System Design Description (SyDD) — ISO/IEC/IEEE 15289 — Description | IEEE 29148 §6.5
Generated 2026-03-27 — UHT Journal / universalhex.org
flowchart TB n0["system<br>Precision Agriculture Drone Fleet"] n1["subsystem<br>Navigation and Flight Control"] n2["subsystem<br>Imaging and Remote Sensing"] n3["subsystem<br>Spray Application"] n4["subsystem<br>Communication and Datalink"] n5["subsystem<br>Ground Control Station"] n6["subsystem<br>Power and Battery Management"] n7["subsystem<br>Data Processing and Analytics"] n8["subsystem<br>Airframe and Propulsion"] n1 -->|Position, ground speed| n3 n1 -->|Trigger signal, geotag| n2 n4 -->|Telemetry, status| n5 n5 -->|Commands, waypoints| n4 n6 -->|Regulated power, SOC| n1 n6 -->|Pump power| n3 n2 -->|Raw imagery| n7 n7 -->|Processed maps, analytics| n5
Precision Agriculture Drone Fleet — Decomposition
| Ref | Requirement | V&V | Tags |
|---|---|---|---|
| SUB-REQS-001 | The Flight Controller Processor SHALL compute a fused navigation solution via extended Kalman filter at 50Hz minimum, combining GNSS PVT, IMU angular rates and accelerations, barometric altitude, radar altimeter AGL, and magnetometer heading, achieving horizontal position accuracy of 10cm CEP95 when RTK corrections are available and 1.5m CEP95 in standalone GNSS mode. Rationale: 50 Hz EKF rate provides 20 ms navigation updates, adequate for 400 Hz attitude control inner loop which interpolates between fixes. 10 cm CEP95 with RTK derives from SYS-REQS-002 spray track accuracy. 1.5 m standalone accuracy provides safe RTH capability when RTK corrections are unavailable. | Test | subsystem, nav-flight-control, session-217 |
| SUB-REQS-002 | The Flight Controller Processor SHALL execute inner-loop attitude control at 400Hz with attitude tracking error not exceeding 2 degrees RMS in roll and pitch during straight-line spray passes in winds up to 15 knots sustained with 20-knot gusts. Rationale: 400 Hz matches DShot600 ESC command rate for synchronous motor control. 2 degree RMS tracking error at 15 kt wind keeps spray pattern centre within plus or minus 5 percent of design application rate. Higher tracking error causes swath misalignment and uneven chemical distribution. | Test | subsystem, nav-flight-control, session-217 |
| SUB-REQS-003 | When the computed navigation position approaches within 5 metres of a geofence boundary, the Flight Controller Processor SHALL initiate a deceleration manoeuvre such that the UAV does not exceed the boundary by more than 3 metres at ground speeds up to 8 m/s. Rationale: 5 m warning threshold provides 0.6 seconds to decelerate from 8 m/s, matching the multi-rotor deceleration capability with 25 kg mass. 3 m maximum overshoot traces directly to SYS-REQS-005 geofence requirement. | Test | subsystem, nav-flight-control, session-217 |
| SUB-REQS-004 | When command-and-control datalink is lost for more than 5 seconds, the Flight Controller Processor SHALL transition to the pre-programmed failsafe sequence (loiter for 30 seconds, then return-to-home at 15m AGL and land) within 500ms of failsafe trigger, while maintaining obstacle avoidance. Rationale: Direct derivation from SYS-REQS-011 C2 loss failsafe. 500 ms transition time to failsafe mode ensures the UAV travels no more than 4 m before entering safe state. Loiter-then-RTH at 15 m AGL provides terrain clearance during autonomous return. | Demonstration | subsystem, nav-flight-control, session-217 |
| SUB-REQS-005 | While multiple UAVs are airborne, the Flight Controller Processor SHALL maintain a minimum separation distance of 20 metres from all other fleet members by exchanging position reports at 5Hz via the fleet mesh network and commanding avoidance manoeuvres when separation decreases below 30 metres. Rationale: Direct derivation from SYS-REQS-012 fleet separation. 5 Hz position broadcast provides 200 ms position freshness, adequate for maintaining 20 m separation at typical closing rates below 10 m/s. 30 m alert threshold gives 2 seconds of manoeuvre time. | Test | subsystem, nav-flight-control, session-217 |
| SUB-REQS-006 | When the Forward-Looking Obstacle Detection Sensor reports an obstacle within 15 metres of the flight path, the Flight Controller Processor SHALL execute an avoidance manoeuvre (climb, lateral offset, or hover-and-alert) within 500ms of detection, clearing the obstacle by at least 5 metres. Rationale: 15 m detection range at 8 m/s gives 1.9 seconds total reaction window. 500 ms response time is achievable with the flight controller compute budget. 5 m clearance margin accounts for obstacle geometry uncertainty and position error. | Demonstration | subsystem, nav-flight-control, safety, session-217 |
| SUB-REQS-007 | The Multi-Constellation GNSS Receiver SHALL provide position integrity monitoring with a protection level computation, and the Flight Controller Processor SHALL reject GNSS fixes where the horizontal protection level exceeds 2 metres, falling back to IMU dead-reckoning for up to 10 seconds before triggering return-to-home. Rationale: GNSS integrity monitoring with 2 m horizontal protection level ensures the navigation solution supports the 3 m geofence overshoot requirement with margin. 10-second dead-reckoning window bridges typical short-duration GNSS outages from terrain masking in hilly agricultural terrain. | Test | subsystem, nav-flight-control, safety, session-217 |
| SUB-REQS-008 | While executing spray passes, the Flight Controller Processor SHALL maintain AGL height within plus or minus 0.3 metres of the commanded spray altitude by fusing radar altimeter measurements with barometric altitude, compensating for terrain slope up to 15 degrees. Rationale: Spray nozzle pattern and droplet spectrum are designed for a specific AGL height. Plus or minus 0.3 m deviation keeps application rate within the plus or minus 5 percent tolerance (SYS-REQS-004). 15-degree terrain slope compensation covers typical agricultural terrain gradients. | Test | subsystem, nav-flight-control, session-217 |
| SUB-REQS-009 | The Flight Controller Processor SHALL detect sensor faults (stuck value, out-of-range, excessive noise) on all navigation sensors within 500ms and reconfigure the navigation filter to exclude the faulty sensor, providing degraded-but-safe navigation with at least 2m horizontal accuracy for return-to-home. Rationale: 500 ms fault detection limits navigation drift during sensor failure to under 0.5 m at typical flight speed. 2 m degraded accuracy is sufficient for safe return-to-home without violating geofence boundaries (3 m margin). Filter reconfiguration preserves navigation continuity without full system reset. | Test | subsystem, nav-flight-control, safety, session-217 |
| SUB-REQS-010 | While executing spray flight paths, the Flight Controller Processor SHALL generate lateral guidance commands to maintain cross-track error of 0.5 metres or less at ground speeds between 3 and 8 m/s, using L1 or equivalent path-following guidance law. Rationale: 0.5 m cross-track error traces to SYS-REQS-016. L1 guidance law provides predictable tracking performance with well-characterised tuning parameters for multi-rotor UAS. Speed range of 3 to 8 m/s extends the system requirement to cover repositioning between spray passes. | Test | subsystem, nav-flight-control, session-217 |
| SUB-REQS-011 | The Multispectral Camera SHALL capture 5-band narrowband imagery (Blue 475nm±10nm, Green 560nm±10nm, Red 668nm±5nm, Red Edge 717nm±5nm, NIR 842nm±10nm) with a minimum resolution of 3.2 megapixels per band and global shutter synchronization across all bands within 1 microsecond. Rationale: Band selection covers NDVI (Red/NIR), NDRE (Red Edge/NIR), and chlorophyll content index (Green/Red Edge), the standard spectral indices for crop health assessment. 3.2 MP per band provides 3 cm GSD at 50 m AGL with typical 8.8 mm focal length. 1 microsecond inter-band sync eliminates registration error at 12 m/s. | Test | subsystem, imaging, session-218 |
