JP5077054B2 - Mobile positioning system - Google Patents

Description

  The present invention relates to a positioning system for a moving body that measures the position of a moving body using observation data on a reference station side.

  Conventionally, the difference between the GPS radio wave propagation time data in the adjacent vehicle and the GPS radio wave propagation time data in the own vehicle is obtained, and the obtained three or more GPS radio wave propagation time difference values and unknowns are obtained. Vehicle-to-vehicle communication, comprising: a relative position calculating means based on a difference in GPS radio wave propagation time for obtaining a relative position of a nearby vehicle based on the vehicle by solving a relational expression with the relative position simultaneously A relative position calculation device is known (see, for example, Patent Document 1).

Further, DGPS (Differential Global Positioning System) is generally known (for example, refer to Patent Document 2). In DGPS, correction data supplied from the base station side is correction data related to a pseudorange, and movement It is used to correct the pseudorange observed on the station side.
JP-A-10-148665 JP 2005-308462 A

  In the technique described in Patent Document 1, the positioning is expressed using the difference in GPS radio wave propagation time and the direction cosine of the angle formed by each axis of the relative coordinate system of the line segment connecting the vehicle and the satellite. The relative position is obtained by setting a geometric relational expression to be used and by connecting the relational expression. However, in such a configuration, only the GPS wave propagation time with a large error is used as observation data, and the direction cosine of the angle between each axis of the relative coordinate system connecting the vehicle and the satellite is accurately determined. There is a problem in terms of positioning accuracy due to points that cannot be obtained.

  Therefore, an object of the present invention is to provide a positioning system for a moving body that can accurately position the position of the moving body using speed correction data derived on the reference station side.

In order to achieve the above object, a mobile positioning system according to a first aspect of the present invention is provided in a reference station arranged at a fixed position, and is based on a Doppler range of satellite radio waves obtained by observation at the reference station. calculating the velocity, and correction data generating means for generating a velocity correction data based on the calculation result,
Data transmission means provided in the reference station, for transmitting observation data of satellite radio waves obtained by observation at the reference station, and the speed correction data to a mobile unit;
Data receiving means provided on the mobile body for receiving the observation data and the speed correction data transmitted from the reference station;
Based on the observation data of the satellite radio waves provided in the mobile body and obtained by observation with the mobile body, the observation data received by the data receiving means, and the speed correction data received by the data receiving means And positioning means for positioning the position of the moving body ,
The speed correction data generating means integrates the calculation result of the speed of the reference station for a predetermined time, calculates a drift rate of the calculation result of the speed of the reference station based on the integrated value, and based on the calculated drift rate Generating the speed correction data .

2nd invention is the positioning system for moving bodies based on 1st invention,
The speed correction data generating means integrates the speed calculation results of the reference station for a predetermined time, and generates the speed correction data based on the integrated value.

4th invention is the positioning system for moving bodies which concerns on 1st invention,
The observation data of the satellite radio wave includes an integrated value of the phase of the carrier wave of the radio wave from the satellite (hereinafter referred to as “carrier wave phase integrated value”),
The positioning means uses a single phase difference or double phase difference of the satellite radio wave observation data acquired on the reference station side and the satellite radio wave observation data acquired on the mobile object side as an observation amount, and the position of the mobile object And, using a relational expression having a single phase difference or a double phase difference of an integer bias included in the carrier wave phase integrated value as a state variable, the position of the moving body is measured by interference positioning, and in the positioning process, The speed correction data is used.

5th invention is the positioning system for moving bodies which concerns on 4th invention,
The positioning means uses the speed correction data as a constraint condition for the relational expression, and as a constraint condition for the relationship between the positioning results of the position of the moving body at two time points.

6th invention is the positioning system for moving bodies which concerns on 4th invention,
In addition to the relational expression, the positioning means
A relational expression in which a Doppler range obtained by observation with the moving body is an observation amount, and a position and a velocity of the moving body are state quantities, and a relational expression in which a correction term reflecting the speed correction data is introduced. And measuring the position of the moving body.

7th invention is the positioning system for moving bodies which concerns on 4th invention,
The positioning means performs the interference positioning by an instantaneous positioning method that uses the satellite radio wave observation data independently for each epoch.

A mobile positioning system according to an eighth invention is provided in a reference station arranged at a fixed position, calculates a velocity of the reference station based on a Doppler range of satellite radio waves obtained by observation at the reference station, and calculates the calculation Correction data generating means for generating speed correction data based on the results;
Speed correction data transmitting means provided in the reference station for transmitting the speed correction data to a moving body;
Speed correction data receiving means provided on the mobile body for receiving the speed correction data transmitted from the reference station;
Based on the Doppler range of the satellite radio wave provided by the mobile body and obtained by observation with the mobile body, and the speed correction data received by the speed correction data receiving means, the speed correction data corrected by the speed correction data. Mobile body speed calculating means for calculating the speed of the mobile body ,
The speed correction data generating means integrates the calculation result of the speed of the reference station for a predetermined time, calculates a drift rate of the calculation result of the speed of the reference station based on the integrated value, and based on the calculated drift rate Generating the speed correction data .

  ADVANTAGE OF THE INVENTION According to this invention, the positioning system for moving bodies which can position the position of a moving body, etc. accurately is obtained using the speed correction data derived | led-out by the reference | standard station side.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 is a system configuration diagram showing the overall configuration of a GPS (Global Positioning System) to which a mobile positioning system according to the present invention is applied. As shown in FIG. 1, the GPS includes a GPS satellite 10 orbiting around the earth.

