JP3303174B2 - On-board positioning device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an on-vehicle positioning device,
In particular, the present invention relates to an on-vehicle positioning device that measures the position of the own vehicle on a vehicle using radio waves from a positioning satellite such as a GPS (Global Positioning System).

[0002]

2. Description of the Related Art As disclosed in, for example, JP-A-61-137909 and JP-A-61-167886, the technology of a positioning device for a vehicle using GPS has been conventionally proposed. Some technologies are already in practical use.

[0003] GPS satellites provide accurate time, orbit functions,
In addition, data indicating the accuracy of information is transmitted on the ground at a predetermined timing through radio waves. The position of the satellite can be known from the function of the time and the orbit, and the distance from the satellite to the receiving point can be known based on the difference between the time of the satellite and the time at the receiving point, that is, the propagation delay time of the radio wave. . If the position of the satellite and the distance from the satellite to the receiving point are known for each of the three satellites located at different positions, the three-dimensional position of the unknown receiving point can be obtained by solving a three-dimensional simultaneous equation. it can. However, since a relatively large error is usually included in the time at the reception point, information on four satellites is required at the same time to compensate for the clock error at the reception point. Further, assuming that the altitude of the receiving point hardly changes, the two-dimensional position (for example, latitude and longitude) of the receiving point on the ground can be obtained from the information of the three satellites.

[0004] However, the number of GPS satellites actually present is limited, and automobiles often enter, for example, a tunnel or a position where radio waves are shielded by buildings. It is difficult to always receive radio waves from four satellites. Therefore, in general, the position cannot be measured unless radio waves from three or more satellites can be received at the same time.

Therefore, in the technique disclosed in Japanese Patent Application Laid-Open No. 61-137,091, an azimuth change of the own vehicle is detected using an optical fiber gyro, and a moving distance of the own vehicle is detected using a vehicle speed sensor. Using information supplementally 1
Even when only radio waves from satellites can be received, the position of the own vehicle can be detected. Also, JP-A-61-16788.
In the technology disclosed in Japanese Patent Laid-Open No. 6-203, the position of the own vehicle can be detected even when only radio waves from two satellites can be received by using a magnetic compass and a distance meter mounted on the vehicle in an auxiliary manner.

[0006]

In the above prior art, when the number of available satellites is insufficient, the amount of movement of the own vehicle is obtained from the signal output from the vehicle speed sensor to compensate for the insufficient information. However, the vehicle speed sensor must be mounted at a specific position near the wheel, and is difficult to use because of the difficulty in mounting.

Accordingly, the present invention provides that the number of available satellites is two.
In the following cases, it is an object to make it possible to measure the position of the own vehicle by supplementing missing information without using a vehicle speed sensor, and to suppress an error in position detection.

[0008]

To solve the above object, according to an aspect of the present onset Ming receives the time and orbital information of the respective emitted from a plurality of satellites, based on the information navigation
The parameters (l′ i, m′i, n ′) of the equation (Equation 1)
i, Δli; i ≧ 3) is calculated based on the navigation equation.
In the on -vehicle positioning device which calculates the own vehicle movement amount (Δx, Δy) : gyro means (14) for outputting a signal corresponding to the rotational angular velocity of the own vehicle; frequency (f) of the signal emitted by the satellite
relative speed detecting means (106) for detecting the relative speed between the satellite and the own vehicle according to o) and the frequency (f) of the actually received signal; and the number of simultaneously available satellites is less than a predetermined number. case, the movement of the at least two axial directions of the vehicle is calculated based on the relative velocity of the vehicle in the rotational angular velocity and the relative velocity detecting means for said gyro means outputs the output of
The amount (δx ', δy'), in supplement parameters missing parameters based on information from the available satellites (l '
i, m'i, n'i, Δli; i ≦ 2) together with navigation
Based on the equation (FIG. 5), the vehicle movement amount (Δx ′, Δ
information processing means (103 ) for calculating y ′) .

In a preferred aspect, the information processing means is provided when the number of simultaneously available satellites is not insufficient.
Based on the azimuth obtained based on the information from the satellite, a reference azimuth indicating the traveling direction of the own vehicle is determined, and when the number of available satellites is less than a predetermined number, the rotational angular velocity of the own vehicle output by the gyro means and the aforementioned Means are provided for determining the traveling direction of the own vehicle based on the reference direction.

In a further preferred aspect, when the number of simultaneously available satellites is insufficient, the information processing means obtains a solution using a predetermined Kalman filter arithmetic expression and calculates the own vehicle position. Means for performing

The symbols shown in the parentheses indicate the reference numerals of the corresponding elements in the embodiments described later for reference, but each component of the present invention is a specific element in the embodiments. It is not limited to only.

[0012]

According to the present invention, when the number of simultaneously available satellites is less than a predetermined number, information from available satellites, the rotational angular velocity of the vehicle output by the gyro means, and the relative speed output by the relative speed detection means are provided. Calculate own vehicle position based on speed.

The relative speed is obtained from the frequency fo of the signal emitted by the satellite and the frequency f of the signal actually received.
That is, the frequency fo (nominal value) of the radio wave actually emitted by the satellite is constant, but the frequency f of the radio wave reaching the vehicle on the ground changes according to the relative speed between the satellite and the own vehicle due to the Doppler effect. I do. Therefore, if the frequency f is detected, f
And fo, the relative speed (Vr) can be obtained.

