CN201364154Y - Embedded type portable air pressure altitude meter - Google Patents

Abstract

The utility model provides an embedded type portable air pressure altitude meter. The embedded type portable air pressure altitude meter is composed of the following four modules: a data collecting unit, an interface communication circuit, a linear voltage stabilizer and an upper computer; wherein the data collecting unit finishes collecting air pressure and temperature data by a sensor chip; the interface communication circuit can adopt any one of a serial communication port RS-232, a USB interface or a 1394 interface to be connected with a PC, so as to finish the function of transmitting the data measured by the data collecting unit to the upper computer; the upper computer comprises an error compensating module, can output more precise altitude data, and can finish follow-up work of the data such as storing, processing and the like at the same time; the linear voltage stabilizer supplies voltage for each module, so that an external power supply is not needed. The embedded type portable air pressure altitude meter is used for measuring altitude, adopts a computer interface to supply power, does not need the external power supply, leads small volume, is convenient to be carried about, can be conveniently used in a combining manner after being embedded into other systems, and has wide application range.

Description

A kind of portable embedded barometric altimeter

Technical field

The utility model relates to a kind of design of barometric leveling instrument, more particularly, provides a kind of portable embedded barometric altimeter.

Background technology

Barometric altimeter is based on air pressure and reduces this principle design with highly raising.At present widely used is digital barometric altimeter, as 2008 disclosed utility model patent barometric altimeter on July 30, (ZL200720041374.3) comprise measuring unit, interface communication circuit and system power supply, wherein measuring unit comprises digital baroceptor and coupled microprocessor; The interface communication circuit comprises logic level converting circuit and interface communication circuit; System power supply comprises reduction voltage circuit, sensor and microprocessor power supply circuit, interface communication power circuit.As can be seen, the barometric altimeter one side complex structure that exists at present, volume is bigger, and inconvenience is carried; On the other hand can only be as the standalone module of measuring height, can't embed other system, be used in combination with other system, follow-up works such as the storage management of finishing altitude information and statistical treatment just can't link to each other barometric altimeter with PC or other system.For example in the satellite navigation field,, or utilize interface directly to be connected, just can utilize altitude information to finish functions such as navigator fix, integrity monitoring with combining of other data with other navigator if altitude information can be outputed in the PC.

The utility model content

The purpose of this utility model is to provide a kind of portable embedded barometric altimeter at the deficiencies in the prior art.

To achieve these goals, the technical solution adopted in the utility model is: the utility model is made up of data acquisition unit, interface communication circuit, linear voltage regulator and four modules of host computer; Data acquisition unit is finished the measurement of air pressure, temperature; The interface communication circuit function is that temperature, pressure data that data acquisition unit collects are passed to host computer, obtain altitude information by the upper computer software processing, the interface communication circuit can adopt communication port RS-232, and any in USB interface and 1394 interfaces links to each other with PC; Linear voltage regulator provides required voltage for each module; Host computer has added the temperature and air pressure correcting module of level altitude reference point, can eliminate the error that the external environment condition variation causes by revising.

The utility model beneficial effect is:

1. adopt any interface communication circuit to link to each other with PC, the power supply power supply that can utilize PC to provide, need not independent power module, again because each chip volume that the utility model adopted is little, barometric altimeter was little a lot of more in the past to cause the utility model final volume, it is little to embody volume, portable advantage.

2. adopt any interface communication circuit in communication port RS-232, USB interface and 1394 interfaces, barometric altimeter can be embedded PC or other system, make things convenient for being used in combination between the processing of data and the different system.

3. added level altitude point temperature in the upper computer module, the atmospheric pressure compensating module can be eliminated the error that causes because of change of external conditions.

Description of drawings

Fig. 1 is a system architecture diagram of the present utility model;

Fig. 2 is a baroceptor element internal structural drawing;

Fig. 3 is a schematic block circuit diagram of the present utility model;

Fig. 4 is a host computer workflow diagram of the present utility model.

Embodiment

In order to make technical problem to be solved in the utility model, technical scheme and beneficial effect are clearer, below in conjunction with drawings and Examples, the utility model are further elaborated, and the interface communication circuit adopts usb circuit in the present embodiment.