  The GPS satellite 10 always broadcasts navigation messages toward the earth. The navigation message includes orbit information about the corresponding GPS satellite 10, a clock correction value, and an ionospheric correction coefficient. The navigation message is spread by the C / A code, is carried on the L1 carrier (frequency: 1575.42 MHz), and is constantly broadcast toward the earth.

  Currently, 24 GPS satellites 10 orbit the earth at an altitude of about 20,000 km, and each of the four GPS satellites 10 is evenly arranged on six Earth orbit planes inclined by 55 degrees. ing. Therefore, as long as the sky is open, at least five GPS satellites 10 can be observed at any time on the earth.

  The reference station 20 is installed at a predetermined position (known point) on the earth. As the position of the reference station 20, a position measured with high accuracy may be used.

  The vehicle 30 is located on the earth and can move on the earth. The vehicle 30 is a target vehicle whose relative position with respect to the reference station 20 is measured. The vehicle 30 is merely an example of a moving body, and other moving bodies include motorcycles, railways, ships, airplanes, hawk lifts, robots, information terminals such as mobile phones that move as people move, and the like. There can be.

  FIG. 2 is a diagram showing the main configuration of the reference station 20 and the vehicle 30. The reference station 20 is provided with a GPS receiver 22 and a communication device 24. The vehicle 30 is provided with a GPS receiver 32 and a communication device 34.

  In the GPS receivers 22 and 32, an oscillator (not shown) whose frequency matches the carrier frequency of the GPS satellite 10 is incorporated. The GPS receivers 22 and 32 convert the radio wave (satellite signal) received from the GPS satellite 10 via the GPS antennas 22a and 32a into an intermediate frequency, and then convert the C / A code generated in the GPS receivers 22 and 32. Used to perform C / A code synchronization and take out the navigation message.

The GPS receiver 22 measures the integrated value Φ _ik (t) of the carrier phase at time t based on the carrier from the GPS satellite 10 _i as shown in the following equation. The phase integrated value Φ _ik may be measured for both the L1 wave and the L2 wave (frequency: 1227.6 MHz).
Φ _ik (t) = Θ _ik (t) −Θ _ik (t−τ _k ) + N _ik + ε _ik (t) Equation (1)
For the phase integration value Φ _ik , the subscript i (= 1, 2,...) Indicates the number assigned to the GPS satellite 10 _i , and the subscript k is an integrated value on the reference station side. Show. N _ik represents an integer value bias, and ε _ik represents noise (error).

Further, the GPS receiver 22 measures the pseudo distance ρ _ik based on the C / A code carried on each carrier wave from the GPS satellite 10 _i .
ρ _ik (t) = c · τ _k + b _k equation (2)
Here, c is the speed of light, and b _k is also called a clock bias and corresponds to a distance error due to a clock error in the GPS receiver 22.

The GPS receiver 22 measures the Doppler range dρ _i (t) at time t as shown in the following equation based on the Doppler frequency of each carrier wave from the GPS satellite 10 _i .
dρ _i (t) = L · Δf _i (t) Equation (2-1)
Here, L is the wavelength of the carrier wave. Δf _i (t) is a Doppler frequency related to the GPS satellite 10 _i , for example, Δf ₁ = fr−f based on the frequency fr of the replica carrier to be reproduced internally and the known carrier frequency f _L1 (1575.42 MHz). Measured by _L1 .

The GPS receiver 22 measures the speed of the reference station 20 based on the measured Doppler range dρ _i (t), and generates speed correction data based on the positioning result. This process will be described later.

The communication device 24 transmits data of the phase integration value Φ _ik and pseudo distance ρ _ik measured by the GPS receiver 22, speed correction data described later, and the like to the communication device 34 of the vehicle 30. Hereinafter, the data of the phase integration value Φ _ik and the pseudorange ρ _ik measured by the GPS receiver 22 are collectively referred to as “observation data”, and the data of the phase integration value Φ _ik is respectively applied to the L1 wave and the L2 wave. Correspondingly, they are also referred to as “L1 data” and “L2 data”, respectively, and the data of the pseudo distance _ρik is also referred to as “C / A data”.

Similarly, the GPS receiver 32 measures the phase integration value Φ _iu of the carrier phase based on the carrier wave from the GPS satellite 10 _i . The phase integrated value Φ _iu may be measured for both the L1 wave and the L2 wave. For the phase integration value Φ _iu , the subscript i (= 1, 2,...) Indicates the number assigned to the GPS satellite 10 _i , and the subscript u is the integrated value on the vehicle 30 side. Indicates. Similarly, as shown in the following equation, the phase integration value Φ _iu includes the phase Θ _iu (t) of the oscillator at the carrier reception time t and the carrier phase Θ _iu (t at the time of generation of the satellite signal at the GPS satellite 10 _i. -Τ) as a difference.
Φ _iu (t) = Θ _iu (t) −Θ _iu (t−τ _u ) + N _iu + ε _iu (t) Equation (3)
Here, τ _u represents the travel time from the GPS satellite 10 to the GPS receiver 32, and ε _iu represents noise (error). Note that at the start of observation of the phase difference, the GPS receiver 32 can accurately measure the phase within one wavelength of the carrier wave phase, but cannot determine what wavelength it corresponds to. For this reason, an integer value bias N _iu is introduced to the phase integrated value Φ _iu (t) as an uncertain element as shown in the above equation.

Further, the GPS receiver 32 measures the pseudo distance ρ _iu based on the C / A code carried on each carrier wave from the GPS satellite 10 _i . The pseudo distance ρ _iu measured here includes an error such as a distance error as follows.
ρ _iu (t) = c · τ _u + _bu equation (4)
Here, b _u is also called a clock bias and corresponds to a distance error due to a clock error in the GPS receiver 32.

