F3G40 Three-Axis FOG

F3G40 Three-Axis FOG Performance Parameters

This document specifies the requirements and methods for the use and maintenance of the F3G40 3-Axis Fiber Optic Gyroscope (hereinafter referred to as the Product).

Product Introduction Working Principle, Function and Scope of Application

Working Principle

This product is an inertial angular rate sensor based on the optical Sagnac effect, used to measure the angular velocity of a carrier along the sensitive axis of the product. The angular velocity sensing unit of this product is a fiber optic coil. A digital closed-loop detection circuit is used to extract the optical path difference of clockwise and counterclockwise propagating light sensed by the fiber optic coil caused by the external physical angular velocity, and simultaneously convert the optical path difference signal into a voltage signal for closed-loop feedback and control, achieving signal modulation and demodulation, and attaining the purpose of high-precision angular velocity signal detection.

Function

This product consists of an optical angular velocity sensing unit and a signal detection unit, providing gyro angular increment information and internal temperature information.

Scope of Application

The product is mainly applicable to medium and high-precision inertial navigation systems, positioning and orientation systems, servo stabilization systems and other applications.

Composition

The main components of the product are as follows:

Optical unit: including SLD light source, fiber optic coil, integrated optical phase modulator, fiber optic coupler, photodetector;

Circuit unit: light source drive circuit, signal detection and control circuit;

Gyro structural components

The structure contains mounting positions for quartz minor accelerometers.

Dimensions and Installation Size

Dimensions and installation size are shown in Figure 1.

Overall dimensions: 71.5mm±0.1mm × 71.5mm±0.1mm × 45.0mm±0.1mm (L×W×H, including sensing head);

Installation dimensions: 58.5mm±0.1mm × 53.0mm±0.1mm × 52.5mm±0.1mm × 44.5mm±0.1mm;

Mounting holes: 4×Φ3.5.

Figure 1 F3G40 Fiber Optic Gyroscope Assembly Installation Diagram

 

Weight

Total product weight: 350g±10g.

 

Main Performance Parameters

The main performance parameters of the product are detailed in Table 1.

Table 1 Main Performance Parameters

No.	Test Item	Technical Requirement
1	Start-up Time (s)	3
2	Bias Stability (10s averaging, °/h)	≤0.1
3	Bias Repeatability (°/h)	≤0.1
4	Angle Random Walk (°/h^1/2)	≤0.01
5	Scale Factor Non-linearity (ppm)	≤20
6	Scale Factor Repeatability (ppm)	≤20
7	Operating Temperature (°C)	-45~+70
8	Storage Temperature (°C)	-55~+80
9	Dynamic Range (°/s)	±500
10	Supply Voltage (V)	+5V
11	Steady-state Power Consumption (full temp, W)	≤8

 

Mechanical and Electrical Interface

Power Requirements

The product is powered by +5V DC power supply. The power supply requirements are shown in Table 2:

Table 2 F3G40 Fiber Optic Gyroscope Power Requirements

No.	Name	Requirements
1	Power Supply Accuracy	±5%
2	Power Supply Ripple (Vpp)	≤20mV
3	Supply Current	＞1A

 

Electrical Connection Interface

The connector for external connection of the product is J30JZLN9ZKCA000. The definition is shown in Table 3.

Table 3 J30JZLN9ZKCA000 Gyro Connector and Test Point Definition

Pin No.	Definition	Notes
1	+5V	Power Input
2	GND	Power Ground
3	Reserved
4	RXD+	Gyro Differential Strobe +
5	TXD+	Gyro RS422 Output +
6	+5V	Power Input
7	GND	Power Ground
8	RXD-	Gyro Differential Strobe -
9	TXD-	Gyro RS422 Output -

Note: When connecting to or contacting this product, anti-static measures shall be taken in accordance with GJB 1649-1993.

 

Communication Protocol

Communication interface: Both RXD and TXD are RS422/485 differential communication interfaces. RXD is used to receive differential pulse (or square wave) synchronous strobe signals, and TXD is used for serial data signal output.

Communication protocol: The strobe signal frequency is not greater than 1kHz. After receiving the falling edge of the strobe signal, the gyro latches the internal angular increment data and starts outputting the gyro data packet through TXD within 1μs. The transmission baud rate is 460.8kbps. The data packet contains 23 Bytes, each Byte has 1 start bit, 8 data bits, 1 stop bit, no parity bit.

The angular increment information is the angular increment value of the gyro during the time between two strobe signals. Dividing the accumulated angular increment value over a period of time by this time interval gives the average angular velocity of the gyro during this period.

