MSN302 High Precision MEMS North Finder

MEMS Gyroscope

Range (°/s)

±200

Bias @ Full temp. (°/h, 3σ)

≤0.3

Bias Stability (°/h, 10s smoothing)

≤0.1

Bias Instability (°/h, Allan, typ)

≤0.02

Bias Repeatability (°/h)

≤0.1

Angular Random Walk (°/√h)

≤0.01

Scale Factor Nonlinearity (ppm)

≤100

Cross-Coupling (rad)

≤0.001

Bandwidth (Hz)

≥50

MEMS Accelerometer

Range (g)

±10

Bias @ Full temp. (mg, 3σ)

≤1

Bias Stability (ug, 10s smoothing)

≤20

Bias Instability (ug, Allan, typ)

≤10

Bias Repeatability (ug)

≤20

Velocity Random Walk (m/s/√h)

≤0.02

Scale Factor Nonlinearity (ppm, ±1g)

≤100

Cross-Coupling (rad)

≤0.001

Bandwidth (Hz)

≥50

Navigation accuracy

North Finding Accuracy (°, 1σ)

≤0.5secL (L for latitude)

Attitude Accuracy (°, 1σ)

≤0.05

Physical Characteristics

Power Supply (V)

5~12 (Ripple ≤ 100mV)

Steady-state Power (W)

≤2

Startup Time (s)

≤2

Update Rate (Hz, max)

200

Dimensions (mm×mm×mm)

47×47×35.5

Weight (g)

100±10g

Operating Environment

Operating Temp. (°C)

-40～+85

Storage Temp. (°C)

-55～+85

Vibration (g, RMS)

6.06,20~2000Hz

Shock (g)

500g/1ms

Gyroscope

Range (°/s)

±200

Bias @Full temp.(°/h,3σ)

≤0.3

Bias Stability (°/h,10ssmoothing)

≤0.1

Bias Instability (°/h,allan,typ)

≤0.02

Bias Repeatability (°/h)

≤0.1

Angle Random Walk (°/√h)

≤0.01

Scale Factor Nonlinearity (ppm)

≤100

Cross-Axis Coupling (rad)

≤0.001

Bandwidth (Hz)

≥50

Accelerometer

Range (g)

±10

Bias @Full temp. (mg, 3σ)

≤1

Bias Stability (ug, 10s smoothing)

≤20

Bias Instability (ug, Allan, typ)

≤10

Bias Repeatability (ug)

≤20

Velocity Random Walk (m/s/√h)

≤0.02

Scale Factor Nonlinearity (ppm, ±1g)

≤100

Cross-Axis Coupling (rad)

≤0.001

Bandwidth (Hz)

≥50

Navigation Accuracy

Auto north finding accuracy (°, 1σ)

≤0.5secL(L represents the local latitude)

Attitude accuracy (°, 1σ)

≤0.05

Physical Characteristics

Power Supply (V)

5~12(Ripple ≤100mV)

Steady-State Power (W)

≤2

Startup Time (s)

≤2

Update rate (Hz, max)

200

Dimensions (mm×mm×mm)

47×47×35.5

Weight (g)

100±10g

Operating Environment

Operating Temperature (°C)

-40～+85

Storage Temperature (°C)

-55～+85

Vibration (g, RMS)

20~2000HZ,6.06

Shock (g)

500g/1ms

CH-26A-10TJ

PinNo.

Definition

Test Equipment Side

1

POWER_IN

DC 5V~12V power supply

6

GND

2

RS422 Rx+

RS422 Tx+

7

RS422 Rx-

RS422 Tx-

3

RS422 Tx+

RS422 Rx+

8

RS422 Tx-

RS422 Rx-

No.

Byte Start

Byte Count

Content

Equivalent

Range

Unit

Remarks

1

0

1

0x55

1

Frame Header

2

1

1

0xAA

1

Frame Header

3

2

1

92

1

Data Length

4

3

4

PC num

1

5ms

5ms count value

5

7

1

System Operating

Status

-

-

-

16 (0x10): Self-test in progress;

18 (0x12): Self-test passed:

31 (0x1F): Self-test error:

51 (0x33): Coarse alignment:

53 (0x35): Fine alignment

65 (0x41): Navigating

67 (0x43): Zero velocity correction

6

8

1

Reserved

-

-

-

7

9

1

Over-Range Status

-

-

-

After the product enters alignment, within one navigation cycle of 5ms,

bit0: X gyroscope over-range set to 1;

bit1: Y gyroscope over-range set to 1;

bit2: Z gyroscope over-range set to 1;

Bit3: X accelerometer over-range set to 1;

Bit4: Y accelerometer over-range set to 1;

Bit5: Z accelerometer over-range set to 1;

After re-alignment, the above status is cleared to 0.

8

10

1

Command Response Status

0x10: Successfully responded to correct command, sending 5 packets continuously.

0x1F: Command error, sending 5 packets continuously, prompting user to check command configuration (output data or command out of range), original process unchanged.

Note: Upon receiving a valid command, 5 packets with 0x10 status are sent as feedback, followed by a soft reset. Upon receiving an invalid command, 5 packets with 0x1F status are sent as feedback, and the original state is maintained.