In addition, the GPS receiver 32 measures the Doppler range dρ _i (t), similarly to the GPS receiver 22. Further, the GPS receiver 32 performs various processes described later with reference to FIG.

  FIG. 3 is a block diagram illustrating main processes executed in the reference station 20 and the vehicle 30 according to this embodiment. In addition, in the configuration on the reference station 20 side, the speed calculation unit 50 and the integration & drift rate calculation unit 52 are realized by the GPS receiver 22, but are realized by another microcomputer connected to the GPS receiver 22. May be. In the configuration on the reference station 20 side, the transmission unit 54 is realized by the communication device 24. In the configuration on the vehicle 30 side, the reception unit 40 is realized by the communication device 34, and the constraint condition setting unit 42, the real number solution calculation unit 44, the integer solution calculation unit 46, and the FIX determination unit 48 are realized by the GPS receiver 32. However, it may be realized by another microcomputer connected to the GPS receiver 32.

As shown in FIG. 3, in the reference station 20, the speed calculation unit 50 calculates the position of the speed v (t) of the reference station 20 based on the Doppler range dρ _i (t) measured by the reference station 20. The positioning method for the speed v (t) of the reference station 20 may be as follows, for example. First, as a premise, the following relational expression holds among the Doppler range dρ _i , the satellite moving velocity vector V, and the velocity vector v = (v _x , v _y , v _z ) of the reference station 20. The symbol black circle on the letter represents a dot (time differentiation). For example, the Doppler range dρ _i is a ρ _i dot (time differentiation).

ここで、Ｉドット及びＴドットは、電離層誤差の変動量及び対流圏誤差の変動量を表すが、非常に小さいので、ここでは、白色ノイズεとして扱う。また、ｂドットは、時計誤差の微分値である。数１の式は、４つのＧＰＳ衛星１０_１、１０_２、１０_３、１０_４からのデータを用いる場合、以下のように変形できる。

Here, the I dot and the T dot represent the variation amount of the ionospheric error and the variation amount of the troposphere error, but are treated as white noise ε because they are very small. The b dot is a differential value of the clock error. Equation 1 can be modified as follows when data from _four GPS satellites 10 ₁ , 10 ₂ , 10 ₃ , 10 ₄ is used.

数２の式において、左辺を、観測量ｚとする。ＧＰＳ衛星１０_ｉに関する観測量ｚ_ｉの「ｄρ_ｉ」は、上述の如くドップラ周波数Δｆ_ｉ（ｔ）に基づいて、搬送波の波長Ｌ（既知）を用いてｄρ_ｉ＝Ｌ・Δｆ_ｉ（ｔ）により算出される。また、ＧＰＳ衛星１０_ｉに関する観測量ｚ_ｉの「ｌ_ｉ・Ｖ_ｉ」は、時刻（ｔ）における視線ベクトルの単位ベクトルｌ_ｉ（ｔ）と衛星移動速度ベクトルＶ_ｉ（ｔ）との内積であり、衛星移動速度ベクトルＶ_ｉ（ｔ）は、航法メッセージの衛星軌道情報に基づいて算出されるＧＰＳ衛星１０_ｉの衛星位置の今回値と前回値の差分を、演算周期の時間幅で除算することにより演算されてよい。単位ベクトルｌ_ｉ（ｔ）は、基準局２０の既知の測量座標（Ｘ_ｋ，Ｙ_ｋ，Ｚ_ｋ）を用いて、以下のように、算出されてよい。

In Equation 2, the left side is the observation amount z. "Dp _i" of observed quantity _{z i} regarding GPS satellites 10 _i, based on as described above Doppler frequency Delta] f _i (t), carrier wavelength L dp with _{(known) i = L · Δf i (} t) Is calculated by Further, _"l i · _{V i"} of observed quantity _{z i} regarding GPS satellites 10 _i is the inner product of the time unit vector of the line-of-sight vector in (t) _l i (t) and the satellite moving velocity vector _V i (t) Yes, the satellite moving speed vector V _i (t) divides the difference between the current value and the previous value of the satellite position of the GPS satellite 10 _i calculated based on the satellite orbit information of the navigation message by the time width of the calculation cycle. May be calculated by The unit vector l _i (t) may be calculated as follows using the known survey coordinates (X _k , Y _k , Z _k ) of the reference station 20.

そして、観測行列Ｇを以下のように設定する。

Then, the observation matrix G is set as follows.

状態量ηは、基準局２０の速度ベクトルｖ＝（ｖ_ｘ，ｖ_ｙ，ｖ_ｚ）とｂドットからなり、η＝（ｖ，ｂドット）とおくと、状態量ηは、最小二乗法により次の通り求まる。

The state quantity η is composed of the velocity vector v = (v _x , v _y , v _z ) of the reference station 20 and b dots. When η = (v, b dots) is set, the state quantity η is calculated by the least square method. It is obtained as follows.

