JPH0894736A - Gps receiver - Google Patents

Abstract

PURPOSE: To provide a GPS receiver, which can obtain the azimuth of a reference point independently by the GPS receiver itself without requiring a magnetic compass, a gyroscope and the like even if a GPS user is in the stationary state. CONSTITUTION: An antenna 1, an antenna moving means 10, an antenna-position detecting part 20 and a reference oscillating part 3 are provided. The radiowave from a GPS satellite and the local oscillating frequency from the reference oscillating part 3 are mixed. A receiving part 2 outputs a 1F signal. A signal processing part 4 performs the synchronization and the tracking of the radiowave from the GPS satellite based on the output of the receiving part 2 and the clock signal formed in the reference oscillating part 3 and outputs the pseudo range data, the pseudo-range changing data and the satellite information data. The position measurement and the bearing computation are performed in this way. An operation memory part 5 stores the respective data, the result of the operation and the like. A display part 6 displays the result of the position measurement and azimuth of the reference point obtained with the operation memory part 5. A data output part 7 outputs the result of the position measurement to external equipment. These parts are also provided.

Description

Detailed Description of the Invention

[0001]

This invention relates to GPS (Global Pos)
itioning System: Global Positioning System).

[0002]

2. Description of the Related Art In a GPS receiver for positioning using GPS, the GPS receiver itself or GPS
An object equipped with a receiver (hereinafter, both are collectively referred to as GPS
User. ) Is in the moving state, GPS
From the Doppler shifts of a plurality of GPS satellite signals generated as the user moves, the moving direction and speed of the GPS user can be calculated as follows. l _i , m _i , n _i (i = 0,1,2,3)
Is the position of the GPS satellite used for positioning of the earth fixed coordinate system (Earth's rotation axis: Z axis Greenwich reference meridian: X axis). ), And the direction vector of the reference GPS satellite (reference direction vector) among them is set as l ₀ , m ₀ , n ₀ . Here, if the difference between the reference direction vector and the direction vector other than the reference GPS satellite is taken, Δl _i = l ₀ −l _i , Δm _i = m ₀ −m _i , Δn _i = n ₀ − n _i (i = 1,2,3) (1). Further, among the Doppler shifts of the signals of the GPS satellites used for positioning, the Doppler shifts excluding the Doppler shifts associated with the orbiting motions of the GPS satellites are orbiting satellites (GPS satellite signals generated with the movement of the GPS user. The Doppler shift of P _i (i = 0,1,2,3),
Among them, the Doppler shift excluding the Doppler shift accompanying the orbital motion of the GPS satellite as the reference is defined as P ₀ . Here, the difference between the Doppler shift P ₀ excluding the Doppler shift associated with the orbital motion of the reference GPS satellite and the Doppler shift P _i excluding the Doppler shift associated with the orbital motion of GPS satellites other than the reference GPS satellite is calculated. Taking this, ΔP _i = P _i −P ₀ (i = 1,2,3) (2).

From (1) and (2), the three-dimensional velocity vectors V _x , V _y , and V _z (moving azimuth and velocity of the GPS user) can be obtained by solving the simultaneous equations of the following three elements. Δl ₁ · V _x + Δm ₁ · V _y + Δn ₁ · V _z = ΔP ₁ Δl ₂ · V _x + Δm ₂ · V _y + Δn ₂ · V _z = ΔP ₂ Δl ₃ · V _x + Δm ₃ · V _y + Δn ₃ · V _z = ΔP ₃

However, when the GPS user is stationary, the Doppler shift (P _i and P ₀ ) that occurs with the movement of the GPS user does not occur, and therefore the direction of the GPS user is related. No information is available.

Therefore, in order to obtain the azimuth (hereinafter referred to as the reference point azimuth) to which the reference relating to the direction of the GPS user is directed when the GPS user is stationary as described above, a magnet compass, a gyro, etc. Had to use.

[0006]

When the GPS user is stationary, a device other than the GPS receiving device such as a magnet compass is required to obtain the reference point direction.

However, due to the characteristic of the magnet compass detecting weak geomagnetism, if any magnetic material is fixedly positioned around the measurement environment or approaches the magnetism irregularly, the influence of them will be great. I received it,
There was a problem that a large error would occur. In addition, the gyro is large in size, and it is inconvenient for a small moving body or a human to move the gyro.

