MyFlyDream Crossbow AAT Automatic Antenna Tracker User Manual

: June 12, 2024
: MyFlyDream

Table of Contents

MyFlyDream Crossbow AAT Automatic Antenna Tracker
Product Information
Product Usage Instructions
Product Introduction
Installation and wiring
Test
Downlink
5(Blue) wire to the upper-connector of the tracker.
AAT menu operation guide
Appendix A
References
Read User Manual Online (PDF format)
Download This Manual (PDF format)

MyFlyDream Crossbow AAT Automatic Antenna Tracker

Product Information

The MyFlyDream Crossbow AAT (Automatic Antenna Tracker) is a precision electromechanical device designed for use with unmanned aerial vehicles (UAVs) on-board antenna systems. Its purpose is to point the antenna precisely in the current direction of the aircraft, allowing the video receiver to pick up the strongest signal possible at a given distance and other factors. To achieve better signal reception quality, it is recommended to use high-gain receiving antennas, as they have very narrow angles of effective reception. The Crossbow AAT requires flight data such as latitude, longitude, and altitude of the tracked target (UAV) at every given moment.

The information of the tracked target can be transmitted to the Crossbow AAT through various methods:

Wireless analog video link from the UAV to the ground station using a MFD Auto Pilot, MFD Crosshair Auto Pilot, or a third-party AP with an MFD TeleFlyTiny tracking module.
Wireless High Definition video link from the UAV to the ground station using a MFD Auto Pilot, MFD Crosshair Auto Pilot, MAVLink-compatible Auto Pilot, or a third-party AP with an MFD TeleFlyTiny tracking module.
Wireless digital data link from the UAV to the ground station using MAVLink protocol. This requires the on-board system to include a digital radio and a flight controller that supports MAVLink protocol.
For specific applications requiring custom signal transmission design, please contact MFD directly.

Product Specifications:

Tracking Ability: Mechanical/Electrical specifications
Protocol Interface: MFD VBI, MAVLink
MAX Pan-Speed: 300 deg/s
MAX Tilt-Speed: 60 deg/s
MAX Pan-Angle: Unlimited/450 deg
MAX Tilt-Angle: -15 deg to 135 deg
Weight: Not specified
MAX Tilt Torque: Not specified
Operating Voltage: Not specified
Power Consumption: Not specified

Product Usage Instructions

Ensure that you have read the product manual carefully before using the Crossbow AAT .Connect the Crossbow AAT to the ground station and power it on. Make sure the UAV is equipped with a compatible tracking module or Auto Pilot:

If using a wireless analog video link, ensure the UAV is equipped with a MFD Auto Pilot, MFD Crosshair Auto Pilot, or a third-party AP with an MFD TeleFlyTiny tracking module
If using a wireless High Definition video link, ensure the UAV is equipped with a MFD Auto Pilot, MFD Crosshair Auto Pilot, MAVLink-compatible Auto Pilot, or a third-party AP with an MFD TeleFlyTiny tracking module.
If using a wireless digital data link, ensure the UAV’s on-board system includes a digital radio and a flight controller that supports MAVLink protocol.

Configure the necessary settings on the Crossbow AAT according to your specific requirements. Refer to the product manual for detailed instructions on configuration. Ensure that the tracked target (UAV) is transmitting the necessary flight data to the Crossbow AAT through the specified communication method (analog video link, HD video link, or digital data link). The Crossbow AAT will automatically track the UAV’s position and adjust the antenna direction to pick up the strongest signal. Monitor the signal reception quality on the ground station and make any necessary adjustments to optimize the antenna positioning. For any specific applications requiring custom signal transmission design, please contact MFD directly for assistance.