9

11

2

Total North Finding Time

1

-

s

10

13

2

Remaining North Finding Time

1

s

11

15

4

Angular Rate X

0.0000005

°/s

Average within output cycle (forward)

12

19

4

Angular Rate Y

0.0000005

°/s

Average within output cycle (upward)

13

23

4

Angular Rate Z

0.0000005

°/s

Average within output cycle (rightward)

14

27

4

Acceleration X

0.000001

m/s2

Average within output cycle (forward)

15

31

4

Acceleration Y

0.000001

m/s2

Average within output cycle (upward)

16

35

4

Acceleration Z

0.000001

m/s2

Average within output cycle (rightward)

17

39

4

Integrated Longitude

0.0000001

°

Instantaneous value at output time

18

43

4

Integrated Latitude

0.0000001

°

Instantaneous value at output time

19

47

2

Integrated Altitude

0.5

m

Instantaneous value at output time

20

49

2

Integrated North Velocity

0.04

m/s

Instantaneous value at output time

21

51

2

Integrated Up Velocity

0.04

m/s

Instantaneous value at output time

22

53

2

Integrated East Velocity

0.04

m/s

Instantaneous value at output time

23

55

2

Roll Angle

0.006

[-180~180]

°

Instantaneous value at output timeint16

24

57

2

Heading Angle

0.006

[0,360]

°

Positive toward north-to-east

Instantaneous value at output timeUint16

25

59

2

Pitch Angle

0.006

[-90,90]

°

Instantaneous value at output timeint16

26

61

1

Gyroscope Temperature

1

℃

Instantaneous value at output time

27

62

1

Accelerometer Temperature

1

℃

Instantaneous value at output time

28

63

4

Quaternion q0

Based on North-Up-East coordinate system.

IEEE 32-bit floating point, little-endian.

29

67

4

Quaternion q1

Same as above

30

71

4

Quaternion q2

-

-

Same as above

31

75

4

Quaternion q3

-

Same as above

32

79

6

IMU over-range counter

1

1

If an over-range occurs once per 5ms navigation cycle, increment by 1. After accumulating to 255, restart counting. If re-alignment occurs, restart counting. Little-endian format, in the order of GxGyGzAxAyAz, each axis is Uint8.

33

85

1

Reserved

1

UInt8

34

86

1

Reserved

1

UInt8

35

87

2

Reserved

UInt8

36

89

2

Virtual Heading Angle

0.006

[0,360]deg

37

91

2

Reserved

Little-Endian Format

38

93

1

Vertical Mode Flag

1

UInt8,

0: Horizontal mode;

1: Vertical launch mode;

39

94

1

Output Protocol Format

1

0x00: General north finder protocol

0xFF: General petroleum north finding protocol

40

95

1

Checksum

1

Low 8 bits of the cumulative sum of bytes at indices 2 to 94

First Byte

Byte Count

Signal Name

Dimension, Unit, or Content

Equivalent

Interface Accuracy Description

1

1

Frame Header 1

Content: 55H

1

8-bit unsigned integer

2

1

Frame Header 2

Content: AAH

1

8-bit unsigned integer

3

1

Data Length

Content: 24H

1

8-bit unsigned integer

4

4

Loaded Longitude

[-180,180]deg

0.0000001

Little-Endian Format

5

4

Loaded Latitude

[-90,90]deg

0.0000001

Little-Endian Format

6

4

Loaded Altitude

m

1

IEEE 32-bit floating point

Little-Endian Format

7

4

Reserved 1

NA

1

-

8

2

Data Validity Mode

NA

1

bit0: 1 = LLA information valid;

bit1: 1 = loaded heading information valid;

bit2: 1 = alignment time valid

bit3: 1 = baud rate and period valid

bit4: 1 = installation misalignment angle valid

All bits being 0 means all invalid.

9

2

Reserved 2

NA

10

2

Reserved 3

NA

11

1

Output Baud Rate Configuration

NA

1

0：9600bps;

1:38400;

2：115200;

3:230400;

4:460800;

5:921600;

12

1

Output Period

NA

1

0：5ms

1:10ms

2：20ms;

3:50ms;

4:100ms;

5:200ms;

6:500ms：

7:1s;

8:2s;

9:5s;

13

2

2

Roll Installation Misalignment Angle Between INS and Target Point UsrTransRoll

0.006

[-180~180]

14

2

2

Yaw Installation Misalignment Angle Between INS and Target Point UsrTransYaw

0.006

[-180~180]

15

2

2

Pitch Installation Misalignment Angle Between INS and Target PointUsrTransPitch

0.006

[-180~180]

16

2

Reserved 4

NA

17

2

User Command

NA

1

16-bit unsigned integer;
0) 0x0000: No command

1) 0x0011: Static auto north finding command;
2) 0x0066: Write LLA to flash command;

3) 0x0077: Write alignment time to flash command;

4) 0x0099: Write baud rate and output frequency to flash command

5)0x00AA:Write attitude installation misalignment angle to flash command

Other invalid values: command not responded;

18

2

Alignment Time

[120,6553.5]

0.1

16-bit unsigned integer;

(1) Under the static auto north finding command, the alignment time value is coarse alignment time (30s) + fine alignment time, which should not be less than 120s.

19

1

Checksum

Low 8 bits of the cumulative sum of all bytes from Data Length (inclusive) to the byte before Checksum

1

Low 8 bits of the cumulative sum of bytes at indices 2 to 38