阅读说明：本技术 基于σ-δ型ad石英表加速度采集系统及采集方法 (Acceleration acquisition system and acquisition method based on sigma-delta type AD quartz watch ) 是由 冯欢 王二伟 于 2019-09-05 设计创作，主要内容包括：本发明涉及基于Σ-Δ型AD石英表加速度采集系统及采集方法,为一种应用于平台系统的石英表加速度采集系统,特别是采用Σ-Δ型AD的石英表加速度采集系统。该采集系统包括切换电路、大量程采样电阻、中量程采样电阻、小量程采样电阻、前置放大电路、Σ-Δ型AD采集电路、温控电路、FPGA控制电路、串口输出电路和系统电源；通过该采集系统提高了系统对微小电流的响应速度,使平台可实时识别当前位置加速度状态,减少了平台系统中调平时间,有利于缩短发射准备时间。(The invention relates to a quartz watch acceleration acquisition system and method based on sigma-delta type AD (analog-to-digital) and is applied to a quartz watch acceleration acquisition system of a platform system, in particular to a quartz watch acceleration acquisition system adopting sigma-delta type AD. The acquisition system comprises a switching circuit, a large-range sampling resistor, a medium-range sampling resistor, a small-range sampling resistor, a pre-amplification circuit, a sigma-delta type AD acquisition circuit, a temperature control circuit, an FPGA control circuit, a serial port output circuit and a system power supply; the acquisition system improves the response speed of the system to micro current, so that the platform can identify the acceleration state of the current position in real time, reduce the leveling time in the platform system and be beneficial to shortening the emission preparation time.)

1. Based on sigma-delta type AD quartz watch acceleration acquisition system, its characterized in that: the acquisition system comprises a switching circuit, a large-range sampling resistor, a medium-range sampling resistor, a small-range sampling resistor, a pre-amplification circuit, a sigma-delta type AD acquisition circuit, a temperature control circuit, an FPGA control circuit, a serial port output circuit and a system power supply;

the system power supply is used for providing working voltage for the switching circuit, the pre-amplification circuit, the sigma-delta type AD acquisition circuit, the temperature control circuit, the FPGA control circuit and the serial port output circuit;

the temperature control circuit is used for acquiring the temperature of the sigma-delta type AD acquisition circuit and outputting an acquired temperature signal to the FPGA control circuit, the FPGA control circuit compares the received temperature signal with a set temperature threshold value, if the received temperature signal is not less than the set temperature threshold value, the temperature control circuit does not heat, and if the received temperature signal is less than the set temperature threshold value, the temperature control circuit heats to enable the temperature signal to be consistent with the set temperature threshold value;

the switching circuit is a plurality of single-pole double-throw switches and is used for switching the current signal output by the quartz meter accelerometer to a large-range sampling resistor, a medium-range sampling resistor or a small-range sampling resistor;

the large-range sampling resistor, the middle-range sampling resistor or the small-range sampling resistor are used for converting a current signal output by the quartz meter accelerometer into a voltage signal and outputting the converted voltage signal to the preamplifier circuit;

the pre-amplification circuit is used for receiving voltage signals output by the large-range sampling resistor, the medium-range sampling resistor or the small-range sampling resistor, amplifying the received voltage signals and outputting the amplified voltage signals to the sigma-delta type AD acquisition circuit;

the sigma-delta type AD acquisition circuit is used for receiving the voltage signal output by the pre-amplification circuit, converting the received voltage signal into a digital signal and outputting the digital signal to the FPGA control circuit;

the FPGA control circuit is used for receiving the digital signal output by the sigma-delta type AD acquisition circuit and outputting the received digital signal to the serial port output circuit;

the serial port output circuit is used for receiving the digital signals output by the FPGA control circuit and outputting the received digital signals.

2. The sigma-delta based AD quartz watch acceleration acquisition system of claim 1, characterized in that: the wide-range sampling resistor is a high-precision low-temperature drift resistor.

3. The sigma-delta based AD quartz watch acceleration acquisition system of claim 1, characterized in that: the coarse and medium range sampling resistor is a high-precision low-temperature drift resistor.

4. The sigma-delta based AD quartz watch acceleration acquisition system of claim 1, characterized in that: the small-range sampling resistor is a high-precision low-temperature drift resistor.

5. The sigma-delta based AD quartz watch acceleration acquisition system of claim 1, characterized in that: when the current output by the quartz meter accelerometer ranges from-50 mA to +50mA, the switching circuit is communicated with the wide-range sampling resistor.

6. The sigma-delta based AD quartz watch acceleration acquisition system of claim 1, characterized in that: when the current output by the quartz meter accelerometer ranges from-1.25 mA to +1.25mA, the switching circuit is communicated with the intermediate-range sampling resistor.