The moving speed v (vector) of the own vehicle is shown in FIG.
, The relative speed Vr (vector) between the satellite and the vehicle, Vs, es, and eg
(Each vector). Vs is a satellite velocity vector, which can be obtained by differentiating satellite orbit information. es is a direction cosine indicating the direction of the satellite with respect to the own vehicle, and can be obtained from the position of the satellite and the position of the own vehicle (predicted position). eg is an azimuth vector indicating the traveling direction of the own vehicle, and can be obtained from the reference azimuth ψref obtained at a certain time and the rotation amount of the own vehicle from that time. The rotation amount Δψg of the own vehicle is obtained by integrating the rotation angular velocity ω output by the gyro means.

The velocity components vx and vy in the respective axial directions can be obtained from the vector of the moving speed v of the own vehicle.
From y and time δt, the amount of movement δx ′ and δ of each vehicle in the axial direction
y ′ can be obtained. These parameters (δ
By using x ′ and δy ′), even if only one satellite is available at a given time, the own vehicle position at that time can be obtained from the navigation equation shown in FIG. 5, for example.

Incidentally, the number of satellites that can be used simultaneously is three.
If the value is less than the above, there is a possibility that a relatively large error is included in the parameters for calculating the position of the own vehicle, and the error particularly increases with time. Therefore, in an embodiment to be described later, a predetermined Kalman is used.
A solution is obtained by using an arithmetic expression of an optimal filter called a filter (FIG. 9).
This suppresses an increase in errors that occur.

[0017]

FIG. 1 shows the configuration of the entire apparatus according to the embodiment. FIG.
This will be described with reference to FIG. This device is mounted on an automobile running on the ground, and includes a receiving antenna 10, a GPS receiver 1
1, GPS demodulator 12, display device 13, piezoelectric vibration gyro 14, altitude sensor 15, and GPS information processing unit 1
6 is provided. 1.57 sent from each GPS satellite
The 542 GHz radio wave is transmitted through the receiving antenna 10 to the GP.
The information received by the S receiver 11 and superimposed on the radio wave, that is, the function indicating the orbit of the satellite, the time, and the code indicating the accuracy of the information are demodulated by the GPS demodulator 12 and input to the GPS information processing unit 16. You. The GPS information processing unit 16
Basically, based on information sent from GPS satellites,
Generates information (latitude, longitude, altitude) indicating the position of the vehicle,
The information is output to the display device 13. Receiving antenna 1
0, the basic configuration of the GPS receiver 11, the GPS demodulator 12, and the display device 13, and the basic operation of the GPS information processing unit 16 are the same as those of the components of a known device already on the market. . When radio waves from four GPS satellites can be received at the same time, the position of the vehicle can be accurately obtained by calculating only information on the radio waves, but the number of usable GPS satellites is insufficient. In such a case, the position of the vehicle cannot be normally calculated.
In this embodiment, in order to enable calculation of the position of the vehicle even when the number of GPS satellites is insufficient, the piezoelectric vibrating gyroscope 1
4 and an altitude sensor 15 are specially provided, and signals detected by them are input to the GPS information processing unit 16. In this example, information on the tuning frequency of the GPS receiver 11 is also input to the GPS information processing unit 16. The piezoelectric vibrating gyroscope 14 is fixedly arranged on the vehicle,
An analog signal having a level proportional to the rotational angular velocity ω about one axis (vertical axis of the vehicle) is output. The altitude sensor 15 outputs an analog signal whose level changes according to a change in atmospheric pressure, that is, a change in altitude.

The GPS information processing unit 16 is a computer system, and has a CPU (microprocessor) 1.
6a, RAM 16b, ROM 16c, I / O port 16
d, an A / D converter 16e, a timer 16f, and an interrupt control circuit 16g. Since the signals output from the piezoelectric vibrating gyroscope 14 and the altitude sensor 15 are analog signals, A
The data is input to the CPU 16a via the / D converter 16e.
The information output by the GPS demodulator 12 and the tuning frequency are:
Since it is a digital signal, it is connected to the CP via the I / O port 16d.
It is input to U16a. The position information (latitude, longitude, altitude) generated by the CPU 16a is transmitted to the display device 13 via the I / O port 16d.

FIG. 2 schematically shows a functional configuration (contents of processing) of the GPS information processing unit 16. This will be described with reference to FIG. The received data SB output from the GPS demodulator 12, that is, the function indicating the orbit of each satellite, the time, and the code indicating the accuracy are input to the GPS data generation operation 101. In the GPS data generation operation 101, the reception data SB
From the data SC. The data SC is input to the GPS independent positioning calculation 102, the composite positioning calculation 103, and the vehicle speed calculation 106. When information of three or more GPS satellites can be received at the same time, the GPS independent positioning calculation 10
2 to execute position information (latitude, longitude, altitude) SJ
Is generated, and when the number of available satellites is insufficient, the position information (latitude, longitude, altitude) SJ is generated by executing the composite positioning operation 103. The generated position information is transmitted to the display device 13 as output data. The position information SJ is fed back to the GPS data generation operation 101 and used for the next operation.

In the composite positioning operation 103, in addition to the data SC output from the GPS data generation operation 101, the output data SI of the azimuth operation 104, the output data SD of the altitude operation 105, and The calculation is executed using the output data SK of the own vehicle speed calculation 106. In the azimuth angle calculation 104, the rotational angular velocity data S obtained by the piezoelectric vibrating gyroscope 14 is used.
An azimuth angle SI indicating the traveling direction of the own vehicle is obtained based on H. In the azimuth calculation 104, the azimuth is corrected using the azimuth data SG obtained as a result of the GPS independent positioning calculation 102. In the altitude calculation 105, the detected altitude data SF obtained by the altitude sensor 15 and the altitude data SE obtained as a result of the GPS independent positioning calculation 102 are
The necessary altitude information SD is generated. In the own vehicle speed calculation 106, information on the tuning frequency of the GPS receiver 11 and the data S
Based on C and the azimuth data SI, the traveling speed of the own vehicle is calculated, and the result SK is output to the composite positioning operation 103.

