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89855926ef
* sensors: move GPS antenna offsets to per-receiver parameters
Move antenna position configuration from the single EKF2_GPS_POS_X/Y/Z
parameter set into per-receiver SENS_GPS{0,1}_OFF{X,Y,Z} parameters in
the sensors module. Each offset slot is matched to a physical receiver
by device ID (SENS_GPS{0,1}_ID), falling back to uORB instance index
when no IDs are configured.
The antenna offset is now carried through the SensorGps uORB message
and blended alongside other GPS states when multi-receiver blending is
active, so EKF2 receives the correct lever arm for whichever receiver
(or weighted combination) is selected.
- Add antenna_offset_{x,y,z} fields to SensorGps.msg
- Remove EKF2_GPS_POS_X/Y/Z params; EKF2 reads offset from gnssSample
- Add SENS_GPS{0,1}_ID and SENS_GPS{0,1}_OFF{X,Y,Z} params (module.yaml)
- Blend antenna offsets in GpsBlending (weighted average)
- Add unit tests for single, blended, and failover antenna offset cases
- Migrate params.c to module.yaml for the vehicle_gps_position module
* sensors: gps_blending: add asymmetric weight and fallthrough offset tests
Add two additional antenna offset test cases:
- dualReceiverAsymmetricWeightAntennaOffset: verify that unequal eph
values produce correctly skewed blend weights (0.8/0.2) and that the
output antenna offset reflects the weighted average
- blendingFallthroughAntennaOffset: verify that when blending is enabled
but can_do_blending evaluates false (eph=0), the non-blending path
correctly assigns the selected receiver's antenna offset
* feat(param_translation): translate EKF2_GPS_POS_ to SENS_GPS0_OFF_
* fix(msgs): proper formatting
* chore(msg): 0 if invalid/unknown
* fix(ROMFS): migrate EKF2_GPS_POS_ params
* fix(docs): migrate EKF2_GPS_POS_ params
* fix(blending): unsigned param
* Update msg/SensorGps.msg
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
* fix(sensors/gps): remove 'values:' tag in module.yaml
* fix(sensors/gps): unsigned instance index
* fix(blending): restore const on gps_blend_states()
Move antenna offset blending into blend_gps_data() where the
weights are computed, keeping gps_blend_states() const.
* fix(sensors/gps): fix msg annotation and restore SENS_GPS_PRIME values
Remove incorrect @invalid NaN annotation from antenna offset fields
(0.0 default is correct, not a sentinel). Restore values tag for
SENS_GPS_PRIME so QGC shows a dropdown.
* fix(gps_blending): fix pre-existing bug to clear _gps_updated flags
The loop iterates over i but always clears gps_select_index. The intent is to clear
all updated flags, but only the selected one gets cleared (N times)
* test(gps_blending): add stale update flag regression test
98 lines
8.1 KiB
Markdown
98 lines
8.1 KiB
Markdown
# Holybro DroneCAN M8N GPS
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The Holybro DroneCAN GPS has an UBLOX M8N module, BMM150 compass, tri-colored LED indicator.
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The GPS module uses the [DroneCAN](index.md) protocol for communication.
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DroneCAN connections are more resistant to electromagnetic interference compared to serial connection, making it more reliable.
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In addition, using DroneCAN means that the GPS and compass do not occupy any flight controller serial ports (different/additional CAN devices can be connected to the same CAN bus via a CAN splitter board).