Therefore, according to the present invention, even when the GPS user is stationary, a device other than the GPS receiving device such as a magnetic compass or a gyro is not required, and the GPS receiving device alone can obtain the reference point direction. The purpose is to provide a simple GPS receiver.

[0009]

According to a first embodiment of the present invention, a GPS user is moved by moving an antenna of a GPS receiving device without moving the GPS user, so that the GPS user is moved in a pseudo manner. The moving direction of the antenna is calculated by the Doppler shift of the GPS satellite signal generated by this, and at the same time, one position serving as a reference when the antenna moves is determined, and a timing signal is output when the antenna passes through the reference position. It is generated, and the moving direction of the antenna at the reference position is calculated and output. Also GP
The antenna of the S receiver is rotationally moved in a horizontal plane to utilize the Doppler shift of a plurality of GPS satellite signals generated with the movement of the antenna, and a timing signal is generated when the antenna passes the reference position. Then, the moving direction of the antenna at the reference position is calculated, and at the same time, the direction of the reference position is calculated and output.

In the second embodiment of the present invention, the GP viewed from the positioning position of the GPS user in the positioning using GPS.
The angle from the east of the S satellite and the angle (line of sight) with the horizontal are the satellite orbit information broadcast by the GPS satellites,
It utilizes what is obtained by performing a geometric operation from the positioning position of the GPS user.

Therefore, in the second embodiment, the change in the Doppler shift of the GPS satellite signal generated by moving the antenna of the GPS receiving device at a predetermined period is the line of sight of the GPS satellite obtained by the geometric calculation. It focuses on the close relationship with the direction.

One reference position when the antenna moves is determined, a timing signal is generated when the antenna passes the reference position, and the antenna of the GPS receiving device is moved at a predetermined cycle. By measuring the change in the Doppler shift of the GPS satellite signal generated by the measurement, the time from the timing signal to the singular point of the change in the Doppler shift is measured.
This is to obtain the reference point direction of the PS user.

In order to obtain the reference point azimuth, according to the present invention, the GP
Antenna 1 for receiving radio waves from S satellite, and antenna 1
A moving means 10 for moving the antenna, an antenna position detecting section 20 for detecting the position of the antenna, a reference oscillating section 3, and a radio wave of a GPS satellite via the antenna 1 and a local oscillation signal generated by the reference oscillating section 3 are mixed. Then, the receiving unit 2 which converts the frequency into a frequency that can be easily digitally processed and outputs it, and the output of the receiving unit 2 is synchronized and tracked by the clock signal generated by the reference oscillating unit 3 from the GPS satellite, and the pseudo range is obtained. A signal processing unit 4 that outputs data, pseudo range change data, and satellite information data, and performs positioning calculation calculation and orientation calculation calculation from the data output from the signal processing unit 4, and also stores each data, calculation result, and the like. A calculation storage unit 5, a display unit 6 that displays the positioning result and the reference point azimuth obtained in the calculation storage unit 5, and a data output unit 7 that outputs the positioning result to an external device. .

[0014]

[First Embodiment] FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. The antenna 1 is rotated by a well-known antenna moving means 10 such as a motor-driven antenna rotating mechanism (not shown) in a horizontal plane having a rotation radius r centering on a rotation center a of the antenna rotating mechanism (not shown). ing. Since the antenna 1 is rotated in this way, a state in which the GPS user is moving is created in a pseudo manner.

The receiving unit 2 receives radio waves from GPS satellites via the rotating antenna 1, and also has a reference oscillating unit 3
The local oscillating signal generated in step 1 is mixed with the received radio wave from the GPS satellite, the frequency is converted into a frequency that can be easily processed, and a digital signal of the frequency is output. The signal processor 4 uses the clock signal generated by the reference oscillator 3 to receive the signal from the receiver 2
The digital storage unit 5 synchronizes and tracks the digital signal output of the
Outputs pseudo range data, pseudo range change data, and satellite information data to.

The calculation storage unit 5 performs positioning calculation calculation and reference point azimuth calculation calculation from each data including various Doppler shifts of GPS satellite signals, and also stores each data, the result of each calculation and the like. The display unit 6 displays the positioning position, the reference point azimuth, and the like obtained in the calculation storage unit 5. The data output unit 7 outputs the positioning position, the reference point azimuth, and the like to an external device.

