JPH08285582A - Altimeter and altitude correcting method using the same - Google Patents

Abstract

PURPOSE: To provide an altimeter in which the deviation of a displayed altitude due to the atmospheric pressure change during the stopping state can be automatically corrected. CONSTITUTION: An absolute altitude value is obtained by an altitude value calculator 11 based on the atmospheric pressure value detected by an atmospheric pressure detector 10, and the value is corrected based on the correction value stored in a correction value holder 14 by an altitude corrector 12 to obtain an accurate corrected altitude value. Since an automobile mounted with an altimeter has a fast moving speed and can arrive at a destination in a short time, the atmospheric pressure change due to the change of the weather conditions is small during the moving, and the accurate altitude value is obtained during the moving. When the corrected altitude value in the case of stopping is held as a reference value in display altitude value holding means 18, since the altitude of the automobile is constant, the reference value represents the accurate altitude value. Accordingly, even if the atmospheric pressure alters during the stopping, new correction value is obtained by using the reference value. Thereafter, the corrected altitude value is obtained based on the correction value, and hence it always becomes the accurate value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an altimeter and an altitude correction method using the same, and more specifically, it is mounted on a vehicle having a high moving speed such as an automobile or a motorcycle.
An altimeter that measures altitude from atmospheric pressure in order to know the altitude at the current location, and an altimeter that corrects errors that occur in the measured altitude due to changes in atmospheric pressure (due to changes in weather) and altitude correction using it It is about the method.

[0002]

As is well known, the atmospheric pressure decreases as the altitude increases, and the standard atmospheric pressure at sea level is about 1013 hPa.
That is, it decreases by about 1.2 hPa each time the height increases by 10 m. Therefore, when trying to measure altitude,
By measuring the atmospheric pressure around it, the altitude value can be obtained by converting from the atmospheric pressure. Actually, the atmospheric pressure at 0 m above sea level increases or decreases from the standard atmospheric pressure due to changes in weather conditions, so that the atmospheric pressure at each altitude also changes accordingly. Therefore, in order to accurately measure the altitude, it is necessary to correct the atmospheric pressure fluctuation.

An example of a conventional altimeter with such a correction function is shown in FIG. That is, the ambient atmospheric pressure detected by the atmospheric pressure detecting device 1 is sent to the altitude value calculating unit 2, and a predetermined arithmetic process is performed there to calculate the altitude based on the atmospheric pressure. This calculation process is performed assuming that the current atmospheric pressure is the standard atmospheric pressure. The calculated altitude value (absolute altitude) is sent to the altitude value correction means 3 to obtain an altitude value in consideration of atmospheric pressure fluctuation based on actual weather conditions. Then, the obtained altitude value is output via the display device 4.

By the way, in the correction processing in the altitude value correction unit 3, the correction value stored in the correction value holding unit 5 is used as an offset value for the absolute altitude value obtained by the altitude value calculation unit 2, and the correction value is subtracted. By doing. The correction value stored in the correction value storage unit 5 is read out by the altitude correction value calculation unit 6 and transferred to the altitude correction unit 3, where the altitude value = absolute altitude value−correction value The calculation process is executed and the obtained altitude is output.

As the correction value, an accurate altitude value given by the user through the manual altitude value input device 6 and an absolute altitude value obtained by the altitude value calculating section 2 are inputted to the altitude correction value calculating section 7. The calculated correction value is stored in the correction value holding unit 5 by calculating the difference between the two. The correct correction value input by the user can be known by looking at the altitude sign, etc., and until the next correct altitude value is input, correction calculation is performed based on the temporarily stored correction value. Then, the altitude value will be calculated.

[0006]

However, in the above-mentioned conventional altimeter, in order to determine the correction value, the user needs to detect an accurate altitude by some means and manually input the altitude value. Therefore, accurate altitude correction cannot be performed in a place where, for example, there is no altitude sign and the exact altitude is unknown. Further, since manual input is indispensable, the process is complicated, and if the input is forgotten, the wrong altitude is displayed.

In the case of an on-vehicle altimeter or the like which is the subject of the present invention, since it is rare that an altitude sign is installed beside the road, there is a low possibility of knowing the accurate altitude. Also, even if there is an altitude sign, it is necessary to enter the accurate altitude value at that position in order to update the correction value, so you must pause at that location and enter the accurate altitude value. I won't. In this way, it is complicated to temporarily stop the process for updating the correction value, and if it becomes late to notice the altitude sign, the vehicle will stop suddenly, which is dangerous. Furthermore, if it has passed, it has to move backward, which is not practical. Furthermore, the installation of altitude signs on the side of the road is common on highways and the like where temporary stop is not possible, and in that respect also the correction process becomes difficult.

On the other hand, the vehicle is often stopped for a long time such as at night. In such a case, the altitude of the position where the vehicle is present does not change, but the atmospheric pressure changes due to changes in weather conditions (atmosphere when the vehicle is stopped). Then, the altitude value calculated based on the atmospheric pressure also differs from the altitude value obtained based on the atmospheric pressure obtained before the vehicle stops. That is, considering the case where the high pressure changes to the low pressure (or vice versa), the pressure rises and falls by about 10 hPa. Then, due to the change of 10 hPa, the obtained altitude value is different by about 80 m (when the altitude is 500 m or less), and the difference cannot be ignored as an error range.

The present invention has been made in view of the above background, and an object of the present invention is to solve the above-mentioned problems and to improve the altitude value even if atmospheric pressure changes due to changes in weather conditions. It is an object of the present invention to provide an altimeter capable of automatically obtaining a correction value for correcting, corrective processing based on the correction value, and notifying the user of an accurate altitude, and an altitude correction method using the same.

[0010]

In order to achieve the above object, in an altimeter according to the present invention, an atmospheric pressure detecting means for detecting an atmospheric pressure, an atmospheric pressure value detected by the atmospheric pressure detecting means, and a correction value are used. It is premised on an altimeter equipped with a means for obtaining a corrected altitude value, an output means for outputting the obtained corrected altitude value, and a correction value storage means for storing the correction value.

