtained by the GPS satellites and dead reckoning are ensured.
[0007]
That is, a radio wave from a GPS satellite is received to obtain pseudo-distance information between a GPS satellite and a device and Doppler velocity information (this Doppler velocity information is tentatively referred to as first Doppler velocity information). In a positioning device that outputs information on the position and speed of a device (a moving body equipped with the device) by calculation using first Doppler speed information as a calculation factor,
Means for receiving a terrestrial radio signal and obtaining Doppler velocity information of the apparatus (a moving body equipped with the apparatus) from the frequency displacement of the terrestrial radio signal (this Doppler velocity information is tentatively referred to as second Doppler velocity information);
Means for outputting information on the position and speed of the device (moving body on which the device is mounted) by calculation using the pseudo distance information, the first Doppler speed information, and the second Doppler speed information as calculation factors. It is characterized by having.
[0008]
Means for receiving the ground radio signal and obtaining the second Doppler velocity information of the device (a moving body equipped with the device) from the frequency displacement of the ground radio signal,
The frequency of the terrestrial radio signal is compared with a reference frequency from an oscillator provided in the device to measure the frequency displacement, and the oscillator is controlled to oscillate at the frequency of a radio wave received from a GPS satellite. And
[0009]
With the above-described configuration, the positioning device of the present invention can also use information other than radio waves from GPS satellites as calculation factors, and is not affected by an increase in the number of calculation factors and the reception state of radio waves from GPS satellites. The calculation of the positioning information can be performed by the calculation factor.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram for explaining an embodiment of the present invention. In the drawing, reference numeral 1 denotes a GPS satellite, 2 denotes a GPS antenna, 3 denotes a GPS receiving unit, and 4 denotes a GPS positioning calculating unit. The configuration is the same as that of the conventional positioning device.
10 is a receiving antenna for receiving terrestrial radio signals such as FM broadcasting, TV broadcasting, mobile phone base station signals, and PHS base station signals, and 11 is for receiving terrestrial radio signals and measuring the Doppler frequency displacement thereof for positioning. A broadcast receiving unit 12 for detecting a Doppler speed of the apparatus (mobile body), and an oscillator 12 for outputting a reference frequency used for detecting a Doppler frequency in the broadcast receiving unit 11, is a positioning device according to the present embodiment. Is configured.
Reference numeral 13 denotes an oscillator, reference numeral 14 denotes a broadcast transmitting unit, and reference numeral 15 denotes a transmission antenna, which is a component related to the present embodiment among terrestrial radio stations such as an FM broadcast station for transmitting terrestrial radio signals.
[0011]
Next, the operation will be described. Radio waves from a GPS satellite 1 are received by a GPS antenna 2 like a conventional device, and a GPS receiver 3 receives information on a distance between a satellite and a positioning device, called a pseudo distance, and a positioning device (with this positioning device mounted). Information on the Doppler velocity between the satellite and the positioning device (hereinafter referred to as first Doppler velocity information) generated by the movement of the moving object) is output and sent to the GPS positioning calculation unit 4.
On the other hand, a terrestrial radio station composed of 13 to 15 generally has an accurate oscillator 13 using rubidium or cesium, so that a terrestrial radio signal transmitted via the transmission antenna 15 is 10 ⁻ A signal of an accurate frequency having a relative error accuracy of ⁹ or less is transmitted. For example, a frequency error of a terrestrial radio signal transmitted from a broadcasting station having a carrier frequency standard value of 90 MHz is only 0.09 Hz.
[0012]
This terrestrial radio signal is received by the positioning device of the present embodiment via the receiving antenna 10, and the broadcast receiving unit 11 uses the terrestrial radio signal based on the reference frequency from the oscillator 12 to determine the position of the terrestrial radio signal (with this positioning device installed). A Doppler velocity, which is a frequency displacement accompanying the movement of the moving object), is detected (second Doppler velocity information) and output to the GPS positioning calculation unit 4.