Precautions
Thank you for purchasing the MyFlyDream Crossbow AAT (Automatic Antenna Tracker, hereafter referred to as Crossbow AAT).
Please familiarize yourself with this product and its operation method described in this document. This product is a precision electromechanical device. Please read this document carefully to prevent damage to the device and minimize the risks of damage to property or people’s lives.
Please only use this device according to local laws, rules, and regulations. Its performance may be affected by a number of factors such as but not only: Strong electromagnetic interference, poor GPS status, etc. All these reasons can lead to unexpected results. All risks and consequences resulting from the use of this product are borne by the user.
We reserve the right to continuously improve and improve the performance of our products, so the content of this document does not necessarily match the specifications of your products. Please download the latest version of this document from our website:
www.MyFlyDream.com/download/

Product Introduction

Crossbow AAT is designed for use with unmanned aerial vehicle (UAV) on-board antenna
system. Its purpose and objective is to point the antenna precisely in the current direction of the aircraft thus allowing the video receiver to pick up the strongest signal possible at given distance and other factors.
In order to obtain better signal reception quality, it is advised to use high- gain receiving antennas. High-gain antennas are known for very narrow angles of effective reception.
For its successful operation, Crossbow AAT requires the flight data such as latitude and longitude of the tracked target (UAV) at every given moment, as well as its altitude.
This is achieved by the following:

Transmitting information of the tracked target over a wireless analog video link from the UAV to the ground station. For that, the UAV must be equipped either by a MFD Auto Pilot, or a MFD Crosshair Auto Pilot, or in case a third party AP is used with a MFD TeleFlyTiny tracking module.
ATTENTION: Using TeleFlyTiny module is possible with many third party flight controllers. MFD does not guarantee that it works with any particular make or model of the autopilot, nor that it will continue to work with any third party autopilot after its firmware or software is updated.
Transmitting information of the tracked target over a wireless High Definition video link from the UAV to the ground station. For that, the UAV must be equipped either by a MFD Auto Pilot, or a MFD Crosshair Auto Pilot, or a MAVLink-compatible Auto Pilot, or in case a third party AP is used, an MFD TeleFlyTiny tracking module. The signal containing encoded tracking data from the TeleFlyTiny module on the aircraft will be transmitted to the Crossbow AAT through the serial port .
Transmitting information of the tracked target over a wireless digital data link from the UAV to the ground station.
MAVLink protocol allows to transmit the information from the UAV through the digital radio link. If the on-board system already includes the digital radio, and the flight controller that supports MAVLink protocol, Crossbow AAT will be able to receive all flight information necessary to track the UAV through the shared TXD line of the digital radio station.
For more specific applications requiring custom design of the signal transmission, please contact MFD directly.

MyFlyDream Crossbow Specifications

Tracking Ability

Mechanical/Electrical specifications

| Weight| 2.6kg
MAX Tilt Torque| 14kgf.cm
Operating

Voltage

| 12~16V DC
Power

Consumption

| < 15W (Typical)

Protocol Interface

| MFD VBI| All MFD Autopilots/TeleFlyPro/TeleFlyTiny supported
MAVLink| MAVLink V1.0/V2.0 supported

Installation and wiring

The AAT can be fixed on the head of a regular camera/camcorder tripod by the means of a standard 1/4-20 threaded interface at the bottom of the main unit. Make sure the tripod you use is capable of supporting the size, weight, and leverage of the battery+AAT+Antenna assembly. Correct choice of a tripod is the user’s responsibility. Please make sure that the quick release plate of the tripod is compatible with the threaded interface on the bottom of the AAT main unit.

Appendix B. shows details of the mounting interface of the AAT.
Crossbow AAT requires =12V to 16V (3S~4S) DC power supply. The recommended power supply solution is 2 x NP-F980 batteries (7.4V 6600mah).

The tracker is powered on by simply plugging the XT60 connector into the corresponding power socket of the AAT, as shown in the picture:

The antenna has to be mounted on the Crossbow AAT with the use of a special bracket.In order to prevent tampering with the normal operation of the compass built into the Crossbow AAT it is recommended to avoid using antennas made with ferromagnetic materials. Wherever possible, use non-magnetic stainless steel bolts, aluminum and other non-magnetic materials.

There is an aviation-socket on the main unit(the upper connector), and a cable with aviation-plug and color coded wires.

