Issue with LoRa - steady rate of corrections, good signal to noise ratio in the Caribbean

fluid.systems.base · August 24, 2019, 10:52pm

Recently I was working on a project in a suburban area, using Reach RS2 GPS.
The mode of cmmunication I used between base station and Rover was LoRa.

Based on where i set up my base station (in close proximity (<15m) to single storey homes and about 800m away from cellphone towers), I experienced difficulty with the rover in receiving a steady rate of corrections, with favourable signal to noise ratio, from the base station.

I tried changing:
Frequency of communication in LoRa mode
Frequency of receiving RTCM3 corrections for GPS, GLONASS AND GALILEO
And also lowering Air Data rate.

All changes were made simultaneously on both Rover and Base.

Within a 1km radius of the base I experienced these difficulties with attempting to achieve a fix and as stated above…steady rate of corrections, with favourable signal to noise ratio.

If anyone has any suggestions they can give I would greatly appreciate it.

timd1971 · August 24, 2019, 11:23pm

You may want to post the SIMPLE SYSTEM REPORT for both BASE & ROVER.

agrimgalina · August 25, 2019, 12:14am

I have noticed the same as you and in ntrip too.

wizprod · August 25, 2019, 5:00am

A few questions:

how many DB are you transmitting with?
What is in between your base and rover (hills, buildings, line-of-sight?)
Have you tried switching around the antennas from base and rover?
have you checked that both antennas are correctly screwed in?

wizprod · August 25, 2019, 5:01am

With this, are you then saying that the corrections do not have the same SNR as when they were received by the base?

agrimgalina · August 25, 2019, 12:41pm

@wizprod I have experience with my RS +, the settings are correct. Less than 100 meters all clear, PDOP 1.3, age 0.4, there are no medium voltage lines and not fixed. I kept thinking if the frequency had changed, it also happened to me with ntrip

agrimgalina · August 25, 2019, 12:56pm

@wizprod if it is difficult to insert the antenna through silicone protection

fluid.systems.base · August 25, 2019, 4:07pm

In the worst case observation point, there is a dense arrangement of single storey homes between the base and rover, as well as moderate shrubbery about 12 ft to 18 ft high.

In other directions there is only a change in topography with little vegetation, however the base station remains partially blocked, in line of sight, to the measurement points.

fluid.systems.base · August 25, 2019, 4:10pm

There are also local electricity transmission lines.

fluid.systems.base · August 25, 2019, 4:11pm

Yes i have checked that the antennas are properly screwed in.

But I have not tried switching around the antennas.

What does DB refer to??

fluid.systems.base · August 25, 2019, 4:12pm

Rover Simple System Report:

Simple system report


app version: 2.20.7-rs2-rc0-r0

'wifi_status, interface: wlan0':

- wifi_mode: infrastructure

- ip: 192.168.100.72

  is_added: true

  is_connected: true

  is_visible: false

  mac_address: 6C:21:A2:92:B2:00

  security: wpa-psk

  ssid: Digicel_WiFi_qx5V

  uuid: e9618f7a-144c-4147-8aab-289986ff00db

base mode:

  base coordinates:

    accumulation: '2'

    antenna offset:

      east: '0'

      north: '0'

      up: '0'

    coordinates:

    - '0'

    - '0'

    - '0'

    format: llh

    mode: single-and-hold

  output:

    enabled: true

    format: rtcm3

    path: tcpsvr://:9000#rtcm3

    type: tcpsvr

  rtcm3 messages:

    '1006':

      enabled: true

      frequency: '0.1'

    '1074':

      enabled: true

      frequency: '1'

    '1084':

      enabled: true

      frequency: '1'

    '1094':

      enabled: false

      frequency: '1'

    '1124':

      enabled: false

      frequency: '1'

bluetooth:

  discoverable: false

  enabled: false

  pin: '***'

correction input:

  input2:

    enabled: true

    format: rtcm3

    path: ttyMFD2:38400:8:n:1:off

    send position to base: 'off'

    type: serial

  input3:

    enabled: false

    format: rtcm3

    path: :9028

    type: tcpsvr

logging:

  base:

    format: RTCM3

    started: true

    version: null

  correction:

    format: RTCM3

    started: true

    version: null

  interval: 24

  overwrite: true

  raw:

    format: UBX

    started: true

    version: null

  solution:

    format: LLH

    started: true

    version: null

lora:

  air rate: 2.6000000000000001

  frequency: 868000

  output power: 20

position output:

  output1:

    enabled: true

    format: nmea

    path: bluetooth

    type: bluetooth

  output2:

    enabled: true

    format: llh

    path: :9001

    type: tcpsvr

  output3:

    enabled: true

    format: llh

    path: :2014

    type: tcpsvr

  output4:

    enabled: true

    format: llh_ext

    path: :2015

    type: tcpsvr

rtk settings:

  elevation mask angle: '15'

  glonass ar mode: 'off'

  gps ar mode: fix-and-hold

  max horizontal acceleration: '1'

  max vertical acceleration: '1'

  positioning mode: kinematic

  positioning systems:

    compass: true

    galileo: true

    glonass: true

    gps: true

    qzss: true

  snr mask: '35'

  update rate: '5'