Further, the correction value updating function is improved so that at least the moving body receiving at least the operating state detecting means for detecting the operating state of the moving body on which the altimeter is mounted and the output signal from the operating state detecting means are received. Output from the operating state detection means, and a reference storage means for storing as a reference value the correction altitude value or the correction result (correction atmospheric pressure value) calculated by using the correction value obtained when the When a signal is received and the moving body starts moving, a correction value is obtained based on the atmospheric pressure value detected by the atmospheric pressure detecting means or a predetermined value based on the atmospheric pressure value and the stored reference value, and the correction value storage is performed. And a correction value calculating means registered in the means (claim 1).

More specifically, the means for obtaining the corrected altitude value is based on the altitude value calculating means for calculating the altitude value from the detected atmospheric pressure value and the altitude value calculated by the altitude value calculating means. An altitude value correction means for performing correction using a correction value to calculate a corrected altitude value, wherein the reference value stored in the reference value storage means is a corrected altitude value, and the correction value calculation means is The correction value is obtained based on the altitude value before correction obtained by the calculation means and the reference value (claim 2).

As another means for solving the problems, the means for obtaining the corrected altitude value includes an atmospheric pressure correcting means for obtaining a corrected atmospheric pressure value using the corrected value for the detected atmospheric pressure value, and the atmospheric pressure correcting means. An altitude value calculating means for calculating a corrected altitude value by obtaining an altitude value corresponding to the calculated corrected atmospheric pressure value, wherein the reference value stored in the reference value storage means is the corrected atmospheric pressure value and the corrected value. It is also possible that the calculating means obtains the correction value based on the atmospheric pressure value before correction detected by the atmospheric pressure detecting means and the reference value (claim 3).

Further, in each of the various configurations described above, an altitude value input means for inputting an altitude value from the outside is further provided,
It is more preferable to add a function of updating the correction value based on the altitude value given through the altitude value input means (claim 4).

Further, in the altitude correction method according to the present invention, an altimeter is mounted in the altitude correction method for obtaining a corrected altitude value considering atmospheric pressure fluctuation based on a correction value stored in advance for the detected atmospheric pressure value. The state of the moving body is monitored, and the calculation processing result based on the correction value obtained when the moving body is stopped is held as a reference value, and then when the moving body starts moving again, the reference value is set. And a predetermined value based on the detected atmospheric pressure value or the atmospheric pressure is compared with the read reference value to calculate a correction value, and the calculated correction value is stored, and the subsequent corrected altitude value is stored. It is used as a correction value when obtaining (claim 5).

As the timing for storing the reference value, the backup power supply requires calculations even if the main power supply for the altimeter does not turn off due to the stop of the moving body or if the main power supply turns off. When the processing or the like is possible, the correction processing result such as the corrected altitude value or the corrected atmospheric pressure value calculated based on the atmospheric pressure value detected when the moving body shifts from the moving state to the stopped state is used as a reference value. It can be held (Claim 6).

On the other hand, when the arithmetic processing after the stop cannot be performed, when the updating is performed at the same time as the detection of the stop as in claim 6, the arithmetic processing and the rewriting of the data accompanying it cannot be performed. The calculation processing result based on the correction value obtained by the calculation processing is sampled at a predetermined timing and constantly updated. And
The updating process is stopped when the moving body shifts from the moving state to the stopped state. Then, since the sample value immediately before that is held, that value can be used as the reference value (claim 7).

[0018]

As is well known, the atmospheric pressure decreases as the altitude increases. Therefore, when the atmospheric pressure value is known, the altitude value is obtained by referring to the table or by a predetermined calculation. But,
Actually, since the atmospheric pressure changes due to changes in weather conditions, the altitude value cannot be uniquely obtained from the atmospheric pressure. Therefore, a predetermined correction process is performed. In general, the altitude value is obtained based on the atmospheric pressure value measured assuming that the state is 013 hPa (1 atmospheric pressure) when the atmospheric pressure at sea level is 013 hPa (1 atmospheric pressure), and is then corrected by the correction value ( Alternatively, the atmospheric pressure value itself is corrected and normalized to a predetermined atmospheric pressure state. This normalization is also performed such that the atmospheric pressure at 0 m above sea level is 1 atmospheric pressure. Then, since the corrected atmospheric pressure value thus obtained does not depend on the weather conditions, an accurate corrected altitude value can be obtained by performing arithmetic processing based on the corrected atmospheric pressure value (claim 3). In addition, it is not normal to normalize at 0 m above sea level as described above.
It can be set to an arbitrary value, and in that case, it suffices to correspond the calculation algorithm in the subsequent altitude value calculation processing.

By the way, in the case where a moving body equipped with an altimeter is a vehicle that moves at high speed such as an automobile, paying attention to the change of the moving state and the driving state with the passage of time, the driving is ascending (climbing) / falling (descent). In the inside, since the moving speed of the vehicle is high, the atmospheric pressure change due to the altitude is very large as compared with the atmospheric pressure change due to the change in weather conditions. Therefore, changes in atmospheric pressure during operation can be regarded as an error range, and if the correction value set at the start of operation is correct without performing correction value update processing, the corrected altitude value calculated thereafter will also be accurate. Becomes Further, when the moving speed is high like an automobile, the destination can be reached in a short time, and therefore the moving time in a day is often much shorter than the stop time. Then, it is unlikely that the atmospheric pressure fluctuates due to changes in meteorological conditions during the movement, and from that point, the accurate altitude value can be obtained during the movement.

On the other hand, when the moving body is in a stopped state, the corrected altitude value obtained at the time of re-moving should match with that at the time of stopping because the altitude does not move, but in reality, it is detected by the change of the weather condition. Since the atmospheric pressure values are different, the corrected altitude values are also different. Therefore, the correction value is automatically updated when the movement starts. That is, the update is to give an accurate altitude value and a value corresponding to it (atmospheric pressure value, etc.), compare that data with the actually detected atmospheric pressure value and the altitude value obtained based on it, and obtain the difference. Thus, a new correction value is obtained, and the data is updated.

Therefore, in the present invention, the accurate altitude value required for updating the correction value is correct when the vehicle is stopped because the altitude value calculated while the vehicle is moving is accurate as described above. Consider the altitude value, corrected atmospheric pressure value, etc. as accurate values and use the relevant data. That is, when it is detected that the moving body is in a stopped state, the final calculated corrected altitude value at the time of stop is held as a reference value, and then when it is detected that the vehicle is in a moving state again, Calculate the absolute altitude value and atmospheric pressure value from the detected atmospheric pressure. With this absolute altitude value and atmospheric pressure value,
The stored reference value is compared to obtain the correction value. After that, the correction process is performed using the obtained correction value, so that accurate correction is always performed.

