Application

1.Application Products

ER-FNS-03 Low Cost 3 Axis FOG North Seeker

2.1 Triaxial Fiber Optic Gyro

2.1.1 Performance Indicators

Table 1 Performance requirements of fiber optic gyroscope

No	Indicator	Value
1	Operating temperature (℃)	-45～+75
2	Start time τ (s)	≤5
3	Dynamic range (° / s)	≥±400
4	Zero-bias stability (1σ,/h) (100s Standard Deviation)	≤0.3
5	Zero bias repeatability (1σ,/h)	≤0.3
6	Random walk coefficient (°/ √h)	≤0.03
7	Non-linearity of scale factor (ppm)	≤100
8	Asymmetry of the scale factor (ppm)	≤100
9	Repeatability of scale factor (ppm)	≤100
10	Extreme temperature scale factor (ppm)	≤200
11	Bandwidth (Hz)	≥200

2.1.2 Interface Protocol

Table 2 FOG interface communication protocol

		Data frame	Output Data	Edition	First edition
		Frame description
Content	Types	Asynchronous serial data frame
	source	Fiber Optic Gyro
	Standards compliant	RS-422; baud rate 614400bits / s; 1bit start bit, 8bit data bit without parity, 1bit stop bit
	Update rate	400Hz
Element	Signal name	Signal description
1	Head of Gyro data	0xEB
2		0x90
3	Gyro Data	4-byte 32-bit signed integer, character 3 is the lowest 8 bits, and character 6 is the highest 8 bits. Negative data are in two’s complement form. The scale factor is: 1
4	Gyro Data	4-byte 32-bit signed integer, character 3 is the lowest 8 bits, and character 6 is the highest 8 bits. Negative data are in two’s complement form. The scale factor is: 1
5	Gyro Data	4-byte 32-bit signed integer, character 3 is the lowest 8 bits, and character 6 is the highest 8 bits. Negative data are in two’s complement form. The scale factor is: 1
6	Gyro Data	4-byte 32-bit signed integer, character 3 is the lowest 8 bits, and character 6 is the highest 8 bits. Negative data are in two’s complement form. The scale factor is: 1
7	Reservation	Fill in 00;
8	Reservation	Fill in 00;
9	Reservation	Fill in 00;
10	Reservation	Fill in 00;
11	Reservation	Fill in 00;
12	Reservation	Fill in 00;
13	Reservation	Fill in 00;
14	Reservation	Fill in 00;
15	Temp/condition	Temperature calculation formula: output according to standard 18B20, the negative number of data is in two’s complement form. The scale factor is: 1/16 (the output code value is multiplied by the scale factor to obtain the temperature in Celsius)
16		Status: 0 ~ 3, update period: 1ms
17	15,16 data description	State 0: gyro temperature; 1: reserved; 2: reserved; 3: working state
18	Cycle count	The value of each packet of data is increased by 1, and after 255, the next packet of data is 0;；
19	Checksum	After accumulating characters from 3 to 18, take the lower 8 bits as the checksum