Chapter 2: Communication Network and Infrastructure
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      Chapter 2: Communication Network and Infrastructure

      Communication Network and Infrastructure

      Background

      XAG is dedicated to bringing drones, robots, autopilot, artificial intelligence, and Internet-of- things into the world of agricultural production. During the development, the XAG UAV experiences a significant change on the communication Mechanisms.

      XAG products roadmap

      Year

      2020

      2021

      2022

      Model

      XP2020

      P40, V40

      P100

      Communication Mechanisms Comparison

       

      XP2020

      P40, V40, P100

      Communication Mechanisms

      Local computing + mesh network

      + 4G

      Cloud Computing in IoT using 4G

      Duo Channel (4G/WIFI)

      Local Network Terminal

      Does it need 4G?

      Yes

      Yes

      Yes

      No

      Does it use WIFI?

      Yes, mesh network

      No

      Yes

      Yes, LNT work as a WIFI hub.

      Remote Controller

      ACS2 2020

      ACS2 2021

      ACS2 2021

      ACS2 2021

      Android APP

       

      XAG Agri 2

       

      XAG One

       

      XAG One

       

      XAG One

      RTK station

      Portable station

      (WIFI)

      Fix Station (4G)

      Fix Station (4G)

      Portable Station

      (WIFI)

      Overview

      For XAG agriculture UAV (model 2021 above), the essential components of UAV-based network and infrastructures are UAV, ACS2 2021, XRTK4 portable station and XAG One App running on smartphone. Respected to different environment, there are three networking mode.

      No.

      Networking mode

      Under Environment

      1

      Cloud Computing in IoT (4G)

      Good 4G Network

      2

      Duo Channel (4G/WIFI)

      Poor 4G Network

      3

      Local Network Terminal

      No 4G Network

      Network Devices

      ACS2 Remote controller

      Model

      Description

      Photo

      ACS2 2020

      Used on XP2020 with XRTK4 portable station, fixed station, and CORS

      Identical hardware as ACS2 2021

      But with ACS2 2020 firmware installed

       

      ACS2 2021

      Used on V40/P40/P100 with XRTK portable, fixed station and CORS

      Identical hardware as ACS2 2020

      but with ACS2 2021 firmware installed

       

      Indeed, you can literally update the ACS2 firmware from 2020 to 2021 as they have the identical hardware, but our backend server will not recognize this device as its serial number is not registered as ACS2 2021 device. Thus, it’s not allowed to add in your XAG One account.

      RTK STATION

      MODEL

      Description

      Photo

      RTK FIX STATION

      Work as RTK base station, sending RTK/RTCM to cloud server through 4G network.

       

      RTK PORTABLE STATION

      As RTK base station, it’s optional to work

      with/without 4G network.

       

      If it works in 4G network, insert the 4G into it and bring the RTK online. It will broadcast RTK/RTCM data through 4G. Add the RTK station in App device list.

       

      If it works in WIFI, please add the RTK station in the LNT network. It will broadcast RTK/RTCM data through WIFI.

       

      Note: please be aware of that after the recent firmware update of RTK station, both portable and fix RTK station can broadcast RTCM/RTK through 4G network.

      UAV Model

      Model

      Variant

      Photo

      P40


       

      (CN) XAG P40 2021 STD UAV

       

      (EN) XAG P40 2021 STD UAV

       

      V40


       

      (CN) XAG V40 2021 STD UAV

       

      (EN) XAG V40 2021 STD UAV

      P100


       

      (CN) XAG P100 2021 STD UAV

       

      (EN) XAG P100 2021 STD UAV

       

      Networking Mode

      4G Networking Mode

      There are two variants of 4G networking mode. One is standard 4G networking mode, the other is Lite 4G networking mode. The difference between them is whether UAV has 4G SIM card inserted.

      #1: Direct 4G Networking Mode: Cloud Computing in IoT

      Introduction

      When the 4G coverage and signal strength are good, all the devices can have the access to the XAG cloud server through 4G network. The advantage of using 4G networking mode is to eliminate the communication range. The disadvantage is that the UAV may be suffered from 4G network delay.