| SUB-REQS-012 | The Thermal Infrared Camera SHALL measure crop canopy temperature with absolute accuracy of plus or minus 2 degrees Celsius and noise-equivalent temperature difference (NETD) of 0.05 degrees Celsius or better at 30 degrees Celsius scene temperature, across the 8 to 14 micrometre LWIR band. Rationale: Plus or minus 2 degrees Celsius absolute accuracy is sufficient for crop water stress index (CWSI) computation where the stressed-unstressed canopy temperature differential is typically 3 to 8 degrees Celsius. 0.05 degrees Celsius NETD detects early-stage irrigation deficits before visible stress symptoms. | Test | subsystem, imaging, session-218 |
| SUB-REQS-013 | The Image Capture Triggering Controller SHALL synchronise trigger pulses to all cameras with inter-camera timing skew of less than 500 microseconds, and SHALL compute trigger intervals from real-time aircraft ground speed to maintain 75 percent forward overlap and 65 percent side overlap at the planned ground sample distance. Rationale: 500 microsecond timing skew at 12 m/s maximum ground speed causes less than 6 mm spatial offset between bands, negligible at 3 cm GSD. 75 percent forward and 65 percent side overlap ensures sufficient tie points for photogrammetric bundle adjustment and orthomosaic generation. | Test | subsystem, imaging, session-218 |
| SUB-REQS-014 | The Camera Gimbal and Stabilization Mount SHALL maintain nadir pointing within plus or minus 0.5 degrees in pitch and roll during survey flight at ground speeds up to 12 metres per second and in wind gusts up to 25 knots, with a stabilization bandwidth of at least 50 Hz to reject airframe vibration from propulsion at 50 to 100 Hz. Rationale: 0.5-degree nadir pointing error causes less than 0.5 percent GSD degradation at 50 m AGL, acceptable for vegetation index accuracy. 50 Hz stabilization bandwidth is required to actively reject propulsion vibration in the 50 to 100 Hz frequency band transmitted through the airframe. | Test | subsystem, imaging, session-218 |
| SUB-REQS-015 | The Onboard Image Storage Module SHALL sustain a continuous write throughput of at least 125 megabytes per second to accommodate simultaneous data streams from multispectral (80 MB/s), thermal (20 MB/s), and RGB (25 MB/s) cameras without frame drops over a full 30-minute flight. Rationale: 125 MB/s is the sum of sustained data rates from all three camera systems: multispectral at 80 MB/s, thermal at 20 MB/s, and RGB at 25 MB/s. Insufficient write throughput causes frame drops, creating gaps in survey coverage that require re-flight. | Test | subsystem, imaging, session-218 |
| SUB-REQS-016 | The Downwelling Light Sensor SHALL measure incoming solar spectral irradiance in the same five bands as the Multispectral Camera with cosine-corrected response within 5 percent of ideal cosine for incidence angles up to 75 degrees, and SHALL timestamp each measurement to within 10 milliseconds of the corresponding multispectral image capture. Rationale: 5 percent cosine correction accuracy is required for radiometric calibration at oblique sun angles up to 75 degrees, which occur during early morning and late afternoon survey windows. 10 ms synchronization matches the multispectral exposure window, ensuring irradiance and reflectance are temporally co-registered. | Test | subsystem, imaging, session-218 |
| SUB-REQS-017 | The High-Resolution RGB Camera SHALL capture images at 20 megapixels or greater with a mechanical global shutter, achieving a ground sample distance of 2.5 centimetres per pixel or finer at 120 metres AGL, with geometric distortion less than 0.5 percent at the image edge after lens calibration. Rationale: 20 MP resolution at 120 m AGL provides 2.5 cm GSD for high-altitude RGB mapping used for field boundary delineation and stand counts. Mechanical global shutter eliminates rolling shutter distortion during flight. 0.5 percent edge distortion ensures photogrammetric orthomosaic geometric accuracy. | Test | subsystem, imaging, session-218 |
| SUB-REQS-018 | The Onboard Image Storage Module SHALL embed EXIF-compatible geolocation metadata in each stored image, including WGS84 latitude, longitude, ellipsoidal altitude, aircraft roll, pitch, yaw, and capture timestamp with resolution of 1 millisecond or better, sourced from the Flight Controller navigation solution. Rationale: EXIF-compatible geolocation metadata enables direct georeferencing in standard photogrammetry software without ground control points, reducing post-processing time. 1 ms timestamp resolution prevents greater than 1 cm position error at 12 m/s maximum flight speed. | Inspection | subsystem, imaging, session-218 |
| SUB-REQS-019 | While operating in ambient temperatures from 0 to 45 degrees Celsius, the Multispectral Camera and Thermal Infrared Camera SHALL maintain their specified accuracy without recalibration, with the Thermal Infrared Camera performing automatic non-uniformity correction at intervals not exceeding 60 seconds. Rationale: Operating temperature range traces to SYS-REQS-014 system environmental requirement. 60-second NUC interval is standard for uncooled microbolometer thermal cameras to maintain NETD specification across varying scene and ambient temperatures. | Test | subsystem, imaging, session-218 |
| SUB-REQS-020 | The Battery Pack Assembly SHALL provide a minimum usable energy capacity of 600 Wh at 25 degrees Celsius, measured from full charge (50.4V) to under-voltage cutoff (33.6V) at a continuous 80A discharge rate. | Test | subsystem, power-battery, session-221 |
| SUB-REQS-021 | The Battery Management System Controller SHALL report state-of-charge with an accuracy of plus or minus 3 percent of actual capacity across the full operating temperature range of 0 to 45 degrees Celsius. | Test | subsystem, power-battery, session-221 |
| SUB-REQS-022 | When any cell voltage exceeds 4.25V or falls below 2.8V, the Battery Management System Controller SHALL open the main contactor within 50 milliseconds, disconnecting the battery pack from the power distribution bus. | Test | subsystem, power-battery, session-221 |
| SUB-REQS-023 | The Power Distribution Board SHALL sustain 150 amperes continuous current on the main bus and 120 amperes burst for 10 seconds without exceeding a PCB temperature rise of 40 degrees Celsius above ambient. | Test | subsystem, power-battery, session-221 |
| SUB-REQS-024 | The DC-DC Voltage Regulator Module SHALL maintain output voltage within plus or minus 2 percent of nominal on all rails (5V avionics, 12V payload, 5V auxiliary) across the full battery voltage range of 33.6V to 50.4V and load range of 10 to 100 percent rated current. | Test | subsystem, power-battery, session-221 |
| SUB-REQS-025 | The Battery Quick-Release Mechanism SHALL withstand a minimum of 10000 insertion and extraction cycles without degradation of mechanical retention force below 90 percent of initial value or electrical contact resistance exceeding 5 milliohms per contact. | Test | subsystem, power-battery, session-221 |
| SUB-REQS-026 | The Battery Charging and Swap Station SHALL charge a depleted battery pack (20 percent SOC) to 95 percent SOC within 90 minutes while maintaining cell temperature below 45 degrees Celsius throughout the charge cycle. | Test | subsystem, power-battery, session-221 |
| SUB-REQS-027 | When any battery thermistor zone exceeds 60 degrees Celsius, the Battery Management System Controller SHALL reduce maximum discharge current to 50 percent of rated value within 100 milliseconds, and when any zone exceeds 70 degrees Celsius SHALL open the main contactor immediately. | Test | subsystem, power-battery, session-221 |
