Overview
This GNSS module series uses the M9140-KB (9th) chipset and an integrated patch ceramic antenna for positioning output over a serial port. Model options include compact PCB sizes for integration with flight control and other embedded systems, with selected variants adding a built-in electronic compass (QMC5883L is listed for compass versions).
Key Features
- Horizontal accuracy: 1.5 m CEP (listed)
- 92 searching channels (listed)
- Update rate: 0.25 Hz to 25 Hz (default 1 Hz)
- Serial output: TTL level; protocols: NMEA, UBX
- Integrated patch antenna network design: impedance matching (50 ohm); antenna standing wave ratio less than 1.6 (listed)
- Selected models with built-in electronic compass: QMC5883L / QMC5883 (as listed by model)
- Support hot, warm and cold start command settings (listed)
Specifications
BK-122 module main performance indicators (listed)
| Chip | M9140-KB |
| Receiver type | GPS L1 C/A, QZSS L1 C/A/S, GLONASS L1OF, BDS B1I, Galileo E1B/C, SBAS L1 C/A: WAAS, EGNOS, MSAS, GAGAN |
| Default position system | GPS, GLONASS, BDS, GALILEO |
| Augmentation system | SBAS, QZSS |
| Channel | 92 Searching Channel |
| Sensitivity (Tracking & Navigation) | -167 dBm |
| Sensitivity (Reacquisition) | -160 dBm |
| Sensitivity (Cold start) | -148 dBm |
| Sensitivity (Hot Start) | -159 dBm |
| Horizontal position | 1.5 m CEP |
| Velocity | 0.05 m/s |
| Dynamic heading | 0.3 deg |
| Time pulse | RMS 30 ns; 99% 60 ns |
| Acquisition (Cold start) | 24 s |
| Acquisition (Hot start) | 2 s |
| Acquisition (Aided start) | 2 s |
| Baud rate | 4800 bps - 921600 bps, Default 115200 bps |
| Level | TTL Level |
| Protocol | NMEA, UBX |
| NMEA messages | RMC, VTG, GGA, GSA, GSV, GLL |
| Update rate | 0.25 Hz - 25 Hz, Default 1 Hz |
| FLASH | With FLASH, the configuration can be changed, and the power will not be lost |
| Work restrictions | High 80,000 m; Speed 500 m/s; Gravitational acceleration <= 4 g |
| Power (Voltage) | DC Voltage 3.6 V - 5.5 V, Typical: 5.0 V |
| Power (Current) | 45 mA / 5.0 V |
| Physical parameters (Size) | 16.5 * 12.3 * 6.0 mm |
| Physical parameters (Weight) | 3 g |
| Package | Welding |
| Temperature (Operating) | -40 C to +85 C |
| Temperature (Storage) | -40 C to +105 C |
| LED | PPS LED: Not positioned, the light is off; after 3D positioning, the blue light flashes |
Model comparison (listed)
| Model | Chip | Channel | Sensitivity | Horizontal | Speed accuracy | Acquisition | Baud rate (bps) | Output level | Output protocol | Update rate | Work restrictions | Voltage | Current | Size | Weight | Connector | Compass |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| BK-122 | M9140-KB | 92 Searching Channel | Cold start -148 dBm; Hot Start -159 dBm | 1.5 m CEP | 0.05 m/s | Cold boot 24 s; Warm boot 2 s | 4800 bps - 921600 bps, Default 115200 bps | TTL level | NMEA, UBX | 0.25 Hz - 25 Hz, Default 1 Hz | High 80,000 m; Speed 500 m/s; Gravitational acceleration <= 4 g | DC 3.6 V - 5.5 V, typical: 5.0 V | 45 mA / 5.0 V | 16.3 * 12.4 * 6.0 mm | 3 g | 1.00 pitch 4pin socket | Not |