The data packet format is as follows:

Table 4 Gyro Data Packet Format

ByteNo.	Content
	0x99
	0x66
	Status word, normal value is 0xFF
	X gyro angular increment 1, LSB
	X gyro angular increment 2
	X gyro angular increment 3
	X gyro angular increment 4, MSB
	Y gyro angular increment 1, LSB
	Y gyro angular increment 2
	Y gyro angular increment 3
	Y gyro angular increment 4, MSB
	Z gyro angular increment 1, LSB
	Z gyro angular increment 2
	Z gyro angular increment 3
	Z gyro angular increment 4, MSB
	Temperature data 1, LSB
	Temperature data 1, MSB
	Temperature data2,LSB
	Temperature data2,MSB
	Temperature data3,LSB
	Temperature data3,MSB
	Frame number, incremented by one each time, cyclic count
	Checksum, sum of bytes 3 to 22

 

The status word meaning is as follows:

Table 5 Gyro Status Word Data Format

bit7	bit6	bit5	bit4	bit3	bit2	bit1	bit0
Reserved	Z-axis circuit control status	Y-axis circuit control status	X-axis circuit control status	Reserved	Z-axis optical path status	Y-axis optical path status	X-axis optical path status

Where: the "Reserved" bit is normally 1;

When the "Circuit Control Status" bit is 1, it indicates that the gyro circuit control status is normal; when it is 0, it indicates that the control status is abnormal;

When the "Optical Path Status" bit is 1, it indicates that the gyro optical path is working normally; when it is 0, it indicates that the gyro optical path status is abnormal.

If any of the above two status bits is normally 0 during the use of the gyro, accompanied by abnormal gyro data, the gyro should be returned for repair.

 

Product Installation and Removal

Requirements

The user is responsible for the installation and removal of the product. During this process, the product must not be subjected to impact, knocking or collision, nor shall mechanical processing be performed on the outer surface of the product; pay attention to the wires and fiber optic sleeves between gyro assemblies, and guard against small-angle bending, squeezing, pulling and collision.

Method and Steps

a) The surface used to fix the product requires flatness better than 0.02mm;

b) The connection line between gyros comes out from the bottom of the sensing head. Pay attention to the exit position and direction during installation;

c) The connection line between gyros must be bonded to the inertial navigation structure with easily removable adhesive (such as 706B silicone, etc.);

d) It is recommended to add spring washers for the sensing head installation. The circuit box part needs to be installed on the back side or add an adapter plate.

Post-Installation Inspection

Check whether each mounting screw matches the mounting hole size and whether it is secure.

Operating Procedures

Pre-Use Inspection

Check the appearance of the product for physical damage such as collision.

Product Usage Instructions

Install the product on the carrier and correctly connect the cable according to the requirements in Table 3;

Connect data according to the communication protocol in Section 2.6.3.

 

Precautions

a) Frequent power on/off operations should be avoided during the use of the 3-Axis fiber optic gyro assembly, so as not to damage the gyro performance and reduce the gyro service life;

b) Before powering on the 3-Axis fiber optic gyro assembly, the power supply system should be checked to ensure that there is no short circuit between various electrical points of the power supply and between the gyro housing and each electrical point;

c) If this product malfunctions, consult the manufacturer. Unauthorized disassembly and repair are prohibited;

d) The 3-Axis fiber optic gyro assembly is a precision instrument. Handle with care during use and transportation;

e) Ensure correct connection of product input, output signal lines and power supply lines;

f) Anti-static measures are required during contact with the product;

g) The optical components in the 3-Axis fiber optic gyro assembly are susceptible to moisture. If conditions permit, it is recommended that the inertial navigation system consider airtightness;

i) The magnetic field strength around the product location should be less than 1 Gauss.

 

Maintenance and Care

Before the product is installed in the carrier, it is required to power on the product at least once every 6 months, with a power-on time of 3600s each time. During the power-on time, it is not required to test the electrical parameters of the product;

After the product is installed in the carrier, it is required to power on at least once a year, with a power-on time of 3600s each time. During power-on, it is not required to test the electrical parameters of the product.

 

Common Fault Symptoms and Troubleshooting

This product is in a sealed state. After any failure occurs at the user, it cannot be repaired on site and needs to be returned to the manufacturer for repair.

The following can only list some fault symptoms that may occur and are not due to the product itself, see Table 6. If other technical problems occur during product use, please contact the product manufacturer.

Table 6 Common Faults and Troubleshooting

No.	Fault Symptom	Cause Analysis	Troubleshooting Method
1	Product powered on, +5V current meter indicates approximately zero	Power not supplied to product or current too low	Check power supply and power circuit, restore product power
2	Product powered on, +5V current meter indicates normal, but computer acquisition program does not work	Test equipment acquisition system abnormal	Check connection cable, equipment power supply
		Software program conflict	Restart computer

 

Transportation and Storage Requirements

Transportation Precautions

Place the product in the direction shown on the packaging box;

Transportation by road, rail, air and water is allowed;

During transportation, ensure that the packaging box is fastened to the carrier and will not move.

 

Storage Conditions, Shelf Life and Precautions

The product placed in the packaging box should be stored in an air-conditioned warehouse under standard atmospheric pressure conditions, with an ambient temperature of 25℃±10℃ and relative humidity of 30%～70%, and the surrounding magnetic field strength is less than 10 Gauss;

The product storage period is 15 years.

 

Unpacking Precautions

Check the appearance of the outer packaging for physical damage such as collision;

Check whether the product and supporting accessories are complete, see Table 7;

Electrostatic protection treatment should be performed when taking out the product.

Table 7 Product Delivery Checklist

No.	Name	Qty
1	F3G403-Axis Fiber Optic Gyro Assembly	1
2	Gyro Assembly Packaging Box	1
3	Gyro Assembly Test Report	1
4	J30JZLN9ZKCA000 Connector	1
5	Certificate of Quality	1