| SUB-REQS-028 | The Battery Charging and Swap Station SHALL reject any battery pack reporting state-of-health below 80 percent or cell voltage imbalance greater than 50 millivolts, and SHALL flag the rejected pack for maintenance via an audible alert and log entry. | Test | subsystem, power-battery, session-221 |
| SUB-REQS-029 | The Power Distribution Board SHALL protect each low-power branch (gimbal, spray pump, auxiliary) with independently resettable overcurrent protection that trips within 100 milliseconds at 150 percent of rated branch current, preventing a fault on one branch from affecting other branches or the main bus. | Test | subsystem, power-battery, session-221 |
| SUB-REQS-030 | The DC-DC Voltage Regulator Module SHALL limit conducted emissions on the 5V avionics rail to less than 10 millivolts peak-to-peak ripple measured at the flight controller input across the switching frequency range of 100 kHz to 2 MHz. | Test | subsystem, power-battery, session-221 |
| SUB-REQS-031 | The Battery Management System Controller SHALL implement a hardware watchdog timer with a maximum timeout of 500 milliseconds. When the BMS firmware fails to reset the watchdog within this period, the watchdog SHALL open the main contactor and assert a dedicated fault output to the flight controller, triggering an immediate forced landing sequence. | Test | subsystem, power-battery, cross-domain, session-221 |
| Ref | Requirement | V&V | Tags |
|---|---|---|---|
| IFC-DEFS-001 | The interface between the Multi-Constellation GNSS Receiver and the Flight Controller Processor SHALL carry NMEA 0183 GGA and VTG sentences and UBX-NAV-PVT binary messages at 10Hz over UART at 115200 baud, 8N1, with message latency not exceeding 50ms from time-of-fix to availability at the flight controller. Rationale: 10 Hz PVT updates match the navigation EKF prediction rate. 115200 baud provides margin for combined NMEA and UBX message volume per epoch. 50 ms message latency is acceptable for the 50 Hz EKF, which extrapolates between GNSS fixes using IMU data. | Test | interface, nav-flight-control, session-217 |
| IFC-DEFS-002 | The interface between the MEMS Inertial Measurement Unit and the Flight Controller Processor SHALL deliver 6-axis inertial data (3-axis angular rate, 3-axis specific force) at 400Hz over SPI bus at 8MHz clock rate, with data-ready interrupt latency not exceeding 100 microseconds. Rationale: 400 Hz sample rate matches the inner-loop attitude control rate. SPI bus chosen over UART for deterministic low-latency data delivery, critical for control loop jitter. 100 microsecond interrupt latency ensures IMU data is available before each control cycle deadline. | Test | interface, nav-flight-control, session-217 |
| IFC-DEFS-003 | The interface between the Millimetre-Wave Radar Altimeter and the Flight Controller Processor SHALL deliver AGL height measurements at 20Hz over UART at 57600 baud, with measurement range 0.3 to 30 metres and accuracy of 2cm within 0.3 to 10 metre range. Rationale: 20 Hz measurement rate oversamples the 10 Hz spray control loop, enabling median filtering of noisy AGL returns over vegetation. 2 cm accuracy within 10 m directly supports the plus or minus 0.3 m AGL spray height requirement (SUB-REQS-008). | Test | interface, nav-flight-control, session-217 |
| IFC-DEFS-004 | The interface between the Flight Controller Processor and the Airframe ESCs SHALL carry individual motor speed commands via DShot600 protocol at the attitude control loop rate of 400Hz, with command-to-thrust response time not exceeding 50ms for a 0-to-80-percent throttle step. Rationale: DShot600 is a bidirectional digital protocol providing motor RPM telemetry alongside commands. 400 Hz command rate matches the attitude control loop. 50 ms thrust response is characteristic of agricultural-class propulsion with large propellers and high inertia. | Test | interface, nav-flight-control, airframe, session-217 |
| IFC-DEFS-005 | The interface between the Flight Controller Processor and the Spray Application Subsystem SHALL carry spray-enable signal, current ground speed, and current AGL height at 10Hz over CAN bus (250kbps, CAN 2.0B extended frame), with end-to-end message latency not exceeding 20ms. Rationale: CAN bus chosen for robustness in the high-EMI environment near propulsion motors. 10 Hz provides adequate ground speed and AGL updates for nozzle flow rate adjustment. 20 ms end-to-end latency keeps spray actuation within the 200 ms shutoff budget (SYS-REQS-004). | Test | interface, nav-flight-control, spray-application, session-217 |
| IFC-DEFS-006 | The interface between the Flight Controller Processor and the Communication Datalink SHALL carry MAVLink v2 messages bidirectionally at a minimum sustained throughput of 5 kbps uplink (commands, waypoints, RTK corrections) and 10 kbps downlink (telemetry, position, status) over UART at 57600 baud, with heartbeat messages at 1Hz for link health monitoring. Rationale: MAVLink v2 is the de facto open UAS command and control protocol. 5 kbps uplink supports waypoint upload and RTK correction streaming. 10 kbps downlink supports position, attitude, and system status telemetry. 1 Hz heartbeat enables the 5-second link loss detection (SYS-REQS-011). | Test | interface, nav-flight-control, communication, session-217 |
| IFC-DEFS-007 | The interface between the Forward-Looking Obstacle Detection Sensor and the Flight Controller Processor SHALL deliver obstacle distance reports (minimum 8 range bins across 60-degree horizontal FOV) at 10Hz over UART at 115200 baud, with each report timestamped to the sensor internal clock with 1ms resolution. Rationale: 8 range bins across 60 degrees provide 7.5-degree angular resolution, sufficient for path-planning obstacle avoidance. 10 Hz measurement rate at 8 m/s gives an obstacle position update every 0.8 m of travel, supporting the 500 ms avoidance response requirement (SUB-REQS-006). | Test | interface, nav-flight-control, session-217 |
| IFC-DEFS-008 | The interface between the Image Capture Triggering Controller and each camera (Multispectral, Thermal, RGB) SHALL carry a hardware trigger pulse via 3.3V GPIO with rising-edge activation, maximum latency of 100 microseconds from pulse to exposure start, and a feedback signal from each camera confirming capture completion within 50 milliseconds. Rationale: Hardware GPIO trigger avoids USB protocol scheduling latency which can exceed 1 ms. 100 microsecond trigger-to-exposure ensures cross-band spatial alignment within 1.2 mm at maximum ground speed, critical for vegetation index computation from co-registered multi-band imagery. | Test | interface, imaging, session-218 |
| IFC-DEFS-009 | The interface between the Downwelling Light Sensor and the Multispectral Camera SHALL deliver per-band irradiance values (watts per square metre per nanometre) over I2C at 1 Hz with 16-bit resolution, synchronised to the multispectral capture trigger via shared timestamp from the Triggering Controller. Rationale: I2C is adequate for 1 Hz low-bandwidth irradiance data. 1 Hz sampling matches the slowly varying solar irradiance cycle. Shared timestamp from the Triggering Controller ensures radiometric calibration pairs each irradiance measurement with its corresponding multispectral exposure. | Test | interface, imaging, session-218 |