Further, as a method of storing the reference value,
It is possible to obtain a corrected altitude value, a corrected atmospheric pressure value and the like based on the atmospheric pressure value when the stop of the moving body is detected, and register the obtained value as a reference value (claim 6). In this case, since the data at the time of the stop is used, the accuracy is increased, but a means for enabling the arithmetic processing even after the stop and supplying the power for rewriting the data is required. Become.

On the other hand, when the value corresponding to the reference value is obtained and sequentially updated during the movement, the data at the time of the stop is held (claim 7). In this case, since the arithmetic processing and the rewriting processing are unnecessary after the stop, the backup power supply for the special rewriting and the arithmetic processing is unnecessary (when the volatile memory is used, the reference value is held. Since the power supply is required), the system can be simplified, but if the sampling time for rewriting causes a time lag and the mobile body moves during that time lag, the accuracy will decrease by the moving distance. .

When a manual correction function is added as in claim 4, when the accurate altitude value is known, the correction value can be updated based on the altitude value. Therefore, even if there is a cumulative error, it is eliminated.

[0025]

Preferred embodiments of an altimeter and an altitude correction method using the same according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows a first embodiment of the altimeter according to the present invention. As shown in the figure, the basic structure of the altimeter is the same as that of the conventional one, and the output of the atmospheric pressure detection device 10 for measuring the atmospheric pressure of the surroundings is connected to the altitude value calculation unit 11 for obtaining the absolute altitude value from the atmospheric pressure value. , The output of the altitude value calculation unit 11 is connected to an altitude value correction unit 12 that performs a correction process in consideration of weather conditions and obtains an actual altitude, and further, this altitude value correction unit 1
The output of 2 is connected to the display device 13. Then, the altitude value correction unit 12 receives the correction value stored in the correction value holding unit 14 via the altitude correction value calculation unit 15. Then, the correction value stored in the correction value holding unit 14 is externally (user) via the manual altitude value input device 16.
The altitude correction value calculation unit 15 calculates and registers based on the accurate altitude value given by This basic configuration is the same as the conventional one.

In the present invention, the correction value is automatically obtained and updated based on the state change of the vehicle from stop to movement. Then, in order to carry out such a function, the operating state detection / memory comparison unit 17 and the display altitude value holding unit 18 that holds the altitude value at the time of stop (correct value after correction)
And are further equipped. The specific connection structure is such that the operation state detection / storage / comparison unit 17 is connected to the altitude correction calculation unit 15 and the display altitude value holding unit 18, respectively, and issues a predetermined control command. Also, the display altitude value holding unit 1
The output of the altitude value correction unit 12 is connected to 8 so that the corrected altitude value data is sent, and the corrected altitude value data sent at a predetermined timing is stored. The altitude value stored and stored at another timing is sent to the altitude correction delay remaining unit 15. And the timing concerned is performed based on the control command from the above-mentioned operation detection storage comparison part 17.

To briefly explain each part, the atmospheric pressure detecting device 10 can use an aneroid barometer or the like which is commonly used for altimeters. Also,
The altitude value calculation unit 11 knows the correlation between atmospheric pressure and altitude in advance. The altitude value calculation unit 11 obtains an absolute altitude value (an altitude value relative to the atmospheric pressure value when the atmospheric pressure at sea level is 1 atmospheric pressure (1013 hPa)). The correlation between values and the reduced atmospheric pressure (in the present specification, the atmospheric pressure that decreases every 100 m increase) are as shown in Tables 1 and 2 below.

[0028]

[Table 1]

[0029]

[Table 2] As is clear from the table, the atmospheric pressure decreases as the altitude increases, but the degree of the decrease is not constant. That is, in the range where the altitude value is low (up to about 500 m above sea level), the pressure decreases by 12 hPa every 100 m, but the decreasing pressure also decreases as the altitude increases. Then, as the altitude increases, the depressurized air pressure also gradually decreases, but in order to simplify the arithmetic processing and enable high-speed processing, it is divided into a certain range, and the altitude regions thus divided are divided. Each table shows the depressurized air pressure that satisfies the relationship between the atmospheric pressure and the altitude value.

Therefore, in the present embodiment, a table is created in which an upper limit value / lower limit value of the atmospheric pressure value for limiting the altitude region and an arithmetic expression for obtaining the altitude value H from the atmospheric pressure value P of the region are paired. Every time, if the atmospheric pressure value is given, the above table is accessed to read out the arithmetic expression of the region to which the atmospheric pressure value belongs, and the atmospheric pressure value P is substituted into the read arithmetic expression to perform arithmetic processing. Then, a specific arithmetic expression is as follows.

When the detected atmospheric pressure value is 656 hPa or less, the altitude is in the altitude range of 3500 m or more and the depressurized pressure is 8, so the altitude H is derived by the equation (1).

[0032]

[Equation 1] When the detected atmospheric pressure value is 656 hPa or more and 745 hPa or less, the altitude is in the altitude range of 2500 m or more and 3500 m or less, and the depressurizing pressure is 9. Therefore altitude H
Is derived by equation (2).

[0033]

[Equation 2] When the detected atmospheric pressure value is 745 hPa or more and 844 hPa or less, the altitude is in the altitude range of 1500 m or more and 2500 m or less, and the depressurizing pressure is 10. Therefore, the altitude H is derived by the equation (3).

[0034]

(Equation 3) When the detected atmospheric pressure value is 844 hPa or more and 953 hPa or less, the altitude is in the altitude range of 500 m or more and 1500 m or less, and the depressurized pressure is 11. Therefore altitude H
Is derived by equation (4).

[0035]

[Equation 4] The detected atmospheric pressure value is 953 hPa or more, 1013 hPa
If it is below, the altitude is in the altitude range from 0 m to 500 m and the depressurized pressure is 12. Therefore, the altitude H is derived by the equation (5).

[0036]

(Equation 5) In order to further speed up the arithmetic processing, the arithmetic expressions shown in the above equations (1) to (5) may be replaced with the following simple arithmetic expressions (1) ′ to (5) ′.

