JP2013195159A - Positioning system, and pseudo signal transmitter and receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positioning system and a pseudo signal transmitter and receiver that allow only a specific receiver out of receivers compatible with a GNSS to receive a signal, and allow receivers other than the specific receiver not to be affected by the signal.SOLUTION: A pseudo signal transmitter 1 transmits a pseudo signal pseudo-reproducing a signal of a GPS satellite 3 inside a building or underground. The pseudo signal transmitter 1 changes an intrinsic frequency off-set subjected to a Doppler shift of the GPS satellite 3 according to a predetermined rule, and transmits the pseudo signal at a frequency in accordance with a changed frequency off-set. Thus, a specific GPS receiver 2 grasping the predetermined rule is allowed to receive the pseudo signal and perform a determination of a positioning and a time. Contrary to this, an existing GPS receiver has no idea about the rule and thus, does not perform the determination of the positioning and the time on the basis of the pseudo signal. That is why the frequency off-set is changed from the intrinsic frequency off-set.

Description

  The present invention relates to a positioning system, and more particularly to a technique for transmitting and receiving a pseudo positioning signal indoors or underground.

  Currently, a global positioning system (GPS) known as a global navigation satellite system (GNSS) is widely used. The GPS receiving device receives a positioning signal transmitted by a GPS satellite and executes positioning. On the other hand, signals from GPS satellites often cannot be received indoors or underground. Therefore, there is a need for an auxiliary system for causing a GPS receiver that is indoors or underground to receive a positioning signal.

  In the inventions described in Patent Documents 1 to 7, it is proposed that a transmission device that artificially generates a signal transmitted by a GPS satellite is disposed indoors or underground. Further, according to Patent Document 8, an apparatus for retransmitting a signal received from a GPS satellite indoors is proposed. Patent Documents 9 to 12 propose a pseudolite or an indoor messaging system (IMES) as an indoor positioning system. Note that pseudolite and IMES are not compatible with widely used GPS receivers. According to Patent Document 13, a device that transmits a signal for causing a GNSS-compatible receiving device to acquire position information and time information indoors or underground is proposed.

Japanese Patent Laid-Open No. 11-304900 JP 2004-286494 A JP 2006-20151 A JP 2008-128934 A Japanese Patent Laid-Open No. 11-304900 JP 2001-507443 A JP 2007-212162 A JP 2007-218651 A JP 07-159508 A JP 2007-278756 A JP 2008-96452 A JP 2009-05928 A JP 2011-242191 A

  In the invention described in Patent Document 13, since a plurality of pseudo satellite signals are multiplexed and transmitted by a single transmitter, it is easy to realize simplification of the device configuration and cost reduction. Of course, if the invention described in Patent Document 13 is used, a GNSS-compatible receiving device can acquire position information and time information indoors or underground.

  However, there is a need to allow only a specific receiving device to receive a signal among the GNSS-compatible receiving devices and to prevent other receiving devices from being affected by this signal. For example, a signal transmitted from a pseudo GNSS satellite (transmitting device) placed indoors to a specific receiving device may cause other receiving devices that receive signals from real GNSS satellites in space to interfere. It is desirable not to receive. In particular, nearly 20 years have passed since the spread of GPS receivers, and the impact on such existing GPS receivers will have to be minimized. Therefore, an object of the present invention is to make a signal received only by a specific receiving device out of GNSS-compatible receiving devices and to make the other receiving devices less likely to be affected by this signal.

The present invention
A positioning system comprising: a receiving device; and a transmitting device that includes position information for measuring the position of the receiving device and time information indicating time, and transmits a pseudo signal of a signal transmitted from a satellite,
The transmitter is
Changing means for changing the frequency offset due to the original Doppler shift of the satellite flying over the installation site where the transmitter is installed according to a predetermined rule;
Transmitting means for transmitting a pseudo signal at a frequency according to the frequency offset changed by the changing means,
The receiving device is:
Receiving means for receiving the pseudo signal transmitted by the transmitting means of the transmitting device;
Determining means for returning the frequency offset changed by the changing means to the original frequency offset according to the predetermined rule, correlating the pseudo signal, and determining at least one of the position and time of the receiving device; A positioning system is provided.