| IFC-DEFS-010 | The interface between each camera and the Onboard Image Storage Module SHALL carry image data over USB 3.0 SuperSpeed (5 Gbps) with guaranteed sustained throughput of 50 megabytes per second per camera channel, using a USB hub with dedicated bandwidth allocation per port to prevent contention. Rationale: USB 3.0 SuperSpeed provides 5 Gbps aggregate bandwidth. Per-port bandwidth allocation prevents camera data contention during burst captures. 50 MB/s per channel accommodates the highest data rate camera (multispectral at 80 MB/s burst, 50 MB/s sustained) with margin. | Test | interface, imaging, session-218 |
| IFC-DEFS-011 | The interface between the Flight Controller Processor and the Image Capture Triggering Controller SHALL carry aircraft position (latitude, longitude, altitude), velocity (north, east, down), and attitude (roll, pitch, yaw) at 10 Hz minimum over UART at 115200 baud using MAVLink v2 GLOBAL_POSITION_INT and ATTITUDE messages. Rationale: Position and attitude at 10 Hz provides geolocation metadata for each captured image at typical trigger rates of 1 to 2 Hz. MAVLink v2 GLOBAL_POSITION_INT and ATTITUDE messages are standard ArduPilot outputs requiring no custom firmware modification. | Test | interface, imaging, session-218 |
| IFC-DEFS-012 | The interface between the Flight Controller Processor and the Camera Gimbal SHALL carry gimbal attitude commands and IMU feedback over CAN 2.0B at 1 Mbps, with commanded pointing angle updates at 100 Hz and measured gimbal attitude feedback at 100 Hz for closed-loop stabilization. Rationale: 100 Hz command and feedback rate exceeds the airframe vibration band of 50 to 100 Hz, enabling active vibration rejection. CAN 2.0B at 1 Mbps provides deterministic timing for closed-loop gimbal stabilization. Dual-direction telemetry enables the flight controller to monitor gimbal health. | Test | interface, imaging, session-218 |
| IFC-DEFS-013 | The interface between the Onboard Image Storage Module and the Data Processing and Analytics Subsystem SHALL deliver the complete flight image dataset as a removable NVMe SSD containing images in standard formats (TIFF for multispectral and thermal, JPEG plus DNG for RGB) with an accompanying JSON flight log mapping each image to its geolocation, attitude, and DLS irradiance record. Rationale: Removable NVMe SSD avoids multi-hour wireless transfer of 50+ GB flight datasets. Standard image formats (TIFF, JPEG, DNG) ensure compatibility with Pix4Dfields, Agisoft Metashape, and QGIS. JSON flight log provides a machine-readable geolocation index for batch processing pipelines. | Inspection | interface, imaging, session-218 |
| IFC-DEFS-014 | The interface between the Battery Pack Assembly and the Battery Management System Controller SHALL provide individual cell voltage measurement for all 12 series groups via dedicated sense wires with plus or minus 5 millivolt accuracy, and pack current measurement via a hall-effect sensor on the main bus with plus or minus 0.5 ampere accuracy at up to 150 amperes. | Test | interface, power-battery, session-221 |
| IFC-DEFS-015 | The interface between the Battery Management System Controller and the Flight Controller Processor SHALL use CAN 2.0B at 1 Mbps, transmitting battery status messages (SOC, SOH, pack voltage, pack current, minimum cell voltage, maximum cell temperature, fault flags) at 10 Hz with a maximum message latency of 5 milliseconds. | Test | interface, power-battery, session-221 |
| IFC-DEFS-016 | The interface between the Battery Pack Assembly and the Power Distribution Board SHALL deliver 33.6 to 50.4 volts DC at up to 150 amperes continuous through the main contactor, with a maximum contact resistance of 2 milliohms and voltage drop not exceeding 0.3 volts at rated current. | Test | interface, power-battery, session-221 |
| IFC-DEFS-017 | The interface between the Power Distribution Board and the DC-DC Voltage Regulator Module SHALL provide filtered battery voltage (33.6 to 50.4V) through a dedicated trace rated for 15 amperes continuous, with input EMI filtering providing at least 40 dB common-mode rejection above 100 kHz. | Test | interface, power-battery, session-221 |
| IFC-DEFS-018 | The interface between the Battery Quick-Release Mechanism and the Battery Pack Assembly SHALL provide positive mechanical retention rated for 6G shock load in any axis, with an XT90-S anti-spark power connector engaging before the CAN bus data connector, and total insertion-to-locked time not exceeding 5 seconds. | Test | interface, power-battery, session-221 |
| IFC-DEFS-019 | The interface between the Battery Charging and Swap Station and the Battery Pack Assembly SHALL implement CC-CV charging at a maximum charge current of 10 amperes (0.6C rate) with constant-voltage phase at 50.4 volts, and SHALL read BMS status over the CAN bus data pins of the quick-release connector to verify cell health before and during charging. | Test | interface, power-battery, session-221 |
| IFC-DEFS-020 | The interface between the Flight Controller Processor and the Power Distribution Board SHALL provide a 3.3V logic-level arm/disarm signal controlling the master power MOSFET, with the disarm state as the default (fail-safe off) requiring continuous assertion to maintain the armed state. | Test | interface, power-battery, session-221 |
| Ref | Requirement | V&V | Tags |
|---|---|---|---|
| ARC-DECISIONS-001 | ARC: Navigation and Flight Control — Centralised flight controller with star-topology sensor architecture. All navigation sensors (GNSS, IMU, barometer, magnetometer, radar altimeter, obstacle sensor) connect directly to a single flight controller processor rather than a distributed sensor fusion network. This topology was chosen because: (1) agricultural UAVs at 25kg MTOW do not have the weight or power budget for redundant processing nodes; (2) a single EKF instance avoids the cross-node synchronisation problem that plagues distributed architectures at 400Hz; (3) PX4/ArduPilot ecosystem maturity provides flight-proven sensor fusion; (4) the obstacle detection sensor is separate from navigation sensors because it requires forward-mounting and a fundamentally different processing pipeline (spatial rather than temporal fusion). CAN bus was selected for the spray controller interface over UART due to superior EMI immunity near the ESC and pump motor noise sources. DShot600 was selected over PWM for motor control to eliminate calibration drift in field conditions. Rationale: Star topology chosen over distributed processing to minimize inter-processor communication latency for the 400 Hz attitude control loop. Centralised EKF fusion avoids the complexity and timing uncertainty of distributed sensor fusion across multiple compute nodes on a weight-constrained UAV platform. | — | architecture, nav-flight-control, session-217 |
| ARC-DECISIONS-002 | ARC: Imaging and Remote Sensing — Centralised trigger architecture with shared gimbal mount and dedicated storage. All cameras share a single 2-axis gimbal rather than individual stabilisation, driven by payload weight constraint (800g total). The Image Capture Triggering Controller acts as a synchronisation hub receiving position from the flight controller and distributing hardware trigger pulses to all cameras, rather than each camera self-triggering on GPS distance. This ensures sub-millisecond inter-band synchronisation critical for co-registered vegetation index computation. Removable NVMe SSD was chosen over wireless downlink for imagery because the 125 MB/s sustained data rate exceeds the practical throughput of any UAV-class datalink. Alternative considered: per-camera SD storage — rejected because it prevents the trigger controller from monitoring write completion and detecting missed frames in flight. Rationale: Shared gimbal reduces payload weight by approximately 400 g versus per-camera stabilisation, directly extending flight endurance. Centralised trigger with hardware GPIO ensures sub-millisecond inter-camera synchronisation that would be difficult to achieve with distributed USB-triggered capture. | Analysis | architecture, imaging, session-218 |