Please connect it to your equipment’s (Data Radio, VideoRX… etc) using the following color coding diagram:

Upper Connector Cable Color Definition

If you wish to use MAVLink protocol to provide tracking data through digital radio link: Fix the digital radio link on the antenna bracket.
Connect the black wire of the plug cable to the ground wire of the digital radio link. Connect the red wire to the power wire of the digital radio link.

ATTENTION: Voltage supplied via the red wire(=12 to16V) may be different from the digital radio needs. Please use a suitable power conversion module if the digital radio power voltage is different from the above mentioned.
Connect the TX (data output line) of the digital radio link to the green line of the cable.
Power on the digital radio link.
Usually, the UAV ground station also needs to be connected to the digital radio link. Sharing the TX line of the digital radio link with Crossbow AAT will not affect the normal ground station operation.

The base of the AAT has 2 similar aviation-sockets for use with 2 matching cable with a aviation-plugs and color coded wires. If the analog video signal is fed to the socket mentioned in clause 3 (right above), this video signal can be obtained from the green line of the socket on the base after passing through the internal slip ring.

Lower Left Connector Cable Color Definition

PIN#| Wiring Color| Definition
#1| Orange| Telemetry Data TX(U3 TX)

(connected with RX of your DataRadio)

#2| Blue| Telemetry Data TX(U3 RX)

(connected with TX of your DataRadio)

#3| Red| 12V~16V power supply (shared AAT power

supply voltage)

There is also a Crossbow RF model which uses a RF-Slipring inside. With this RF version, users can mount their antenna on the tracker and access the signal(Up to 3GHz) with the lower N-Connector of the Crossbow. The RF model looks a little bit different:

Choose the GPS + Compass module to get better tracking performance:

The Crossbow will recognize the GPS + Compass module once it’s plugged. The screen will display something like GPS:12/L14 to show the number of satellites locked by remote GPS/ local GPS. With this module, The tracker will start to track when it locks enough satellites without setting home operation.

Test

Please make sure the tripod is securely set up, and its legs are well tightened. Then power on the AAT.
Normally, the tilt angle will return to the horizontal 0 degrees (pointing to the horizon), and the AAT will be rotate several times for initialization. The following information will be displayed on the OLED screen of the Crossbow AAT:

Main Screen Descriptions

Display Item| Description
GPS/LocalGPS Batt| GPS Satellites locked. If an external GPS is connected, GPS/LocalGPS will be displayed in 12/11 formation (GPS=12, Local=11)

Batt (Voltage of the main battery) will be displayed alternatively here.

Dist| Distance of the plane (Not Available before SetHome)
Alt| Altitude of the plane (Not Available before SetHome)
Azim| Azimuth of the plane (Not Available before SetHome)
VLink/DLink| Video/Data downlink quality. (in %, ref to the “Downlink” chapter)
Dir/EDir| Current heading diretion of the tracker.

If an external compass is connected, EDir will be displayed alternatively

When you get enough satellites locked (usually 8 or more), press the right button on the base to SetHome for the tracker. With MFD AP/MFD Crosshair you can SetHome for your plane, meanwhile the Home location of the tracker will also be set.
Once the plane flies to 10 meters away, the tracker will start to track.
Crossbow can work in 2 modes: Unlimited/450degrees.
In Unlimited mode the Crossbow AAT can rotate in one direction continuously.
In 450degrees mode, The tracker will rotate back 360 degrees when it reached its limits (to avoid twisting cables between tracker upper rotating part and the ground devices. To use 450deg mode, please turn the tracker manually to point to your favorite direction (the opposite direction is rarely used in the flight). Then hold the right button of the tracker for 3 seconds or longer. The heading direction of the tracker will be stored as the current favorite direction until power off.
The below diagram describes how 450deg mode works.
We assume that the plane is circling above the tracker in counterclockwise direction (Top view, Look from the sky). The tracker starts from the point A. It rotates 360 degrees in CCW direction. It won’t rotate in opposite direction immediately now to avoid oscillating in this position. It keeps rotating until it reaches the point B. To avoid twisting cables the Crossbow will quickly rotate 360 degrees clockwise and point to B again.
If the plane circles clockwise, something similar will happen in the opposite way. Mostly the tracker can rotate 360+45+45=450degrees. That’s why we call it “450degrees mode”.