The present invention also provides:
A pseudo signal including position information for measuring the position of the receiving device and time information indicating the time, the transmitting device transmitting the pseudo signal of the signal transmitted from the satellite,
Changing means for changing the frequency offset due to the original Doppler shift of the satellite flying over the installation site where the transmitter is installed according to a predetermined rule;
There is provided a transmission apparatus comprising: transmission means for transmitting a pseudo signal at a frequency corresponding to the frequency offset changed by the changing means.

Furthermore, the present invention provides
A receiver that receives a pseudo signal of a signal transmitted from a satellite from a transmitter and obtains a position and time,
Receiving means for receiving the pseudo signal transmitted by the transmitting device;
Determining means for returning the frequency offset of the pseudo signal to the original frequency offset according to a predetermined rule, correlating the pseudo signal, and determining at least one of a position and a time of the receiving device. Is provided.

  According to the present invention, the frequency offset due to the original Doppler shift of the satellite is changed according to a predetermined rule, and the pseudo signal is transmitted at a frequency corresponding to the changed frequency offset. It is possible to receive and position. In addition, since the frequency offset due to the Doppler shift is changed, a reception device other than the specific reception device is hardly affected by the pseudo signal.

FIG. 1 is a diagram showing a positioning system of the present invention. FIG. 2 is a block diagram showing the pseudo signal transmitting apparatus 1. FIG. 3 is a block diagram showing the GPS receiver 2. FIG. 4 is a diagram illustrating a predetermined rule for changing the frequency offset fd (t). FIG. 5 is a diagram illustrating a predetermined rule for changing the frequency offset fd (t). FIG. 6 is a diagram illustrating a predetermined rule for changing the frequency offset fd (t). FIG. 7 is a diagram illustrating a predetermined rule for changing the frequency offset fd (t).

  EMBODIMENT OF THE INVENTION The form for implementing this invention is demonstrated in detail below using drawing. In the following description, a pseudo signal of a signal transmitted by a GPS satellite (Navstar) is generated by a pseudo signal transmitting device and transmitted to the GPS receiving device. However, the present invention is not limited to other GNSS satellites. It can also be applied to pseudo signal generation.

  FIG. 1 shows a positioning system of the present invention. The pseudo signal transmission device 1 is a device that generates and transmits a pseudo signal of a signal transmitted from the GPS satellite 3. The pseudo signal includes position information for measuring the position of the GPS receiver 2 and time information indicating the time. The pseudo signal transmission device 1 is generally installed in an area where it is difficult to receive a signal transmitted by the GPS satellite 3, for example, indoors such as a building or underground facilities such as an underground shopping center or a subway station. The GPS receiving device 2 may receive a signal from the GPS satellite 3 and perform positioning, or may receive the pseudo signal received from the pseudo signal transmitting device 1 and perform positioning. The positioning is generally a process for acquiring the position information of the GPS receiver 2, but in a broad sense, it also includes a process for acquiring time information indicating the current time.

  The pseudo signal transmission device 1 generates and transmits a signal transmitted by the GPS satellite 3 flying over the place where the pseudo signal transmission device 1 is installed. Since the GPS satellite 3 is constantly moving, the distance between the GPS satellite 3 and the GPS receiver 2 is also variable. That is, since the GPS satellite 3 moves, the transmission signal from the GPS satellite 3 is affected by the Doppler effect. Here, the frequency shift due to the Doppler effect is referred to as a Doppler shift. Therefore, the pseudo signal transmission device 1 reflects the Doppler shift amount (hereinafter referred to as frequency offset) by the Doppler shift in the pseudo signal. Note that this pseudo signal generation method has already been described in Patent Document 13 and the like, and is therefore omitted here. In general, the sky is not only the position on the orbit of the GPS satellite 3 that is the shortest distance from the place where the pseudo signal transmission device 1 is installed, but also the pseudo signal transmission device 1 is installed. It means the position on the orbit where the radio wave can be received by the GPS receiver 2 from the roof of the building.

