ULS-ProCopter Operation Manual

ULSDC-PBOM070425 · version 1.0.0 · issued June 14, 2025
The numbered PDF is the controlled copy: download it from the portal.

Introduction

Purpose

The purpose of this operation manual is to provide comprehensive guidance on the installation, configuration, operation, and troubleshooting of the ULS-ProCopter System. This manual is designed to help users effectively integrate and utilize the system for precision landing and navigation applications.

Scope

This document is intended for use by system engineers, integrators, operators, and developers working with ULS-ProCopter systems. It provides detailed information on system operation, configuration procedures, and integration with autopilot systems.

System Base Components

Transmitter (Ground Unit)

Figure: ULS-ProCopter 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. Transmitter marks 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 onboard the ULS-ProCopter. This signal contains critical information needed for the operation of the ULS-ProCopter, such as positional data, commands, and system status.

Receiver (Onboard Unit)

Figure: ULS-ProCopter Receiver

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

The receiver decodes this signal to derive flight information such as positional coordinates, real-time transmitter status updates, and landing guidance. It interprets the data to navigate accurately and ensure drone follows the intended flight path. It provides feedback to the autopilot systems, such as Ardupilot and PX4, to adjust the flight parameters as needed for optimal and safety landing or hovering above.

Operation theory

All data communication from the transmitter to the receiver is done in the optical band, which eliminates interference with other radio devices and radio signals.

The transmitter contains an array of emitting elements that operate in the infrared range. The transmitter emits a modulated signal with each of the transmitter emitters transmitting a unique signal. Each of the transmitter emitters emits in a unique direction. The receiver receives the signal from the transmitter decodes it and by analyzing the signal can determine in which direction relative to the transmitter it is located. The distance to the transmitter is determined by the signal strength. Thus the system determines the position in a polar coordinate system with the origin at the center of the transmitter.

It is worth noting that due to the features described above, the receiver position readings will change when the transmitter orientation is changed, but the change in receiver orientation will have no effect if the transmitter and receiver are within the range of visibility of the systems specified in the specification.

This must be taken into account when working with the system. In order to calculate the position of the receiver without errors in case of orientation changes, the transmitter is equipped with an inertial orientation measurement system. This system allows you to determine the orientation of the module and transmit this information to the receiver by means of an infrared signal so that it can correct the position according to the inclination of the transmitter (transmitter level correction function).

The system can then convert the polar coordinate system to a Cartesian coordinate system. In this case, this coordinate system originates at the center of the transmitter.

Usually, to navigate and ensure a precise landing, the autopilot needs information about the position of the landing point in a coordinate system either attached to the drone’s body or in a global coordinate system.

The system can then convert the polar coordinate system to a Cartesian coordinate system. In this case, this coordinate system originates at the center of the transmitter.

To navigate and ensure a precise landing, the autopilot needs information about the position of the landing point in a coordinate system either attached to the drone’s body or in a global coordinate system. For this purpose, the receiver requests information from the autopilot about its position and orientation. Then, using this information and information about the orientation of the ground transmitter, the receiver can calculate the position of the transmitter relative to the drone in the required coordinates.

It important to point out that the system will act as a navigation sensor. The information from our system can be used by autopilots and drones for various purposes:

• Landing vehicle on platform
• Hovering over a point of interest
• Accurately dropping a load or precisely lowering it on a tether.

Functional description diagram

System specification.

Common specification:

Table: Common System Specifications Receiver (on board unit):

Table: Receiver Specifications Transmitter (on ground)

Table: Transmitter Specifications

Pinout information

Transmitter Pinout

Figure: ULS-ProCopter Transmitter Pinout Diagram

Table: Transmitter 8-pin Main Connector Pinout

Table: Transmitter 4-pin Connector Pinout

Receiver Pinout

Figure: Receiver Top Side Connector Variant

Figure: Receiver Strait Variant

Figure: ULS-ProCopter Receiver connector

Table: Receiver JX1 Connector Pinout (External Power and Control)

Mechanical dimensions

Figure: ULS-ProCopter Receiver dimensions

Figure: ULS-ProCopter Transmitter Mechanical Dimensions

Integration

Ground unit installation (transmitter)

The device must be installed on a clean surface to avoid any obstacles. The device must be installed in an open area. There must be no obstacles in the radiation field of the transmitting device. If possible, avoid installing the system near vertical surfaces that can strongly reflect infrared radiation. Device developed to be installed in panel and bolted with M4 screw. All customers get 3d model of system and cut panel as reference to make integration process more simple.

Panel cut-out drawing.

After installation, it is recommended to verify the correctness of the compass reading and, if necessary, correct the compass calibration.

Wiring Transmitter

The transmitter only requires power to operate. The transmitter can be powered via a 8-pin connector located nearby. External compass (IMU) and control data can be send over UART and CAN protocol. See pinout information of transmitter.

Configure transmitter in ULS-Tools

Table: Transmitter Configuration Parameters

Compass calibration

This compass is used to calculate an absolute heading of the ground unit. This information is transmitted to the Receiver and used to calculate NED coordinates. To be able to use compass, it needs to be calibrated before. To calibrate compass:

• Press “Reset calibrations”.
• Rotate device in different directions until you get 3 circles on charts (see picture below).
• Press “Apply calibration” & “Apply configuration”.

Compass chart after calibration:

Charts Transmitter

Program display several parameters of the device on charts:

• IMU data.
• Voltage (not valid when powered from USB).
• Temperature data.

Led Indicator

You can check the status of the transmitter looking on the LED indicator on the transmitter. LED flashes in sequences of colors, so it can flash green-red-off-off or green-off-blue-off.