| BK-180 | M9140-KB | 92 Searching Channel | Cold start -148 dBm; Hot Start -159 dBm | 1.5 m CEP | 0.05 m/s | Cold boot 24 s; Warm boot 2 s | 4800 bps - 921600 bps, Default 115200 bps | TTL level | NMEA, UBX | 0.25 Hz - 25 Hz, Default 1 Hz | High 80,000 m; Speed 500 m/s; Gravitational acceleration <= 4 g | DC 3.6 V - 5.5 V, typical: 5.0 V | 45 mA / 5.0 V | 18 * 18 * 6.0 mm | 5 g | 1.00 pitch 4pin socket | Not |
| BK-182 | M9140-KB | 92 Searching Channel | Cold start -148 dBm; Hot Start -159 dBm | 1.5 m CEP | 0.05 m/s | Cold boot 24 s; Warm boot 2 s | 4800 bps - 921600 bps, Default 115200 bps | TTL level | NMEA, UBX | 0.25 Hz - 25 Hz, Default 1 Hz | High 80,000 m; Speed 500 m/s; Gravitational acceleration <= 4 g | DC 3.6 V - 5.5 V, typical: 5.0 V | 45 mA / 5.0 V | 18 * 18 * 8.1 mm | 5.8 g | 1.00 pitch 4pin socket | Not |
| BK-220 | M9140-KB | 92 Searching Channel | Cold start -148 dBm; Hot Start -159 dBm | 1.5 m CEP | 0.05 m/s | Cold boot 24 s; Warm boot 2 s | 4800 bps - 921600 bps, Default 115200 bps | TTL level | NMEA, UBX | 0.25 Hz - 25 Hz, Default 1 Hz | High 80,000 m; Speed 500 m/s; Gravitational acceleration <= 4 g | DC 3.6 V - 5.5 V, typical: 5.0 V | 45 mA / 5.0 V | 22 * 20 * 6.2 mm | 5.3 g | 1.00 pitch 4pin socket | Not |
| BK-220Q | M9140-KB | 92 Searching Channel | Cold start -148 dBm; Hot Start -159 dBm | 1.5 m CEP | 0.05 m/s | Cold boot 24 s; Warm boot 2 s | 4800 bps - 921600 bps, Default 115200 bps | TTL level | NMEA, UBX | 0.25 Hz - 25 Hz, Default 1 Hz | High 80,000 m; Speed 500 m/s; Gravitational acceleration <= 4 g | DC 3.6 V - 5.5 V, typical: 5.0 V | 45 mA / 5.0 V | 22 * 20 * 6.2 mm | 5.5 g | 1.00 pitch 6pin socket | Built-in QMC5883L |
| BK-250 | M9140-KB | 92 Searching Channel | Cold start -148 dBm; Hot Start -159 dBm | 1.5 m CEP | 0.05 m/s | Cold boot 24 s; Warm boot 2 s | 4800 bps - 921600 bps, Default 115200 bps | TTL level | NMEA, UBX | 0.25 Hz - 25 Hz, Default 1 Hz | High 80,000 m; Speed 500 m/s; Gravitational acceleration <= 4 g | DC 3.6 V - 5.5 V, typical: 5.0 V | 45 mA / 5.0 V | 25 * 25 * 6 mm | 8 g | 1.00 pitch 4pin socket | Not |
| BK-250Q | M9140-KB | 92 Searching Channel | Cold start -148 dBm; Hot Start -159 dBm | 1.5 m CEP | 0.05 m/s | Cold boot 24 s; Warm boot 2 s | 4800 bps - 921600 bps, Default 115200 bps | TTL level | NMEA, UBX | 0.25 Hz - 25 Hz, Default 1 Hz | High 80,000 m; Speed 500 m/s; Gravitational acceleration <= 4 g | DC 3.6 V - 5.5 V, typical: 5.0 V | 45 mA / 5.0 V | 25 * 25 * 6 mm | 9 g | 1.00 pitch 4pin socket | Built-in QMC5883L |
| BK-252Q | M9140-KB | 92 Searching Channel | Cold start -148 dBm; Hot Start -159 dBm | 1.5 m CEP | 0.05 m/s | Cold boot 24 s; Warm boot 2 s | 4800 bps - 921600 bps, Default 115200 bps | TTL level | NMEA, UBX | 0.25 Hz - 25 Hz, Default 1 Hz | High 80,000 m; Speed 500 m/s; Gravitational acceleration <= 4 g | DC 3.6 V - 5.5 V, typical: 5.0 V | 45 mA / 5.0 V | 25 * 25 * 8 mm | 13.5 g | 1.00 pitch 6pin socket | Built-in QMC5883L |
| BK-280 | M9140-KB | 92 Searching Channel | Cold start -148 dBm; Hot Start -159 dBm | 1.5 m CEP | 0.05 m/s | Cold boot 24 s; Warm boot 2 s | 4800 bps - 921600 bps, Default 115200 bps | TTL level | NMEA, UBX | 0.25 Hz - 25 Hz, Default 1 Hz | High 80,000 m; Speed 500 m/s; Gravitational acceleration <= 4 g | DC 3.6 V - 5.5 V, typical: 5.0 V | 45 mA / 5.0 V | 28 * 28 * 8.4 mm | 11.8 g | 1.25 pitch 6pin socket | Not |