As shown in Figure 1, barometric altimeter of the present utility model is by data acquisition unit 1, interface communication circuit 2, linear voltage regulator 3 and host computer 4 are formed, and principle of work is that data acquisition unit 1 is measured current air pressure, temperature data, interface communication circuit 2 is that usb circuit is finished usb function, give host computer 4 with the data transfer that data acquisition unit 1 records, 4 pairs of data of host computer are handled and are obtained the current position altitude information, and each module required voltage is provided by linear voltage regulator.

The SCP1000-D01 sensor chip that data acquisition unit 1 adopts Finland VTI company to provide is finished the measurement of air pressure, temperature; Interface communication circuit 2 comprises USB2.0 controller CY7C68013-56SSOP chip, USB-A connecting line and USB-A connector three parts, and usb function is finished in triplicity; Linear voltage regulator 3 adopts LM1117T-3.3, is that the 5V voltage transitions that host computer 4 provides is that 3.3V voltage is to interface communication circuit 2 and data acquisition unit 1 power supply with the computing machine USB interface; Host computer 4 has added level altitude point temperature, atmospheric pressure compensating module, can finish the calculating and the storage of height.Below system's each several part is described respectively.

Fig. 2 is a baroceptor element SCP1000-D01 cut-away view, the SCP1000-D01 pressure transducer is used to measure barometric absolute pressure, pressure measurement range is between 30kPa to 120kPa, and the temperature change scope is between-30 ℃ to 85 ℃, and operating voltage requires between 2.4V to 3.3V.This chip is made up of pressure sensor component and the application-specific integrated circuit ASIC that is used for Signal Regulation.Wherein, pressure sensor component is used to measure current air pressure; ASIC comprises following modules: analog-to-digital conversion module ADC is used for temperature, air pressure analog quantity that sensor element is measured are converted to digital quantity; The ASIC control module; Nonvolatile memory EEPROM is being stored the element initial settings information, the initial configuration when at every turn starting; Temperature-measuring module; Calculation of pressure and linearization block; The SPI interface, chip links to each other with interface communication circuit 2CY7C68013 by this SPI interface; Carry temperature compensation module among the ASIC, be used to compensate the inconsistent of temperature and environment temperature in the sheet that causes because of the device inside heat radiation.In addition, the SCP1000-D01 chip is worked under internal clocking drives, and need not external timing signal.

Fig. 3 is circuit theory diagrams of the present utility model.The SCP1000-D01 chip operation is under the high speed measurement pattern, outputting data updating rate is 9Hz, adopt the SPI communication mode to communicate by letter with CY7C68013, CY7C68013 itself does not provide the SPI interface, therefore needs the common I/O mouth simulation SPI serial bus interface with chip.Adopt the PB port of CY7C68013 universaling I/O port to link to each other in the utility model, carry out communication with the SPI interface pin of SCP1000-D01.Pin connects as shown in the table between the two.

Table 1SCP1000-D01 chip SPI pin is connected with the CY7C68013 chip

In addition, the pin 5,13 of the utility model chips SCP1000-D01 is respectively by the shunt capacitance ground connection of 470nF electric capacity as the input power supply.

USB2.0 controller chip CY7C68013 is connected with the SCP1000-D01 chip on the one hand as the bridge between SCP1000-D01 and the USB-A connector, and pin 16,15 is respectively at the D-of USB-A connector on the other hand, and the D+ pin connects.In the utility model, CY7C68013 chip and SCP1000-D01 chip all are operated under the 3.3V power supply, the 5V power supply that the user can directly use on the USB connector removes to drive the 3.3V voltage stabilizer, so that needed power supply to be provided, has simplified the design of bus-powered USB device.As being 3.3V voltage by adopting the linear voltage regulator LM1117T-3.3 pin 3 5V voltage transitions that USB interface is provided that links to each other with the pin 1 of USB-A connector among Fig. 3, this 3.3V voltage provides power supply for SCP1000-D01 and CY7C68013, promptly require 2 whiles and the pin 5,13 of SCP1000-D01 and the pin 6,10 of CY7C68013 of LM1117T-3.3 pin, 14,18,24,34,39,50 link to each other.In addition, LM1117T-3.3 pin 2 is by 10 μ F tantalum capacitor ground connection, and purpose is in order to improve transient response and loop stability; Pin 3 is by 10 μ F tantalum electric capacity shunt capacitance ground connection as the input power supply in parallel with 0.1 μ F tantalum electric capacity.