| ARC-DECISIONS-003 | ARC: Power and Battery Management — Centralised BMS with ground-based swap station rather than onboard redundant power. The subsystem separates battery intelligence (BMS controller) from power routing (PDB) and voltage conversion (DC-DC) as physically distinct modules rather than integrating them onto a single board. This was chosen because: (1) the BMS must remain powered during battery swap to maintain SOC state, so it is embedded in the battery pack itself, not the airframe; (2) the PDB handles 150A continuous where thermal management dominates the PCB design, making co-location with sensitive BMS measurement circuits impractical due to thermal gradient-induced measurement drift; (3) the DC-DC converters are isolated to prevent switching noise from coupling into BMS cell voltage measurements. The ground-based charging and swap station was included as a subsystem component rather than external infrastructure because it is the primary availability enabler — without automated swap capability, the 85% fleet availability target (SYS-REQS-015) is unachievable with manual battery swap workflows. Hall-effect current sensing was chosen over shunt resistors to avoid adding resistance to the main power bus, which at 150A would dissipate 22.5W through even a 1-milliohm shunt. | — | architecture, power-battery, session-221 |
flowchart TB n0["component<br>Flight Controller Processor"] n1["component<br>GNSS Receiver (RTK)"] n2["component<br>MEMS IMU"] n3["component<br>Barometric Altimeter"] n4["component<br>Radar Altimeter"] n5["component<br>Magnetometer"] n6["component<br>Obstacle Detection Sensor"] n7["external<br>ESCs / Motors"] n8["external<br>Datalink"] n9["external<br>Spray Controller"] n10["component<br>Flight Controller Processor"] n11["component<br>GNSS Receiver (RTK)"] n12["component<br>MEMS IMU"] n13["component<br>Barometric Altimeter"] n14["component<br>Radar Altimeter"] n15["component<br>Magnetometer"] n16["component<br>Obstacle Detection Sensor"] n17["external<br>ESCs / Motors"] n18["external<br>Datalink"] n19["external<br>Spray Controller"] n20["component<br>TestBlock"] n21["component<br>GNSS Receiver (RTK)"] n22["component<br>MEMS IMU"] n23["component<br>Barometric Altimeter"] n24["component<br>Radar Altimeter"] n25["component<br>Magnetometer"] n26["component<br>Obstacle Detection"] n27["external<br>ESCs / Motors"] n28["external<br>Datalink"] n29["external<br>Spray Controller"] n21 -->|PVT UART 10Hz| n10 n22 -->|Rates/Accel SPI 400Hz| n10 n23 -->|Altitude I2C 25Hz| n10 n24 -->|AGL Height UART 20Hz| n10 n25 -->|Heading I2C 100Hz| n10 n26 -->|Obstacles UART 10Hz| n10 n10 -->|Motor Cmds PWM/DShot| n27 n10 -->|MAVLink Telemetry| n28 n28 -->|Commands/Waypoints| n10 n10 -->|Spray On/Off, Position| n29 n28 -->|RTK Corrections RTCM| n21
Navigation and Flight Control — Internal
flowchart TB n0["component<br>Multispectral Camera"] n1["component<br>Thermal IR Camera"] n2["component<br>RGB Camera"] n3["component<br>Downwelling Light Sensor"] n4["component<br>Camera Gimbal"] n5["component<br>Trigger Controller"] n6["component<br>Image Storage"] n7["external<br>Flight Controller"] n8["external<br>Data Processing"] n9["external<br>Power Bus"] n10["component<br>Multispectral Camera"] n11["component<br>Thermal IR Camera"] n12["component<br>RGB Camera"] n13["component<br>Downwelling Light Sensor"] n14["component<br>Camera Gimbal"] n15["component<br>Trigger Controller"] n16["component<br>Image Storage"] n17["external<br>Flight Controller"] n18["external<br>Data Processing"] n19["external<br>Power Bus"] n15 -->|Trigger pulse| n10 n15 -->|Trigger pulse| n11 n15 -->|Trigger pulse| n12 n10 -->|5-band images| n16 n11 -->|Thermal frames| n16 n12 -->|RGB images| n16 n13 -->|Irradiance cal| n10 n14 -->|Stabilization| n10 n14 -->|Stabilization| n11 n14 -->|Stabilization| n12 n17 -->|Position/velocity| n15 n17 -->|Attitude data| n14 n16 -->|Image dataset| n18 n19 -->|28V regulated| n14
Imaging and Remote Sensing — Internal
flowchart TB n0["component<br>Battery Pack Assembly"] n1["component<br>BMS Controller"] n2["component<br>Power Distribution Board"] n3["component<br>DC-DC Voltage Regulator"] n4["component<br>Quick-Release Mechanism"] n5["component<br>Charging and Swap Station"] n6["actor<br>Flight Controller"] n7["actor<br>ESCs and Motors"] n8["actor<br>Payload Systems"] n9["component<br>Battery Pack Assembly"] n10["component<br>BMS Controller"] n11["component<br>Power Distribution Board"] n12["component<br>DC-DC Voltage Regulator"] n13["component<br>Quick-Release Mechanism"] n14["component<br>Charging and Swap Station"] n15["actor<br>Flight Controller"] n16["actor<br>ESCs and Motors"] n17["actor<br>Payload Systems"] n9 -->|44.4V DC power bus| n11 n9 -->|Cell voltage and thermistor lines| n10 n13 -->|Mechanical rail and electrical contacts| n9 n10 -->|Main contactor control| n11 n10 -->|CAN bus: SOC, SOH, faults| n15 n11 -->|Battery voltage input| n12 n11 -->|Motor power 30A per channel| n16 n12 -->|5V/3A avionics rail| n15 n12 -->|12V/8A payload rail| n17 n14 -->|Automated battery insertion| n13 n15 -->|Arm/disarm command| n11
Power and Battery Management — Internal
| Entity | Hex Code | Description |
|---|---|---|
| Airframe and Propulsion Subsystem | DFC51018 | Agricultural multirotor UAV airframe optimised for precision spraying and sensor payload operations. Hexacopter configuration (6 motors) for motor-out redundancy with coaxial X8 option for heavy-lift variants. Carbon fibre and aluminium frame with folding arms for transport, 1.8 m motor-to-motor span. Maximum takeoff weight 25 kg (FAA Part 107 waiver limit) with 16 kg useful payload capacity split between spray tank and sensor gimbal. Brushless outrunner motors (KV 100-150) driving 28-inch carbon fibre propellers with T-motor or equivalent agricultural-grade reliability. IP54 sealed motor and ESC housings for chemical spray resistance. Quick-release payload mounting system supports hot-swap between spray rig and imaging payload. Vibration isolation mounts for flight controller and camera gimbal. Corrosion-resistant landing gear with 300 mm ground clearance for crop overfly during takeoff/landing. |
| Barometric Pressure Altitude Sensor | D4C50008 | High-resolution barometric pressure sensor providing relative altitude measurement for UAV height-above-launch estimation. Resolution better than 10cm altitude equivalent, 25Hz update rate. Used for altitude hold during spray passes at 2-5m above crop canopy. Fused with GNSS altitude and radar altimeter in the navigation filter. Connected to flight controller via I2C bus. Sensitive to propeller wash — requires static port placement and pneumatic isolation. Operating range 300-1100 hPa. |
| Battery Charging and Swap Station | D7F77218 | Ground-based fleet battery management station for the precision agriculture drone fleet. Houses 8 independent charging bays, each with a 44.4V/10A CC-CV lithium-ion charger (charge time: 90 minutes 20-100% SOC). Includes motorised battery extraction arm and insertion mechanism for automated battery swap without human intervention. Station communicates with approaching drones via 2.4GHz WiFi to coordinate landing, swap sequence, and launch. Integrated battery health screening: rejects packs below 80% SOH or with cell imbalance >50mV. Environmental enclosure rated IP55 with forced-air cooling, operating in 0-50°C ambient. Powered from single-phase 240V mains or 5kW solar/generator input. Logs all charge cycles, SOH trends, and swap events to SD card and uploads to cloud via LTE modem. Weighs approximately 45kg, transportable by two operators. |