尚、ここでは、説明の便宜上、基準局２０の速度ベクトルｖ＝（ｖ_ｘ，ｖ_ｙ，ｖ_ｚ）は、地球重心を原点にして北極方向をz軸、グリニッジ子午線面をx軸に、右手直交座標系を成すようy軸を定めた地球固定座標系で表されているが、他の座標系（例えば基準局２０の位置を原点として東、北、上方向を各軸とする局地水平面座標系）でも同様である（各座標系間の変換式は広く知られている）。このようにして速度演算部５０にて演算される基準局２０の速度ｖ（ｔ）は、演算周期毎に、積算＆ドリフト率算出部５２に入力される。

Here, for convenience of explanation, the velocity vector v = (v _x , v _y , v _z ) of the reference station 20 is right-hand orthogonal with the earth's center of gravity as the origin and the north pole direction as the z axis and the Greenwich meridian plane as the x axis. Although expressed in a fixed earth coordinate system in which the y-axis is defined to form a coordinate system, other coordinate systems (for example, a local horizontal plane coordinate system with the position of the reference station 20 as the origin and the east, north, and upward directions as axes) ) Is the same (the conversion formula between each coordinate system is widely known). The speed v (t) of the reference station 20 calculated by the speed calculation unit 50 in this way is input to the integration & drift rate calculation unit 52 for each calculation cycle.

  In the integration & drift rate calculation unit 52, the speed v (t) of the reference station 20 calculated by the speed calculation unit 50 is integrated (integrated) for a predetermined time, and the drift rates (α, β, γ) is calculated.

  Here, the speed v (t) of the reference station 20 should be essentially zero because it is a fixed facility where the reference station 20 does not move. However, actually, there is a minute offset in the calculated speed v of the reference station 20 depending on the number of satellites, the satellite arrangement, etc., and the integrated value (integrated position) of the speed v of the reference station 20 drifts. . It can be considered that the drift rate at this time is substantially the same even in the vehicle 30 that is located near the reference station 30.

Specifically, in the integration & drift rate calculation unit 52, first, the components (v _x , v _y , v _z ) in each direction of the speed vector v of the reference station 20 calculated by the speed calculation unit 50 are initial values. Accumulated as zero. This integration time is an appropriate time for which the drift rate can be calculated, but may be about 1 minute, for example. As a result, for example, as shown in FIGS. 4A, 4B, and 4C, the integrated position in the x direction, the integrated position in the y direction, and the integrated position in the z direction are calculated. Next, the integration & drift rate calculation unit 52 calculates the drift rates (inclination angles α, β, γ) of the integration position in the x direction, the integration position in the y direction, and the integration position in the z direction. For example, the drift rate (α, β, γ) is calculated by dividing each of the accumulated position in the x direction, the accumulated position in the y direction, and the accumulated position in the z direction by the accumulated time. From the same point of view, by drifting the components in each direction of each speed vector v of the reference station 20 calculated by the speed calculation unit 50 over a predetermined time (= integrated time), the drift rate (α, β, γ) may be calculated. Further, the drift rate may be derived in a two-dimensional direction in addition to being calculated in each direction. For example, as shown in FIG. 5, for example, when the velocity vector of the reference station 20 is calculated in the local horizontal plane coordinate system, the drift rate ζ representing the relationship between the accumulated position of the east-west direction component and the accumulated position of the north-south direction component is It may be calculated. That is, in the example shown in FIG. 5, the drift rate ζ is calculated by dividing the accumulated position of the north-south direction component by the accumulated position of the east-west direction component.

  The transmission unit 54 is supplied with observation data composed of the L1 data, the L2 data, and the C / A data observed as described above at predetermined intervals, and is calculated by the integration & drift rate calculation unit 52 as described above. Drift rate data (hereinafter referred to as “speed correction data”) is supplied. And in the transmission part 54, observation data and speed correction data are transmitted to the vehicle 30 as transmission data. The transmission data may include other information (for example, position information of the reference station 20 known by surveying or a satellite number used for calculating the drift rate). Further, the speed correction data does not necessarily need to be always included in the transmission data every observation data transmission cycle (observation cycle), and may be included periodically every longer period than the observation data transmission cycle. Good.

In the vehicle 30, transmission data from the reference station side is received every predetermined period. Further, the GPS receiver 32 acquires the phase integrated value Φ _iu (L1 data, L2 data) and the pseudorange ρ _iu (C / A data) on the vehicle 30 side. The observation data on the reference station side and the observation data on the vehicle 30 side may be synchronized using the GPS time, the PSS signal, or the like. The observation data on the reference station side and the observation data on the vehicle 30 side are supplied to the real number solution calculation unit 44. The speed correction data received from the reference station side is supplied to the constraint condition setting unit 42.

  In the restraint condition setting unit 42, a restraint condition used for positioning calculation of the position of the vehicle 30, which will be described later, is set based on the speed correction data. That is, a condition for the speed of the vehicle 30 is set based on the speed correction data, and the condition for the speed of the vehicle 30 is used as a constraint condition during positioning calculation of the position of the vehicle 30 described later. The conditions for the speed of the vehicle 30 may be as follows using the drift rates (α, β, γ), for example.

数６において、（ΔＸ_u，ΔＹ_u，ΔＺ_u）は、時間ΔＴ間での車両３０の移動量を表し、（ｖ_ux，ｖ_uy，ｖ_uz）は、車両３０の速度ｖ_uを表す。尚、車両３０の移動量及び速度の各成分は、地球固定座標系で表されているが、他の座標系（例えば局地水平面座標系）でも考え方は同様である。但し、局地水平面座標系を用いる場合は基準局２０側と車両３０側とで用いるそれぞれの局地水平面座標系の原点を一致させる必要があり、例えば基準局２０の位置に原点を一致させる。また、数６において、ｋはエポック（即ち観測周期番号）を表し、従って、ΔＴは、１エポックの周期であり、（ΔＸ_u，ΔＹ_u，ΔＺ_u）は、ｋ−１エポックからｋエポックまでの１エポック間での移動量を表す。

In Equation 6, (ΔX _u , ΔY _u , ΔZ _u ) represents the amount of movement of the vehicle 30 during the time ΔT, and (v _ux , v _uy , v _uz ) represents the speed v _{u of the} vehicle 30. In addition, although each component of the moving amount and speed of the vehicle 30 is represented in the earth fixed coordinate system, the concept is the same in other coordinate systems (for example, a local horizontal plane coordinate system). However, when the local horizontal plane coordinate system is used, it is necessary to match the origins of the local horizontal plane coordinate systems used on the reference station 20 side and the vehicle 30 side. For example, the origin is matched with the position of the reference station 20. In Equation 6, k represents an epoch (that is, an observation period number), and therefore ΔT is a period of one epoch, and (ΔX _u , ΔY _u , ΔZ _u ) is from k−1 epoch to k epoch. Represents the amount of movement in one epoch.