CPU 16 of GPS information processing unit 16
FIG. 3 shows an outline of the operation a. Referring to FIG.
The operation of 6a will be described. When the power is turned on, first, initialization is executed in step 21. That is, the output port is cleared, the memory is cleared, various parameters are initialized, the mode setting of the interrupt operation, the mode setting of the timer, and the like are executed. When step 21 ends, the process proceeds from step 22 to 23 every time a predetermined timing is reached, and various processes are executed.

In step 23, the latest received data SB
Enter In the next step 24, a GPS data generation operation (corresponding to 101 in FIG. 2) is executed based on the received data SB. In the next step 25, the current vehicle altitude is obtained, in the next step 26, the traveling direction (azimuth) of the current vehicle is obtained, and in the next step 27, the current vehicle speed is obtained.

When signals from three or more satellites can be received at the same time, the process proceeds to steps 28 to 29. Otherwise, that is, when the number of available satellites is two or less, the process proceeds to steps 28 to 32. In step 29, GP
An S independent positioning operation (corresponding to 102 in FIG. 2) is executed. In the next step 30, various parameters used when obtaining the altitude (SD) (when calculating in step 25) are corrected by using the calculation result in step 29. Further, in the next step 31, various parameters used when obtaining the azimuth angle (SI) (when calculating in step 26) are corrected using the calculation result in step 29. If the number of available satellites is two or less, at step 32,
The maximum value is stored in the error register E1.

In step 33, it is checked whether or not signals from one or more satellites can be received. If the signals can be received, the flow advances to step 34 to execute a composite positioning operation (corresponding to 103 in FIG. 2). If there are no satellites available, as in the case of a car traveling in a tunnel, for example, step 35 is executed and the maximum value is stored in the error register E2.

In the next step 36, G in step 29
The error detected when executing the PS independent positioning operation is stored in the register E1, and in the next step 37, the error detected when executing the composite positioning operation in step 34 is stored in the register E2. Then, in the subsequent step 38, it is checked whether or not both of the registers E1 and E2 are the maximum value, and the process proceeds to step 39 or 40 according to the result. In step 39, the contents of the registers E1 and E2 are compared,
If E1 <E2, that is, if the error in the GPS independent positioning calculation is smaller than the error in the composite positioning calculation, step 41
And outputs the result (position information) calculated by the GPS independent positioning calculation (29) as SJ. Step 3
When E1 <E2 is not satisfied in step 9, the result (position information) calculated by the composite positioning operation (34) is output as SJ. The output data SJ is used for the next calculation.
Will be played back.

In step 43, the azimuth angle data (SI) obtained in step 26 is output to the display device 13.
Also, even when there are no available satellites,
When there is valid azimuth data, the program goes through steps 38 to 40 and proceeds to step 43, so that the azimuth data is output to the display device.

The above operation is repeatedly executed. In this embodiment, the period for calculating the position information is 1 second. However, processes such as sampling of the output signal of the piezoelectric vibrating gyroscope and calculations related thereto, sampling of the output signal of the altitude sensor, sampling of the tuning frequency, and the like are repeatedly executed in a relatively short cycle by a timer interrupt. For example, the output signal of the piezoelectric vibrating gyroscope is 20
It is sampled every msec.

In this embodiment, even when three or more satellites can be used, the GPS independent positioning calculation (29) is executed, and further the composite positioning calculation (34) is executed. Normal,
Although the exact position of the vehicle can be determined by the GPS independent positioning calculation, for example, if the accuracy of the information transmitted by one of the three GPS satellites is low, a large error occurs in the result of the GPS independent positioning calculation. Therefore, an increase in the detection error is suppressed by comparing the errors included in the results of the two types of calculations and using the smaller error. The accuracy of the information transmitted by the GPS satellites can be known by the accuracy code SVACC included in the transmitted information. But,
When three or more satellites are available, the execution of the composite positioning operation may be omitted.

FIG. 4 shows the contents of the composite positioning calculation (34) in FIG.
Shown in This will be described with reference to FIG. First, step S41
Then, the measurement value is input, and the navigation equation is determined in the next step S42. That is, as shown in FIG. 5, when the number of available satellites is one, the equation shown in step S52 is used. When the number of available satellites is two, step S53 is used.
Use the equation shown in

In these equations, .DELTA.x ', .DELTA.y and .DELTA.z' are the moving distances (unknown numbers) in the respective axial directions from the last measured position of the vehicle to the present, .DELTA.t is the clock error (unknown number) of the apparatus, and c is the speed of light. It is. L _i ′, m _i ′, and n _i ′ are direction cosine indicating the direction of the i-th satellite viewed from the own vehicle, and are obtained based on transmission data of each satellite.
Δx ′ and δy ′ are the movement amounts of the vehicle in the respective axial directions. .DELTA.l _i 'is the amount of change to the current from the previous calculation of the distance from the position of the vehicle to the i-th satellite, transmission data of each satellite - is determined based on the data. The method of calculating each parameter will be described later in detail.