The 24MHz crystal oscillator is as the clock circuit of system among Fig. 3, the input of crystal oscillator, and output pin links to each other with the pin 12,11 of CY7C68013 respectively, and respectively by the 22pF capacity earth.

Fig. 4 is the host computer workflow diagram, and the program run initial period is at first finished the initial configuration of barometric altimeter; On host computer user oriented interface, finish the input of measuring number of times, reference station temperature, pressure, altitude information then, wherein, the user is the setting measurement number of times as required, the measurement number of times of acquiescence is 10 times, if measuring number of times reaches 10 times, then measure and finish, beginning computation of mean values, variance, and data storage; Whole procedure is to circulate as main body, can every circulation primary all will be judged in advance carry out reading of temperature, pressure data, after satisfying under the condition of reading of data, read the order of pressure data and obtain this measurement data with first reading temperature data, then temperature, pressure data are delivered to high computational module output altitude information, the line height data processing of going forward side by side, comprise and averaging, variance and data storage work etc.Detailed process is as follows:

In barometric altimeter initial configuration module, finish the normal startup of barometric altimeter and its measurement pattern is configured to the high speed measurement pattern.At first carry out check of barometric altimeter init state and the check of EEPROM verify error in the program, promptly determine by the value of check register 0x07 whether SCP1000-D01 sensor start-up course successfully finishes, if being 0 explanation start-up course, finishes register 0x07 lowest order, otherwise illustrate that start-up course still carrying out, program reexamines register 0x07 lowest-order values after postponing 10ms, redefine and whether finish start-up course, if lowest order still is 1 circulation said process, for avoiding down because of sensor fault causes starting state check infinite loop, the regulation maximum cycle is 6 in the program, the start-up course that is not over yet after 6 loop ends, the prompting baroceptor starts failure; Similarly determine the EEPROM verify error, if be 0x01 explanation verification and correct by check register 0x1F value.After said process finished, barometric altimeter was configured to the high speed measurement pattern.

About obtaining of temperature, pressure data, judge by the DRDY pin and can read this measurement data, obtain binary data to read the order that reads pressure after the temperature earlier in the time of can reading.The data of obtaining need be passed through specific processing: for the temperature data of representing with the two's complement form, at first be converted into the scale-of-two true form, be converted to decimal format then, at last the decimal data that obtains obtained degree centigrade being the temperature data of unit divided by 20; For representing pressure data, be converted into that directly promptly to obtain with the handkerchief divided by 4 behind the decimal data be the pressure data of unit with the scale-of-two true form.

In the high computational module, suppose that level altitude point represents that with A this temperature, pressure, gravity potential altitude information are respectively T _a, p _a, H _aWait to ask a little and represent with B, the temperature, the pressure data that record are respectively T _b, p _bB point gravity potential height H _bSolution procedure is as follows:

Step 1: according to A point temperature T _a, the gravity potential height H _aCalculate current mean sea level place temperature T ₀':

T ₀′＝T _a-βH _a [1]

According to the standard pressure-height formula: $H=\frac{T_0}{\mathrm{\β}}[{\left(\frac{p_H}{p_0}\right)}^{-\mathrm{\βR}/g_n}-1],$ Obtain another kind of representation:

$p_a={p_0}^{\′}{(\frac{H_a\mathrm{\β}}{{T_0}^{\′}}+1)}^{-\frac{g_n}{\mathrm{\βR}}}---\left[2\right]$

[1] is brought into [2] to be obtained:

$p_a={p_0}^{\′}{\left(\frac{T_a}{{T_0}^{\′}}\right)}^{-\frac{g_n}{\mathrm{\βR}}}---\left[3\right]$