The speed (v _ux , v _uy , v _uz ) of the vehicle 30 used in the above formula 6 is the speed of the reference station 30 shown in the above formulas 1 to 5 using the Doppler range dρ _i observed by the vehicle 30. Positioning may be performed in the same manner as described above. In this case, the unit vector _l i (t), the position of the vehicle 30 which is derived by single point positioning may be calculated using the _{(X u (t), Y} u (t), Z u (t)).

  Here, in the above equation 6, the second term on the right side is a correction term for the amount of movement of the vehicle 30 expressed by the drift rate (α, β, γ). This is based on the fact that, as described above, the drift rate on the reference station 30 side is substantially the same for the vehicle 30 that is located near the reference station 30.

  In the real number solution calculation unit 44, the position of the vehicle 30 (typical) is obtained by the least square method using the double phase difference of the observation data as the observation amount and the position of the vehicle 30 and the double phase difference of the integer value bias as the state variables. The relative position with respect to the reference station 20 is measured. At this time, the constraint condition set by the constraint condition setting unit 42 is used.

  Here, first, an example of a positioning method of the position of the vehicle 30 will be described, and subsequently, a usage mode of the constraint condition will be described. In the following, for simplification of explanation, the case where only the L1 wave is used as the phase integration value will be described. However, when the phase integration value of the L2 wave is also used, the phase integration value of the L2 wave is changed to the phase integration value of the L1 wave. It may be added in the same manner as.

First, the double phase difference between the phase integration values for the two paired GPS satellites 10 _j , 10 _h (i = j, h, where j ≠ h) is expressed by the following equation.
Φ ^jh _ku = (Φ _jk (t) −Φ _ju (t)) − (Φ _hk (t) −Φ _hu (t)) Equation (5)
On the other hand, the double phase difference Φ ^jh _ku of the phase integration value is based on the physical meaning of (distance between GPS satellite 10 _i and GPS receiver 22 or 32) = (wavelength L of carrier wave) × (phase integration value). It becomes as follows.

ここで、式（６）における［Ｘ_k（ｔ）、Ｙ_k（ｔ）、Ｚ_k（ｔ）］は、時刻ｔにおける基準局２０の地球固定座標系における座標値であり、［Ｘ_u（ｔ）、Ｙ_u（ｔ）、Ｚ_u（ｔ）］は、時刻ｔにおける車両３０の座標値（未知）であり、［Ｘ_j（ｔ）、Ｙ_j（ｔ）、Ｚ_j（ｔ）］及び［Ｘ_h（ｔ）、Ｙ_h（ｔ）、Ｚ_h（ｔ）］は、時刻ｔにおける各ＧＰＳ衛星１０_j、１０_hの座標値である。Ｎ^jh _kuは、整数値バイアスの２重位相差である（即ち、Ｎ^jh _ku＝（Ｎ_jk−Ｎ_ju）−（Ｎ_hk−Ｎ_hu））。尚、時刻ｔは、例えばGPS時刻で同期が取られているものとする。

Here, [X _k (t), Y _k (t), Z _k (t)] in the equation (6) is a coordinate value in the earth fixed coordinate system of the reference station 20 at time t, and [X _u (t ), Y _u (t), Z _u (t)] are the coordinate values (unknown) of the vehicle 30 at time t, and [X _j (t), Y _j (t), Z _j (t)] and [X _h (t), Y _h (t), Z _h (t)] are coordinate values of the GPS satellites 10 _j and 10 _h at time t. N ^jh _ku is a double phase difference of an integer value bias (that is, N ^jh _ku = (N _jk −N _ju ) − (N _hk −N _hu )). The time t is assumed to be synchronized with, for example, GPS time.

Further, the double phase difference of the pseudoranges for the two GPS satellites 10 _j , 10 _h (i = j, h, where j ≠ h) at time t is expressed by the following equation.
ρ ^jh _ku = (ρ _jk (t) −ρ _ju (t)) − (ρ _hk (t) −ρ _hu (t)) Equation (7)
The double phase difference ρ ^jh _ku of the pseudorange can be expressed as follows.

ここで、式（８）における［Ｘ_k（ｔ）、Ｙ_k（ｔ）、Ｚ_k（ｔ）］、［Ｘ_u（ｔ）、Ｙ_u（ｔ）、Ｚ_u（ｔ）］、［Ｘ_j（ｔ）、Ｙ_j（ｔ）、Ｚ_j（ｔ）］及び［Ｘ_h（ｔ）、Ｙ_h（ｔ）、Ｚ_h（ｔ）］は、上記式（６）と同様である。また、時刻ｔは、例えばGPS時刻で同期が取られているものとする。

Here, the formula (8) in the _{[X k (t), Y} k (t), Z k (t)], [X u (t), Y u (t), Z u (t)], [X _j (t), Y _j (t), Z _j (t)] and [X _h (t), Y _h (t), Z _h (t)] are the same as in the above formula (6). Further, the time t is assumed to be synchronized with, for example, GPS time.