7. The sigma-delta based AD quartz watch acceleration acquisition system of claim 1, characterized in that: when the current output by the quartz meter accelerometer ranges from-0.125 mA to +0.125mA, the switching circuit is communicated with the small-range sampling resistor.

8. The sigma-delta based AD quartz watch acceleration acquisition system of claim 1, characterized in that: the chip in the sigma-delta type AD acquisition circuit adopts sigma-delta type AD.

9. The sigma-delta based AD quartz watch acceleration acquisition system of claim 1, characterized in that: the serial port output circuit is an RS485 conversion interface.

10. The acceleration acquisition method based on the sigma-delta type AD quartz watch is characterized by comprising the following steps:

(1) the current output by the quartz meter accelerometer is accessed to a sampling resistor through a switching circuit and is converted into a voltage signal, different sampling resistors respectively correspond to a large-range state, a medium-range state and a small-range state, and the switching circuit introduces the current into different sampling resistors through a single-pole double-throw switch;

(2) after the voltage signal is amplified by the preamplification circuit, the amplified voltage signal is cumulatively sampled by a sigma-delta type AD acquisition circuit, and the cumulatively sampled voltage signal is output to the FPGA control circuit;

the temperature control circuit acquires environmental temperature information of the sigma-delta type AD acquisition circuit, and the working temperature is maintained at a set temperature through the heating sheet;

(3) and the FPGA control circuit outputs the accumulated and sampled voltage signal through a serial port output circuit.

Technical Field

The invention relates to a quartz watch acceleration acquisition system and method based on sigma-delta type AD (analog-to-digital) and is applied to a quartz watch acceleration acquisition system of a platform system, in particular to a quartz watch acceleration acquisition system adopting sigma-delta type AD.

Background

The quartz watch accelerometer is a main component for measuring the linear acceleration of a moving carrier, and the measurement response speed and accuracy of the quartz watch accelerometer directly influence the precision of inertial navigation. The accelerometer acquisition circuitry as part of the accelerometer measurement system will directly affect the accuracy of the acceleration information. The traditional quartz watch acceleration acquisition system adopts an I/F circuit mode, uses a built analog circuit to convert output current into frequency pulse output, and has the characteristics of large signal threshold and strong anti-interference capability. However, the I/F circuit has many analog devices and large volume, and the pulse number output time is long when small current is input, and the response speed is slow, so the leveling time is long.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the system adopts sigma-delta type AD to replace an I/F measuring circuit formed by analog devices, thereby overcoming the defects of large volume, slow response speed and overlong measuring range time in a platform system of the quartz watch acquisition circuit.

The technical solution of the invention is as follows:

the system comprises a switching circuit, a large-range sampling resistor, a medium-range sampling resistor, a small-range sampling resistor, a pre-amplification circuit, a sigma-delta type AD acquisition circuit, a temperature control circuit, an FPGA control circuit, a serial port output circuit and a system power supply;

the large-range sampling resistor, the middle-range sampling resistor and the small-range sampling resistor are all high-precision low-temperature drift resistors;

when the current output by the quartz meter accelerometer ranges from-50 mA to +50mA, the switching circuit is communicated with the wide-range sampling resistor;

when the current output by the quartz meter accelerometer ranges from-1.25 mA to +1.25mA, the switching circuit is communicated with the intermediate-range sampling resistor;

when the current output by the quartz meter accelerometer ranges from-0.125 mA to +0.125mA, the switching circuit is communicated with the small-range sampling resistor;

a chip in the sigma-delta type AD acquisition circuit adopts sigma-delta type AD;

the serial port output circuit is an RS485 conversion interface;

the system power supply is used for providing working voltage for the switching circuit, the pre-amplification circuit, the sigma-delta type AD acquisition circuit, the temperature control circuit, the FPGA control circuit and the serial port output circuit;

the temperature control circuit is used for acquiring the temperature of the sigma-delta type AD acquisition circuit and outputting an acquired temperature signal to the FPGA control circuit, the FPGA control circuit compares the received temperature signal with a set temperature threshold value, if the received temperature signal is not less than the set temperature threshold value, the temperature control circuit does not heat, and if the received temperature signal is less than the set temperature threshold value, the temperature control circuit heats to enable the temperature signal to be consistent with the set temperature threshold value;

the switching circuit is a plurality of single-pole double-throw switches and is used for switching the current signal output by the quartz meter accelerometer to a large-range sampling resistor, a medium-range sampling resistor or a small-range sampling resistor;