The antenna 1 makes a rotational movement in a horizontal plane with a radius of rotation r centered on the rotation center a of the antenna rotation mechanism. Therefore, the moving direction and speed of the antenna 1 are G
From the Doppler shift of a plurality of GPS satellite signals generated as the PS user moves, the moving direction and speed of the GPS user can be determined.

2. Description of the Related Art As described in (1) and (2) above, the ternary simultaneous equations can be calculated by the calculation storage unit 5, and can be calculated as the tangential direction and velocity. it can.

FIG. 2 shows the antenna 1 in the first embodiment,
It is a figure showing the relation between antenna detection part 20 and a reference point direction. The antenna position detector 20 outputs a position pulse every time the antenna 1 passes through the antenna position detector 20.
The tangential direction δ in the tangential direction of the antenna 1 and the velocity at the time of outputting the position pulse are calculated by the calculation storage unit 5.

The tangential azimuth δ in the tangential direction calculated by the arithmetic storage unit 5 is the tangential azimuth in the circular motion as is clear from FIG. If the rotation direction of the circular motion is counterclockwise, the reference point azimuth γ can be obtained by subtracting 90 degrees from the obtained tangential azimuth δ. The calculation storage unit 5 performs a calculation for subtracting 90 degrees from the calculated tangential direction δ in the tangential direction, and outputs the result to the display unit 6 and the data output unit 7.

FIG. 3 is a flow chart of the first embodiment, which operates as follows. The position pulse from the antenna position detector 20 is detected (S200). The azimuth δ from the east of the antenna 1 at the time when the position pulse is detected is obtained from (1) and (2) as a solution of the simultaneous equations of three elements (S210). The reference point azimuth γ is calculated by subtracting 90 degrees from the azimuth δ (S220). The reference point azimuth γ is displayed on the display unit and output to the data output unit (S230).

[0021]

[Second Embodiment] FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention. The antenna 1 is defined by a well-known antenna moving means 10 such as a motor-driven antenna rotating mechanism (not shown) in a horizontal plane having a radius r centered on a rotation center a of the antenna rotating mechanism (not shown). It is rotating at a constant speed at T. FIG. 4 shows the antenna 1
Direction of rotation of the uniform rotational movement of the
It is a figure showing the relation between 0 and a reference point direction. The antenna position detection unit 20 is attached to a predetermined position around the rotation radius r of the antenna 1, and outputs the timing signal Tbow for each rotation of the antenna 1. The position where the antenna position detector 20 is attached becomes the reference point azimuth. The reference point azimuth can be visually confirmed by attaching an arrow or the like to an antenna rotating mechanism (not shown).

The receiving section 2 receives radio waves from GPS satellites via the rotating antenna 1, and at the same time, the reference oscillating section 3
The local oscillating signal generated in step 1 is mixed with the received radio wave from the GPS satellite, the frequency is converted into a frequency that can be easily processed, and a digital signal of the frequency is output. The signal processor 4 uses the clock signal generated by the reference oscillator 3 to receive the signal from the receiver 2
The digital storage unit 5 synchronizes and tracks the digital signal output of the
Outputs pseudo range data, pseudo range change data, and satellite information data to.

The calculation storage unit 5 calculates a positioning calculation from each of the above data, an azimuth β of the specific GPS satellite from the east and an angle (elevation angle) α formed with the horizontal plane, that is, a line-of-sight direction calculation calculation.
A reference point azimuth calculation calculation is performed, and each data, the result of each calculation, and the like are stored. The display unit 6 displays the positioning position, the reference point azimuth, and the like obtained in the calculation storage unit 5. The data output unit 7 outputs the positioning position, the reference point azimuth, and the like to an external device.

FIG. 5 shows the azimuth β from the east of the horizontal plane projection line of the line connecting the rotation center a and the specific GPS satellite when the antenna 1 is rotated counterclockwise, the horizontal plane projection line and the rotation center. The relationship between the angle θ of the line connecting a and the antenna 1 and the azimuth γ from the east of the reference point azimuth are shown.