The relationship between the observed quantity Z and the state variable η is expressed by the following linear model.
Z = H · η + V Formula (9)
Here, V indicates observation noise. η represents a state variable and is a double phase difference between a coordinate value (unknown) of the vehicle 30 and an integer value bias. For example, when the pair (j, h) of the paired GPS satellites 10 is four sets of (1, 2), (1, 3), (1, 4) and (1, 5), η = [X _{u, Y u, Z u,} N 12 ku, N 13 ku, N 14 ku, an N ¹⁵ _ku] ^{T (T} denotes the transpose). The observed quantity Z in the equation (9) is the double phase difference Φ ^jh _ku of the phase integration value (see the above equation (5)) and the double phase difference ρ ^jh _{ku of the} pseudorange (see the above equation (7)). . For example, when the pair (j, h) of the paired GPS satellites 10 is four sets of (1, 2), (1, 3), (1, 4) and (1, 5), Z = [ Φ ¹² _ku , Φ ¹³ _ku , Φ ¹⁴ _ku , Φ ¹⁵ _ku , ρ ¹² _ku , ρ ¹³ _ku , ρ ¹⁴ _ku , ρ ¹⁵ _ku ] ^T. Since the observation equation of the equation (9) is a linear, in Formula (6) and (8), the observed amount Z is non-linear with respect to the state variables X _u, Y _u and Z _u, equation (6) and each term state variable X _u of the formula (8) is partially differentiated by each Y _u and Z _u, the observation matrix H of the equation (9) is obtained. For example, when the pair (j, h) of the paired GPS satellites 10 is four sets (1, 2,), (1, 3), (1, 4) and (1, 5), The observation matrix H is as follows.

ここで、数８のＨ_１は、観測量Ｚ_１＝［Φ¹² _ku、Φ¹³ _ku、Φ¹⁴ _ku、Φ¹⁵ _ku］^Ｔとした場合の観測行列であり、数８のＨ_２は、観測量Ｚ_２＝［ρ¹² _ku、ρ¹³ _ku、ρ¹⁴ _ku、ρ¹⁵ _ku］^Ｔとした場合の観測行列であり、観測行列Ｈは、２つの観測行列Ｈ_１、Ｈ_２が組み込まれた形となる。

Here, H ₁ in _Equation 8 is an observation matrix when the observation amount Z ₁ = [Φ ¹² _ku , Φ ¹³ _ku , Φ ¹⁴ _ku , Φ ¹⁵ _ku ] ^T, and H ₂ in Equation 8 is an observation. Quantity Z ₂ = [ρ ¹² _ku , ρ ¹³ _ku , ρ ¹⁴ _ku , ρ ¹⁵ _ku ] ^T is an observation matrix, and the observation matrix H is a form in which _two observation matrices H ₁ and H ₂ are incorporated. It becomes.

  In this embodiment, the relational expression (9) is prepared for each epoch using k epoch observation data and k-1 epoch observation data. Then, the constraint condition shown in Expression 6 is applied to the positions (unknown numbers) of the vehicles 30 of the k epoch and the k-1 epoch. That is, when all of the relational expression of the above equation (9) of the k epoch and the k-1 epoch and the constraint condition equation shown in Equation 6 are combined and solved by the method of least squares, a real solution of η (float solution) Is obtained.

  Instead of using the observation data of k epoch and k-1 epoch, the observation data of k epoch and kp epoch may be used simultaneously. In this case, the initial value of t of Σ is k−p under the constraint condition shown in Equation 6.

  The integer solution calculation unit 46 calculates an integer solution of integer value bias based on the integer value bias real solution (float solution) calculated by the real solution calculation unit 44. For example, an integer solution (that is, wave number) having the smallest error with respect to the real number solution calculated by the real number solution calculation unit 44 is obtained as a first candidate, and an integer solution having the next smallest error is obtained as a second candidate. As this method, the LAMBDA method may be used in which the integer value bias is decorrelated and the search space for the integer solution is narrowed to specify the solution. Alternatively, instead of the LAMBDA method, an integer solution may be derived by another integer least square method or simple rounding.

The FIX determination unit 48 determines whether or not the integer solution derived by the integer solution calculation unit 46 is the FIX solution. That is, the reliability of the integer solution derived by the integer solution calculation unit 46 is determined, and when an integer solution with high reliability is obtained, the integer solution is FIXed, and thereafter the integer solution is used. The positioning result is output by RTK positioning. There are various methods for determining the reliability of the integer solution, and any appropriate method may be used. For example, the reliability of the integer solution may be determined by applying a ratio test. For example, as an example of the ratio test, a pair (j, h) of paired GPS satellites 10 has four sets (1, 2,), (1, 3), (1, 4), and (1, 5). There are four integer value bias real solutions (n ¹² , n ¹³ , n ¹⁴ , n ¹⁵ ) and integer value bias first candidates (N ¹² ₁ , N ¹³ ₁ , N ¹⁴ ₁ , N ^15). ₁ ) and the second candidate (N ¹² ₂ , N ¹³ ₂ , N ¹⁴ ₂ , N ¹⁵ ₂ ) are assumed to be calculated. At this time, the ratio R is expressed as follows: the distance (norm) between the integer value bias real solution and the integer value bias integer solution first candidate, and the integer value bias real solution and integer value bias, as shown below. The ratio between the integer solution and the second candidate.
R = {(n ¹² −N ¹² ₂ ) ² + (n ¹³ −N ¹³ ₂ ) ² + (n ¹⁴ −N ¹⁴ ₂ ) ² + (n ¹⁵ −N ¹⁵ ₂ ) ² } / {(n ¹² −N ¹² ₁ ) ² + (n ¹³ −N ¹³ ₁ ) ² + (n ¹⁴ −N ¹⁴ ₁ ) ² + (n ¹⁵ −N ¹⁵ ₁ ) ² } Formula (11)
The ratio R generally indicates that the higher the value, the higher the reliability of the first candidate of the integer solution with the integer bias. Therefore, when an appropriate predetermined threshold value α is set and the ratio R is larger than the predetermined threshold value α, it is determined that the reliability of the integer solution is high, and the first candidate of the integer solution with the integer value bias is adopted. It is good to do.