[0037]

(Equation 6) Furthermore, instead of performing the arithmetic processing as described above,
A table (for example, a table as shown in Tables 1 and 2) in which the correlation (atmospheric pressure and altitude value) is associated is created in advance, and the altitude value is obtained by referring to the table based on the given atmospheric pressure. Is also good.

The altitude value correction unit 12 takes an offset by adding and subtracting a correction value to and from the absolute altitude value H which is the above calculation result given from the altitude value calculation unit 11. Which of addition and subtraction is performed is determined by how to obtain the correction value. In this example, the altitude value = absolute altitude value−correction value is calculated.

The correction value holding unit 14 stores a correction value used when performing a correction (offset) calculation in the altitude value correction unit 12, and since it is necessary to hold the correction value even when the main power is turned off, for example, an EEPROM. A non-volatile memory such as Further, it is not always necessary to use a non-volatile memory, and a normal volatile memory such as RAM or DRAM may be used if a backup power supply is provided.

The altitude correction value calculation unit 15 has a function of obtaining a correction value and storing the calculation result in the correction value holding unit 14, and reading the correction value stored in the correction value holding unit 14 at the time of actual altitude calculation. It has a function of giving to the altitude value correction unit 12. Furthermore, in the former function to obtain the correction value,
A function for obtaining a correction value based on the actual accurate altitude value given from the manual altitude value input device 16 similar to the conventional one and the absolute altitude value calculated by the altitude value calculation unit 11, and a function of stopping / moving the vehicle. There is a function to automatically obtain a correction value based on a change in state. Then, the function for obtaining the correction value is executed as follows: correction value = absolute altitude value−altitude value (accurate value). As the accurate altitude value, the data provided from the manual altitude value input device is used as it is in the case of manual correction by the user. In the case of automatic correction, the altitude value at stop (correct value after correction) given from the display altitude value holding unit 18 is used.

As the manual altitude value input device 16, various input devices such as a numeric keypad, a trackball, and a touch panel can be used, and it is sufficient that at least the function of inputting the altitude (numerical value) is provided.

The operation state detection / storage / comparison unit 17 detects the state of whether the vehicle is moving or is stopped, a buffer for storing the state at the time of the previous sampling, the state stored in the buffer, and the current state detection. It has a function of comparing the generated state with the changed state to determine whether there is a change and outputting a predetermined control command. Further, as a device for detecting whether or not it is moving, there are a vibration sensor (stops when there is no vibration or small), an ignition key position sensor, a side brake position sensor (stops when the brake is applied), and the like. . The function of comparing, etc., compares the previous state (stored in the buffer) with the current state for each sampling, and when the movement is stopped during movement, a read command is issued to the display altitude value holding unit 18. Will be sent. Along with this, the display altitude holding unit 18 stores and holds the corrected altitude value output from the altitude value correction unit 12 as an altitude reference value when stopped. Also,
When moving from a stop, the display altitude value holding unit 18
To the altitude correction value calculation unit 1
5, a correction value calculation command is sent.

The display altitude value holding unit 18 is based on a control command from the moving body state detection / memory comparison unit 17, and the altitude correction unit 12
Has a function of reading the output data from, and outputting the stored altitude reference value to the altitude correction value calculation unit 15,
The storage medium used may be a non-volatile memory like the correction value holding unit 14 or a volatile memory if it has a backup power supply.

Further, in the present embodiment, although not shown, power can be supplied from a backup power source so that various arithmetic processing can be performed even when the vehicle is stopped (ignition key off). Has become. Then, as the backup power source, a battery provided separately or a vehicle-mounted battery may be used together.

Next, a first embodiment of the altitude value correction method according to the present invention will be described using the above-mentioned embodiment. First, since the present invention is an altimeter mounted on a vehicle such as an automobile,
Focusing on the movement speed and changes in driving conditions over time, the moving speed of the vehicle is high during uphill (climbing) / downhill (downhill) driving, so compared to atmospheric pressure changes due to changes in weather conditions. Atmospheric pressure changes greatly with altitude. Therefore, changes in atmospheric pressure during operation can be regarded as an error range, and if the correction value at the start of operation is correct without performing correction value update processing, the corrected altitude value calculated thereafter will also be accurate. Will be things. Therefore, the correction value is not automatically updated during the movement. However, only manual updating of correction values is allowed.

When the vehicle is stopped, since the altitude does not move, the atmospheric pressure value that is normally detected is constant, and the corrected altitude value obtained by the altitude value correction unit 12 is also constant. Actually, as pointed out in the above-mentioned problems, the atmospheric pressure at 0 m above sea level itself changes according to the change in the weather conditions, so the atmospheric pressure measured by the atmospheric pressure detection device 10 also changes, and after the correction finally calculated. The altitude value of is also different. That is, in the case of a vehicle, an error in the correction value mainly occurs during the stop. Therefore, in this embodiment, when the stopped vehicle starts moving, the correction process is automatically performed to update the correction value, and the accurate altitude value required when updating the correction value is Since the altitude value calculated while the vehicle is moving is accurate as described above, the corrected altitude value when the vehicle is stopped is regarded as an accurate altitude value and the data is used.

That is, when the vehicle is detected to be in a stopped state, the rough processing holds the corrected altitude value finally calculated when the vehicle is stopped as an altitude reference value. Next, when it is detected that the vehicle is in the moving state again, the absolute altitude value is calculated from the detected atmospheric pressure. This absolute altitude value is compared with the altitude reference value that is held to find the difference between the two,
The difference is used as a correction value, and the correction value is updated by holding the correction value. After that, the absolute altitude value calculated based on the atmospheric pressure during the moving state is corrected by the updated new correction value, and the accurate altitude is calculated.