When the antenna of the GPS receiving apparatus is rotated at a constant speed in the horizontal plane at a predetermined period T as in the second embodiment, the respective data when the arithmetic processing is carried out by the arithmetic storage unit 5 include: Doppler shift Δ caused by rotating the antenna of the GPS receiver at a predetermined cycle
fx (Hz), the Doppler shift Δfsv (Hz) that exists because the GPS satellite is an orbiting satellite, the frequency offset Δfosc (Hz) of the reference oscillator 3, and the GPS
The Doppler shift Δfu (Hz) associated with the movement of the user is included. Therefore, the total Δf (Hz) of the Doppler shift processed by the arithmetic storage unit 5 is expressed by the following equation. Δf = Δfx + Δfsv + Δfosc + Δfu (3) Among these, Δfsv is a change rate per unit time of the distance from the positioning position to the specific satellite, which is obtained from the positioning position and the orbit information included in the satellite information data of the specific satellite. (Rr) and the source frequency of the satellite (f
(Hz)) and the speed of light (c (m / s)). Δfsv = f · Rr / c Further, Δfosc is the rate of change (Sr) per unit time of the amount of influence on the distance due to the error in the frequency of the reference oscillator 3 obtained from the deviation of the frequency of the reference oscillator 3, The source frequency (f (Hz)) of the satellite and the speed of light (c (m /
s)) and the following. Δfosc = f · Sr / c

In the second embodiment, as described above, the antenna 1 makes a constant-velocity rotational movement at a predetermined period T within a horizontal plane having a radius r centering on the rotation center a, and therefore Δ
fx also changes in the cycle T. Furthermore, if the GPS user is stationary or moving at a sufficiently low speed, Δfu << Δfx
Therefore, since Δfu can be ignored, the unknown number in equation (3) is Δ
Only fx.

The Doppler shift Δfx (Hz) is
The source frequency of the GPS satellite is f (Hz) and the speed of light is c (m
/ S), where the line-of-sight velocity of the antenna of the GPS receiver for the specific GPS satellite is v (m / s), it is expressed by the following equation. Δfx = ± f · v / c (4) As in the second embodiment, the antenna 1 is rotated counterclockwise at a constant speed in a horizontal plane centered on the rotation center a and having a radius r. In this case, the velocity v (m / s) of the line-of-sight direction of the antenna 1 with respect to the specific GPS satellite (the angle from the east is β) is the tangential velocity of the uniform circular motion vr (m / s), The angle between the horizontal projection line and the line connecting the rotation center a and the antenna 1 is θ (degrees),
Assuming that the elevation angle of the S satellite viewed from the positioning point is α (degrees) (FIG. 6), v = −vr · sin (θ) · cos (α) (5) where (0 ≦ α ≧ 90 (degrees)) expressed.

If the radial distance from the center of rotation a to the antenna 1 is r (m) and the rotation period is T (seconds) and the angular velocity is ω, the tangential velocity vr is vr = rω = 2πr / T It is represented by (6).

When the antenna 1 is rotated counterclockwise at a constant speed in a horizontal plane having a radius r centering on the rotation center a at a predetermined period T, the angle from (4), (5) and (6) Doppler shift Δfx is 0 when θ is 0 degrees and 180 degrees
Becomes Hz. In other words, in the antenna 1, the horizontal plane projection line of the line connecting the rotation center a and the specific GPS satellite is the radius r.
The Doppler shift Δfx becomes 0 Hz when passing through two places crossing the circumference of.

Therefore, the antenna 1 coincides with the azimuth β of the specific GPS satellite at one of the two locations. FIG. 7 shows changes in the Doppler shift Δfx when the antenna 1 is rotated counterclockwise at a constant speed when a specific GPS satellite is in the position shown in FIG. Doppler shift Δfx is (4), (5), (6)
Changes from 0 to positive or negative depending on the angle θ. Depending on whether the change is from positive to negative or from negative to positive, the orientation β of the specific GPS satellite of interest among the two locations
Can be determined. When the antenna 1 is rotated counterclockwise as in the second embodiment, when the change of the Doppler shift Δfx changes from positive to negative (timing Ts).
In v), the azimuth β of the specific GPS satellite and the antenna 1 match. By measuring the time interval ΔTs from the timing signal Tbow to the timing Tsv, the reference point azimuth γ (degree) from the true east can be obtained as in the following equation. γ = β + (T−ΔTs) · 360 / T (7)