      When to use Direct 4G networking mode?
      1.  Good 4G coverage in operation area
      2.  Users have access to CORS or XAG Fixed station

      Equipment Status on Wireless

      Equipment

      4G Sim Card Inserted?

      Wi-Fi

      UAV

      Yes

      Connected to RC

      RC

      Yes

      AP (Access Point)

      XRTK4 (optional)

      Yes

      Disabled

      Smartphone/Pad

      Yes

      Disabled

      Requirements:

      1. Good4G network coverage
      2. If use GNSS/XRTK Fix station, the distance between operation and station must be within 30km because the common number of satellites should be above 16 and the weather condition can 
      3. All the devices (XRTK Fixed Station/Smartphone/ACS2 2021/UAV) need to have 4GSIM card inserted. Depending on the use of UAV, the data plans can be varied. For reference:

      Items (device)

      Data Plan

      GNSS/RTK Fix Station

      500M/month

      Smartphone (XAG One App)

      1G/month

      ACS2 2021

      300M/month

      UAV

      1G/month

      #2: Semi-Direct 4G Networking Mode

      Introduction

      Our user is allowed to enable Wi-Fi communication channel between remote controller and UAV. In such way, the UAV is no longer required to insert 4G SIM card. However, it requires users manually pair the UAV to remote controller. This mode allows UAV to access internet through remote controller.

      When to use Semi-Direct 4G networking mode?
      1.  Good 4G coverage in operation area
      2. Users have CORS account / XAG Fixed station.

      Equipment Status on Wireless

      Equipment

      4G Sim Card Inserted?

      Wi-Fi

      UAV

      No

      Connected to RC

      RC

      Yes

      AP (Access Point)

      XRTK4

      Yes

      Disabled

      Smartphone

      Yes

      Disabled

      LNT Networking Mode

      There are two variants of LNT networking mode. One is standard LNT networking mode, the other is Field mapping LNT Networking Mode. The difference between them is whether UAV has 4G SIM card inserted.

      #1: Standard LNT Networking Mode

      Local network terminal, abbr, LNT, is a type of networking mode that works without internet. It works as a local IOT server and communicate with other devices through the local Wi-Fi network. You can regard the LNT as the substitution of the cloud Server. LNT and its IOT devices must be properly upgraded and configured before use.

      DESCRIPTION

      ITEMS (DEVICE)

      4G network

      WIFI (2.4/5.8GHz)

      GNSS/RTK PORTABLE STATION

      Not in use

      Sent RTK/RTCM reference to LNT;

      XAG ONE APP

      Not in use

      Communicate with LNT; UAV setting; Flight mission, UAV status, Field mapping, etc. firmware downloads and update,

      ACS2 2021

      Not in use

      Communicate with LNT; Send manual control command to LNT

      UAV

      Not in use

      Communicate with LNT

      LNT

      N/A

      Local IOT server

      Requirements:

      • GNSS/XRTK portable station is a must
      • LNT must be put in a high place, with battery supply. The LNT WIFI only allows the maximum communication range of 800m without any interference.

      Awareness

      • As the smartphone can only reach the LNT within 100m, if the ACS2 hotspot is unstable during field mapping, user can switch to the field mapping of LNT. Please read the next page.

      Advantage:

      • No 4G network is required. Thus, Smartphone, ACS2 2021 and UAV do not need 4G Due to the hardware safety check, XRTK portable station still need 4G Sim inserted but will use no data.
      • No RTK fix station is required. Instead, the RTK portable station will be used. It means that the users no longer rely on the RTK fix station (only 30km) and can move around as they want.

      Disadvantage:

      • LNT has limited communication range, maximum 800m. Depending on various environments, this communication range can differ.
      • Smartphone has limited communication. only the maximum range of 100mbetween smartphone and LNT
      • LNT and its battery can be an extra cost.

      #2: Field mapping LNT Networking Mode

      This networking mode is only used in field mapping, please do not use it in flight mission. Otherwise, the UAV will suffer from huge network delay and keep switching between online and offline.

      This mode is designed for field mapping. Some users may encounter huge network delay when using smartphone on field mapping as they usually walk into the field and stay far away from the LNT. As the smartphone only has the physical WIFI range less than 100 meters, the smartphone will disconnect from LNT if the smartphone stays too far from LNT. To solve the issue of short physical WIFI range between smartphone and LNT, we can connect our smartphone to ACS2 remote controller. From here, we can enhance the physical WIFI range of smartphone as ACS2 work as RP repeater.