In this embodiment, an operation of an optimum filter called a Kalman filter is executed in order to reduce an error in obtaining an unknown value of a navigation equation. That is, in this embodiment, it is assumed that the vector Xi at a certain time changes to the vector Xi _{+ 1} at the next time according to the physical model matrix Ci. The vector Xi is Δx, Δy, Δz and cΔt
Is represented by In step S43 of FIG. 4, the physical model matrix Ci is determined. Specifically, the physical model matrix Ci shown in FIG. 6 is used. In the next step S44, a measurement error estimation matrix indicating the error of each measurement value is determined. The contents of this matrix are shown in FIG. In a next step S45, a matrix indicating an error of the physical model is determined. The contents of this matrix are shown in FIG.

In step S46, the composite positioning operation (3
It is determined whether the content of the counter i indicating the number of calculations in 4) is 0, that is, whether it is the first calculation. If i = 0, the initial value is set in the register in the next step S47. That is,
The latest calculation result (Δx, Δy, Δz, cΔt calculated by GPS independent positioning calculation (29))
And the expected errors contained in each of them) are stored in a predetermined register. If i is 1 or more in step S46, in the next step S48, the previous composite positioning operation (3
4) The calculation result (Δx, Δ
y, Δz, cΔt and the expected errors included in each of them are stored in a predetermined register.

Then, in the next step S49, the measured values are substituted into the Kalman filter calculation formula, and the solution of the calculation formula (the optimal estimated value and its error) is obtained. Specifically, the matrix of the navigation equation, the physical model matrix, the measurement error estimation matrix, and the physical model error matrix are substituted into the calculation formula of step S91 shown in FIG. can get.

The parameters to be substituted into each matrix of the navigation equation can be obtained by executing the processing shown in FIG. First, in step S201, coordinates Sxi, Syi, and Szi (earth-centered system coordinates: a coordinate system based on the center of the earth) in the respective axial directions indicating the position of the i-th satellite are input. This value is obtained from the function of the orbit transmitted by the satellite and the time. In the next step S202, the coordinates Ux0, Uy0 and Uz0 (geocentric coordinates) indicating the vehicle position at the time of the previous calculation are input. This value is obtained from the result of the previous calculation. In the next step S203, a distance ri from the position of the i-th satellite to the own vehicle position is calculated. In further subsequent step S204, S205 and S206, obtaining the direction cosines l _i, m _i and n _i indicating the direction viewed i-th satellite from the vehicle.

[0035] _{l i = (Ux0-Sxi)} / ri m i = (Uy0-Syi) / ri n i = (Uz0-Szi) / ri Further, the direction cosines of the navigation equations (see FIG. 5), the ground-based coordinates Since it is used, coordinate transformation is performed in the next step S207, and the direction cosine l _i ′, m _i ′ and n _i ′ of the earth surface system are generated from the direction cosine l _i , _mi and n _i of the earth-centered system. This coordinate conversion process is shown in FIG.

In the next step S208, the movement amounts δx ′ and δy ′ of the own vehicle from the previous calculation to the present are obtained. The contents of this processing are shown in FIG. This will be described with reference to FIG. In step S221, a reference frequency fo is input. Since fo is the frequency of the radio wave actually emitted by the GPS satellite and is considered to be substantially unchanged, the calculation is made here by assigning a constant to fo. In the next step S222, the tuning frequency f of the GPS receiver
Enter Then, in the next step S223, the relative speed Vr in the axial direction connecting the own vehicle and the satellite is calculated.

That is, when the satellite which is the source of the radio wave and the own vehicle at the reception point of the radio wave move relatively, the frequency f.sub.of the radio wave at the reception point becomes constant even if the frequency fo of the radio wave emitted by the satellite is constant. Has a relative velocity Vr due to the Doppler effect.
Changes in response to Since the GPS receiver 11 tunes so as to automatically follow the frequency f of the received radio wave, the relative speed Vr can be obtained based on the tuning frequency f output from the GPS receiver and the reference frequency fo. . The calculation formula is shown in step S223.

In the next step S224, a velocity vector Vs of the satellite is obtained. That is, since the information on the orbit of each satellite is known, the orbit is differentiated using the information to obtain the velocity vector Vs of the satellite.

In the next step S225, the direction cosine es (unit vector) of the satellite is determined. This direction cosine es
Are l _i ′, m _i ′, and n _i ′, which have already been obtained in the processing up to step S207, and the results are used.

In the next step S226, a unit vector eg indicating the traveling direction of the own vehicle is obtained. Heading direction (azimuth)
ψ is obtained by integrating the rotational angular velocity ω output from the piezoelectric vibrating gyroscope 14.

By the following formula at step S227, the relative speed vector Vr, the satellite speed vector Vs, the direction cosine es, and the unit vector e indicating the traveling direction of the own vehicle are obtained.
From g, the speed vector v of the own vehicle is obtained.

In the next step S228, the axial movement amounts δx and δy of the own vehicle are obtained from the axial components vx and vy of the velocity vector v and the time δt.

Description will be made again with reference to FIG. In step S209, a change to the current from the previous calculation of the distance between the position of the vehicle position and the i-th satellite ri (referred to as pseudo range) is calculated, and the result with .DELTA.l _i.

FIG. 10 shows the contents of the own vehicle azimuth angle calculation process executed in step 26 of FIG.
FIG. 11 shows the contents of the azimuth angle coefficient correction processing executed in step S1. First, the vehicle azimuth angle calculation processing will be described with reference to FIG.

First, at step 101, integration of the sampled angular velocity ω is executed. Actually, 20msec
The A of the angular velocity signal is synchronized with the timer interrupt generated every time.
/ D conversion output AD _G samples, integrating the result of calculation using the coefficients ADc and ADarufa, determining the angle change theta _G.