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<img src="../../assets/hardware/gps/hb_dronecan_m8n/hb_dronecan_m8n_gps.jpg" width="400px" title="Hero diagram for the GPS module" />
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## Where to Buy
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Order this module from:
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- [Holybro](https://holybro.com/products/dronecan-m8n-gps)
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## Hardware Specifications
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| | DroneCAN M8N |
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| ------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------- |
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| GNSS Receiver | Ublox NEO M8N |
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| Number of Concurrent GNSS | 2 (Default GPS + GLONASS) |
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| Processor | STM32G4 (170MHz, 512K FLASH) |
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| Compass | BMM150 |
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| Frequency Band | <p>GPS: L1C/A<br>GLONASS: L10F<br>Beidou: B1I<br>Galileo: E1B/C</p> |
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| GNSS Augmentation System | SBAS: WAAS, EGNOS, MSAS, QZSS |
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| Navigation Update | 5Hz Default(10Hz MAX) |
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| Navigation sensitivity | –167 dBm |
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| Cold starts | \~ 26s |
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| Accuracy | 2.5m |
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| Speed Accuracy | 0.05 m/s |
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| Max # of Satellites | 22+ |
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| Default CAN BUS data rate | 1MHz |
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| Communication Protocol | DroneCAN @ 1 Mbit/s |
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| Supports Autopilot FW | PX4, Ardupilot |
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| Port Type | GHR-04V-S |
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| Antenna | 25 x 25 x 4 mm ceramic patch antenna |
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| Voltage | 4.7-5.2V |
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| Power consumption | Less than 200mA @ 5V |
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| Temperature | -40\~80C |
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| Size | <p>Diameter: 54mm<br>Thickness: 14.5mm</p> |
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| Weight | 36g |
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| Cable Length | 26cm |
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| Other | <ul><li>LNA MAX2659ELT+ RF Amplifier</li><li>Rechargeable Farah capacitance</li><li>Low noise 3.3V regulator</li><li>26cm cable included</li></ul> |
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## Hardware Setup
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### Mounting
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The recommended mounting orientation is with the arrow on the GPS pointing towards the **front of vehicle**.
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The sensor can be mounted anywhere on the frame, but you will need to specify its position, relative to vehicle centre of gravity, during [PX4 configuration](#px4-configuration).
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### Wiring
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The Holybro DroneCAN GPS is connected to the CAN bus using a Pixhawk standard 4 pin JST GH cable.
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For more information, refer to the [CAN Wiring](../can/index.md#wiring) instructions.
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### Pinout
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### Dimensions
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## PX4 Configuration
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You need to set necessary [DroneCAN](index.md) parameters and define offsets if the sensor is not centred within the vehicle.
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The required settings are outlined below.
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::: info
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The GPS will not boot if there is no SD card in the flight controller when powered on.
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:::
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### Enable DroneCAN
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In order to use the ARK GPS board, connect it to the Pixhawk CAN bus and enable the DroneCAN driver by setting parameter [UAVCAN_ENABLE](../advanced_config/parameter_reference.md#UAVCAN_ENABLE) to `2` for dynamic node allocation (or `3` if using [DroneCAN ESCs](../dronecan/escs.md)).
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The steps are:
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- In _QGroundControl_ set the parameter [UAVCAN_ENABLE](../advanced_config/parameter_reference.md#UAVCAN_ENABLE) to `2` or `3` and reboot (see [Finding/Updating Parameters](../advanced_config/parameters.md)).
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- Connect GPS CAN to the Pixhawk CAN.
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Once enabled, the module will be detected on boot.
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GPS data should arrive at 5Hz.
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DroneCAN configuration in PX4 is explained in more detail in [DroneCAN > Enabling DroneCAN](../dronecan/index.md#enabling-dronecan).
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### Sensor Position Configuration
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If the sensor is not centred within the vehicle you will also need to define sensor offsets:
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- Enable GPS yaw fusion by setting bit 3 of [EKF2_GPS_CTRL](../advanced_config/parameter_reference.md#EKF2_GPS_CTRL) to true.
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- Enable [UAVCAN_SUB_GPS](../advanced_config/parameter_reference.md#UAVCAN_SUB_GPS), [UAVCAN_SUB_MAG](../advanced_config/parameter_reference.md#UAVCAN_SUB_MAG), and [UAVCAN_SUB_BARO](../advanced_config/parameter_reference.md#UAVCAN_SUB_BARO).
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- Set [CANNODE_TERM](../advanced_config/parameter_reference.md#CANNODE_TERM) to `1` if this is that last node on the CAN bus.
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- The parameters [SENS_GPS0_OFFX](../advanced_config/parameter_reference.md#SENS_GPS0_OFFX), [SENS_GPS0_OFFY](../advanced_config/parameter_reference.md#SENS_GPS0_OFFY) and [SENS_GPS0_OFFZ](../advanced_config/parameter_reference.md#SENS_GPS0_OFFZ) can be set to account for the offset of the ARK GPS from the vehicles centre of gravity.
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