Downlink

The Crossbow AAT needs a downlink to get the information of the tracking plane.
Usually this is the most difficult part to get your system to work. Because you have to merge several devices came from different manufactories.
We may extend this chapter in the future. Currently we discuss only VBI solution and dataradio solution(Based on MAVLink).

VBI
VBI stands for “vertical blanking interval”. It’s a term of the analog video signal technology. Many MFD products use VBI to carry flying information from the plane to the tracker.
The advantage of VBI is that you don’t need an extra dataradio if you already have a video TX and RX. These MFD products will encode the necessary data on your analog video signal (usually comes from an onboard camera). Your VideoTX emits it. Once your Video Receiver receives the video signal, and feeds the signal to a MFD tracker, the tracker will extra tracking data from the analog video signal and use the data to track.
Early MFD AP / TeleFlyPro support our VBI protocol V1.
Our Crossbow supports V1. (Menu “VBIVersion=>V1″)
Later MFD Crosshair / TeleFlyTiny support V1 and V2.
V2 works better in long range.
To use VBI for the tracker, please setup your plane correctly. Make sure your video RX outputs clear videos (check with an AV monitor) . Feed the signal to PIN#2 of the upper socket (of course you need a common Ground wire between your VideoRX and the tracker).
Note that you need to make sure the plane side and the tracker are using the same VBI version. If the tracker decodes information from the video signal successfully, the main screen will display like”VLink:90%”.

DataRadio (MAVLink):
With a pair of DataRadio you can send data from the plane to your tracker. There are many protocol can be use to establish a downlink, private ones, and open ones. MAVLink is one of the most popular ones. It’s not perfect but it’s common. Many autopilots support it, including MFD Crosshair AP.
If you use a Pixhawk/ArduPilot device, I assume you already connect your DataRadios and they are working well. Now we are going to integrate the MFD Crossbow AAT to your system.
The DataRadio device can be mounted to the tracker and rotates together with the tracker. In this case the tracker still has the ability to rotate continuously without any limitation.

But if the DataRadio is very heavy or you have some other reasons to keep it on the ground, you have to connect a cable from your antenna to your DataRadio in this case. You need to set FavDir (Favorite Direction) of your flight. The tracker will work in 450 degrees mode to avoid twisting cables.
More and more HighDefinition Video devices are available on the market. Most of them also support a built-in serial port datalink. (For example, the OpenHD project). If you are using this kind of video link and running MAVLink protocol on it, you can simply consider it’s serial port as a DataRadio output. Feed data to the RX wire(blue) to the upper-connector of the tracker to establish a downlink. In this case usually you also need a HDMI cable or Ethernet cable to get video signal from the VideoRX on the tracker. These cables limits the tracker to rotate continuously. You need to use the tracker in 450 degrees mode.
Finally you have this solution: The tracker pitch/yaw the antenna only. Your VideoRX and DataRadio stay on the ground and connect with your antenna via feeder cables.
No matter where you install your DataRadio, you need to share its TX line to

5(Blue) wire to the upper-connector of the tracker.