| Battery Management System Controller | 55F77A18 | Dedicated BMS IC and microcontroller monitoring all 12 series cell groups in the UAV battery pack. Measures individual cell voltages (±5mV accuracy), pack current via hall-effect sensor (±0.5A), and 4 thermistor zones across the pack. Performs passive cell balancing at 100mA during charging. Enforces protection limits: over-voltage cutoff at 4.25V/cell, under-voltage cutoff at 2.8V/cell, over-current at 150A, over-temperature at 60°C. Calculates state-of-charge (coulomb counting + OCV correction) and state-of-health (cycle count, impedance tracking). Reports SOC, SOH, cell voltages, temperature, and fault status over CAN bus to the flight controller at 10Hz. Controls main contactor for emergency disconnect. |
| Battery Pack Assembly | D6D51018 | 12S4P lithium-ion battery pack for agricultural UAV, 44.4V nominal, 16Ah capacity (~710Wh). Uses 21700-format high-discharge cells (e.g. Samsung 40T or Molicel P42A) rated for 30A continuous per parallel group. Pack provides 120A burst for motor transients during wind gust recovery. Operates in 0-45°C ambient with passive thermal pads conducting heat to aluminium enclosure. IP54-sealed for dust/spray resistance. Quick-release rail mounting with XT90-S anti-spark connector and CAN bus data pins for BMS communication. Target: 30 minutes flight at 25kg MTOW with 15% energy reserve. |
| Battery Quick-Release Mechanism | DE8D1008 | Electromechanical quick-release rail system for rapid battery pack exchange on the agricultural UAV. Consists of aluminium dovetail rail on the airframe and matching slide on the battery pack, with spring-loaded latch pins engaging detent slots for positive retention. Rated for 6G shock load in any axis. Battery slides in from the rear, contacts engage in sequence: first mechanical lock, then XT90-S power connector (anti-spark), then 4-pin Molex for CAN bus data. Release via single lever actuated by operator or by motorised servo for automated swap station. Total insertion-to-locked time under 5 seconds. IP54 sealed contacts with gold-plated CAN pins. Designed for 10,000 insertion cycles before replacement. |
| Camera Gimbal and Stabilization Mount | DE941008 | Two-axis (pitch/roll) brushless motor gimbal providing nadir-pointing stabilization for the multi-camera payload. Maintains pointing accuracy within ±0.5 degrees during agricultural survey flight at up to 12m/s. IMU-based stabilization with 1kHz inner loop. Supports 800g payload (multispectral + thermal + RGB cameras). Vibration-isolated from airframe via damping mounts to prevent image blur from propeller vibration at 50-100Hz. |
| Communication and Datalink Subsystem | 54F57018 | Dual-band communication system providing command-and-control (C2) and payload data links between agricultural UAVs and ground control station. Primary C2 link on 900 MHz ISM band (LoRa-based, 200 kbps) for telemetry and commands with 5 km range in open agricultural terrain. Secondary high-bandwidth 5.8 GHz link (802.11ac, up to 50 Mbps) for real-time video preview and bulk data transfer at shorter range (<2 km). Mesh networking capability enables drone-to-drone relay for fleet operations beyond direct GCS range. FAA Remote ID compliant broadcast module transmitting on 2.4 GHz BLE and Wi-Fi Aware. Automatic link-loss detection with configurable failsafe behaviour (loiter, RTH, or land). AES-256 encrypted C2 channel to prevent command injection. |
| Data Processing and Analytics Subsystem | 50F73318 | Ground-based data processing pipeline for agricultural drone imagery and spray operation records. Ingests geotagged multispectral and thermal imagery from post-flight SD card download or wireless transfer. Photogrammetry engine (structure-from-motion) generates georeferenced orthomosaics, digital surface models, and point clouds at 2-3 cm resolution. Vegetation index computation pipeline produces NDVI, NDRE, GNDVI, and CWSI maps with per-pixel georeferencing. Zone-based analytics engine segments field into management zones by clustering vegetation indices, generating variable-rate prescription maps in ISO-XML and Shapefile formats for FMIS export. Spray log reconciliation compares as-applied records (GPS track, nozzle states, flow rates) against prescription maps to compute coverage accuracy and identify skips or overlaps. Historical trend analysis across growth stages for yield prediction modelling. Runs on ruggedised field laptop (GPU-accelerated) or cloud upload to processing service. |
| DC-DC Voltage Regulator Module | D6C51018 | Multi-output DC-DC converter module for the agricultural UAV, stepping down the 44.4V battery bus to regulated low-voltage rails. Provides three isolated outputs: 5V/3A for flight controller, GPS, and avionics (buck converter with 93% efficiency); 12V/8A for camera gimbal, imaging payload, and communications equipment (synchronous buck); 5V/2A auxiliary rail for BMS telemetry and LED indicators. Input range 36-50.4V (accommodates full Li-ion discharge to charge range). EMI-filtered with common-mode chokes to prevent conducted emissions from coupling into sensitive sensor signals. Operating temperature -20 to 85°C. Mounted on the PDB via board-to-board connector for vibration resistance. |
| Downwelling Light Sensor | D4C50208 | Top-mounted irradiance sensor measuring incoming solar spectral irradiance in the same 5 bands as the multispectral camera (Blue, Green, Red, Red Edge, NIR). Critical for calibrating multispectral imagery from raw digital numbers to absolute reflectance values, compensating for changing illumination conditions during flight. GPS-timestamped irradiance logging at 1Hz. Cosine-corrected diffuser optics for hemispherical field of view. |
| Flight Controller Processor | D1F77A18 | Central flight control computer running real-time autopilot firmware (PX4/ArduPilot-class). Fuses GNSS, IMU, barometer, magnetometer, and radar altimeter into a navigation solution via extended Kalman filter. Executes inner-loop attitude control at 400Hz and outer-loop position/velocity control at 50Hz. Generates motor commands via PWM/DShot for ESCs. Manages autonomous waypoint navigation, geofence enforcement, failsafe state machine, and fleet separation logic. Interfaces with ground control station via MAVLink over the datalink. ARM Cortex-M7 or equivalent, running on RTOS with deterministic 2.5ms control loop timing. Safety-critical: must detect and respond to actuator failures, sensor faults, and geofence violations within 100ms. |
| Forward-Looking Obstacle Detection Sensor | D5E55018 | Forward and lateral-facing obstacle detection array using solid-state lidar or ToF technology. Detection range 30m minimum at 10Hz for powerlines, poles, trees in the flight path. Must detect thin obstacles (powerlines 10mm diameter) at 15m. Provides distance array to flight controller for reactive avoidance during low-altitude spray passes. FOV 60 degrees horizontal, 30 degrees vertical. Connected via UART or CAN. Power under 5W. Must operate in bright sunlight, dust, and light rain. |
| Ground Control Station | D6ED7018 | Ruggedised portable ground control station for multi-UAV agricultural fleet management in field conditions. Tablet-based (IP65-rated, sunlight-readable 1000-nit display) running mission planning and fleet coordination software. Supports simultaneous monitoring and control of up to 8 UAVs with individual and fleet-level command authority. Mission planning functions: field boundary import from Shapefile/KML, automatic survey path generation with configurable overlap, prescription map overlay from FMIS, no-fly zone geofencing, and takeoff/landing zone designation. Real-time display of fleet positions, battery states, spray tank levels, and mission progress. Emergency override capability for immediate all-fleet RTH or individual drone hold. Tripod-mounted directional antenna array for extended C2 range. Runs on internal battery (8 hr) or vehicle 12V supply. |