| BK-280U | M9140-KB | 92 Searching Channel | Cold start -148 dBm; Hot Start -159 dBm | 1.5 m CEP | 0.05 m/s | Cold boot 24 s; Warm boot 2 s | 4800 bps - 921600 bps, Default 115200 bps | PL2303HX/TA chip TTL to USB driver, USB level | NMEA, UBX | 0.25 Hz - 25 Hz, Default 1 Hz | High 80,000 m; Speed 500 m/s; Gravitational acceleration <= 4 g | DC 3.6 V - 5.5 V, typical: 5.0 V | 45 mA / 5.0 V | 28 * 28 * 8.4 mm | 11.8 g | 1.25 pitch 6pin socket | Not |
| BK-357 | M9140-KB | 92 Searching Channel | Cold start -148 dBm; Hot Start -159 dBm | 1.5 m CEP | 0.05 m/s | Cold boot 24 s; Warm boot 2 s | 4800 bps - 921600 bps, Default 115200 bps | TTL level | NMEA, UBX | 0.25 Hz - 25 Hz, Default 1 Hz | High 80,000 m; Speed 500 m/s; Gravitational acceleration <= 4 g | DC 3.6 V - 5.5 V, typical: 5.0 V | 45 mA / 5.0 V | 35 * 27 * 8.5 mm | 13.9 g | 1.25 pitch 6pin socket | Not |
| BK-880 | M9140-KB | 92 Searching Channel | Cold start -148 dBm; Hot Start -159 dBm | 1.5 m CEP | 0.05 m/s | Cold boot 24 s; Warm boot 2 s | 4800 bps - 921600 bps, Default 115200 bps | TTL level | NMEA, UBX | 0.25 Hz - 25 Hz, Default 1 Hz | High 80,000 m; Speed 500 m/s; Gravitational acceleration <= 4 g | DC 3.6 V - 5.5 V, typical: 5.0 V | 45 mA / 5.0 V | 28 * 28 * 11 mm | 12 g | 1.25 pitch 6pin socket | Built-in QMC5883 |
| BK-880Q | M9140-KB | 92 Searching Channel | Cold start -148 dBm; Hot Start -159 dBm | 1.5 m CEP | 0.05 m/s | Cold boot 24 s; Warm boot 2 s | 4800 bps - 921600 bps, Default 115200 bps | TTL level | NMEA, UBX | 0.25 Hz - 25 Hz, Default 1 Hz | High 80,000 m; Speed 500 m/s; Gravitational acceleration <= 4 g | DC 3.6 V - 5.5 V, typical: 5.0 V | 45 mA / 5.0 V | 28 * 28 * 8.5 mm | 12 g | 1.25 pitch 6pin socket | Built-in QMC5883 |
NMEA-0183 data content (listed)
| Get Parameters | Get Content |
|---|---|
| GGA | Time, position, number of satellites |
| GLL | Longitude, latitude, UTC time |
| GSA | GPS receiver operation mode, satellite used for positioning, DOP value, positioning status |
| GSV | Visible GPS satellite information, elevation angle, azimuth angle, signal-to-noise ratio |
| RMC | Time, date, position, speed |
| VTG | Ground speed information |
Test data (9th vs 10th generation tables shown)
| Test | Item | 9th | 10th |
|---|---|---|---|
| Capture sensitivity test | Track | -167 dBm | -166 dBm |
| Capture sensitivity test | Recapture | -160 dBm | -160 dBm |
| Capture sensitivity test | Cold start | -148 dBm | -148 dBm |
| Capture sensitivity test | Hot Start | -159 dBm | -160 dBm |
| Positioning accuracy test | Horizontal Accuracy | 1.5 m CEP | 2.0 m CEP |
| Positioning accuracy test | Speed Accuracy | 0.05 m/s | 0.05 m/s |
| Positioning accuracy test | Dynamic Heading Accuracy | 0.3 deg | 0.3 deg |
| Positioning accuracy test | 1PPS Time Precision | RMS 30 ns; 99% 60 ns | RMS 30 ns; 99% 60 ns |
| Startup time test | Cold start | 24 s | 27 s |
| Startup time test | Hot Start | 2 s | 1 s |
| Startup time test | Auxiliary start | 2 s | 2 s |
| Power consumption test | Voltage | DC 3.6 V - 5.5 V, typical: 5.0 V | DC 3.6 V - 5.5 V, typical: 5.0 V |
