ULS-ProCopter-G3 Interface Control Document

ULSDC-PBICD271026 · version 0.2.0 · issued November 8, 2026
The numbered PDF is the controlled copy: download it from the portal.

Introduction

Purpose

This document outlines the interfaces between the ULS-ProCopter-G3 system components, including the transmitter, receiver, and autopilot systems (ArduPilot, PX4 and similar).

Scope

This document is intended for use by system engineers, integrators, and developers working with ULS-ProCopter-G3 systems. It provides detailed information on the interfaces between the system components, ensuring seamless integration and operation.

Differences from ULS-ProCopter (G2)

ULS-ProCopter-G3 keeps the receiver electrical and communication interfaces of the previous generation. On the transmitter, RS-422 replaces UART, and USB moves from the external connectors to a USB-C port. The optical link carries an additional DACS (Distance and Azimuth Correction System) stage, and the receiver reports DACS yaw correction data to the host.

System Components

Transmitter (Ground Unit)

Figure: ULSDV-PC-G3-TX Transmitter

A transmitter is a device placed on the ground (platform, moving object). It emits a signal in the infrared range and serves as a kind of beacon. The transmitter marks the position for drone landing.

The primary function of the transmitter is to continuously send out a coded signal that can be detected and interpreted by the receiver unit on board. This signal contains the information the receiver needs to operate: positional data, DACS correction data, commands, and system status.

Receiver (Onboard Unit)

Figure: ULSDV-PC-G3-RX Receiver

A receiver is a device that is placed on board an aircraft.

The receiver decodes the transmitter signal to derive flight information such as positional coordinates, real-time transmitter status updates, DACS yaw correction, and landing guidance. It provides this information to the autopilot (ArduPilot, PX4 and similar), which adjusts the flight parameters for a precise and safe landing or hover.

Interface Overview

Figure: ULS-ProCopter-G3 System Interface Overview

Transmitter to Control PC Interface (External Sensors)

Data Types

• Status information
• Control signals
• Transmitter configuration
• External IMU/COMPASS data

Connection Types

• CAN Bus – For network communication
• USB – USB-C port, for configuration and firmware updates
• RS-422 – For serial communication with external sensors

Pinout

Figure: ULSDV-PC-G3-TX Transmitter Connector Side

Figure: ULSDV-PC-G3-TX Transmitter Pinout Diagram

Table: Transmitter 8-pin Connector J3 Pinout (SA812-S8B-PS0.6)

Table: Transmitter 4-pin Connectors J1 and J2 Pinout (SA612-S4B-PS0.6)

Transmitter to Receiver Interface

The transmitter and receiver use an optical interface to exchange data. Transmission uses pulsed IR emission at 940 nanometers. Data transmission is only in the direction from the transmitter to the receiver.

Data Types

• Position encoded
• Status encoded data (transmitter orientation and instructions)
• DACS stage (Distance and Azimuth Correction System) for receiver yaw estimation

Connection Type

• Optical IR 940nm (pulsed) – Infrared optical link

Receiver to Autopilot and Receiver to PC Interfaces

Data Types

• MAVLink messages
• ULS-Blitz frames, including DACS information (RX_DACS, 0x0014)
• ASCII protocol

Connection Types

• UART – Serial communication with autopilot
• CAN – Network communication
• USB – Direct PC connection

Pinout

Figure: ULSDV-PC-G3-RX Receiver Rear View, Connector Side

Figure: ULSDV-PC-G3-RX Receiver Connector

Table: Receiver 10-pin Connector Pinout

Powering Interfaces

Figure: ULS-ProCopter-G3 Powering Interfaces and Electrical Characteristics

Transmitter Electrical Characteristics

• Supply Voltage: 12.0V - 25V
• Supply Current: 2A
• Power Consumption: 18.1 W

Receiver Electrical Characteristics

• Supply Voltage: 5.0V
• Supply Current: 0.6A
• Power Consumption: 3 W

Functional Interfaces

Figure: ULS-ProCopter-G3 Functional Interfaces and Data Flow

Data Exchange

• Control PC is used to configure and view the status of the transmitter.
• Control PC is used to set the configuration of the receivers.
• Control PC (or embedded equipment instead of a control PC) can be used to send control signals (on/off, compass override information).
• External IMU/Compass equipment can be used to override internal IMU/compass information.
• Receiver accepts data from the transmitter over the IR signal. This data includes position field information, DACS correction data and ground unit IMU data.
• Receiver accepts NED and attitude information from the autopilot to convert the coordinate system to one the autopilot accepts.
• Receiver calculates yaw orientation relative to the transmitter with DACS, as an aid to compass and MRX modes.
• Several receivers can communicate to calculate vehicle orientation (YAW) in MRX mode.
• Receiver sends position offset data to the autopilot.