Table: LED Indicator Status Colors

On-board unit installation (receiver)

The receiver can be installed both inside and outside the vehicle. However, please note that this version of the system is not equipped with protection against moisture and dust. The orientation of the receiver does not matter - however, when installing the receiver, care should be taken to ensure line-of-sight conditions between the transmitter and receiver throughout the entire field of view of the receiver (100 deg). The receiver sensor zone is indicated in the figure.

Once the receiver is installed, enter the appropriate receiver offset information into the configuration.

Wiring Receiver Pixhawk 4 autopilot connection using UART

Wiring for MultiRX mode (MRX)

Configure Receiver in ULS-Tools

Note:

To apply any changes, press “Apply Config” button at the bottom of the field.

Table: Receiver Configuration Parameters

Status Information field

In the status display area, you can check the status of the receiver and visualise the position of the receiver relative to the drone.

Table: Receiver Status Information Fields

Setup MRX mode

This option enables to use data from two receivers to calculate position. It allows calculating receiver yaw orientation using triangular method. In this mode, compass data (on ground and on board) is not affecting the position estimation, so it is more durable way to land. In this mode the maximum distance is limited by 10 m and at altitude above, it will use compass mode.

To set up and check MRX mode do the following:

• Connect receivers on board with CAN BUS.
• Configure “Receiver offset” for both receivers.
• Configure “Receiver orientation YAW” for both receivers (XCopter-G2).
• Enable option “MRX mode”.
• After set up, hover the drone above the transmitter (1 m - 2 m) and check that Tdistance and Distance are the same (+/- 20%).
• Correct “Receiver offset” option in case of TDistance and Distance are not approximately the same. Increasing position between receivers increases Tdistance and backwards.
• Rotate Drove over transmitter (1 m - 2 m) and check the value of the MRX-YAW on chart “GU Orientation”. It needs to be corresponding to the heading of the drone relatively to the transmitter.

Receiver Charts

Program display several parameters of the device on charts:

• Angles, Positions in different coordinate systems
• Distance
• Vehicle information (position and velocity)
• Data from Transmitters IMU.

Integration instructions for Ardupilot based systems.

Preparing for integration:

• Download the latest version of the ULSTools software. It is recommended to connect all sensors to PC and update the firmware for all UAVLAS devices in the system.
• Update autopilot with Arducopter latest version.
• Configure transmitter.
• Configure receiver.

Example of receiver configuration:

Autopilot configuration

Setup PLND section

Table: Ardupilot PLND Section Parameters All other parameters in PLND section defaults or use accordingly to your vehicle set up requirements.

On a picture example configuration provided.

Set up serial communication in SERIALx Section.

Table: Serial Communication Configuration (SERIALx Section) Set up serial communication messages in SRx Section. Sensor requires some data from autopilot to work in different modes.

Table: Serial Communication Messages (SRx Section) Check setup.

If all settings are done correct, autopilot has GPS data and receiver in the field of view of the transmitter, you can find LANDING_TARGET message in mavlink inspector (a screenshot from Mission Planner)

Setup Precision loiter mode.

To enable precision loiter mode you need attach any unused switch to PrecLoiter option see picture below:

Try to use this switch and you must get messages: “PrecLoiter: LOW” and “PrecLoiter: HIGH” After test flight above target check telemetry - you will find PL data contains offsets form landing target.

PID tuning

In case of oscillations and other issues at landing stage, pls, check PID parameters of Ardupilot.

It is recommended to check the Position XY, Velocity XY and Loiter speed parameters in “Extended tuning” section to achieve the best performance.

For additional information, see Ardupilot manual.

Integration instructions for PX4 based systems.

Preparing for integration:

• Download the latest version of the ULSTools software. It is recommended to connect all sensors to PC and update the firmware for all UAVLAS devices in the system.
• Update autopilot with PX4 latest version.
• Configure transmitter.
• Configure receiver.

Current version of the system can use MavlinkV2 protocol to communicate with PX4 autopilots (for now it supports MAV_FRAME_LOCAL_NED).

Example of receiver configuration:

Configure PX4 autopilot.

Values are provided as example (in our case, Pixhawk4-mini AP)

Table: PX4 Autopilot Configuration Parameters

Running and testing

After configuration and wiring, power up drone and transmitter. On QGround control, go “Analyze Tools” -> MAVLINK Inspector. Check LANDING_TARGET MAVLINK message

In case the vehicle provide LOCAL_POSITION_NED message to UAVLAS system, and it hovers over beacon, you get “position_valid = 1” in LANDING_TARGET

To perform precision landing, you need to create a flight plan and enable Precision Landing option on the landing point.

Troubleshooting

Before of all check:

• You are using latest version of ULS-Tools, latest firmware on ULS-XCOPTER transmitter and receiver, and latest Ardupilot (PX4) firmware.

No mavlink message:

• Transmitter are switched on and receiver in field of view of transmitter.
• Red light on receiver flashes fast ( > 5 times per second ). If it flash 2 times per sec it mean that transmitter not switched on, or not in field of view. If it not flash - check power.
• Check Serial setting on AP params and on receiver be sure you are set EXTRA params for corresponding serial port on AP.
• Check wiring power and RX, TX (see pinouts and wiring diagram)
• Check on receiver that MAV_FRAME_BODY_FRD (MAV_FRAME_LOCAL_NED) enabled.

Not holding in precision loiter mode but mavlink message ok:

• Check that you setup Precision loiter mode on AP

Circular motions during landing:

• Check compass calibration on ground unit.
• Check Compass calibration on AP.
• Check magnetic interference on ground.
• Use compass override mode to debug landing.
• Check precision landing PID settings.

The landing is not precise enough:

• Check the position control PID settings of AP.
• For Ardupilot check Kalman filter settings.
• Check filter smoothness param on receiver.
• Check trajectory Jerk settings on AP.

Change Control

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