In like manner, for the B point:

$p_b={p_0}^{\′}{\left(\frac{T_b}{{T_0}^{\′}}\right)}^{-\frac{g_n}{\mathrm{\βR}}}---\left[4\right]$

Step 2: [3] [4] two formulas are compared and are obtained:

$\frac{p_a}{p_b}={\left(\frac{T_a}{T_b}\right)}^{-\frac{g_n}{\mathrm{\βR}}}---\left[5\right]$

Step 3: A, 2 temperature relations of B:

T ₀′＝T _a-βH _a＝T _b-βH _b [6]

Step 4: [6] formula [5] formula of bringing into is obtained A, and the pass is between 2 gravity potential height of B:

$H_b=\frac{T_a}{\mathrm{\β}}[{\left(\frac{p_b}{p_a}\right)}^{-\mathrm{\βR}/g_n}-1]+H_a---\left[7\right]$

Meaning of parameters is as follows in the above-mentioned formula:

R: air special gas constant, R=287.05287 (m ²/ (S ²* K));

g _n: be free-fall acceleration;

β: the vertical rate of temperature (β=dT/dH)

Can calculate the gravity potential altitude information that correction back B is ordered by said process.Need declare a bit at this, if the gravity potential height that A is ordered is not given in advance, and the accurate GPS height H that given A is ordered _GPSa, in [7] formula, use H _GPSaReplace H _a, the gained result levels off to B point GPS highly.Above-mentioned analysis is to be based upon A, and 2 of B are separated by nearer, under the more consistent hypothesis of external condition.

After measuring end, the altitude information that measures is handled, found the solution average, the variance of measuring height data several times, can store measurement and result of calculation at last.

The present embodiment adopts USB interface-based barometric altimeter design, and advantage is: need not to adopt independent power module, each chip volume of employing is little, is easy to carry; Plug and play is convenient to embed other system and other system and is used in combination; Utilize upper computer software, can eliminate, be convenient to follow-up works such as the storage of data and statistical treatment simultaneously because of extraneous weather condition changes the height measuring error that causes.

It is emphasized that, adopt communication port RS-232, any interface communication circuit in USB interface and 1394 interfaces links to each other with computing machine and all has above-mentioned advantage, and specific embodiment described herein is only in order to explaining the utility model, and is not used in qualification the utility model.

Claims (4)

1, a kind of portable embedded barometric altimeter comprises data acquisition unit, it is characterized in that: also comprise interface communication circuit, linear voltage regulator and host computer; Temperature, pressure data that the interface communication circuit can collect data acquisition unit pass to host computer, are handled obtaining altitude information by host computer; The 5V voltage transitions that linear voltage regulator provides host computer is that 3.3V voltage is to interface communication circuit and data acquisition unit power supply.

2, portable embedded barometric altimeter according to claim 1 is characterized in that: the interface communication circuit adopts any in communication port RS-232, USB interface and 1394 interfaces to link to each other with PC or miscellaneous equipment.

3, portable embedded barometric altimeter according to claim 1 and 2, it is characterized in that: data acquisition unit adopts baroceptor element SCP1000-D01 chip, and this chip is made up of pressure sensor component and the application-specific integrated circuit ASIC that is used for Signal Regulation; Wherein, pressure sensor component is used to measure current air pressure; ASIC comprises following modules: analog-to-digital conversion module ADC is used for temperature, air pressure analog quantity that sensor element is measured are converted to digital quantity; The ASIC control module; Nonvolatile memory EEPROM is being stored the element initial settings information, the initial configuration when at every turn starting; Temperature-measuring module; Calculation of pressure and linearization block; The SPI interface, chip links to each other with interface communication circuit 2CY7C68013 by this SPI interface; Carry temperature compensation module among the ASIC, be used to compensate the inconsistent of temperature and environment temperature in the sheet that causes because of the device inside heat radiation, in addition, the SCP1000-D01 chip is worked under the internal clocking driving, need not external timing signal.

4, portable embedded barometric altimeter according to claim 1 is characterized in that: the temperature, the air pressure correcting module that have added the level altitude reference point in the host computer.

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