ReplyForward

fluid.systems.base · August 25, 2019, 4:14pm

Base Simple System Report

Simple system report


app version: 2.20.7-rs2-rc0-r0

'wifi_status, interface: wlan0':

- wifi_mode: infrastructure

- ip: 192.168.100.71

  is_added: true

  is_connected: true

  is_visible: false

  mac_address: 6C:21:A2:92:96:60

  security: wpa-psk

  ssid: Digicel_WiFi_qx5V

  uuid: fb311c80-3fd9-48e0-bfeb-bc74e8fc9b7c

base mode:

  base coordinates:

    accumulation: '2'

    antenna offset:

      east: '0'

      north: '0'

      up: '1'

    coordinates:

    - '17'

    - '-76'

    - '10'

    format: llh

    mode: manual

  output:

    enabled: true

    format: rtcm3

    path: lora

    type: lora

  rtcm3 messages:

    '1006':

      enabled: true

      frequency: '0.1'

    '1074':

      enabled: true

      frequency: '1'

    '1084':

      enabled: true

      frequency: '1'

    '1094':

      enabled: false

      frequency: '1'

    '1124':

      enabled: false

      frequency: '1'

bluetooth:

  discoverable: false

  enabled: false

  pin: '***'

correction input:

  input2:

    enabled: false

    format: rtcm3

    path: ttyMFD2:38400:8:n:1:off

    send position to base: 'off'

    type: serial

  input3:

    enabled: false

    format: rtcm3

    path: :9028

    type: tcpsvr

logging:

  base:

    format: RTCM3

    started: false

    version: null

  correction:

    format: RTCM3

    started: true

    version: null

  interval: 24

  overwrite: true

  raw:

    format: UBX

    started: false

    version: null

  solution:

    format: LLH

    started: false

    version: null

lora:

  air rate: null

  frequency: 868000

  mode: write

  output power: '20'

position output:

  output1:

    enabled: false

    format: nmea

    path: bluetooth

    type: bluetooth

  output2:

    enabled: false

    format: llh

    path: :9001

    type: tcpsvr

  output3:

    enabled: true

    format: llh

    path: :2014

    type: tcpsvr

  output4:

    enabled: true

    format: llh_ext

    path: :2015

    type: tcpsvr

rtk settings:

  elevation mask angle: '15'

  glonass ar mode: 'off'

  gps ar mode: fix-and-hold

  max horizontal acceleration: '1'

  max vertical acceleration: '1'

  positioning mode: static

  positioning systems:

    compass: true

    galileo: true

    glonass: true

    gps: true

    qzss: true

  snr mask: '35'

  update rate: '1'

ReplyForward

fluid.systems.base · August 25, 2019, 5:46pm

The Rover status for signal to noise ratio would show:
Rover: (Fluctuating values close to 30)
Base: (Fluctuating values less than 10)

wizprod · August 25, 2019, 6:02pm

Can you post a few screenshots of this?

timd1971 · August 25, 2019, 6:26pm

Probably means dBm decibels per meter. Volume.

timd1971 · August 25, 2019, 6:28pm

Probably won’t make a ton of difference (unless unusually high voltage, electromagnetic interference) since multi-freq receivers, but may affect the LoRa transmission. You could try NTRIP.

What are coordinates and may some environment photos? Your base may need to be relocated away from high power voltage lines if under or adjacent to them.

tatiana.andreeva · August 27, 2019, 7:55am

Hi @fluid.systems.base,

I’d also recommend going through this guide to tune the LoRa radio.

Please keep us posted.

fluid.systems.base · August 27, 2019, 4:25pm

Thank you.

I’ve been using the recommendations of this guide from the very beginning.

I will continue to troubleshoot with the frequencies and try to share screenshots as soon as I get a chance.

dmitriy.ershov · August 28, 2019, 1:18pm

Hi Mo,

Some raw logs from your tests would be also of interest for investigation

fluid.systems.base · September 15, 2019, 8:39pm

Good day All,

I have been able to play around with the settings (frequency, air data rate, RTCM3 messages) and get steady communication between base and rover in more urban and semi-urban environments that I have been working in, with several kilometers baseline.

I am assuming that my previous issue is based on a bad placement area for the base and based on interference from other communications as well as line of sight.

I was working on another project where there was moderately dense vegetation between the base and rover over a baseline less than 500 m. There was immediately some difficulty in getting good communication between the units. However, I was able to get a fix status for some points by lowering the air data rate, changing communication frequency and the update rate of the RTCM3 messages.

What is apparent is, working in such environments requires some trial and error in tuning the radio communications.