  In particular, in the present invention, the specific GPS receiving device 2 can perform positioning by receiving a pseudo signal, but the existing GPS receiving device is devised so as not to perform an unintended operation by the pseudo signal. For example, the pseudo signal transmission device 1 changes the frequency offset due to the original Doppler shift for the GPS satellite 3 in accordance with a predetermined rule, and transmits the pseudo signal at the carrier frequency corresponding to the changed frequency offset. The predetermined rule may be stored in the storage device included in the pseudo signal transmission device 1 or may be stored in the server device 5 connected via the network 4. The GPS receiver 2 of the present invention receives the pseudo signal transmitted by the pseudo signal transmitter 1, and returns the frequency offset applied to the pseudo signal to the original frequency offset according to a predetermined rule to correlate the pseudo signal. Process and determine at least one of the position and time of the GPS receiver 2. As described above, the pseudo signal transmission device 1 and the GPS reception device 2 need to share a rule for modifying the frequency offset of the Doppler shift. The GPS receiving device 2 may store the rules in a storage device included in the GPS receiving device 2 or may obtain the rules from the server device 5 through the access device 6. The access device 6 may be a mobile phone network base station, a WiMAX (registered trademark) base station, a wireless LAN access point, or the like.

  FIG. 2 is a block diagram showing the pseudo signal transmitting apparatus 1. The processor 10 is a CPU, MPU, ASIC, or the like, and has a plurality of functions. The processor 10 communicates with the server device 5 via the network interface 11 and receives a rule for changing the frequency offset by Doppler shift, a rule for changing the code offset of the C / A code, time information, satellite information, and the like. The time information is time information synchronized with a reference time with high accuracy by a time synchronization protocol such as NTP (Network Timing Protocol) or PTP (Precision Time Protocol) defined by IEEE 1588. The time information processing unit 12 acquires time information from the server device 5 and holds it. The satellite information includes information on each satellite to be simulated, specifically, orbit information for specifying the orbit of the satellite, information on the PRN code assigned to the satellite for code division multiplexing, and the like. PRN is pseudo noise (Pseudo Random Noise). The satellite information processing unit 13 acquires satellite information from the server device 5 and holds it. In addition, the satellite information processing unit 13 calculates the position of each satellite from the orbit information, identifies the satellite that passes over the place where the pseudo signal transmission device 1 is installed, and uses the identified satellite information as the pseudo signal. The data is passed to the generation unit 14. The satellite passing through the sky is a satellite that can receive signals from the rooftop of the floor where the pseudo signal transmission device 1 is installed. Since the GPS satellite 3 orbits the earth, it cannot be seen from the roof of the installation place in a certain time zone. In such an invisible time zone, the pseudo signal transmission device 1 omits the transmission of the pseudo signal of the GPS satellite 3. In addition, the satellite information processing unit 13 passes the distance and speed information about the GPS satellite 3 to the pseudo signal generation unit 14.

  The pseudo signal generation unit 14 generates a signal (pseudo signal) that simulates a signal transmitted by the GPS satellite 3 according to the time information received from the time information processing unit 12 and the satellite information received from the satellite information processing unit 13. The navigation message generator 15 generates a navigation message of the simulation target GPS satellite 3 based on the satellite information. The PRN code generator 16 generates a PRN code for the simulation target satellite based on the satellite information. The PRN code is a spreading code for performing code division multiplexing. The GPS receiver 2 acquires the transmission timing of the PRN code from the GPS satellite 3 based on the PRN code, and transmits the position information of the satellite and the The transmission time of the PRN code is acquired. The GPS receiver 2 acquires time information synchronized with UTC (Coordinated Universal Time) and current position information by receiving signals from four or more GPS satellites. The EXOR unit 17 outputs a C / A code that is an exclusive OR value of the PRN code generated by the PRN code generator 16 and the satellite navigation message generated by the navigation message generator 15.

  The Doppler shift controller 18 obtains a change amount of the frequency caused by the Doppler effect based on the speed of the satellite to be simulated, and changes the frequency of the C / A code output from the EXOR unit 17 by this change amount. Thereby, the Doppler shift which arises with the speed of the GPS satellite 3 seen from the installation place is given to the pseudo signal of the GPS satellite 3 to be simulated.

  The delay controller 19 gives a propagation delay corresponding to the distance between the installation location and the GPS satellite 3 to the pseudo signal. The delay controller 19 obtains a propagation delay amount based on the speed and position of the GPS satellite 3 and determines the phase of the C / A code. That is, the propagation delay amount is a code offset of the C / A code. The pseudo signal generated by the pseudo signal generation unit 14 is orthogonally modulated by the RF unit 21 and transmitted from the antenna.

