ER-MNS-08 Ultra Low Cost Single Axis MEMS North Seeker 

Introduction

The ER-MNS-08 Single-Axis MEMS North Seeker (hereafter referred to as the Gyro North Seeker) is primarily designed for rapid and autonomous determination of true north direction. It employs a navigation grade MEMS gyroscope to measure the Earth's rotational rate. This signal is then processed to calculate the angle between the gyro's primary axis and true north, providing accurate azimuth information for the carrier platform.

The device is an integrated mechatronic system, comprising a MEMS gyroscope, accelerometer, mechanical rotation control mechanism, and an embedded computer.

Key Features

High North-seeking Accuracy: 0.25° secψ

Wide Attitude Measurement Range: -30° to +30°

Short North-Seeking Time: find the true north within 180s

Strong Anti-Interference: Operates independently without external signals; unaffected by surrounding magnetic fields or other environmental interference

Compact & Lightweight: Dimensions: 80×85×72.5mm; Weight: ≤700g

Applications

• Intelligent tunneling in coal mine roadways and directional drilling
• Challenging engineering projects such as longwall mining and deep shaft penetration
• Integration into engineering equipment like directional drilling rigs and bridge erection machines
• Emergency response and other scenarios requiring rapid north finding

Specifications

Model No.	ER-MNS-08A	ER-MNS-08B	ER-MNS-08C
North seeking accuracy	1°secψ	0.5°secψ	0.25°secψ
Attitude accuracy（1σ）	0.5°
Measurement range of north seeking	0°~360°
Measurement range of attitude	-30°~+30°
North seeking time	180s
Voltage and environment
Working temperature	5℃~+55℃
Power supply	DC24V
Output interface	RS422
Physical characteristics
Dimensions (mm)	80×85×72.5
Weight (g)	≤700

 Wiring Definition

J30J-15

Pin No.	Electrical Characteristics	Remark
1	VCC	24VDC
2	/
3	GND
4-5	/
6	RS422,TX+
7	RS422,TX-
8	RS422,RXD+
9	RS422,RXD-
10-15	/

 Communication protocol

• Receiving Data Protocol

No.	Data definition	Data Type	Number of bytes	Byte sequence number	Unit	Note                 (First low, then high)
1	FH         (frame header)	short	2	0-1	/	0x55，0xAA
2	Protocol version number	Unsigned char	1	2	/	0x01
3	Frame number	Unsigned int	4	3-6	/	For every 1 package of data collected, add 1.
4	Reserved for backup	/	1	7	/	/
5	Pitch angle	Float	4	8-11	°	Multiply the result by 0.01
6	Roll angle	Float	4	12-15	°	Multiply the result by 0.01
7	Heading angle	Float	4	16-19	°	Multiply the result by 0.01
8	Main gyro	Float	4	20-23	°/s	Divide the obtained result by 18000
9	X-axis accelerometer	Int	4	24-27	m/s/s	Divide the obtained result by 1000000
10	Y-axis accelerometer	Int	4	28-31	m/s/s	Divide the obtained result by 1000000
11	Z-axis accelerometer	Int	4	32-35	m/s/s	Divide the obtained result by 1000000
12	Reserved for backup	/	12	36-47	°/s	/
13	Temperature	Float	4	48-51	°
14	Reserved for backup	/	47	48-94	/	/

 

• Sending Data Protocol

1. Start work

Byte sequence number	Definition	Note
1	0xEB
2	0x80
3	0x00
4	0xCC
5-8	0x00
9-12	0x00
13-16	0x00
17-21	0x00

2. Send the longitude, latitude, altitude

Byte sequence number	Definition	Note
1	0xEB
2	0x80
3	0x00
4	0xAA
5-8	Longitude	The unit is °, int type.  The floating-point number before sending should be multiplied by 1e6 and sent as int type to avoid loss of precision.
9-12	Latitude	The unit is °, int type.  The floating-point number before sending should be multiplied by 1e6 and sent as int type to avoid loss of precision.
13-16	Altitude	The unit is meter, int type.
17	0xAA
18	0xBB
19	0xCC
20	0xDD
21	5~20 XOR check

Data Definition Based on Byte 4:

1. If control_flag == 0xCC: Restart operation.
2. If control_flag == 0xAA: Send longitude, latitude, and altitude.

Transmission Order:

Bytes 5-8: Latitude (Latitude * 1e6, unit: degrees °)

Bytes 9-12: Longitude (Longitude * 1e6, unit: degrees °)

Bytes 13-16: Altitude (Altitude * 1, unit: meters m)

For example, the C code for sending the latitude and longitude instructions (with the remaining bytes configured arbitrarily), Latitude is "latitude * 1e6", and the longitude is similar. The height ratio is 1.

bytSend[0] = 0xeb;

bytSend[1] = 0x80;

bytSend[2] = 0x00;

bytSend[3] = 0xaa;

bytSend[4] = (Latitude>>24) & 0xff;

bytSend[5] = (Latitude>>16) & 0xff;

bytSend[6] = (Latitude>>8) & 0xff;

bytSend[7] = (Latitude) & 0xff;

bytSend[8] = (Longitude>>24) & 0xff;

bytSend[9] = (Longitude>>16) & 0xff;

bytSend[10] = (Longitude>>8) & 0xff;

bytSend[11] = (Longitude) & 0xff;

bytSend[12] = (Height>>24) & 0xff;

bytSend[13] = (Height>>16) & 0xff;

bytSend[14] = (Height>>8) & 0xff;

bytSend[15] = (Height) & 0xff;

bytSend[16] = 0xaa;

bytSend[17] = 0xbb;

bytSend[18] = 0xcc;

bytSend[19] = 0xdd;

bytSend[20] = b[4]^b[5]^...b[19];

 Maintenance and Usage

If no serial port data output is observed during the gyro north seeker, one should check whether the connections are correct, whether the serial port settings and data reception format are correct. If the checks are all correct, professional personnel should be sought for repair.

Notes:

1. During transportation and installation of the gyronorthseeker, it should be handled with care and no impact should be applied.
2. During the north seekingprocess, the carrier should remain absolutely stationary; otherwise, the north seeking accuracy will be affected.

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Application Techniques

1.Applicable to coal mines, tunnels, and exploration! North seeker's strength revealed

2.How important is the North Seeker in the field of oil、mining and drilling?

3.OEM customization, easy integration! The North Seeker helps operations in multiple fields to be more accurate and efficient!

4.Efficient mining, north seeker assists mining drilling operations

5.Accurate orientation, easy to deal with! North seeker helps work more efficiently

6.Not restricted by the environment, MEMS north finders help various fields achieve high-precision orientation

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