When the reference azimuth ψref is valid, the process proceeds from step S102 to S103, and the azimuth ψ at that time is calculated. That is, the calculation result of {ref + αθ _G '+ θo' is set as the azimuth angle ψ. In the next step S104, the current azimuth ψ is set as a new reference azimuth ψref.

If the expected error of the azimuth ψ is the upper limit, that is, if the correct azimuth cannot be calculated, the process proceeds from step S105 to S106, where the maximum value is stored in a register indicating the expected error of the azimuth, and the reference azimuth is stored. Set the invalid flag and clear the correction counter.

Next, the azimuth coefficient correction processing will be described with reference to FIG. In this embodiment, four types of correction modes are provided, and depending on the contents of the mode register MD at that time, # 0 mode processing, # 1 mode processing, # 2 mode processing, or # 3 mode processing. The mode processing is executed. When there is an instruction of “numerical value correction”, steps S 119 to S 11
Go to A. In step S11A, the azimuth data ψg calculated based on the output of the gyro is corrected using the azimuth data ψGPS obtained as a result of the GPS independent positioning calculation. However, since the azimuth data ΔGPS has a time delay of t seconds, the azimuth data Δg to be compared is the one before t seconds. That is, the difference ψGPS (-t) -ψg (-t) between the two types of azimuth data at the same time is regarded as the azimuth error Δψg, and the azimuth error Δψg is added to the current azimuth data ψg. Is corrected. In this embodiment, the azimuth data is set every 0.1 seconds so that the past azimuth data Δg can be referred to.
The calculation of the data ψg is executed, and the azimuth data ψg of the past several seconds are stored in the memory. In the next step S11B, the corrected current azimuth data ψg is stored in the reference azimuth ψref, and in the following step S11C, the reference azimuth valid flag is set.

FIG. 12 shows the contents of the # 0 mode processing of FIG. 11, and FIG. 13 shows the contents of the # 1 mode processing.
FIG. 14 shows the contents of the mode processing, and FIGS. 15 and 16 show the contents of the # 3 mode processing. First, the # 0 mode processing will be described with reference to FIG. In the first step S121, the latest azimuth data obtained as a result of the GPS independent positioning calculation 方位 the azimuth data t seconds before the azimuth data ψg (-t) corresponding to the time delay of GPS is obtained by a delay process (not shown). Check if it exists. When the azimuth data ψg (-t) exists, the process proceeds to step S122, where the vehicle speed v is compared with a predetermined threshold value V1min. If v> V1min, the process proceeds to step S1.
Proceed to 23. That is, the azimuth error of the solution obtained by the GPS independent positioning calculation is represented by arctan (0.72 / (v + 0.72)), and becomes large when the vehicle speed v is low. Therefore, when the error is small, that is, when the vehicle speed v is smaller than V1min. When larger, azimuth data @ GPS is considered valid.

In step S123, the latest azimuth angle data
Data is stored in the register $ 0, and the next step S1
At 24, 1 is set in the mode register MD. At the next step S125, the time register T # is cleared, and at the next step S126, the counter count # 0 is cleared. When 1 is set in the mode register MD, the operation shifts to the # 1 mode next time. The # 1 mode processing will be described with reference to FIG. In the first step S131, the counter
Increment count + 1 (+1). In the next step S132, it is determined whether or not there is the latest azimuth data obtained as a result of the GPS independent positioning calculation 方位 azimuth data ｔg (-t) t seconds ago corresponding to the GPS time delay. Find out.
When the azimuth data Δg (−t) exists, the process proceeds to step S133, in which the vehicle speed v is set to a predetermined threshold value V1min.
If v> V1min, the process proceeds to step S134. In step S134, T # and counter count # 1
Are compared, and if they match, then step S135 is performed.
Proceed to.

In step S135, it is checked whether the azimuth of the own vehicle is stable. That is, the rate of change of the azimuth angle obtained by dividing the difference between $ 0 detected in the $ 0 mode and the latest azimuth data @GPS by the time interval T (0) at which they are detected is defined as an upper limit value ΔψGPSmax. If the change rate is smaller than the upper limit value, the process proceeds to the next step S137. Step S137
Then, it is further checked whether or not the counter count # 1 has reached a predetermined value C # 10OK. Note that d_GPS_0 is a time delay of $ 0,
d_GPS_1 is the latest ψGPS time delay. When the azimuth of the own vehicle is stabilized, the process proceeds to step S138.

In step S138, a numerical correction flag (a numerical correction instruction) is set, and a stand-alone timer (counts the time during which the azimuth data has not been corrected) T
Clear A. In the next step S139, the latest azimuth data @GPS is stored in the register # 1, and in the next step S13A, the latest azimuth data @GPS azimuth data which coincides with the GPS in time is stored. Read from memory and store in register $ 1raw.

In step S13B, the mode register M
D is set to 2, the time register T # is cleared, and the counters count # 1 and count # 2 are cleared. When 2 is set in the mode register MD, the mode shifts to the # 2 mode next time. Steps S132, S133, S134,
Alternatively, when the condition of S135 is not satisfied, step S1
Since the mode register MD is cleared at 36, the mode returns to the $ 0 mode next time.