Note: About the MAVLink
The MAVLink protocol has been used/implemented in many Flight Controllers, Ground Control Stations(GCS) and trackers. But actually many devices use the MAVLink in their own way. One of the reasons is that MAVLink is not clear enough to define how to send some important data between the Plane And GCS. There are so many different MAVLink messages which can be used to send GPS Coordinates, Altitudes…
Crossbow AAT needs both these 2 MAVLink messages to track.
MAVLINK_MSG_ID_GPS_RAW_INT
MAVLINK_MSG_ID_GLOBAL_POSITION_INT
If the Crossbow AAT receives some correct MAVLink data packs (Heartbeat?) but not able to find the above 2 messages, it will display “DLink:1% msg?” to remind you to check if the above 2 messages are sent at 1Hz or a higher frequency.
In Crossbow AAT, If you choose menu “Protocol->ALT=BARO”,
MAVLINK_MSG_ID_GLOBAL_POSITION_INT.relative_alt is used as the data source of the altitude. This works for most ArduPilots. (APM), and MFD Crosshair AP.
You can check “FlightInfo-> ALT/BARO” to read the current GPS-ALT and Baro- Alt.
Crossbow uses “Baro” Alt to track.
Another option is “Protocol->ALT=GPS”. In this case, MAVLINK_MSG_ID_GPS_RAW_INT will be used as the data source of the altitude. This works for most PIX4 Flight Controllers.
In this case, “FlightInfo-> ALT/BARO” are both from MAVLINK_MSG_ID_GPS_RAWINT message.
We recommend our users to set the update frequency of the above 2 messages higher to get better tracking performance. The method varies from different Flight Controllers. Take the ArduPilot Mega as an example, you can search for string”SR1” in Mission Planner “All parameters List” to get a table of MAVLink messages updating frequency for Telemetry1 port. Please set SR1_POSITION to 5Hz or higher in this case. 0=Disable.

TroubleShooting: My Data Radio doesn’t work with Crossbow. Only VLink:0% is displayed

Check if the tracker is receiving data from your date radio. Check Menu item
“Factory->CoreData->RX”. This number will increase when the tracker receives any data from U3RX (Datalink port) or U2RX(External GPS port). If the RX doesn’t increate at all, please check your cables again and make sure your DataRadio is sending out date on its TX wire.
Check menu “Baud Rate” again to make sure you are using a proper baudrate, especially after you apply a new firmware.

After power on the screen shows main parameters of the current status.

To enter/quit the menu system, hold the LEFT button for 2 seconds or longer. You can also choose “Exit” in the menu to quit the menu system.
Please use the LEFT button to browse the menu.
Use the RIGHT button to enter sub-menu or change values.

If the tracker is slightly tracking the plane left or right, you can apply some YawTrim to make it more accurate. Use Negative values to trim the tracker to LEFT. Use Positive values to trim the tracker to RIGHT.
You can also use the Pitch item to trim the tracker UP/DOWN.
The valid parameter range is [-20,20]

H1~H5 is the Home Positions which you recently have used. H1 is the most recent home position. H5 is the earliest one.
The distances between your plane and the H1~H5 stored home positions are displayed in a D:XXXXX formation. Also the longitude and latitude of each home position will be displayed alternatively to help the user to decide which Home Position should be load to use.
Click the right button to load a high-light (selected) home position.
If you forgot to Set Home before takeoff, this function will be helpful especially you have a proper pre-saved home position in the tracker.
AutoLoad=N means the tracker will not load the most recent home position when it starts up. Click the right button to set AutoLoad=Y to enable it.
CalCompass:

Click the right button to execute a compass calibrate the compass of the tracker.
Before doing that please make sure the tracker is locked on the tripod well.
It takes about 20 seconds to finish the calibration. You can ignore the parameters showing on the screen during the procedure.
MotorCurr:

Use the right button to set the maximum current for the Pitch or Yaw motor. (in mA) Valid range of these parameters are [0,4500] mA
You can also use “AutoDetect” to measure the proper settings of your setup. Remember to fasten your tracker and clear all objects nearby before doing that. Because the tracker may yaw and pitch to any direction during the procedure.

CalPitch:

Use this function to calibrate the pitch sub-system of your tracker. Tracker needs to know the horizontal position to work well. Please follow these instructions to Cal. Pitch:

Use “Pitch UP” and “Pitch DOWN” to adjust the tracker until it points to horizon. (Imaging that the plane is very far and low).
Use “Save L Pos” to save this Low Position.
Use “Pitch UP” and “Pitch DOWN” to adjust the tracker until it is about 110 degrees. (Not restrict 110 degrees, but it must > 90 degrees.) That means the tracker reaches vertical position and goes further.
Use “Save H Pos” to save this High Position.
Save & Exit.