FIG. 8 is a flow chart showing the processing operation in the arithmetic storage unit 5 of the present invention. First, the position of the GPS user is calculated from each data output of the signal processing unit 4 by a known method (S100). Next, the rotation cycle T of the antenna 1 is calculated from the repeating interval of the timing signal Tbow from the antenna position detector 20 (S1).
10). Subsequently, from the plurality of GPS satellites used to calculate the position of the GPS user, the azimuth angle β from the east of a specific GPS satellite and the angle (elevation angle) with the horizontal plane.
α, that is, the line-of-sight direction is calculated from the position of the GPS user and the position of the specific GPS satellite (S120). The timing Tsv when the Doppler shift ΔfxHz accompanying the antenna 1 performing the uniform circular motion is changed from positive to negative is detected, and the time interval ΔTs from the timing signal Tbow is measured (S130). Measure the time interval ΔTs,
The numerical value is substituted into (7) to calculate the reference point direction γ from the true east (S140). The reference point azimuth γ is displayed on the display unit and output to the data output unit (S150).

Needless to say, it is possible to determine the reference point azimuth γ for a plurality of receivable GPS satellites by switching a specific GPS satellite. At this time, it is possible to reduce the measurement error by calculating an average value using the respective reference point azimuths γ determined using a plurality of specific GPS satellites.

[0033]

As described above, according to the present invention, the GPS
Even when the user is stationary, the GPS user's reference point direction can be obtained only by the GPS receiver. Moreover, since this reference point azimuth can be obtained as an absolute azimuth, no magnet compass, gyro, or the like is required. For this reason, it is effective for downsizing of a small moving body or a device carried by a person.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a relationship among an antenna 1, an antenna detection unit 20, and a reference point azimuth in the first embodiment.

FIG. 3 is an operation flowchart of the first embodiment.

FIG. 4 shows an antenna 1 and an antenna detection unit 2 of the second embodiment.
The figure which shows the positional relationship of 0 and a reference point direction.

FIG. 5: Specific GPS satellite and antenna 1 of the second embodiment
FIG.

FIG. 6 is a diagram showing a line-of-sight direction.

FIG. 7 is a diagram showing a relationship among a timing signal, a Doppler shift, and an azimuth according to the second embodiment.

FIG. 8 is an operation flowchart of the second embodiment.

[Explanation of symbols]

 1 Antenna 2 Receiver 3 Reference Oscillator 4 Signal Processor 5 Calculation Memory 6 Display 7 Data Output 10 Antenna Moving Means 20 Antenna Position Detector

Claims (6)

[Claims] 1. A GPS receiver for performing positioning using GPS, comprising: a. Means for moving the antenna of the GPS receiver; b. Means for detecting a reference position of movement of the antenna; c. Means for calculating the moving direction of the antenna from the Doppler shift of the GPS satellite signal associated with the movement of the antenna. 2. The apparatus of claim 1, comprising: a. Means for calculating a moving direction of the antenna at the time of passing the reference position; b. Means for displaying and / or outputting the result of calculating the moving direction of the antenna, and the GPS receiving device. 3. The apparatus of claim 2, comprising: a. A GPS receiving device comprising means for rotating and moving the antenna of the GPS receiving device in a horizontal plane. 4. The apparatus of claim 2, wherein a. A GPS receiving device comprising means for rotating the antenna of the GPS receiving device in a horizontal plane at a constant speed and rotating at a constant speed. 5. The apparatus of claim 3 or claim 4, wherein: a. Means for calculating the azimuth of the reference position; b. Means for displaying and / or outputting the result of calculating the azimuth; 6. A GPS receiver for positioning using GPS, comprising: a. A means for rotating the antenna of the GPS receiving device in a horizontal plane at a constant speed and rotating, b. Means for detecting a reference position for rotational movement of the antenna; c. A means for calculating a Doppler shift of a GPS satellite signal relating to a change in the line-of-sight velocity of the antenna due to the movement of the antenna; d. Means for calculating the azimuth of the reference position; e. Means for displaying and / or outputting the result of calculating the azimuth;