Next, the # 2 mode processing will be described with reference to FIG. In the first step S141, the counter coun
tψ2 is incremented (+1). Next step S
At 142, it is checked whether or not the latest azimuth data obtained as a result of the GPS independent positioning calculation (the azimuth data Δg (-t) t seconds ago corresponding to the time delay of GPS) exists. If the azimuth data ψg (-t) exists, then step S1
The process proceeds to 43, where the vehicle speed v is compared with a predetermined threshold value V1min. If v> V1min, the process proceeds to step S144.
In step S144, the counter count # 2 is checked, and if count # 2> 1, the process proceeds to step S145.
Otherwise, in step S146, the latest azimuth data $ GPS is stored in $ 2, and the flow advances to step S148.

In step S145, it is checked whether the azimuth of the own vehicle is stable. That is, the rate of change of the azimuth angle obtained by dividing the difference between # 1 detected in the {1 mode} and the latest azimuth data @GPS by the time interval T (1) at which they were detected is defined as the upper limit value ΔψGPSmax. If it is determined that the rate of change is smaller than the upper limit, the process proceeds to the next step S148. Step S148
Then, it is further checked whether or not the counter count # 2 has reached a predetermined value C # 2OK. Note that d_GPS_1 has a time delay of $ 1,
d_GPS_2 is the latest ψGPS time delay. When the azimuth of the own vehicle is stabilized, the process proceeds to step S149.

In step S149, first, a numerical value correction flag (a numerical value correction instruction) is set, and the stand-alone timer TA is cleared. Next, the latest azimuth data @ GP
S is stored in register # 2, and the latest azimuth data
The azimuth angle data of the past gyro, which coincides with the GPS time, is read from the memory and stored in the register # 2raw.

In the next step S14A, necessary parameters are calculated in preparation for A / D conversion coefficient correction and successive approximation processing. That is, the result of dividing the difference between the azimuth data # 2 and # 1 by the time interval T21 at which they were detected is θc
2 and the result of dividing the difference between the azimuth data ψ2 raw and ψ1 raw by the time interval T21 at which they were detected is θ
Store in g2.

In the next step S14B, 3 is set in the mode register MD, the time register T $ is cleared,
Clear the counters count # 2 and count # 3. When 3 is set in the mode register MD, the operation shifts to the # 3 mode next time. Steps S142, S143, or S
If the condition of 145 is not satisfied, the counter count # 2 is cleared in step S147.

Next, the # 3 mode processing will be described with reference to FIG. In the first step S151, the counter coun
tψ3 is incremented (+1). Next step S
In step 152, it is checked whether or not the latest azimuth data obtained as a result of the GPS independent positioning operation {azimuth data t (t) t seconds before the time corresponding to the GPS time delay exists. If the azimuth data ψg (-t) exists, then step S1
Proceeding to 53, the vehicle speed v is compared with a predetermined threshold value V1min, and if v> V1min, the flow proceeds to step S154.
In step S154, the counter count # 3 is checked, and if count # 3> 1, the process proceeds to step S155.
Otherwise, in step S156, the latest azimuth data $ GPS is stored in $ 3, and the flow advances to step S158.

In step S155, it is checked whether the azimuth of the own vehicle is stable. That is, the rate of change of the azimuth obtained by dividing the difference between # 2 detected in the # 2 mode and the latest azimuth data @GPS by the time interval T (2) at which they were detected is defined as an upper limit value ΔψGPSmax. If the change rate is smaller than the upper limit value, the process proceeds to the next step S158. Step S158
Then, it is checked whether or not the counter count # 3 has reached the predetermined value C # 3OK. Note that d_GPS_2 is delayed by $ 2,
d_GPS_3 is the latest ψGPS time delay. When the azimuth of the own vehicle is stabilized, the process proceeds to step S159.

In the next step S15A, necessary parameters are calculated in preparation for A / D conversion coefficient correction and successive approximation processing. That is, the result of dividing the difference between the azimuth data # 3 and # 2 by the time interval T32 at which they were detected is given by θc
3 and the result of dividing the difference between the azimuth data ψ3raw and ψ2raw by the time interval T32 at which they were detected is θ
Store in g3.

In the next step S15B, θc3 and θc2
Is compared with the lower limit Δcmin, and | θc3−θc2 |
If it is the lower limit value, the process proceeds to step S15C; otherwise, the process proceeds to step S161 in FIG.

In step S15C, | Δψg |
> ΔADαcmin (lower limit), θc3 <Δcmin, and T32 <Tω0max (upper limit). If all the conditions are satisfied, “zero ω correction” is executed in step S15D.

Referring to FIG. 16, in step S161, the condition of | θg3-θg2 | <Δrmax is checked, in step S162, the condition of | θg3-θg2 |> Δrmin is checked, and in step S163, | θc3−θc2 | <Δcmax
Is checked, and in step S164, | Δψg |> AD
Check the condition of αcmin. Steps S161 and S162
If all the conditions of S163 and S163 are satisfied, step S
According to the identification result of the condition 164, either the A / D conversion coefficient correction mode or the successive approximation correction mode is selected.

That is, if | Δψg |> ADαcmin, the A / D conversion coefficient correction mode is selected; otherwise, the successive approximation correction mode is selected. A / D conversion coefficient correction mode
If | Δψg | ≦ ADαcmin at the time of the mode, the process proceeds from step S169 to S16B, and a flag is set so as to select the successive approximation correction mode. If | Δψg |> ADαcmin in the successive approximation correction mode, the process proceeds from step S165 to S166, where A / A
A flag is set so as to select the D conversion coefficient correction mode, and parameters (the number of successive approximations, the previous solution) are initialized in the next step S167.

Then, in the successive approximation correction mode, the process proceeds from step S169 to S16A to execute the "successive approximation" process. In the A / D conversion coefficient correction mode, the process proceeds from step S165 to S168. , Α, clearing θo ′, executing “A / D conversion coefficient correction” processing, and setting an error prediction matrix.