Choose a downlink baudrate to match your dataradio setting.

This screen displays some useful information of the plane which is being tracked.
Lon/Lat is the GPS coordinates of the plane.
ASL: AboveSeaLevel altitude of the plane. Usually comes from the GPS data of the plane. BARO: Barometer altitude of the plane. Usually comes from the barometer of the plane.

Choose the OSD(OnScreenDisplay) brightness level of the tracker. The tracker is able to overlay some graphics information on the analog video signal. Higher value will choose brighter OSD images. With the CAN-BUS and our new “FlyTogether” feature, users now can connect up to 10 trackers. Everybody can see other’s relative position/altitude on the screen. Valid range of this parameter is [0,100].

VBISetting:

Choose V1 to work with old MFD products (MFD AP, MFD TeleFlyPro).
Choose V2 to work with new MFD products(MFD Crosshair AP, MFD TeleFlyTiny. You can also choose V1 for Crosshair/TeleFlyTiny with their own menu).
This is about how to use the analog video to carry flying information.
MFD devices can encode information to the analog video signal.
The tracker will extract necessary information from it. V2 works better in long range.

Choose ALT=BARO or ALT=GPS to determine what altitude data of the MAVLink data stream will be used to track. We will discuss this in the chapter “5. Downlink”.

Choose the numeral ID of the tracker. When you use “FlyTogether” function, your ID will be displayed on other’s OSD screen. You need a unique ID when you joining a “FlyTogether” CAN-Bus network.
The valid range is [0,9]

This screen shows version number of the firmware (1.83) and Hardware (1)

This screen is reserved for the manufacture.

Appendix A

Appendix B:
MAVLink support of MyFlyDream Crossbow AAT
Crossbow AAT supports MAVLink V1.1 protocol.
The system requires at least these 2 MAVLink Messages with a 2Hz or higher update rate.

When you set menu [Protocol->ALT=BARO], the Crossbow [MAVLINK_MSG_ID_GLOBAL_POSITION_INT.relative_alt] field for pitch tracking. When you set menu [Protoco->ALT=GPS], the Crossbow AAT uses
[MAVLINK_MSG_ID_GPS_RAW_INT.alt] for pitch tracking.
Which specific ALT setting you need to use depends on the behaviour of your AutoPilot.
Due to the imperfect world of MAVLink you need to pay more attention about the Altitude information of MAVLink. There are about 6~7 places allow the autopilots to send altitude data or barometer data. It’s difficult to tell which altitude is exact you need. There are altitudes based on GPS (ASL), based on a baro-altimeter, or based on a combination result of GPS+Baro+Accelerometer… etc. Different AutoPilots use these altitude fields in the way they understand. That’s why we offer this [Protocol.ALT] menu to allow users to choose a altitude field to match their AutoPilot.

Appendix C:
How to update Firmware for the Crossbow

Please connect the update tool to your Crossbow tracker.
Insert the USB plug to your windows PC.
Install the driver for USB-TTL if necessary:
http://www.myflydream.com/inc/lib/download/download.php?DId=30 download the MFD FW & update tool (you need .Net 4.0 framework to use it) http://www.myflydream.com/inc/lib/download/download.php?DId=61

Choose “38400” baudrate for Crossbow <<<
You need to power on your Crossbow to update firm wares <<<

Run MFD_Update.exe. Choose “MFD_AAT”. Choose correct COM port of your computer (The specific COM port number depends on your system). Browse for the firmware on your computer by clicking “choose the file”. Then click “Update” button.
A popup window will appear to ask you to confirm the update. Click “YES”.
Just wait for a few seconds until the update finishes.

Please check these settings after update:

Set Baudrate to the value that you need to work with your gears.
Set Current of your 2 motors by menu “MotorCurr”. Usually you can use 2000ma for both motors.
Calibrate the compass module with menu “CalCompass”. If you have an external GPS+compass module please plug it to the tracker before calibration.