  According to the moving body positioning system of the present embodiment described above, the following excellent effects can be obtained, among others.

  As described above, by generating speed correction data (drift rate) from the Doppler range observed on the reference station 20 side and using the speed correction data for positioning of the position of the vehicle 30, an integer solution obtained by interference positioning calculation is obtained. It becomes easy to perform FIX, and a highly accurate positioning solution can be obtained. Further, it is not necessary to transmit Doppler range data from the reference station 20 side to the vehicle 30 for each epoch, and it is only necessary to transmit speed correction data with a small amount of data from the reference station 20 side to the vehicle 30, thereby reducing the communication load. be able to.

  In the above-described embodiment, the speed correction data is reflected in the positioning of the position of the vehicle 30 using the equation (6), but various other methods are conceivable. For example, the positioning solution is derived by the least square method in combination with the following equation (10) in which the speed of the vehicle 30 and the position of the vehicle 30 are unknown, and the relational expression of the above equation (9) based on observation data for one epoch. May be. Also in this case, the positioning solution can be derived with high accuracy using the speed of the vehicle 30 corrected by the speed correction data.

数１０の式は、上記の数１の式と関連しており、車両３０の速度ｖ_u＝（ｖ_ｘ，ｖ_ｙ，ｖ_ｚ）を、速度補正データ（α，β，γ）を用いて補正した速度（ｖ_ｘ−α，ｖ_ｙ−β，ｖ_ｚ−γ）に置き換えたものである。数１０の式は、観測可能なＧＰＳ衛星１０（又はそのうちの干渉測位に用いるＧＰＳ衛星１０）のそれぞれに対して立てられてよい。

The equation (10) is related to the equation (1) described above, and the speed v _u = (v _x , v _y , v _z ) of the vehicle 30 is calculated using the speed correction data (α, β, γ). These are replaced with corrected velocities (v _x −α, v _y −β, v _z −γ). Equation 10 may be established for each of the observable GPS satellites 10 (or GPS satellites 10 used for interfering positioning among them).

In the equation (10), the speed of the vehicle 30 is an unknown, but only the position of the vehicle 30 can be used as an unknown. For example, the speed of the vehicle 30, the position of the vehicle 30 which is derived by single positioning using the _{(X u (t), Y} u (t), Z u (t)), indicated by the number 1 to number 5 above Positioning in the same manner as the speed of the reference station 30, and then substituting the speed of the vehicle 30 obtained by the positioning into the formula 10 to create a relational expression in which only the position of the vehicle 30 is unknown, The positioning solution may be derived by the least square method in combination with the created relational expression and the relational expression (9) based on the observation data for one epoch.

  The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

For example, in the above-described embodiment, the speed correction data is used for interference positioning. For example, as shown in FIG. 6, the speed correction data is used for correcting the single positioning result of the speed of the vehicle 30. Also good. In this case, only the speed correction data may be transmitted from the reference station 20 to the vehicle 30 (that is, it is not necessary to transmit observation data such as L1 data). Also, the speed measurement unit 49 of the vehicle 30 side, the position of the vehicle 30 which is derived by single positioning using the _{(X u (t), Y} u (t), Z u (t)), the number of above 1 The speed of the vehicle 30 (v _x , v _y , v _z ) is measured from the Doppler range by the same method as the speed of the reference station 30 expressed by Equation 5, and the positioning result is converted into speed correction data (α, β, γ ) May be corrected as (v _x −α, v _y −β, v _z −γ).

In the above-described embodiment, as a preferred embodiment, a real number solution for integer value bias is obtained by an instantaneous positioning method. However, there are various methods for calculating a real number solution for integer value bias. Other methods may be employed. For example, it is possible to use only the double phase difference Φ ^jh _ku of the phase integration value without using the double phase difference ρ ^jh _ku of the pseudorange. Further, when the GPS receivers 22 and 32 are two-frequency receivers that can receive both the L1 wave and the L2 wave (frequency: 1227.6 MHz) emitted from the GPS satellite 10, the phase integrated value with respect to the L2 wave. The double phase difference Φ ^jh _ku may be used as the observation quantity Z additionally or alternatively. Further, the double phase difference Φ ^jh _ku of the phase integration value with respect to another band carrier wave (for example, an L5 band radio wave scheduled to be added in the future) may be additionally or alternatively used as the observation amount Z. Similarly, for the pseudo phase double phase difference ρ ^jh _ku , the pseudo phase single phase or double phase difference based on the same PRN code (pseudo noise code) other than the C / A code (for example, P code). ρ ^jh _ku may additionally or alternatively be used as the observable Z. In the above-described method of calculating the real solution of the integer bias, the influence of the initial phase of the oscillator and the clock error in the GPS receivers 22 and 32 is eliminated by taking the double phase difference as described above. However, the structure which takes a single phase difference may be sufficient. In the above method, the ionospheric refraction effect, the tropospheric refraction effect, and the influence of multipath are ignored, but these may be taken into consideration. As another example, a Kalman filter may be used instead of the least square method. In this case, instantaneous positioning that initializes state variables and error covariance matrix for each epoch may be realized so that the estimation (positioning) result in the previous epoch does not affect the estimation result of the current epoch. Instead of initializing the state variables and error covariance matrix, the state variables and error covariance matrix may be updated (taken over) for each epoch by applying a normal Kalman filter. Further, in order to take into account the dynamic state quantity peculiar to the vehicle caused by the movement of the vehicle 30, the dynamic state quantity of the vehicle speed corrected by the speed correction data may be introduced into the Kalman filter as a known input (for example, see JP 2005-147952). Further, a moving body model that predicts the current time state of the vehicle 30 from the movement history of the vehicle 30 may be introduced into the Kalman filter. In this case, the moving body model may be configured using any parameter that can represent the moving state of the vehicle 30 such as the speed and acceleration corrected by the speed correction data. For example, the moving body model may be configured assuming that the speed v _u of the vehicle 30 corrected by the speed correction data is a first-order Markov process, and introduced into the Kalman filter.