In the next step S16C, register # 3
Is stored in $ 2, and the contents of register $ 3raw are stored in $ 2.
2 Raw is stored, the contents of register $ c3 are stored in $ c2, the contents of register $ g3 are stored in $ g2, and again
The three modes are set to be executed, the register T # is cleared, and the flow advances to step S157 in FIG.

FIG. 17 shows the contents of the zero ω correction in step S15D. This will be described with reference to FIG. When there is almost no change in the azimuth data ψGPS obtained by the GPS independent positioning calculation, the error Δψg between the azimuth data ψg calculated by the output of the gyro and ψGPS is almost equal to the A / D conversion coefficient ADc. It is considered to have been caused. Therefore, in the zero ω correction, the A / D conversion coefficient ADc is corrected. In step S172, the angle change amount θg is obtained from the sampling results ADg of the N angular velocities ω in a certain period.
From the sampling results ADg of the N angular velocities .omega. After the time T32. Then, the angle change .theta.gT is determined.
Then, in the next step S173, a difference between the two angle change amounts is set as an error Δψg, and a coefficient correction amount Δ is obtained from Δψg. In step S174, a coefficient correction amount Δ is added to the A / D conversion coefficient ADc.

FIG. 18 shows the contents of the "A / D conversion coefficient correction" in step S168. This will be described with reference to FIG. In step S181, at three different points, G
The GPS azimuth data # 1 GPS, # 2 GPS, and # 3 GPS obtained by the PS independent positioning calculation are input.
In practice, the azimuth data # 1 GPS has been detected in the # 1 mode and has already been stored in the register # 1 in step S139, and the # 2 GPS has been detected in the # 2 mode and has already been stored in the register # 2 in step S149. Since the # 3 GPS is detected in the # 3 mode and has already been stored in the register # 3 in step S159, these data are used.

In the next step S182, the difference between the azimuth data at two points, # 2GPS and # 1GPS, is divided by the time T21, and the result, that is, the azimuth change per unit time is θc
Store in 2. Orientation data at another two points @ 3GP
The difference between S and ψ2GPS is divided by time T32, and the result, that is, the azimuth change per unit time is stored in θc3.
Actually, the azimuth change θc2 has already been obtained by the processing in step S14A in the # 2 mode, and the azimuth change θc3 has already been obtained in the processing in step S15A in the # 3 mode. Use the information as is. In step S14A, the azimuth change θc
The azimuth change θg2 detected by the gyro corresponding to 2 is calculated, and in step S15A, the azimuth change θc3
Is obtained, which information is also used in the next step.

In step S183, the parameters .theta.g2, .theta.g3, .theta.c2 and .theta.c3 are substituted into predetermined relational expressions to determine coefficients .alpha. And .theta.o '. Using the coefficients α and θo ′ obtained here, the next step S184
Then, the A / D conversion coefficients ADα and ADc are corrected.

FIG. 19 shows the contents of "successive approximation" in step S16A. This will be described with reference to FIG. Step S
In 191, the GPS azimuth data obtained by the GPS independent positioning calculation at three different points is {1GP
Enter S, $ 2GPS, and $ 3GPS. Actually, the azimuth data # 1GPS is detected in the mode # 1 and has already been stored in the register # 1 in step S139.
$ 2 GPS is detected in $ 2 mode and step S
149 already stored in register $ 2, $ 3GP
S is detected in the # 3 mode, and step S159 is executed.
Since these data have already been stored in the register # 3, these data are used.

In the next step S192, the difference between the azimuth data at two points, # 2GPS and # 1GPS, is divided by the time T21, and the result, that is, the azimuth change per unit time is θc
Store in 2. Orientation data at another two points @ 3GP
The difference between S and ψ2GPS is divided by time T32, and the result, that is, the azimuth change per unit time is stored in θc3.
Actually, the azimuth change θc2 has already been obtained by the processing in step S14A in the # 2 mode, and the azimuth change θc3 has already been obtained in the processing in step S15A in the # 3 mode. Use the information as is. In step S14A, the azimuth change θc
The azimuth change θg2 detected by the gyro corresponding to 2 is calculated, and in step S15A, the azimuth change θc3
Is obtained, which information is also used in the following steps.

In step S193, a relational expression for determining a correction coefficient is determined, and in the next step S194, a measurement error estimation matrix is determined. In the next step S195,
Check if the previous solution exists. If there is no previous solution, that is, if this time is the first calculation, the process proceeds to step S196 to set an initial value to the solution. Use this solution for the next calculation. When the previous (i-th) solution exists, the process proceeds from step S195 to S197, where the successive approximation calculation is executed, and the (i + 1) -th solution X (coefficient α
And θo ′) and its error. The coefficient α found here
And θo ′, the coefficient A is calculated in the same manner as in step S184.
Dα and ADc are modified.

In the “altitude coefficient correction processing” of step 30 shown in FIG. 3, although not shown, correction is performed in the same manner as the above-mentioned “azimuth coefficient correction processing”. That is, the altitude z (A) obtained from the output signal of the altitude sensor 15 by the accurate altitude z (GPS) obtained by the “GPS independent positioning calculation”
LT), and various coefficients used when converting the output signal level of the altitude sensor 15 to the altitude z (ALT) are corrected based on the value of the altitude z (GPS). As with the "azimuth coefficient correction process", "numerical value correction", "A / D conversion coefficient correction", and "successive approximation" are prepared, and any of these processes is executed according to the conditions at that time. You.