      The benefit of this solution is that the communication range between smartphone and LNT increase from 100m to 800m in ideal environment. It’s useful during field mapping, which the smartphone will be carried away from LNT.

      Requirements:

      • GNSS/XRTK portable station is a must.
      • LNT must be put in a high place, with battery. The WIFI antenna of LNT only allows the maximum communication range of 800m.
      • Connect smartphone to ACS2 2021 remote controller’s hotspot.

      Advantage/disadvantage:

      Same as local network terminal

      DESCRIPTION

      ITEMS (DEVICE)

      4G network

      WIFI (2.4/5.8GHz)

      GNSS/RTK PORTABLE STATION

      Not in use

      Sent RTK/RTCM reference to LNT;

      XAG ONE, ANDROID APP

      Not in use

      Communicate with LNT through ACS2 2021 remote controller; UAV setting; Flight mission; Field mapping; firmware downloads and update

      ACS2 2021

      Not in use

      Communicate with LNT; Send manual control command to LNT

      UAV

      Not in use

      Communicate with LNT

      LNT

      N/A

      Local IOT server

      Remote Controller Networking Mode (RCN)

      There are four variants of RCN mode.

      RCN Local
      Semi-DirectRCN4G
      Direct RCN4G
      RCNWiFi

      #1: RCN Local

      Introduction

      RC (Remote controller) networking mode is a type of networking mode that works without internet. It uses remote controller as the communication host in the local Wi-Fi network.

       

      Local RCN

       

      4G SIM inserted?

      Wi-Fi

      UAV

      N

      Connect to RC

      RC

      N

      AP

      Smartphone/Pad

      N

      Connect to RC

      #2: Semi-Direct RCN4G (Standard)

      As local RCN mode is based on the local Wi-Fi network, which works perfectly fine when the field has no internet access. However, the internet inaccessibility will also affect the use of this UAV system. Basically, users may not be able to update the firmware online, or not able to use CORS, etc. Thus, semi-Direct RCN4G mode could solve these issues. Once a valid 4G SIM card is inserted into remote controller, the local RCN mode can automatically change to Semi-Direct RCN4G mode. Our UAV system will have communication to internet and allow users to use CORS or update firmware online.

       

      Semi-Direct RCN4G

       

      4G SIM inserted?

      Wi-Fi

      UAV

      N

      Connect to RC

      RC

      Y

      AP

      Smartphone/Pad

      N/Y

      Connect to RC

      #3: Direct RCN4G

      Semi RCN4G mode is good as our UAV system can have access to internet. But the remote controller works as AP and all other devices must go through it to access internet. However, the semi RCN4G may result in the high latency of CORS as the Wi-Fi network delay between UAV and RC happens in field operation. In this scenario, Direct RCN4G can solve this issue because the UAV can access internet directly without accessing RC Wi-Fi network. Once a valid 4G SIM card is inserted into remote controller, the Semi-Direct RCN mode can automatically change to Direct RCN4G mode.

       

      Direct RCN4G

       

      4G SIM inserted?

      Wi-Fi

      UAV

      Y

      Connect to RC

      RC

      Y

      AP

      Smartphone/Pad

      N/Y

      Connect to RC

      RCN4G – CORS

      RCN4G – RTK Portable Station 

      RCN4G – RTK Fixed Station 

      #4: RCNWiFi

      RCNWiFi mode is very similar to Semi Direct RCN4G mode. In Semi Direct RCN4G, the remote controller connects to router. While in RCNWiFi, the remote controller connects to wireless access point (wired router or portable router). Field WiFi network may be provided by portable LTE router, wired router or mobile hotspot.

       

      RCNWiFi

       

      4G SIM inserted?

      Wi-Fi

      UAV

      N

      Connect to RC

      RC

      N

      AP1: UAV/Phone;

      AP2: office/home router

      Smartphone/Pad

      N

      Connect to RC

      RCNWiFi - CORS

      RCNWiFi - RTK portable station 

      RCNWiFi – RTK fixed station