White Paper – LEO Satellite Telemetry & Monitoring vs Cellular


LEO Satellites Data Services a Viable Alternative to Cellular

The Iridium LEO Satellite constellation offers coverage across the entire surface of the plant enabling a whole variety of monitoring and/or control applications to be deployed in locations where previously this was considered inconceivable due to lack of cellular coverage or other forms of terrestrial communications infrastructure.

Unlike traditional satellite data links that require a relatively large dish antenna and clear line-of-sight to the equator, Iridium’s network has the big advantage that its satellites are low earth orbiting (LEO) North to South crossing the poles 24/7/365, meaning that they offer equal coverage and do not fade away the further you get from the Equator. Low earth orbit also equates to short distance, reducing the size of the antenna from a dish to a small hockey puck size unit, that simply has to point straight up, without need for alignment.

With the antenna pointing up and orbiting satellites this means signals can be uploaded an downloaded from previously deemed awkward locations such as from behind tall buildings, cliffs, from deep valleys, railway and road cuttings and even the centre of forests, with at worst a small delay.

Safe Investment for the future

When considering an investment in any communications media it is crucial to look and to understand the operators crystal ball vision of the future. With the cellular operators focusing on faster and faster networks to serve people it is highly unlikely that the network blackspots we have will ever entirely disappear. Simply it has been and will always be a revenue driven model. However, more importantly is future proofing against obsolescence, as the networks upgrade from 2G, 3G, 4G to 5G and 6G in years to come, who only knows what will happen to 2G, GPRS, 3G…? 2G has already closed in parts of the US, so even if the UK were to say we are keeping it open a day will come when spare parts could run leading to holes in the networks.

With iridium this is different as they can testify that what worked decades ago, works now and will operate into the distant future and thanks to a recent 4$b investment in brand new state-of-the-art military grade satellite network.

Multi-Redundant Moving Networks

If you compare the Iridium network to cellular, then its like having masts that move to you, 66 in total. If the coverage from one satellite is poor because your installation is behind a hill from one satellite then it isn’t too long before another moves above you into a more favourable position.

In the unlikely event of one satellite being down unlike cellular where you could be offline for days or even weeks, with 65 other satellites in orbit it is not long before anther satellite comes along. So at worst you can suffer is  typically a short delay and not a complete outage.

SIM Free Operation

Not requiring a SIM card is key to driving up reliability for any system. Further it also eliminates the risk of SIM theft and SIM card de-registration issues.

SIM theft is a constant problem to the remote monitoring / telemetry community and accounts for numerous outages per annum. Further it can become a epidemic once criminals relate a particular installation/instrument to having a SIM card.

Satellite Economics

Using the LEO satellite network and its SBD (Small Burst Data) mode can be very affordable especially when you consider all the advantages. Billing is for data delivered only and is measured by the byte. There are no network overheads added to the package.

With cellular this is not the case. If we look at just a 14-bit telemetry data packet as an example, this with satellite SBD would just be 14-bytes, whereas with cellular it could easily equate to several kb when the network overheads are added. However, in a poor coverage areas, cellular could be much worse as you are also charged for dropped calls/retries in addition making budgeting for both data usage challenging.

Although not as cheap as a SIM card, satellite can deliver hourly river levels for as little as £15.00 per month. But the real economics are those when you include site visits, outages, SIM theft and obsolescence into the equation.

Data Delivery

Data delivery by the Iridium satellite network very flexible, there is e-mail service as standard and for larger uses the choice of a direct VPN into a data our or their data servers.

Units can also send SBD messages to each other for control purposes. Where the message goes up to the satellite from one unit and back down to another single or multiple units to implement control etc.



Suggested Applications 

  • River Level Monitoring
  • Reservoir / Lake levels
  • Thermal Stratification Monitoring
  • Borehole Monitoring
  • Groundwater Level Monitoring
  • Water quality – pollution monitoring
  • Flood alarm and sign control
  • Railway track flooding alerts
  • Oil Interceptor Monitoring
  • Storage Tank and Silo Monitoring
  • Asset Security
  • Rail Temperature Monitoring
  • Road Ice Hollow Warning Reporting
  • Remote Rain Gauges
  • Weather Stations

RDN’s Sensor Interfaces and Bespoke Interface Service

At RDN we have 30-years experience in interfacing and powering sensors for a variety of applications and are an approved Iridium VAR (Value Added Reseller) and VAM (Value Added Manufacturer). As such we are able to offer a mixture of off the shelf and semi-custom solutions to meet out clients needs.

This include interfaces such as:

  • 0-2V
  • 4-20mA
  • SDI-12
  • Volt Free Digital
  • Alarm
  • Pulse Count

In addition we offer a choice of power solutions from battery, mains to solar.