the large-range sampling resistor, the middle-range sampling resistor or the small-range sampling resistor are used for converting a current signal output by the quartz meter accelerometer into a voltage signal and outputting the converted voltage signal to a pre-amplifying circuit;

the pre-amplification circuit is used for receiving voltage signals output by the large-range sampling resistor, the medium-range sampling resistor or the small-range sampling resistor, amplifying the received voltage signals and outputting the amplified voltage signals to the sigma-delta type AD acquisition circuit;

the sigma-delta type AD acquisition circuit is used for receiving the voltage signal output by the pre-amplification circuit, converting the received voltage signal into a digital signal and outputting the digital signal to the FPGA control circuit;

the FPGA control circuit is used for receiving the digital signal output by the sigma-delta type AD acquisition circuit and outputting the received digital signal to the serial port output circuit;

the serial port output circuit is used for receiving the digital signals output by the FPGA control circuit and outputting the received digital signals.

The acceleration acquisition method based on the sigma-delta type AD quartz watch comprises the following steps:

(1) the current output by the quartz meter accelerometer is accessed to a sampling resistor through a switching circuit and is converted into a voltage signal, different sampling resistors respectively correspond to a large-range state, a medium-range state and a small-range state, and the switching circuit introduces the current into different sampling resistors through a single-pole double-throw switch;

(2) after the voltage signal is amplified by the preamplification circuit, the amplified voltage signal is subjected to accumulative sampling by a sigma-delta type AD acquisition circuit so as to ensure that the output information of the quartz meter accelerometer is complete and has no loss, and the voltage signal subjected to accumulative sampling is output to the FPGA control circuit;

the temperature control circuit acquires environmental temperature information of the sigma-delta type AD acquisition circuit, and the working temperature is maintained at a set temperature through the heating sheet;

(3) and the FPGA control circuit outputs the voltage signal after accumulated sampling to the platform control circuit through the serial port output circuit.

Compared with the prior art, the invention has the beneficial effects that:

(1) the quartz watch acceleration acquisition system adopts sigma-delta type AD conversion, so that the resolution ratio of the acceleration is improved;

(2) compared with the traditional I/F conversion circuit, the sigma-delta type AD conversion circuit has smaller volume, reduces the whole circuit volume and can be placed in the platform body;

(3) the response speed of the system to the micro current is improved, so that the platform can identify the acceleration state of the current position in real time, the measuring time in the platform system is reduced, and the transmitting preparation time is favorably shortened.

(4) The output current of the quartz watch is input into the switching circuit through the interface, the sampling resistor is selected by the switching circuit to correspond to different detection states, the current enters the pre-amplification circuit after being converted into a voltage signal by the sampling resistor, the voltage is zoomed to a proper AD acquisition range, the sigma-delta type AD is converted into a digital signal, the FPGA reads the acquisition signal and then transmits the acquisition signal to the platform control circuit in a serial port mode, and the FPGA performs temperature acquisition control in real time to ensure that the acquisition system works in a constant temperature state.

Drawings

FIG. 1 is a schematic diagram of a circuit structure of an acceleration acquisition system based on a sigma-delta type AD quartz watch according to the present invention.

Detailed Description

The switching circuit module comprises three different gears which respectively correspond to three states of a large range, a medium range and a small range, and the switching circuit accesses current to sampling resistors with different resistance values through a single-pole double-throw switch.

The sampling resistor is a high-precision low-temperature drift resistor, and the resistance value is less influenced by the outside.

The selected AD chip is sigma-delta type AD, so that the accumulated sampling of signals can be realized, and the information of the quartz watch is ensured to be not lost.

The temperature control circuit can collect temperature information of the acquisition system and maintain the working temperature of the system at a stable temperature through the heating sheet.

Based on a sigma-delta type AD quartz watch acceleration acquisition system, quartz watch output current is input to a low-temperature drift high-precision sampling resistor, and signal conversion from current to voltage is completed; the switching circuit is controlled by the FPGA and guides current into different sampling resistors to realize the conversion of the detection state; the signal pre-amplifying circuit scales the obtained voltage signal to an AD input voltage range; the sigma-delta type AD converts the analog voltage signal into a digital signal and reads the digital signal by the FPGA; the temperature control circuit collects the operating temperature of the circuit by using a thermosensitive platinum resistor and keeps the temperature of the circuit by using a heating sheet; the FPGA comprehensively controls the switching circuit, the AD data acquisition and the operation temperature control, and transmits the navigation data to the platform control circuit through the serial port. The invention reduces the volume of the quartz watch acquisition circuit, improves the response speed and reduces the measuring time in the platform system.

The invention is further illustrated by the following figures and examples.