  The changing unit 20 changes the original frequency offset fd (t) to be given by the Doppler shift controller 18 to the frequency offset fd ′ (t) according to a predetermined rule held in the rule holding unit 30. . The Doppler shift controller 18 temporarily outputs the frequency offset fd (t) to the changing unit 20, receives the frequency offset fd ′ (t) from the changing unit 20, and uses the frequency offset fd ′ (t) to perform C Change the frequency of the / A code. As an option, the delay controller 19 may change the code offset of the C / A code in accordance with an instruction from the changing unit 20. The changing unit 20 instructs the delay controller 19 to change the code offset of the C / A code according to a predetermined rule held in the rule holding unit 30. Thus, by changing the frequency offset by the Doppler shift and the code offset of the C / A code from the original one, the existing GPS receiver can demodulate the pseudo signal transmitted by the pseudo signal transmitter 1 of the present invention. Disappear. On the other hand, since the GPS receiver 2 of the present invention can return the frequency offset by the Doppler shift and the code offset of the C / A code to the original one according to a predetermined rule, the pseudo signal transmitter 1 transmits. By demodulating the pseudo signal, position information and time information can be acquired. The rule holding unit 30 may be a ROM or a RAM. Further, the processor 10 may download a predetermined rule from the server device 5 through the network interface 11 and store it in the rule holding unit 30. A predetermined rule may be written in the rule holding unit 30 when the pseudo signal transmission device 1 is shipped from the factory.

  FIG. 3 is a block diagram showing the GPS receiver 2. The RF unit 22 amplifies or frequency-converts the pseudo signal received via the antenna, converts the pseudo signal into a baseband pseudo signal, and outputs the baseband pseudo signal to the baseband unit 29. The baseband unit 29 includes a correlator 23, a positioning unit 24, a rule holding unit 25, a position determination unit 27, and the like. The correlator 23 performs correlation processing on the pseudo signal in consideration of the frequency offset and the code offset according to a predetermined rule held in the rule holding unit 25. The correlator 23 passes the result of the correlation process to the positioning unit 24. The positioning unit 24 acquires position information and satellite information based on the result of the correlation process.

  By the way, the frequency offset and the code offset may be common to all the satellites or may be different. When using a different one, the frequency offset and the code offset may be changed according to the installation location. For example, different frequency offsets and code offsets may be used for the pseudo signal transmission apparatus 1 installed on the first floor and the pseudo signal transmission apparatus 1 installed on the second floor in a building. In this case, the correlator 23 can specify the offset amount actually used by trying correlation processing for a plurality of offset amounts.

  The position determination unit 27 specifies a rough position from the position information obtained by the positioning unit 24, and further specifies a more detailed position based on the offset amount. For example, by assigning a different offset amount to each of the plurality of pseudo signal transmission devices 1, the position determination unit 27 can specify which pseudo signal transmission device 1 has received the signal. Further, if the offset amount and the position information indicating the installation position of the pseudo signal transmission device 1 are previously tabulated or made into a database, the position determination unit 27 determines the position of the installation position of the pseudo signal transmission device 1 from the specified offset amount. Information can be acquired. For example, by setting the offset amount of the pseudo signal transmitting apparatus 1 installed on the first floor in a building to be different from the offset amount of the pseudo signal transmitting apparatus 1 installed on the second floor, the position determination unit 27 can identify whether the GPS receiver 2 is on the first floor or the second floor. The position determination unit 27 acquires the three-dimensional coordinate position and time information from the positioning unit 24, and further specifies the floor information from the offset amount, thereby improving the position information of the GPS receiver 2 to detailed information. it can. This is called refinement of position information. The offset amount and the detailed position information may be held in a storage device such as the rule holding unit 25, or may be downloaded from the server device 5 via the network interface 26. For the present invention, the position determination unit 27 is not essential but optional. The display unit 28 renders and displays a map based on the position information obtained by the positioning unit 24 or the position information refined (refined) by the position determination unit 27. For example, the display unit 28 may display a planar or pseudo-stereoscopic map, and may also display information on the floor and height estimated that the GPS receiver 2 is present. Thus, if the offset amount of the frequency offset and the code offset is made unique, it is useful for improving the accuracy of positioning.

  4 to 7 are diagrams illustrating predetermined rules for changing the frequency offset fd (t). The vertical axis represents the offset amount, and the horizontal axis represents time. fd (t) indicates the frequency offset due to the original Doppler shift, and fd ′ (t) indicates the frequency offset added to the pseudo signal of the present invention. Thus, the frequency offsets fd (t) and fd ′ (t) can be expressed as functions of time, respectively. As is well known, the frequency offset fd (t) is a Doppler shift amount, and is thus obtained from the orbit information of the GPS satellite 3. The orbit information of the GPS satellite 3 is broadcast by a navigation message.