Then, specifically, the processing is performed according to the flowchart shown in FIG. First, the operating state detector 17
The operating state of the vehicle (moving / stopped) is detected by (ST101). If the detected result is the stopped state, the previous operating state held in the buffer in the operating state detecting unit 17 is checked (ST102), and if the previous operating state is the moving state (moving) When the vehicle inside stops, the atmospheric pressure is detected by the atmospheric pressure detection device 10 (S
(T103), this atmospheric pressure is sent to the altitude value calculation unit 11 to calculate an absolute altitude value (ST104). This absolute altitude value is sent to the altitude value correction unit 12, and the correction value held in the correction value holding unit 14 is sent to the altitude value correction unit 12 via the altitude correction value calculation unit 15 so that the stop position A corrected altitude value indicating an accurate altitude is calculated (ST105). This calculated corrected altitude value (accurate altitude value at the vehicle stop position)
Is sent to the display altitude value holding unit 18 and is updated and registered as a reference value (ST106). The reference value thus stored is held as data even when the main power supply that is stopped is off.

In this embodiment, since each unit can be operated even when stopped by the backup power supply,
The reference value stored in the display altitude value holding unit 18 is displayed on the display device 1
Although it is possible to output to No. 3 and to always display or display according to a display command from the user (ST107), such a function may not be necessary. Further, if the previous state is also stopped by the branch determination in step 102, that is, if the stopped state is already in progress, the processes of steps 103 to 106 are skipped.

On the other hand, when the detection result of the operation state in step 101 is the moving state, the atmospheric pressure detecting device 10 measures the atmospheric pressure (ST108), and the atmospheric pressure is sent to the altitude value calculation unit 11 to obtain the absolute altitude. Calculate the value (ST10
9). Further, the previous operating state stored in the operating state detecting unit 17 is checked (ST110). Then, when the previous operating state is the stopped state, that is, when the main power supply is turned on (immediately after the start of movement), the correction value updating process is performed (ST111). That is, the absolute altitude value calculated in step 109 and the reference value held in the display altitude value holding unit 18 are sent to the altitude correction value calculation unit 15, and the difference between the absolute altitude value and the reference value is obtained and corrected there. Calculate the value. This correction value is updated in the correction value holding unit 14
Retained.

After the completion of the automatic update processing of the correction value at the start of the movement, or if it is determined in step 110 that the vehicle is already moving, it is determined whether user correction is performed (ST112). Specifically, the determination is made based on whether or not the altitude value is input from the manual altitude value input device. When the user correction is performed, the process jumps to step 113, and the accurate altitude value obtained from the altitude indicator or the like input by the user via the manual altitude value input device 24 is the altitude correction value calculation unit 1
5 (ST113). Then, the altitude correction value calculation unit 15 receives the absolute altitude value output from the altitude value calculation unit 11 at that time, and calculates the correction value by subtracting the input altitude value from the absolute altitude value (ST11).
4). Then, the calculated correction value is stored and held in the correction value holding unit 14 (ST115).

The absolute altitude value calculated from the atmospheric pressure at the current position is sent to the altitude value correction unit 12, and the correction value held in the correction value holding unit is passed through the altitude correction value calculation unit 15 to the altitude value correction unit 12 The corrected altitude value is calculated by subtracting the corrected value from the absolute altitude value (ST116). Then, the corrected altitude value is displayed on the display device 23. Then, by repeating the above processing, the correction value is automatically updated each time when the vehicle moves again after stopping, so that the correction value suitable for the weather condition at that time is always secured,
The altitude can be accurately corrected when the vehicle moves.

In the above-described embodiment, the backup power supply is also supplied to each arithmetic processing unit. Therefore, after confirming that the state changed from moving to stopped as in the above correction method, the operation was stopped. Although the corrected altitude value at the time (immediately after) is extracted and stored as the reference value in the display altitude value holding unit 18, the present invention can be applied to a configuration having no such backup power source (backup system). .
That is, the block diagram of the altimeter is as shown in FIG.
Although it is the same as that of the first embodiment shown in, the function of the display altitude holding unit 18 is different in this embodiment. That is, in the above-described first embodiment, the corrected altitude value output from the altitude value correction unit 12 at that time is stored / held as the reference value based on the control command from the operation state detection / storage / comparison unit 17 which wants to detect the stop. However, in this embodiment, since various arithmetic processing units do not operate after the stop (after the main power is turned off),
The reference value is sequentially updated every predetermined sampling while moving. That is, the output from the altitude value correction unit 12 is sent to the display device 13 and also to the display altitude value holding unit 18, and the display altitude value holding unit 18 updates the transferred corrected altitude value as the reference value each time. I try to register. Then, when the movement is changed to the stop, the update registration is not performed by the control command from the operation state detection storage comparison unit 17. As a result, the corrected altitude value immediately before the stop is held as the final reference value. The shorter the sampling time, the more accurate the reference value.
Note that this update registration may be performed every time the altitude value correction unit 12 performs the altitude value correction process (every cycle until the atmospheric pressure value is detected and the final altitude value is calculated). Alternatively, aside from the cycle, the data may be acquired for a certain number of times or for a certain period of time.

Next, a second embodiment of the altitude correction method according to the present invention using the altimeter having the structure of the second embodiment will be described. The processing flow of this embodiment is as shown in FIG. 3, and the operating state detecting unit 17 detects whether the operating state is stop or movement (ST201).
If the operating state remains stopped, the display device 2
The altitude value of the current position is output to 3 (ST202), and the operation state detection unit 17 detects the state again (ST20).
1). This output display reads and displays the reference value stored in the display altitude value holding unit 18. However, in the altimeter of the second embodiment, no backup power is supplied to the arithmetic processing system. In order to provide the above, it is necessary to at least supply power to the display device and supply power to operate the reading function from the holding unit 18. And, of course, such a function (display function at the time of stop) may be omitted.

On the other hand, when the operating state detecting section 17 detects that the operating state is the moving state in the branch judgment of step 201, the atmospheric pressure detecting device 10 measures the atmospheric pressure (ST2
03), this atmospheric pressure is sent to the altitude value calculation unit 11 to calculate an absolute altitude value (ST204).

Further, the previous operating state stored in the operating state detecting unit 17 is checked (ST205), and if the previous operating state was the stopped state (at the time of movement start), the absolute altitude value calculated above is calculated. The reference value stored in the display altitude value storage unit 18 is sent to the altitude correction value calculation unit 15, and the correction value is calculated by comparing the absolute altitude value and the reference value and obtaining the difference between them. This correction value is updated and held in the correction value holding unit 14 (ST206). The process is similar to that of the first embodiment described above.