| Power consumption test | Current | 45 mA / 5.0 V | 30 mA / 5.0 V |
Pin Definition (BK-122, 4pin)
| PIN | Name | I/O | Description |
|---|---|---|---|
| 1 | RX | I | Serial Data Input. |
| 2 | TX | O | Serial Data Output. |
| 3 | VCC | I | DC 3.6 V - 5.5 V supply input, Typical: 5.0 V |
| 4 | GND | G | Ground |
Wiring & Debugging (listed diagrams)
- USB to TTL cable wiring: GND to GND, TX to RX, RX to TX, VCC to VCC.
- Microcontroller wiring diagram labels: 1PPS, GND, TX, RX, VCC, BOOT (module) and IO, GND, TX, RX, VCC (single chip microcomputer).
- Debugging: Connect to the computer using a USB to TTL adapter for configuration; PL-2303HX/TA chip USB to TTL level conversion cable is specified.
Mechanical Dimensions (module size diagram shown)
- Overall: 16.50 ± 0.2 mm x 12.30 ± 0.2 mm
- Additional marked dimensions: 12.00 mm; 6.1 ± 0.2 mm; 0.80 mm; 3.00 mm; 2.00 mm; 6.0 mm; 0.50 max; 11.80 mm; 10.45 mm; 2.60 mm; 2.20 mm
What's Included
- GNSS module (model selected)
- Some kits show a connector cable/harness included (model dependent)
- BE-122 kit image: connector + module + thermal casing
- BE-182 / BE-252Q kit images: connector + module + one piece of 3M glue
Applications
- Flight control integration and embedded positioning output via serial port
- Shared bike
- Electric vehicle
- Scientific research
Support & Documentation
- Support Customization: It can be adjusted according to the product to meet requirements.
- Support Customization: Various modules can be customized according to the sample.
- Support Customization: Various modules can be customized according to the concept.
- Complete Product Documentation: Provide rich development materials to help users use and secondary development.
For model selection help, wiring questions, or documentation access, contact support via https://rcdrone.top/ or email support@rcdrone.top.
Available Model Options (Shopify variants)
BK-122; BK-180; BK-182; BK-220; BK-250; BK-280; BK-357; BK-280U; BK-180i; BK-252i; BK-220i; BK-250i; BK-882; BK-882i.
Details

Optional customization and downloadable documentation are available for integration and development needs.

Choose the module size and feature set that fits your flight controller build, with multiple BK-series options listed.

The M9140-KB platform targets fast satellite acquisition and stable positioning output for RC flight control projects.

Compass variants add heading support for navigation, alongside strong multi-constellation satellite tracking.


Lab-style test summaries list tracking sensitivity and horizontal accuracy figures for the M9140 generation.

Compact PCB footprints help match the right module size to your stack while keeping power draw low.

Pin definitions make wiring simple for TTL serial GNSS output and power on embedded controllers.

Clear wiring diagrams cover basic TX/RX hookups for USB‑TTL configuration and direct MCU connections.

Configuration can be done over a USB‑to‑TTL adapter when connecting the module to a PC.


Accessory bundles can include wiring leads and mounting materials, depending on the selected model.
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