  In FIG. 4, the changing unit 20 determines the frequency offset fd ′ (t) for the pseudo signal by inverting the sign of the frequency offset fd (t) due to the original Doppler shift. That is, fd ′ (t) = − fd (t).

In FIG. 5, when the sign of the original frequency offset fd (t) by the Doppler shift is positive, the changing unit 20 shifts fd (t) by Δ in the positive direction to shift the pseudo signal frequency offset fd ′. (T) is being sought. Further, when the sign of the frequency offset fd (t) due to the original Doppler shift is negative, the changing unit 20 shifts fd (t) by Δ in the negative direction to shift the pseudo signal frequency offset fd ′ (t ) That is, when fd (t)> 0, fd ′ (t) = fd (t) + Δ, and when fd (t) <0, fd ′ (t) = fd (t) −Δ.
In FIG. 6, the changing unit 20 obtains the frequency offset fd ′ (t) of the pseudo signal by shifting the frequency offset fd (t) due to the original Doppler shift every fixed period t1. Here, the shift amount Δ in the positive direction and the shift amount Δ in the negative direction are common, but these shift amounts Δ may be different. Further, the shift in the positive direction and the shift in the negative direction are alternately performed, but they may not be alternately. For example, shifting in the positive direction in the first to second cycles, shifting in the negative direction in the third, and shifting in the positive direction in the fourth to fifth cycles may be repeated. As described above, the changing unit 20 may dynamically change the shift amount added to the frequency offset due to the original Doppler shift.

  In FIG. 7, the changing unit 20 obtains the frequency offset fd ′ (t) of the pseudo signal by shifting the frequency offset fd (t) due to the original Doppler shift with a variable period. In FIG. 7, the shift amount Δ in the positive direction and the shift amount Δ in the negative direction are common, but these shift amounts Δ may be different. As described above, the changing unit 20 may change the shift amount Δ at a constant cycle or a variable cycle.

  4 to 7 show the rules for generating various frequency offsets fd '(t), it is sufficient if the rules used by the pseudo signal transmitter 1 and the GPS receiver 2 are common. In addition, although it may increase noise for an existing GPS receiver, any rule can be used as long as a pseudo signal that does not decisively interfere with reception of a signal from the GPS satellite 3 can be generated. Good. Although the frequency offset has been mainly described, the frequency offset may be changed, and the changing unit 20 may change the code offset (time offset) of the C / A code.

  As described above, according to the present invention, the frequency offset due to the original Doppler shift of the satellite is changed according to a predetermined rule, and the pseudo signal is transmitted at a frequency corresponding to the changed frequency offset. Only the receiving device can receive the pseudo signal and determine the position and time. In addition, since the frequency offset due to the Doppler shift is changed, a reception device other than the specific reception device is hardly affected by the pseudo signal.

As a predetermined rule,
-Rules for inverting the sign of the frequency offset due to the original Doppler shift
When the sign of the frequency offset due to the original Doppler shift is positive, the frequency offset of the pseudo signal is shifted in the positive direction, and when the sign of the frequency offset due to the original Doppler shift is negative, the frequency offset of the pseudo signal・ Rule for dynamically changing the amount of shift added to the frequency offset due to the original Doppler shift ・ Specific example for the rule for changing the amount of shift at a fixed period or variable period I gave it as an explanation. However, it has almost no effect on receiving devices other than the specific receiving device, and on the other hand, what rules are adopted as long as the specific receiving device can receive the pseudo signal and determine the position and time normally. May be. In addition, while artificially changing the frequency offset (shift amount) due to the Doppler shift can be realized relatively easily, it is difficult to affect the existing GPS receiver, and thus the present invention is very excellent. I can say that.

  The predetermined rule may be a rule that is commonly applied to each of the plurality of satellites, or may be a specific rule corresponding to the installation location where the transmission apparatus is installed. The pseudo signal transmission device 1 includes a plurality of pseudo signal generation units 14, so that a single pseudo signal transmission device 1 can perform a simulation operation of a plurality of GPS satellites 3. Therefore, a common rule may be applied to each of the plurality of GPS satellites 3. In particular, if the rule specific to the installation location where the pseudo signal transmission device 1 is installed, the GPS reception device 2 specifies which rule is used for the pseudo signal, thereby refining the position information. Can be realized. For example, if individual rules are set for each floor or individual rules are set for each room, it becomes easy to measure in detail where the user is in the building by the rule matching process.