Next, it is judged whether or not the user correction is to be performed (ST207). When the user correction is to be performed, this is also the same as in the first embodiment.
The accurate altitude value input via the
The absolute altitude value obtained in step 3 is given to the altitude correction value calculation unit 15,
Therefore, a subtraction process is performed to calculate a correction value, and the calculated correction value is updated and held in the correction value holding unit 14 and used for the subsequent correction process (ST208 to 210).

After the above-mentioned automatic or manual predetermined correction value updating processing, or if such correction is skipped, the latest correction value held in the correction value holding unit 14 is calculated as the altitude correction value. It is sent to the altitude value correction unit 12 via the unit 15, where the correction value is subtracted from the absolute altitude value to calculate an accurate altitude value (ST211).
The corrected altitude value is sent to the display altitude value holding unit 18, is updated and held as a reference value (ST212), and is output via the display device 23 (ST213).

Therefore, when the vehicle is stopped, the reference value updating process (ST212) is not executed, so that the reference value updated to the corrected altitude value immediately before the stop is held during the stop. As a result, the display altitude value holding unit 1 can be used when moving again.
Since the reference value stored in 8 is the accurate altitude value immediately before the stop without the current altitude movement of the vehicle, even if there is a change in the weather conditions, a correct correction value corresponding to it can be obtained. .

FIG. 4 shows a third embodiment of the altimeter according to the present invention. In this embodiment, unlike the above embodiments, the atmospheric pressure value is corrected and the altitude value is obtained based on the corrected atmospheric pressure value. As a specific circuit configuration, as shown in FIG. 4, the atmospheric pressure value (absolute atmospheric pressure value) detected by the atmospheric pressure detection device 20 is given to the atmospheric pressure value correction unit 21, and a predetermined correction process is performed there to obtain an altitude of 0 m above sea level. Atmospheric pressure is 10
Atmospheric pressure (corrected atmospheric pressure value) at the current measurement point when 13 hPa is assumed is obtained. The corrected atmospheric pressure value is used as the altitude value calculation unit 2
2 is assigned to P in each of the equations (1) to (5) or (1) 'to (5)' in the same manner as in the altitude value calculation unit of the first embodiment to obtain the altitude value H. Then, since the atmospheric pressure value has already been corrected, an accurate altitude value is calculated, and the calculation result is displayed and output via the display device 23.
The atmospheric pressure detecting device 10 may have the same structure as the atmospheric pressure detecting device 10 of each of the above-described embodiments.

The basic principle of the atmospheric pressure value correction unit 21 is the same as that of the altitude value correction unit 12 in the first and second embodiments, and the correction value stored in the correction value holding unit 24 is stored in the atmospheric pressure correction value calculation unit 25. The correction value is subtracted from the actual atmospheric pressure value (absolute atmospheric pressure value) received and measured via Then, the correction value stored in the correction value holding unit 24 compares the absolute atmospheric pressure value detected by the atmospheric pressure detecting device 20 with the atmospheric pressure value at the measurement point when the atmospheric pressure at sea level of 0 m is assumed to be 1013 hPa, It is obtained by performing subtraction processing. At this time, since the user cannot directly know the target atmospheric pressure value, an accurate altitude value given from the outside (user) via the manual altitude value input device 26 is calculated by the altitude value-atmospheric pressure value conversion unit 27. After being converted into the atmospheric pressure value, the converted atmospheric pressure value is given to the atmospheric pressure correction value calculation unit 25. As a result, when the user knows an accurate altitude from an altitude sign or the like, the user only has to input the altitude value as in the first and second embodiments, and the operability does not change.

The altitude value-atmospheric pressure value conversion unit 27, contrary to the processing performed by the altitude value calculation unit 11 of the first embodiment described above, has an atmospheric pressure of 013 meters above sea level at a given altitude of 1013.
The pressure value is calculated assuming that it is hPa. The tables shown in Tables 1 and 2 above are created, and the pressure value is calculated by referring to the tables, or the equations (1) to
Inverse operation of equation (5) or equations (1) ′ to (5) ′ (P in each equation)
Is substituted into the altitude value H in the formula obtained by converting into

Here, in the present invention, in order to automatically obtain and update the correction value based on the state change of the vehicle stopping → moving, the operation state detection / memory comparing unit 28 and the altitude value at the time of stop (after correction) A corrected atmospheric pressure value holding unit 29 for holding an accurate value) is further provided. The specific connection structure is such that the operation state detection / memory comparison unit 28 is connected to the atmospheric pressure correction calculation unit 25 and the corrected atmospheric pressure value holding unit 29, respectively, and issues a predetermined control command. Further, the corrected atmospheric pressure value holding unit 29 is connected to the output of the atmospheric pressure value correction unit 21 so that the corrected atmospheric pressure value data is sent and is also sent at a predetermined timing. The corrected atmospheric pressure value data is stored and held, and the stored atmospheric pressure value at another timing is sent to the atmospheric pressure correction value calculation unit 25. Then, the timing is performed based on the control command from the operation detection / memory comparison unit 28.

Along with this, the atmospheric pressure correction value calculation unit 25
In addition to the correction value update processing based on the above user input,
There is a function that automatically obtains a correction value based on the change in the stop / movement state of the vehicle. Based on the reference value stored in the corrected atmospheric pressure value holding unit and the absolute atmospheric pressure value given from the atmospheric pressure value detecting device 20, Value = absolute pressure value−reference value is executed.

Since the specific constructions of the manual altitude value input device 26 and the holding portions 24 and 29 are the same as those shown in the first embodiment, detailed description thereof will be omitted. As in the case of the first embodiment, this embodiment also has a backup power supply, which enables arithmetic processing even during suspension. Therefore, the reference value update registration in the corrected atmospheric pressure holding unit 29 is performed by the atmospheric pressure value correction unit 2 when the moving state is changed to the stopped state.
The data output from 1 is read so that the updating process during the movement is not performed.

Next, a third embodiment of the correction method according to the present invention using the above altimeter will be described with reference to the flow chart shown in FIG. First, the outline will be described. As in the first embodiment, when the vehicle is in a moving state, the correction value is not updated and stored in the correction value holding unit 24 to obtain the correction value based on the correction value. The altitude value is obtained based on the corrected atmospheric pressure value. The difference between the absolute atmospheric pressure value measured when the vehicle is moving again and the reference value is obtained by acquiring the corrected atmospheric pressure value when the vehicle is moving and then stopping. From this, a new correction value is obtained and the update processing is performed.

