Citizen Geo-Positioning

Citizen Built Geo-positioning Systems

Through geopos.org ordinary citizens can enhance the geo-positioning infrastructure of their country substantially by increasing the accuracy of existing satellite positioning systems (e.g. through RTK) or participating in building their own sovereign terrestrial positioning systems (e.g. through WiFi signals).

While a citizen owned high precision positioning system (what works seamlessly indoors and outdoors) has numerous peacetime applications, the benefits of having ownership really shine through in wartime, when the citizens can deny enemies of accurate positioning information (e.g. introducing errors or encryption) at will.

Citizen Satellite Positioning Systems

Citizen Satellite Positioning is not about citizens sending positioning satellite into space (which is already too crowded and we are trying to address that with our Float Mesh). This is about citizens adding positioning base stations on the ground to improve the accuracy of existing satellite based positioning.

In order to get satellite positioning accuracy down to the centimetre level, Real Time Kinematic (RTK) can be used for online operation, while Post Processing Kinematic (PPK) or Precise Point Positioning (PPP) for offline operation.

1. RTK

A typical RTK deployment has a GNSS receiver with RTK capability connected to a mobile phone via bluetooth and with a NTRIP client software downloading correction data over the internet via NTRIP protocol from the most relevant NTRIP caster. Resulting positions with centimetre accuracy are normally marked with words like "RTK-FIXED".

NTRIP is a communication protocol that enables FIXED satellite positioning base stations to work together to provide RTK based corrections to your own MOBILE satellite positioning receiver, thus increasing its accuracy substantially.

ntrip

1.1. Hardware

You can build your own NTRIP hardware

  1. GitHub - Stefal/rtkbase: Software for your own GNSS base station for RTK localization
  2. How to Build a DIY GNSS Reference Station - learn.sparkfun.com
  3. DIY RTK BASE-NTRIP Caster CORS Server with ESP32 and Free DDNS provider - F9P PX1122R - GPS / RTK / GNSS - AgOpenGPS
  4. GitHub - charlesquick/ntripcaster-containerised: Another containerised ntripcaster!

We do not have any relationship with u-blox but the F9P's internal RTK seemed to give good price performance without the hassle of running external RTK software:

  1. 日記・備考録 (in Japanese)
  2. ZED-F9P module

1.2. Software

  1. Branches · tomojitakasu/RTKLIB · GitHub
  2. NTRIP Software
  3. GitHub - eringerli/RpiNtripBase
  4. GitHub - fguiet/gnss-rtk: My own RTK network
  5. GitHub - google/gps-measurement-tools
  6. GitHub - rokubun/android_rinex: This repository contains a python script that converts logs from Google's GNSS measurement tools to RINEX

1.3. Centpede

Instead of creating a new project, 88.io always prefer to support and grow existing commuity based open sourced projects. Centipède is one of the community projects in the RTK space.

Centipède is a shared network of GNSS RTK bases, managed by research institutes in Charente-Maritime. It aims to provide a free and open RTK correction signal in order to have centimetre precision over a continuous territory.

  1. https://centipede.fr/
  2. Une Balise Open Source pour le monitoring des océans - Centipede RTK
  3. informatique:gps:centipede [Cyrille Giquello]
  4. GitHub - jancelin/centipede: Centipède: un réseau collaboratif de Bases GNSS RTK low-cost
  5. GitHub - jancelin/RtkBaseVar: 🛰️ 📡 Broadcasting the RTCM3 correction from the nearest RTK base 📍

1.4. References

  1. International GNSS Service
  2. https://rtklibexplorer.wordpress.com/
    Networked Transport of RTCM via Internet Protocol - Wikipedia
  3. Real-time kinematic positioning - Wikipedia
  4. Network Real Time Kinematic (NRTK) Positioning – Description, Architectures and Performances | IntechOpen
  5. RINEX - Wikipedia

1.4. Future

The development of State Space Representation (SSR) means devices using virtual base stations can share one stream, instead needing a dedicated stream for each device.

2. PPP

Precise Point Positioning (PPP) uses satellites signals directly, without the need of any correction (unlike RTK). It is a great solution when there is no RTK coverage.

3. Government NTRIP

Many government provides free NTRIP Castors, citizen deployed NTRIP Servers and Castors can help plug gaps in the government infrastructure.

3.1. Australia

https://gnss.ga.gov.au/stream

3.2. Canada

https://webapp.csrs-scrs.nrcan-rncan.gc.ca/geod/data-donnees/rtk.php?locale=en

Citizen Terrestrial Positioning Systems

Ubiquitous deployment of Bluetooth device and emerging [WiFi with Fine Time Measurement] (FTM)(IEEE 802.11mc - Wikipedia) support means Citizen can built up their own Terrestrial Positioning Systems to provide high precision location data in both indoor and outdoor settings.

Although the performance of early generation of WiFi FTM is not much better than normal WiFi, it is already been collected by our 88collect Android App so it can be used along with numerous other data points on our Data Fusion platform.