  In addition to the frequency offset, the time offset (code offset) of the C / A code may optionally be changed. In this case, the pseudo signal transmission device 1 changes the original time offset of the C / A code for each of the plurality of GPS satellites 3 by a predetermined time, and the GPS reception device 2 changes the original code offset of the C / A code. Is restored for a predetermined time, and the pseudo signal is correlated. That is, a very sharp correlation peak is obtained for the C / A code at the timing when the original code offset is restored by a predetermined time. As described above, the above-described refinement of the position information can also be achieved by changing the code offset. In other words, if a database is created by associating multiple types of code offsets with detailed position information (eg, floors and rooms), detailed position information can be obtained from the code offset and database specified by the correlation process. Easy to get. For example, an application in which a floor is specified by a frequency offset and a room is specified by a code offset is also possible.

  The predetermined rule may be stored in a nonvolatile storage device such as a ROM at the time of factory shipment, or may be downloaded from the server device 5 and written or updated. Since indoor positioning is expected to spread in the future, the predetermined rule may be updated according to the spread of the pseudo signal transmission device 1.

Claims (13)

A positioning system comprising: a receiving device; and a transmitting device that includes position information for measuring the position of the receiving device and time information indicating time, and transmits a pseudo signal of a signal transmitted from a satellite,
The transmitter is
Changing means for changing the frequency offset due to the original Doppler shift of the satellite flying over the installation site where the transmitter is installed according to a predetermined rule;
Transmitting means for transmitting a pseudo signal at a frequency according to the frequency offset changed by the changing means,
The receiving device is:
Receiving means for receiving the pseudo signal transmitted by the transmitting means of the transmitting device;
Determining means for returning the frequency offset changed by the changing means to the original frequency offset according to the predetermined rule, correlating the pseudo signal, and determining at least one of the position and time of the receiving device; A positioning system characterized by comprising.   The positioning system according to claim 1, wherein the changing unit determines a frequency offset for the pseudo signal by inverting a sign of a frequency offset due to the original Doppler shift.   When the sign of the frequency offset due to the original Doppler shift is positive, the changing means shifts the frequency offset of the pseudo signal in the positive direction, and when the sign of the frequency offset due to the original Doppler shift is negative. The positioning system according to claim 1, wherein a frequency offset of the pseudo signal is shifted in a negative direction.   The positioning system according to claim 1, wherein the changing unit dynamically changes a shift amount added to the frequency offset due to the original Doppler shift.   The positioning system according to claim 4, wherein the changing unit changes the shift amount at a constant cycle or a variable cycle.   6. The positioning system according to claim 1, wherein the predetermined rule is a common rule for each of a plurality of satellites.   The positioning system according to any one of claims 1 to 5, wherein the predetermined rule is a rule specific to an installation location where the transmission device is installed.   The determination unit specifies which rule is applied to the pseudo signal by executing the correlation process for a plurality of rules, and refines the position of the receiving device based on the specified rule. The positioning system according to claim 7. The transmitter is
The positioning system according to any one of claims 1 to 8, wherein the predetermined rule is downloaded from a server. The receiving device is:
The positioning system according to claim 1, wherein the predetermined rule is downloaded from a server. The changing means changes the original time offset of the C / A code for each of a plurality of satellites by a predetermined time,
The receiving device is:
The positioning system according to any one of claims 1 to 10, wherein the pseudo signal is correlated by returning the original code offset of the C / A code by the predetermined time. A pseudo signal including position information for measuring the position of the receiving device and time information indicating the time, the transmitting device transmitting the pseudo signal of the signal transmitted from the satellite,
Changing means for changing the frequency offset due to the original Doppler shift of the satellite flying over the installation site where the transmitter is installed according to a predetermined rule;
A transmission apparatus comprising: transmission means for transmitting a pseudo signal at a frequency corresponding to the frequency offset changed by the changing means. A receiver that receives a pseudo signal of a signal transmitted from a satellite from a transmitter and obtains a position and time,
Receiving means for receiving the pseudo signal transmitted by the transmitting device;
Determining means for returning the frequency offset of the pseudo signal to the original frequency offset according to a predetermined rule, correlating the pseudo signal, and determining at least one of a position and a time of the receiving device. A receiving device.

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