Next, the third embodiment will be described in detail with reference to the flow chart shown in FIG. First, the operation state detection unit 28 detects the operation state of the vehicle, that is, whether the vehicle is moving or stopped (ST301). If it is in the stopped state, the previously detected operating state held in the operating state detection / storage detection unit 28 is further extracted and compared with the current detection result (ST302), and the current stopped state is set. If it is determined that the atmospheric pressure has been changed, the atmospheric pressure detecting device 20 detects the atmospheric pressure (ST303), and the atmospheric pressure (absolute atmospheric pressure value) is detected.
Is sent to the atmospheric pressure value correction unit 21, and the correction value holding unit 24
The correction value held at is sent to the atmospheric pressure value correction unit 21 through the atmospheric pressure correction calculation unit 26, and the corrected atmospheric pressure value is calculated from the absolute atmospheric pressure and the correction value (ST304). The calculated corrected atmospheric pressure value is updated and held as a reference value in the atmospheric pressure value holding unit 29 (ST305).

On the other hand, when the detection result of the operation state performed in step 301 is the moving state, step 307
Then, the atmospheric pressure is detected by the atmospheric pressure detecting device 20. Then, the previous operating state held in the operating state detection unit 28 is further checked (ST308), and if the detection result is the stopped state, it can be determined that the movement has started this time.
The detected absolute atmospheric pressure value and the reference value held in the corrected atmospheric pressure value holding unit 29 are sent to the atmospheric pressure correction value calculation unit 26,
A correction value is calculated by subtracting the reference value from the absolute atmospheric pressure value. This correction value is updated and held in the correction value holding unit 24 (ST309).

Next, it is judged whether the user correction is to be performed (ST310). If the user correction is to be performed,
An accurate altitude value is input by the manual altitude value input device 24 (ST311), and the input altitude value is sent to the altitude value-atmospheric pressure value conversion unit 25 and converted into an atmospheric pressure value (ST31).
2) Send the converted atmospheric pressure value and the absolute atmospheric pressure value to the atmospheric pressure correction calculation unit 26, and calculate the correction value by subtracting the converted atmospheric pressure value from the measured absolute atmospheric pressure value (ST).
313). This correction value is updated and held in the correction value holding unit 24 (ST314). After that, the normal correction process (ST
Return to 315).

After the various correction values have been updated, or if they have not been updated, step 307 is performed.
The absolute atmospheric pressure value detected in step S1 and the correction value stored in the correction value storage portion 24 are transferred to the atmospheric pressure value correction portion 21, where they are subjected to subtraction processing for correction, and the corrected atmospheric pressure value is calculated (S
T315). Then, the altitude value calculation unit 22 calculates the altitude value from the corrected atmospheric pressure value (ST316). This altitude value is output and displayed via the display device 23 and transmitted to the user.

After that, by repeating the above-mentioned processing, even if the vehicle stops, the correction value is updated when the vehicle moves again, and when the accurate altitude is known, the correction value is manually operated. Is updated, so that accurate altitude correction can be performed when the vehicle is moving.

The altimeter for correcting the atmospheric pressure value described above can also be applied to the altimeter having the configuration (fourth embodiment) in which the backup power supply corresponding to the second embodiment is not supplied. That is, similar to the relationship between the first embodiment and the second embodiment described above, it is the same as the block configuration diagram of the third embodiment, but the function of the corrected atmospheric pressure value holding unit 29 is different. That is, the output from the atmospheric pressure value correction unit 21 is sent to the altitude value calculation unit 22 and also sent to the after-correction atmospheric pressure value value holding unit 29.
The corrected atmospheric pressure value holding unit 29 updates and registers the transferred corrected atmospheric pressure value as a reference value each time. Then, when the movement is changed to the stop, the update registration is not performed by the control command from the operation state detection memory comparison unit 28. As a result, the corrected altitude value immediately before the stop is held as the final reference value. The other structure is basically the same as that of the third embodiment described above, and thus detailed description thereof will be omitted.

Next, a fourth embodiment of the altitude correction method according to the present invention using the altimeter of the fourth embodiment will be described. Figure 6
As shown in, the operating state detecting unit 68 detects the operating state (ST401), and when the operating state is the moving state, the atmospheric pressure detecting device 20 measures the atmospheric pressure (ST40).
3). Then, the previous operating state held in the operating state detecting unit 28 is extracted and compared with the current state (ST4).
04). If they are different, that is, if the movement is changed this time, it can be determined that the movement has started, and therefore the correction value is updated (ST405). That is, the detected absolute atmospheric pressure value and the reference value held in the corrected atmospheric pressure holding unit 29 are sent to the atmospheric pressure correction value calculation unit 25, the atmospheric pressure and the reference value are compared, and the correction value is calculated. This correction value is updated and held in the correction value holding unit 24.

After the automatic updating process described above, or if it is determined in step 404 that the user is already moving, the process jumps to step 406, and it is determined whether user correction is performed (ST406). When the user correction is performed, since the user inputs an accurate altitude value by the manual altitude value input device 64 (ST407), the altitude value-atmospheric pressure value conversion unit 27 converts the altitude value into an input atmospheric pressure value (S).
(T408), the converted atmospheric pressure value and the current absolute atmospheric pressure value detected by the atmospheric pressure detection device are sent to the atmospheric pressure correction value calculation unit 25, and the atmospheric pressure value is subtracted from the absolute atmospheric pressure value to calculate the correction value ( ST409), the obtained correction value is the correction value holding unit 2
4 is updated and held (ST410).

The detected absolute atmospheric pressure value is the atmospheric pressure correction unit 21.
Then, offset is performed based on the correction value held in the correction value holding unit 24, and the corrected atmospheric pressure value at the current measurement point when the sea level 0 m is 1 atmospheric pressure is obtained (ST411).
Then, the calculated corrected atmospheric pressure value is updated and held in the corrected atmospheric pressure value holding unit 29 as a reference value (ST412).
At the same time, it is sent to the altitude value calculation unit 22 and an accurate altitude value is calculated there (ST413). This altitude value is displayed on the display device 63 and transmitted to the user (ST414).