  In the above-described embodiment, an example in which the present invention is applied to the GPS has been shown. However, the present invention can also be applied to satellite systems other than GPS, for example, other GNSS (Global Navigation Satellite System) such as Galileo. is there.

1 is a system configuration diagram showing an overall configuration of GPS to which a mobile positioning system according to the present invention is applied. FIG. 2 is a diagram illustrating main configurations of a reference station 20 and a vehicle 30. It is a block diagram which shows the main processes each performed in the reference | standard station 20 and the vehicle 30 of a present Example. It is a figure which shows the relationship between the integrated value of each component of the velocity vector v of the reference | standard station 20, and a drift rate. It is a figure which shows the other calculation aspect of a drift rate. 3 is a diagram showing a configuration in which speed correction data is used for correcting a single positioning result of the speed of a vehicle 30. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 GPS satellite 20 Reference station 22 Reference station side GPS receiver 24 Reference station side communication device 30 Vehicle 32 Vehicle side GPS receiver 34 Vehicle side communication device 40 Reception part 42 Restriction condition setting part 44 Real number solution calculation part 46 Integer solution calculation part 48 FIX determination 50 Speed calculator 52 Total & drift rate calculator

Claims (7)

Provided reference station disposed in a fixed position, and calculates the speed of the reference station on the basis of the Doppler range of satellite radio waves obtained by observation with the reference station, the correction data generation for generating velocity correction data based on the calculation result Means,
Data transmission means provided in the reference station, for transmitting observation data of satellite radio waves obtained by observation at the reference station, and the speed correction data to a mobile unit;
Data receiving means provided on the mobile body for receiving the observation data and the speed correction data transmitted from the reference station;
Based on the observation data of the satellite radio waves provided in the mobile body and obtained by observation with the mobile body, the observation data received by the data receiving means, and the speed correction data received by the data receiving means And positioning means for positioning the position of the moving body ,
The speed correction data generating means integrates the calculation result of the speed of the reference station for a predetermined time, calculates a drift rate of the calculation result of the speed of the reference station based on the integrated value, and based on the calculated drift rate And generating the speed correction data . The mobile positioning system according to claim 1, wherein the speed correction data generation unit integrates the calculation result of the speed of the reference station for a predetermined time, and generates the speed correction data based on the integrated value. The observation data of the satellite radio wave includes an integrated value of the phase of the carrier wave of the radio wave from the satellite (hereinafter referred to as “carrier wave phase integrated value”),
The positioning means uses a single phase difference or double phase difference of the satellite radio wave observation data acquired on the reference station side and the satellite radio wave observation data acquired on the mobile object side as an observation amount, and the position of the mobile object And, using a relational expression having a single phase difference or a double phase difference of an integer bias included in the carrier wave phase integrated value as a state variable, the position of the moving body is measured by interference positioning, and in the positioning process, The positioning system for moving bodies according to claim 1, wherein the speed correction data is used. The positioning means is a constraint for the relationship, as a constraint condition for the relationship between the positioning result of the position of the moving body at two time points, using the velocity correction data, mobile body according to claim 3 Positioning system. In addition to the relational expression, the positioning means
A relational expression in which a Doppler range obtained by observation with the moving body is an observation amount, and a position and a velocity of the moving body are state quantities, and a relational expression in which a correction term reflecting the speed correction data is introduced. The positioning system for a moving body according to claim 3 , wherein the positioning of the moving body is used. The mobile positioning system according to claim 3 , wherein the positioning means performs the interference positioning by an instantaneous positioning method that uses the observation data of the satellite radio waves independently for each epoch. Provided reference station disposed in a fixed position, and calculates the speed of the reference station on the basis of the Doppler range of satellite radio waves obtained by observation with the reference station, the correction data generation for generating velocity correction data based on the calculation result Means,
Speed correction data transmitting means provided in the reference station for transmitting the speed correction data to a moving body;
Speed correction data receiving means provided on the mobile body for receiving the speed correction data transmitted from the reference station;
Based on the Doppler range of the satellite radio wave provided by the mobile body and obtained by observation with the mobile body, and the speed correction data received by the speed correction data receiving means, the speed correction data corrected by the speed correction data. Mobile body speed calculating means for calculating the speed of the mobile body ,
The speed correction data generating means integrates the calculation result of the speed of the reference station for a predetermined time, calculates a drift rate of the calculation result of the speed of the reference station based on the integrated value, and based on the calculated drift rate And generating the speed correction data .

Images