| High-Resolution RGB Camera | D4CC1008 | 20MP RGB camera with mechanical global shutter for distortion-free agricultural orthomosaic generation. Used for plant counting, crop emergence assessment, weed mapping, and visual anomaly detection. 1-inch CMOS sensor with 35mm equivalent focal length. GSD 2.5cm/pixel at 120m AGL. Captures JPEG+DNG raw for post-processing flexibility. Triggered synchronously with multispectral camera for co-registered multi-layer mapping. |
| Image Capture Triggering Controller | 50F77208 | Microcontroller-based synchronization unit that triggers all cameras simultaneously based on distance intervals computed from flight controller position data. Ensures consistent image overlap (75% forward, 65% side) by computing trigger spacing from ground speed and desired GSD. Issues hardware trigger pulses via GPIO with sub-millisecond timing accuracy across all cameras. Logs trigger events with GPS timestamp and aircraft attitude for post-processing geolocation. |
| Imaging and Remote Sensing Subsystem | 54C71018 | Multi-sensor payload for crop health assessment and yield mapping on agricultural UAVs. Primary sensor is a 5-band multispectral camera (Blue, Green, Red, Red Edge, NIR at 1.2 MP per band) with integrated downwelling light sensor for radiometric calibration. Secondary thermal infrared camera (640x512, 7.5-13.5 μm LWIR) for canopy temperature and water stress detection. Captures imagery at 2-3 cm/pixel GSD from 30-50 m AGL. Geotagged frames triggered by autopilot at computed intervals to achieve 75% frontal and 65% side overlap. Outputs raw band imagery to onboard storage (256 GB industrial microSD) for post-flight orthomosaic and vegetation index processing. |
| MEMS Inertial Measurement Unit | D4F55018 | Six-axis MEMS IMU (3-axis accelerometer, 3-axis gyroscope) providing body-frame angular rates and specific force measurements at 400Hz for UAV attitude estimation and navigation filter fusion. Gyroscope bias stability less than 10 deg/hr, accelerometer noise density less than 100 ug/sqrt(Hz). Communicates via SPI bus to the flight controller. Mounted at the UAV center of gravity to minimise lever-arm effects. Operates across -40 to 85 degrees Celsius. Critical for attitude hold during gusty agricultural operations and for dead-reckoning during brief GNSS outages near tree lines. |
| Millimetre-Wave Radar Altimeter | D5E57018 | Downward-looking 77GHz FMCW radar altimeter providing above-ground-level height measurement from 0.3m to 30m with 2cm accuracy. Critical for maintaining precise spray height of 2-5m above variable crop canopy during application passes. 20Hz update rate, narrow beam 15 degrees. Must penetrate light foliage canopy. Connected to flight controller via UART. Power under 2W. Operates in rain, dust, and fog. |
| Multi-Constellation GNSS Receiver with RTK | D4F57218 | Multi-constellation GNSS receiver (GPS L1/L5, Galileo E1/E5a, GLONASS L1/L2) with real-time kinematic correction capability. Receives RTCM 3.x corrections via the datalink from a ground-based reference station or NTRIP caster. Provides 10cm CEP95 horizontal position at 10Hz update rate for precision agriculture flight path tracking. Must operate in open-sky agricultural environments with potential multipath from tree lines, buildings, and irrigation pivots. Outputs NMEA 0183 and UBX binary position/velocity/time to the flight controller via UART at 115200 baud. |
| Multispectral Camera | D4C41008 | 5-band agricultural multispectral camera (Blue 475nm, Green 560nm, Red 668nm, Red Edge 717nm, NIR 842nm) with global shutter and 3.2MP per band. Captures narrowband reflectance images for vegetation index computation (NDVI, NDRE, GNDVI). Radiometrically calibrated using downwelling light sensor and ground calibration panels. Typical GSD 8cm/pixel at 120m AGL. Integrated GPS for image geotagging. 1-second capture interval for 75% forward overlap at 10m/s cruise. |
| Navigation and Flight Control Subsystem | 51F73818 | Onboard autopilot and navigation system for agricultural UAVs operating BVLOS over crop fields. Integrates multi-constellation GNSS (GPS L1/L5, GLONASS, Galileo) with RTK corrections from a base station for <10 cm positioning accuracy. Dual-redundant IMU (accelerometer, gyroscope, magnetometer) with EKF sensor fusion. Executes pre-planned survey and spray flight paths with terrain-following using downward-facing LiDAR altimeter. Obstacle avoidance via forward-facing mmWave radar for power lines and structures. Handles autonomous takeoff, landing, and return-to-home on link loss or low battery. Must maintain stable flight in winds up to 25 kt with <0.5 m cross-track error during spray passes. |
| Onboard Image Storage Module | D2851008 | High-speed removable NVMe SSD storage system handling simultaneous write streams from multispectral (5 bands × 3.2MP × 1Hz = ~80MB/s), thermal (640×512 × 16-bit × 30Hz = ~20MB/s), and RGB (20MP × 1Hz = ~25MB/s) cameras. Total sustained write rate 125MB/s minimum. Hot-swappable for rapid turnaround between flights. Includes onboard metadata database linking each image to GPS position, attitude, DLS irradiance, and flight plan waypoint. |
| Power and Battery Management Subsystem | 55F73218 | Onboard electrical power system for agricultural multirotor UAVs with high energy density requirements to support 30-45 minute flight endurance while carrying 16 kg spray payload. Dual 6S LiPo battery packs (22.2V nominal, 16,000 mAh each) in parallel with individual cell monitoring and balancing. Smart BMS with per-cell voltage, temperature, and internal resistance tracking. Current sensing on each motor ESC for load monitoring and motor health diagnostics. Autonomous battery swap station at field edge: robotic arm replaces depleted packs in <90 seconds per drone, enabling continuous fleet operations across 8+ hour daily windows. Charging station with 6-bay fast charger (1C rate, 45 min charge cycle) powered by trailer-mounted diesel generator or grid connection. Low-voltage cutoff protection, thermal runaway detection with automatic motor shutdown, and SOC-based mission abort thresholds. |
| Power Distribution Board | D6851008 | Central power distribution node for the agricultural UAV, receiving 44.4V nominal from the battery pack via the main contactor. Distributes high-current power to 4 or 6 ESCs (30A per channel continuous) via direct copper bus bars, and provides switched outputs for payload power (spray pump 12V/20A, gimbal 12V/5A). Includes resettable polyfuses on each low-power branch and a master arm/disarm MOSFET controlled by the flight controller. Integrates a hall-effect current sensor on the main bus for total power monitoring (reported to BMS and flight controller). PCB designed for 150A continuous with 2oz copper and thermal relief. Conformal coated for agricultural chemical exposure resistance. |
| Precision Agriculture Drone Fleet | D5F77259 | Autonomous multi-UAV system for precision agriculture operations over large-scale crop fields (500-5000 hectares). Fleet of 4-8 fixed-wing and multirotor drones coordinated by a ground control station for crop health monitoring via multispectral/hyperspectral imaging, variable-rate pesticide and fertiliser application via onboard spray systems, and yield mapping through NDVI analysis. Operates in Class G airspace under Part 107 waiver for BVLOS operations. Key constraints: FAA compliance, chemical drift containment, GPS-denied operation near tree lines, wind tolerance to 25 kt, battery endurance 30-45 min per sortie, and sub-field-level application accuracy of 10 cm. Integrates with farm management information systems (FMIS) for prescription map ingestion and yield data export. |
