F3G20 Three-Axis FOG

F3G20 Three-Axis FOG Performance Parameters

This document specifies the requirements and methods for the operation and maintenance of the F3G20 3-axis fiber optic gyroscope (hereinafter referred to as "the Product").

Product Introduction Product Working Principle, Function and Application Scope

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 coil. A digital closed-loop detection circuit is used to extract the optical path difference between clockwise and counterclockwise propagating light caused by external physical angular velocity sensed by the fiber coil, and the voltage signal converted from the optical path difference signal is subjected to closed-loop feedback and control to realize signal modulation and demodulation, achieving 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 angle increment information and internal temperature information.

Application Scope

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

Composition

The product mainly consists of the following components:

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

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

Gyro structural parts

Dimensional and Installation Drawings

The dimensional and installation drawings are shown in Figure 1.

Overall dimensions: 52mm±0.1mm × 51mm±0.1mm × 52mm±0.1mm (L×W×H);

Installation dimensions: 44mm±0.1mm × 44mm±0.1mm;

4×Mounting holes M3, depth 6mm.

 

Figure 1 F3G20 3-Axis Fiber Optic Gyroscope Assembly Installation Schematic

 

Weight

Total product weight < 300g.

 

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	Overall Dimensions	52×51×52
2	Start-up Time (s)	3
3	Null Bias (°/h)	≤1
4	Bias Stability at Room Temp. (10s smoothing, °/h)	≤1
5	Bias Stability under Temp. Variation (1℃/min, 100s smoothing, °/h)	≤1
6	Bias Repeatability (°/h)	≤1
7	Bias Magnetic Sensitivity (°/h/Gs)	≤0.2
8	Random Walk Coefficient (°/√h)	≤0.1
9	Scale Factor Non-linearity (ppm)	≤50
10	Scale Factor Asymmetry (ppm)	≤20
11	Scale Factor Repeatability (ppm)	≤50
12	Threshold (°/h)	≤0.5
13	Resolution (°/h)	≤0.5
14	Bandwidth (Hz)	≥200
15	Operating Temperature (℃)	-45～+70
16	Storage Temperature (℃)	-55～+80
17	Dynamic Range (°/s)	±500
18	Supply Voltage (V)	+5
19	Steady-State Power Consumption (W)	≤4
20	Full-Temp. Steady-State Power Consumption (W)	≤8
21	Start-up Inrush Current (A)	＜2

 

Mechanical and Electrical Interface

Power Supply Requirements

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

Table2 F3G20 3-Axis Fiber Optic GyroscopePower Supply Requirements

No.	Name	Requirements
1	Power Supply Accuracy	±5%
2	Power Supply Ripple (Vpp)	≤50mV
3	Supply Current	＞2A

 

Electrical Connection Interface

The connector used for external connection of the product is J30JZLN9ZKCA000, definitions see Table 3.

Table 3 J30JZLN9ZKCA000 Gyroscope Connector and Test Point Definitions

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

Note: When connecting to or handling 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 the differential pulse (or square wave) synchronous strobe signal, and TXD is used for serial data signal output.

Communication protocol: The strobe signal frequency shall not exceed 1kHz. After receiving the falling edge of the strobe signal, the gyro latches the internal angle increment data and starts outputting the gyro data packet via 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, and no parity bit.

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

The data packet format is as follows:

Table 4 Gyro Data Packet Format

Byte No.	Content
	0x99 (Hex)
	0x66 (Hex)
	Status word, normal value is 0xFF (Hex)
	X Gyro Angle Increment 1, LSB
	X Gyro Angle Increment 2
	X Gyro Angle Increment 3
	X Gyro Angle Increment 4, MSB
	Y Gyro Angle Increment 1, LSB
	Y Gyro Angle Increment 2
	Y Gyro Angle Increment 3
	Y Gyro Angle Increment 4, MSB
	Z Gyro Angle Increment 1, LSB
	Z Gyro Angle Increment 2
	Z Gyro Angle Increment 3
	Z Gyro Angle Increment 4, MSB
	Temperature Data 1, LSB
	Temperature Data 1, MSB
	Temperature Data 2, LSB
	Temperature Data 2, MSB
	Temperature Data 3, LSB
	Temperature Data 3, MSB
	Frame number, incremented by 1 per transmission, cyclic counting
	Checksum, sum of bytes 3 to 22

 

The status word meanings are 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" bits are normally 1;

"Circuit Control Status" bit: 1 indicates normal gyro circuit control status; 0 indicates abnormal control status;

"Optical Path Status" bit: 1 indicates normal gyro optical path operation; 0 indicates abnormal gyro optical path status.

If any of the above two status bits is constantly 0 during gyro operation, accompanied by abnormal gyro data, the gyro shall be returned for repair.

 

Product Installation and Removal

Requirements

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

Method and Steps

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

b) It is recommended to apply a uniform layer of 0.2~0.5mm thick thermal conductive silicone on the bottom of the product during installation;

c) It is recommended to place an aluminum plate (with dimensions larger than the product) under the product installation surface during product testing;

d) The magnetic field strength at the product installation position shall not exceed 1 Gauss.

Post-Installation Inspection

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

Operation Procedures

Pre-Use Inspection

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

Product Operation Instructions

Install the product on the carrier and connect the cable correctly 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 gyro performance and reduce gyro service life;

b) The power supply system shall be checked before powering on the 3-axis fiber optic gyro assembly to ensure there is no short circuit between electrical points of the power supply and between the gyro housing and each electrical point;

c) If this product shows abnormal operation, 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) Correct connection of product input/output signal lines and power supply lines must be ensured;

f) Anti-static measures shall be taken during the process of handling the product;

g) The optical devices in the 3-axis fiber optic gyro assembly are susceptible to moisture. If conditions permit, it is recommended that the inertial navigation system be designed with hermetic sealing;

i) The magnetic field strength around the product location shall 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 each power-on time being 3600s. No electrical parameter testing is required during power-on;

After the product is installed in the carrier, it is required to power on at least once a year, with each power-on time being 3600s. No electrical parameter testing is required during power-on.

 

Common Fault Symptoms and Troubleshooting

This product is in a sealed state. No on-site repair can be performed when any fault occurs at the user end. The product needs to be returned to the manufacturer for repair.

The following only lists some fault symptoms that may occur which are not caused by the product itself. See Table 6. For other technical problems 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 ammeter indicates approximately zero	Product not powered or insufficient current supplied	Check power supply and power circuit, restore product power supply
2	Product powered on, +5V ammeter indicates normal, but computer acquisition program does not work	Test equipment acquisition system abnormal	Check connection cable, equipment power supply status
		Software program conflict	Restart the computer

 

Transportation and Storage Requirements

Transportation Precautions

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

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

Ensure the packaging box is secured to the carrier and will not move during transportation.

 

Storage Conditions, Shelf Life and Precautions

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

The product storage period is 15 years.

 

Unpacking Precautions

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

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

Anti-static protection shall be applied when taking out the product.

Table 7 Product Delivery Checklist

No.	Name	Qty
1	F3G20 3-Axis Fiber Optic Gyroscope	1
2	Gyro Packaging Box	1
3	Gyro Test Report	1
4	J30JZ/XN9TJCAL01Connector	1
5	Certificate of Conformity	1