Mechanical Interfaces

Transmitter Mechanical Interface

Figure: ULS-ProCopter-G3 Transmitter Front View, Mounting Dimensions in mm

Figure: ULS-ProCopter-G3 Transmitter Side View, Dimensions in mm

Figure: ULS-ProCopter-G3 Transmitter Rear View, Dimensions in mm

Overall dimensions 183 x 183 x 29.8 mm, weight 1.2 kg.

Receiver Mechanical Interface

Figure: ULS-ProCopter-G3 Receiver Front View, Outline Dimensions in mm

Figure: ULS-ProCopter-G3 Receiver Side View, Dimensions in mm

Overall dimensions 30 x 34 x 10 mm including the connector (body thickness 9 mm), weight 20 g.

Environmental Conditions - Industrial Grade

Equipment is designed to operate reliably in demanding environmental conditions typical of aerospace, industrial automation, and outdoor applications.

Operating Temperature Range

• Standard operating range: -20°C to +55°C
• Covers most industrial and outdoor applications
• Reliable performance across temperature extremes
• No performance degradation within specified range

Humidity Tolerance

• Relative humidity: Up to 70% (non-condensing)
• Protected against moisture in typical operating conditions
• Suitable for outdoor and semi-protected installations
• Condensation prevention through sealed design

Ingress Protection

• IP67 rated (Dust tight and water immersion resistant)
  • 6 - Complete protection against dust ingress
  • 7 - Protected against temporary immersion in water (up to 1 meter depth for 30 minutes)
• Suitable for harsh industrial environments
• Protected against rain, splashing, and temporary submersion
• Dust-tight sealing for contaminated environments

Storage Conditions

• Storage temperature: -40°C to +70°C
• Relative humidity: Up to 95% (non-condensing)
• Long-term storage in industrial facilities

Operational Environment Standards

• Designed to meet industrial equipment requirements
• Suitable for UAV/drone applications
• Outdoor installation capable
• Protected against:
  • Dust and particulate matter
  • Water spray and rain
  • Temporary water immersion
  • Temperature fluctuations
  • High humidity

Optical Radiation Safety (IR Emission)

The transmitter (ground unit) emits pulsed infrared optical radiation with a centre wavelength of 940nm. The receivers are optical sensors only and do not emit optical radiation.

Why This Warning Is Given

Radiation at 940nm is outside the visible range. The protective mechanisms that limit exposure to bright visible sources — the blink reflex, pupil constriction, and the instinct to look away — are not triggered by an invisible source. Exposure time is therefore limited only by operator behaviour, which is why the precautions below are given as operating instructions and not left to the operator’s judgement.

The transmitter is a positioning beacon. It is not an illumination product and is not intended to be viewed at any time.

Operating Precautions

• Do not look directly into the transmitter emitter apertures from a distance of less than 1 metre while the unit is powered.
• Treat the transmitter as emitting whenever supply voltage is applied, including when no receiver is present and no positioning data is being transferred.
• Switch emission off before working directly in front of the transmitter. Use the Illumination parameter in ULS-Tools to disable emission, or disconnect supply power.
• Do not view the powered transmitter through binoculars, telescopes, camera lenses, magnifiers, or any other light-collecting instrument. Such optics concentrate the emission and can raise the exposure at the eye by orders of magnitude compared with unaided viewing.
• Do not add, remove, or modify optical elements of the transmitter. Added optics change the emission characteristics and invalidate any photobiological classification of the unit.
• Position the transmitter so that the emission field is directed away from work positions and walkways where personnel stay for extended periods.
• Servicing personnel working inside the emission field at close range should disable emission first rather than rely on viewing distance.

Classification and Applicable Standards

Table: Optical Radiation Safety Data

For a 940nm source the applicable exposure limits are the retinal thermal hazard (380nm to 1400nm), the retinal thermal hazard for a weak visual stimulus (780nm to 1400nm, which applies specifically to sources that give no visual cue), and the infrared hazard to the cornea and lens (780nm to 3000nm). The corneal and lens limits are intended for chronic exposures longer than 1000s at a daily averaged irradiance of 100 W/m² or more.

Organisations operating this equipment within the European Union are additionally subject to Directive 2006/25/EC on the exposure of workers to artificial optical radiation, which requires the employer to assess worker exposure against the exposure limit values given in Annex I of that directive. UAVLAS provides the emission data needed for that assessment on request.

Part Numbering

Table: ULS-ProCopter-G3 Part Numbers and Descriptions

Applicable Documents

• ULSDC-PBDS271026-ULS-ProCopter-G3-Datasheet
• ULSDC-PBOM271026-ULS-ProCopter-G3-Operation-Manual
• ULSDC-PBDS051125-ULS-DeCoNet Blitz Messages Specification

Change Control

All changes to this document must be reviewed and approved by the relevant technical leads and stakeholders