| Spray Application Subsystem | D5F73019 | Variable-rate liquid application system mounted on multirotor agricultural UAVs for precision pesticide, herbicide, and foliar fertiliser delivery. 16-litre tank with diaphragm pump delivering 0.4-1.2 L/min at 2-4 bar through 4 hydraulic flat-fan nozzles (Teejet XR110-02 or equivalent) producing 150-300 μm VMD droplets. Centrifugal atomiser option for ultra-low-volume applications at 50-80 μm. PWM-controlled nozzle solenoids enable individual nozzle shut-off and variable rate based on prescription map zones. Flow sensor feedback loop maintains ±5% application rate accuracy. Spray boom width 2.5 m matched to swath for 3 m AGL application height. Automatic shut-off triggered by wind speed >15 kt, rain detection, or geofence boundary crossing to prevent off-target drift. |
| Thermal Infrared Camera | D4EC1018 | Uncooled microbolometer LWIR camera operating in 8-14 micrometre band with 640x512 resolution. Measures crop canopy temperature for water stress detection and irrigation scheduling. Temperature accuracy ±2°C absolute, ±0.05°C NETD for relative measurements. Radiometric calibration with onboard shutter-based NUC. 30Hz frame rate, nadir-pointing via shared gimbal mount. Output: 16-bit radiometric temperature images. |
| Three-Axis Magnetometer | D4E51018 | Three-axis AMR magnetometer providing magnetic heading reference for UAV yaw estimation. Mounted on GPS mast to maximise separation from motor currents. Resolution better than 1 mGauss, 100Hz. Provides heading initialisation and drift correction for INS/GNSS navigation filter. Must be calibrated for hard-iron and soft-iron distortion. Connected via I2C. Subject to interference from agricultural power lines. |
| Component | Belongs To |
|---|---|
| Navigation and Flight Control Subsystem | Precision Agriculture Drone Fleet |
| Imaging and Remote Sensing Subsystem | Precision Agriculture Drone Fleet |
| Spray Application Subsystem | Precision Agriculture Drone Fleet |
| Communication and Datalink Subsystem | Precision Agriculture Drone Fleet |
| Ground Control Station | Precision Agriculture Drone Fleet |
| Power and Battery Management Subsystem | Precision Agriculture Drone Fleet |
| Data Processing and Analytics Subsystem | Precision Agriculture Drone Fleet |
| Airframe and Propulsion Subsystem | Precision Agriculture Drone Fleet |
| Multi-Constellation GNSS Receiver with RTK | Navigation and Flight Control Subsystem |
| MEMS Inertial Measurement Unit | Navigation and Flight Control Subsystem |
| Flight Controller Processor | Navigation and Flight Control Subsystem |
| Barometric Pressure Altitude Sensor | Navigation and Flight Control Subsystem |
| Millimetre-Wave Radar Altimeter | Navigation and Flight Control Subsystem |
| Three-Axis Magnetometer | Navigation and Flight Control Subsystem |
| Forward-Looking Obstacle Detection Sensor | Navigation and Flight Control Subsystem |
| Multispectral Camera | Imaging and Remote Sensing Subsystem |
| Thermal Infrared Camera | Imaging and Remote Sensing Subsystem |
| High-Resolution RGB Camera | Imaging and Remote Sensing Subsystem |
| Downwelling Light Sensor | Imaging and Remote Sensing Subsystem |
| Camera Gimbal and Stabilization Mount | Imaging and Remote Sensing Subsystem |
| Image Capture Triggering Controller | Imaging and Remote Sensing Subsystem |
| Onboard Image Storage Module | Imaging and Remote Sensing Subsystem |
| Battery Pack Assembly | Power and Battery Management Subsystem |
| Battery Management System Controller | Power and Battery Management Subsystem |
| Power Distribution Board | Power and Battery Management Subsystem |
| DC-DC Voltage Regulator Module | Power and Battery Management Subsystem |
| Battery Quick-Release Mechanism | Power and Battery Management Subsystem |
| Battery Charging and Swap Station | Power and Battery Management Subsystem |
| From | To |
|---|---|
| Multi-Constellation GNSS Receiver with RTK | Flight Controller Processor |
| MEMS Inertial Measurement Unit | Flight Controller Processor |
| Barometric Pressure Altitude Sensor | Flight Controller Processor |
| Millimetre-Wave Radar Altimeter | Flight Controller Processor |
| Three-Axis Magnetometer | Flight Controller Processor |
| Forward-Looking Obstacle Detection Sensor | Flight Controller Processor |
| Navigation and Flight Control Subsystem | Airframe and Propulsion Subsystem |
| Navigation and Flight Control Subsystem | Communication and Datalink Subsystem |
| Navigation and Flight Control Subsystem | Spray Application Subsystem |
| Navigation and Flight Control Subsystem | Power and Battery Management Subsystem |
| Image Capture Triggering Controller | Multispectral Camera |
| Image Capture Triggering Controller | Thermal Infrared Camera |
| Image Capture Triggering Controller | High-Resolution RGB Camera |
| Multispectral Camera | Onboard Image Storage Module |
| Thermal Infrared Camera | Onboard Image Storage Module |
| High-Resolution RGB Camera | Onboard Image Storage Module |
| Downwelling Light Sensor | Multispectral Camera |
| Camera Gimbal and Stabilization Mount | Multispectral Camera |
| Camera Gimbal and Stabilization Mount | Thermal Infrared Camera |
| Camera Gimbal and Stabilization Mount | High-Resolution RGB Camera |
| Imaging and Remote Sensing Subsystem | Navigation and Flight Control Subsystem |
| Imaging and Remote Sensing Subsystem | Data Processing and Analytics Subsystem |
| Imaging and Remote Sensing Subsystem | Power and Battery Management Subsystem |
| Battery Pack Assembly | Battery Management System Controller |
| Battery Pack Assembly | Power Distribution Board |
| Battery Pack Assembly | Battery Quick-Release Mechanism |
| Battery Management System Controller | Power Distribution Board |
| Battery Management System Controller | Flight Controller Processor |
| Power Distribution Board | DC-DC Voltage Regulator Module |
| Battery Charging and Swap Station | Battery Pack Assembly |
| Battery Charging and Swap Station | Battery Quick-Release Mechanism |
| Component | Output |
|---|---|
| Multi-Constellation GNSS Receiver with RTK | Position/Velocity/Time at 10Hz |
| MEMS Inertial Measurement Unit | Angular rates and accelerations at 400Hz |
| Flight Controller Processor | Motor commands, navigation solution, telemetry |
| Barometric Pressure Altitude Sensor | Relative altitude at 25Hz |
| Millimetre-Wave Radar Altimeter | Above-ground-level height at 20Hz |
| Three-Axis Magnetometer | Magnetic heading reference at 100Hz |
| Forward-Looking Obstacle Detection Sensor | Obstacle distance array at 10Hz |
| Multispectral Camera | 5-band narrowband reflectance images at 1Hz |
| Thermal Infrared Camera | Radiometric temperature images at 30Hz |
| High-Resolution RGB Camera | 20MP geotagged RGB images at 1Hz |
| Downwelling Light Sensor | 5-band solar irradiance measurements at 1Hz |
| Camera Gimbal and Stabilization Mount | Stabilized nadir pointing within 0.5deg |
| Image Capture Triggering Controller | Synchronised camera trigger pulses and metadata log |
| Onboard Image Storage Module | Flight imagery dataset with embedded geolocation metadata |
| Battery Pack Assembly | 44.4V nominal DC power at up to 120A burst |
| Battery Management System Controller | SOC, SOH, cell voltages, temperature, fault status at 10Hz over CAN |
| Power Distribution Board | Switched power distribution to ESCs and payload branches |
| DC-DC Voltage Regulator Module | Regulated 5V/3A avionics, 12V/8A payload, 5V/2A auxiliary rails |
| Battery Quick-Release Mechanism | Mechanical and electrical battery-to-airframe connection |
| Battery Charging and Swap Station | Charged battery packs, SOH screening, swap cycle logs |