In the “GPS independent positioning calculation”, unknowns Δx ′, Δy ′, Δz ′ and cΔt are obtained by solving the following navigation equations (1) or (2).

[0077]

(Equation 1)

[0078]

As described above, according to the present invention, even when the number of available satellites is two or less, the rotational angular velocity of the own vehicle is detected using the gyro means, and the signal emitted from the satellite is detected. According to the frequency and the frequency of the actually received signal, the relative speed between the satellite and the vehicle is detected, and the detected information is used to supplement the missing information, and the
The moving amount of the own vehicle is calculated based on the moving amount . Therefore, there is no need to provide a vehicle speed sensor.

As in this embodiment, when three or more satellites are available and an accurate azimuth can be obtained by independent positioning calculation, a reference azimuth is determined, and the azimuth is determined from the reference azimuth and the rotational angular velocity detected by the gyro means. By calculating
Even when the number of available satellites is two or less, a relatively accurate direction can be detected.

Further, as in the embodiment, by calculating the unknown using the Kalman filter, an increase in the positioning error when the number of available satellites is two or less can be suppressed.

It is to be noted that an accurate altitude can be detected by calibrating the altitude detected by the altitude detecting means using the result of the independent positioning calculation.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of an entire apparatus according to an embodiment.

FIG. 2 is a block diagram showing a functional configuration of a unit 16 of FIG.

FIG. 3 is a flowchart showing the operation of the CPU of FIG. 1;

FIG. 4 is a flowchart showing processing of a composite positioning operation.

FIG. 5 is a flowchart showing the contents of step S42 in FIG. 4;

FIG. 6 is a flowchart showing the contents of step S43 in FIG. 4;

FIG. 7 is a flowchart showing the contents of step S44 in FIG. 4;

FIG. 8 is a flowchart showing the contents of step S45 in FIG. 4;

FIG. 9 is a flowchart showing a part of the contents of step S49 in FIG. 4;

FIG. 10 is a flowchart showing the contents of step 26 in FIG. 3;

FIG. 11 is a flowchart showing the contents of step 31 in FIG. 3;

FIG. 12 is a flowchart showing the contents of a part of the processing in FIG. 11;

FIG. 13 is a flowchart showing the contents of a part of the processing in FIG. 11;

FIG. 14 is a flowchart showing the contents of a part of the processing in FIG. 11;

FIG. 15 is a flowchart showing the contents of a part of the processing in FIG. 11;

FIG. 16 is a flowchart showing the contents of a part of the processing in FIG. 11;

FIG. 17 is a flowchart showing the contents of zero ω correction.

FIG. 18 is a flowchart showing the contents of A / D conversion coefficient correction.

FIG. 19 is a flowchart showing the contents of successive approximation.

FIG. 20 is a flowchart showing the contents of a navigation equation parameter calculation process.

FIG. 21 is a flowchart showing the contents of a coordinate conversion process.

FIG. 22 is a flow chart showing the contents of a movement amount calculation process;
It is.

FIG. 23 is a vector diagram showing speeds of a satellite and a reception point.

[Explanation of symbols]

10: Receiving antenna 11: GPS receiver 12: GPS demodulator 13: Display device 14: Piezoelectric vibration gyro 15: Altitude sensor 16: GPS information processing unit 101: GPS data
Data generation calculation 102: GPS independent positioning calculation 103: complex positioning calculation 104: azimuth calculation 105: altitude calculation 106: own vehicle speed calculation

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-265879 (JP, A) JP-A-4-213083 (JP, A) JP-A-63-302317 (JP, A) I. Snyder, AN INT EGRATED NAVIGATION SYSTEM FOR ADVANCED ATTACK HELICOPT ERS, Proc IEEE / AIAA 7th Digit Avionics Syst Conf 1986, USA, IE. 150-156, 1986 (58) Fields investigated (Int. Cl. ⁷ , DB name) G01S 5/00-5/14 G01C 21/00-21/24 G01C 23/00-25/00 JICST file (JOIS)

Claims (3)

(57) [Claims] 1. A method for receiving time and orbits respectively emitted from a plurality of satellites, and performing navigation based on the information.
In the on -vehicle positioning device that calculates the parameters of the equation and calculates the amount of movement of the vehicle based on the navigation equation : Gyro means for outputting a signal corresponding to the rotational angular velocity of the vehicle; frequency and actual frequency of the signal emitted by the satellite depending on the frequency of the signal received, the relative speed detecting means for detecting the relative velocity between the satellite and the vehicle; if and simultaneously the number of available satellites is insufficient than a predetermined, the gyro means outputs At least two axial directions of the own vehicle calculated based on the rotational angular speed of the own vehicle and the relative speed output by the relative speed detecting means.
Movement amount, in supplement missing parameters, with the parameters based on information from the available satellites, the navigation equations
An on -vehicle positioning device, comprising: information processing means for calculating a moving amount of the own vehicle based on the information. 2. The information processing means, when the number of simultaneously available satellites is not insufficient, determines a reference direction indicating the traveling direction of the own vehicle based on the direction obtained based on information from the satellites, When the number of available satellites is less than a predetermined number, the traveling direction of the own vehicle is obtained based on the rotational angular velocity of the own vehicle output by the gyro means and the reference azimuth.
The on-vehicle positioning device according to 1. 3. The method according to claim 1, wherein when the number of simultaneously available satellites is insufficient, the information processing means obtains a solution using a predetermined Kalman filter arithmetic expression and calculates a position of the own vehicle. Item 4. The on-vehicle positioning device according to item 1.