Unidata has continued to work with microsatellite companies, and we believe that these systems will become significantly important in the telemetry market in the next few years.
Last year we started working with Swarm Space (LEO) Microsatellite based in California, USA, and those tests are going well. Swarm has a payload of 200 bytes. It has a back channel, which aligns it more closely with the higher cost and very robust Iridium short-burst data service. The Swarm Microsatellite service is not an always-on service, delivering messages in under one minute like Iridium, but for applications such as groundwater monitoring where daily or hourly messages are needed, it is a good fit and substantially lower cost when compared to iridium SBD.
We continue to work with other microsatellite companies such as Hiber (144-byte payload).
We also note that others, such as Myriota (20 Byte payload), are growing their satellite deployment. Systems with very small payloads seem suitable for some applications, especially soil moisture, but higher payloads are needed for other applications.
For groundwater monitoring, the typical payloads of 500 bytes per day are needed, so the smaller payload systems struggle to keep up with the data load. The other consideration is that microsatellite systems and Iridium SBD are message-based systems, sending and receiving text messages like messages with long latencies.
Other systems, such as Inmarsat, Globalstar and Iridium Certus, offer a full IP communications channel which allows for much better over the air (OTA) capabilities, which minimise visits to the site. The cost of site visits needs to be compared with the higher capability satellite services airtime cost to determine which approach is lower cost overall.
Above is a summary of the microsatellite industry participants; some will do well, and many will fail.
Unidata has two test Starflow QSD instruments in a tidal harbour setting as long-term test instruments. The tidal area is saltwater, and it appears to be very healthy water because the marine life which grows on the Starflow QSD instruments is prolific. This was after around four months in the water.
Interestingly, despite the bio foul, the Starflow QSD instrument continued to perform well, and that surprised us. Looking at the graph, you can see that the U Depth and P Depth were working before and after with little or no errors. The Velocity was also still working, though the reverse flow had become noisy. However, it returned to noise-free after the instruments were cleaned and the bio foul was removed. The graph shows the time the Starflow QSD instruments were cleaned and the effect of the cleaning. The Starflow QSD conductivity sensor was still measuring EC variations in the heavy bio-fouled state, but its calibration was around 10% incorrect. After cleaning, it jumped back to the correct readings for this time last year. It is not difficult to understand that the calibration would be affected by biofouling as the conductivity electrodes are in electrical contact with the water, and any additional interface material will cause measurement errors. We could “assume” that the biofouling formed an electrical insulation layer, thereby reducing the measured conductivity.
It is remarkable that this Starflow QSD instrument can perform reasonably despite a large amount of bio foul. It is also great to be reminded that the water is healthy and there is an abundance of sea life.
Unidata has an environmental management system as well as a quality management system which is audited annually. We need to continue to reduce our impact on the environment year on year. This year we replaced all our fluorescent lights with LED lights, this reduced our power usage by about 50%.
Kevin Chung suggested this initiative, and through his idea, we are saving money and reducing our impact on the environment.
The lights used were a direct mechanical replacement; it was a simple matter to have the electrical contractor unplug the old ones and plug in the new ones. The new lights are also 25% of the weight of the old lights. We could also choose the colour temperature of the new LED lights, and we chose the middle temperature, slightly warmer looking light which is easier on the eyes.
The photo shows the small form factor of the new lights and our electrical contractor doing the replacement. The electrical contractor then took the old lights for recycling.