The specific processing for obtaining the altitude value from the atmospheric pressure value and the specific processing for correcting the atmospheric pressure value and the altitude value are not limited to the above, and various methods can be adopted. Further, although the display device is used as the output device in the above-described embodiments, a voice output device may be used instead of or in combination with the display device.

[0077]

As described above, in the altimeter and the altitude correction method using the same according to the present invention, since the moving body on which the altimeter is mounted moves at a relatively high speed, it is unlikely to be affected by atmospheric changes. If the vehicle moves for a short period of time, the atmospheric pressure fluctuation itself due to the change in the weather condition is unlikely to occur, so that the correct corrected altitude value can be calculated without updating the corrected value during the movement. Therefore, the reference values such as the corrected atmospheric pressure value and the corrected altitude value, which are obtained when the operating state of the moving body shifts from the moving state to the stopped state, indicate the accurate altitude value and the normalized atmospheric pressure value of the stopped place. . Therefore, the absolute altitude value and the atmospheric pressure value, which are calculated when the operating state becomes the moving state again, are compared with the reference value, and thus the correction value for correcting the deviation caused by the atmospheric pressure change is accurately calculated. can do.

Further, since the correction is automatically performed, it is possible to omit the complicated work of manually inputting an accurate altitude and updating the correction value each time the user starts moving. Along with this, there is no post-operation due to forgetting to update, and an accurate corrected altitude value can always be obtained.

According to the fourth aspect of the present invention, the user is allowed to input an accurate altitude value, and the correction value can be updated based on the input, so that the accumulated error is not accumulated and is more accurate. It is possible to calculate and output various corrected altitude values.

[Brief description of drawings]

FIG. 1 is a block diagram showing first and second embodiments of an altimeter according to the present invention.

FIG. 2 is a flowchart showing a first embodiment of an altitude correction method according to the present invention.

FIG. 3 is a flowchart showing a second embodiment of the altitude correction method according to the present invention.

FIG. 4 is a block diagram showing an altimeter according to a third embodiment and a fourth embodiment of the present invention.

FIG. 5 is a flowchart showing a third embodiment of the altitude correction method according to the present invention.

FIG. 6 is a flowchart showing a fourth embodiment of the altitude correction method according to the present invention.

FIG. 7 is a block diagram showing an example of a conventional altimeter.

[Explanation of symbols]

 10 Atmospheric pressure detection device 11 Altitude calculation unit 12 Altitude value correction unit 13 Display device 14 Correction value storage unit 15 Altitude value correction value calculation unit 16 Manual altitude value input device 17 Operating state detection unit 18 Displayed altitude value storage unit 20 Atmospheric pressure detection device 21 Atmospheric pressure value correction unit 22 Altitude calculation unit 23 Display device 24 Correction value storage unit 25 Atmospheric pressure correction value calculation unit 26 Manual altitude value input device 27 Altitude value-atmospheric pressure value conversion unit 28 Operation state detection unit 29 Corrected atmospheric pressure value storage unit

Claims (7)

[Claims] 1. An atmospheric pressure detecting means for detecting atmospheric pressure, an atmospheric pressure value detected by the atmospheric pressure detecting means, a means for obtaining a corrected altitude value based on a correction value, and an output for outputting the obtained corrected altitude value. Means and a correction value storage means for storing the correction value, wherein an operation state detecting means for detecting an operation state of a moving body on which the altimeter is mounted and an output signal from the operation state detecting means are received. A reference storage means for storing, as a reference value, at least the corrected height value obtained when the moving body is stopped, or the correction result calculated by using the corrected value; and an output signal from the operating state detecting means. When the moving body starts moving, a correction value is obtained based on the atmospheric pressure value detected by the atmospheric pressure detecting means or a predetermined value based on the atmospheric pressure value and the stored reference value. An altimeter, characterized in that it comprises a correction value calculating means which is registered in the correction value storing means. 2. A means for obtaining the corrected altitude value, wherein the altitude value calculating means for obtaining the altitude value from the detected atmospheric pressure value and the altitude value obtained by the altitude value calculating means are corrected using the correction value. And an altitude value correction means for calculating a corrected altitude value, wherein the reference value stored in the reference value storage means is a corrected altitude value, and the correction value calculation means is obtained by the altitude value calculation means. The altimeter according to claim 1, wherein the correction value is obtained based on the altitude value before correction and the reference value. 3. The atmospheric pressure correction means for obtaining the corrected atmospheric pressure value by using the corrected value for the detected atmospheric pressure value, and the corrected atmospheric pressure value obtained by the atmospheric pressure correction means. And an altitude value calculating means for calculating a corrected altitude value by calculating the altitude value, the reference value stored in the reference value storage means is a corrected atmospheric pressure value, and the correction value calculating means is configured to detect the atmospheric pressure. The altimeter according to claim 1, wherein the correction value is obtained based on the atmospheric pressure value before correction detected by the means and the reference value. 4. An altitude value input means for inputting an altitude value from the outside is further provided, and a function for updating the correction value is added based on the altitude value given through the altitude value input means. The altimeter according to any one of claims 1 to 3. 5. An altitude correction method for obtaining a corrected altitude value in consideration of atmospheric pressure fluctuations based on a detected atmospheric pressure value and a correction value stored in advance, wherein a state of a mobile body equipped with an altimeter is monitored, The calculation processing result based on the correction value obtained when the mobile body is stopped is held as a reference value, and when the mobile body starts moving again after that, the reference value is read out, or the detected atmospheric pressure value or A predetermined value based on the atmospheric pressure is compared with the read reference value to calculate a correction value, and the calculated correction value is stored and used as a correction value when obtaining a corrected altitude value thereafter. Altitude correction method 6. The correction processing result such as the corrected altitude value and the corrected atmospheric pressure value calculated based on the atmospheric pressure value detected when the moving body shifts from the moving state to the stopped state is held as a reference value. The altitude correction method according to claim 5, wherein: 7. A calculation processing result based on a correction value obtained by performing calculation processing while the moving body is moving is sampled at a predetermined timing and constantly updated, and the moving body shifts from a moving state to a stopped state. The altitude correction method according to claim 5, wherein the update process is stopped at some times, and a sample value immediately before the update process is held as a reference value.