The GPS positioning calculation unit 4 adds information on a distance between the satellite and the positioning device called a pseudo distance from the GPS receiving unit 3 and information on a first Doppler velocity between the satellite and the positioning device caused by movement of the positioning device. Then, the position and the speed of the positioning device (the moving body on which the positioning device is mounted) are output using the information of the second Doppler speed output from the broadcast receiving unit 11.
In this case, the information on the second Doppler speed from the broadcast receiving unit 11 can be obtained by assuming that the terrestrial radio station is a GPS satellite fixed on the ground, as in the pseudo-range from the GPS satellite and the Doppler speed. The positioning information is output by a calculation using more calculation factors than the conventional device by using a sequential expression that constitutes a Kalman filter with the observation value of the signal and the absolute position and speed of the positioning device as state variables. And more accurate and reliable positioning information can be obtained.
If a plurality of terrestrial radio signals are used, it is needless to say that positioning information can be output using even more calculation factors, and the accuracy and reliability of the output positioning information can be further improved.
[0013]
In order for the broadcast receiving unit 11 to obtain accurate second Doppler velocity information from the terrestrial radio signal, the reference frequency used for its detection needs to be accurate. For this reason, rubidium or cesium is also used in the oscillator 12. Although a high-precision oscillator used is required, it is well known that the reception frequency received from the GPS satellite 1 can be obtained very accurately, and this frequency is used as a control signal, for example, in a PLL (Phase Locked Loop) control. If the oscillator 12 is controlled by using a low-cost crystal oscillator or the like as the oscillator 5, an accurate frequency with a relative error of 10 ⁻⁹ or less can be obtained as a reference frequency. Is far from the terrestrial radio station, the frequency displacement at the carrier frequency standard value of 90 MHz is 0.83 Hz, and the frequency error is Since the value is sufficiently larger than 0.09 Hz, sufficient speed information for positioning calculation can be obtained.
[0014]
Note that when a high-precision oscillator such as rubidium or cesium is used as the oscillator 12, it is not necessary to receive a GPS satellite, and can be used for performing dead reckoning navigation.
[0015]
【The invention's effect】
As described above, the positioning device of the present invention performs a calculation using not only the information received from the GPS satellites but also the Doppler speed obtained from the terrestrial radio signal as a calculation factor, and outputs position and speed positioning information. Therefore, there are effects that the positioning accuracy can be improved and highly reliable positioning information can be output.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining an embodiment of a positioning device of the present invention.
FIG. 2 is a diagram for explaining a conventional positioning device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 GPS satellite 2 GPS antenna 3 GPS receiving part 4 GPS positioning calculation part 10 Receiving antenna 11 Broadcast receiving part 12 Oscillator 13 Oscillator 14 Broadcast transmitting part 15 Transmitting antenna

Claims (2)

Radio waves from GPS satellites are received to obtain pseudo distance information between GPS satellites and devices and Doppler velocity information (this Doppler velocity information is tentatively referred to as first Doppler velocity information), and these pseudo distance information and first Doppler velocity information are obtained. In a positioning device that outputs information on the position and speed of the device (a moving body equipped with the device) by calculation using Doppler speed information of
Means for receiving a terrestrial radio signal and obtaining Doppler velocity information of the apparatus (a moving body equipped with the apparatus) from the frequency displacement of the terrestrial radio signal (this Doppler velocity information is tentatively referred to as second Doppler velocity information);
Means for outputting information on the position and speed of the device (moving body on which the device is mounted) by calculation using the pseudo distance information, the first Doppler speed information, and the second Doppler speed information as calculation factors;
A positioning device comprising: Means for receiving the above-mentioned terrestrial radio signal and obtaining second Doppler velocity information of the device (a mobile body equipped with the device) from the frequency displacement of the terrestrial radio signal,
The frequency of the terrestrial radio signal is compared with a reference frequency from an oscillator provided in the device to measure the frequency displacement, and the oscillator is controlled to oscillate at the frequency of a radio wave received from a GPS satellite. The positioning device according to claim 1, wherein:

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