TE KOHINGA HARAKEKE O AOTEAROA

Manaaki Whenua – Landcare Research (MWLR) is custodian of Te Kohinga Harakeke o Aotearoa, comprising three Phormium (flax) collections: the Māori Weaving Collection, the Provenance Collection, and the Plant Variety Rights Reference Collection. They are managed by Katarina Tawiri.   These important collections require irrigation during the dry Canterbury summer months, when their transpiration is higher, and so the opportunity to have a near-real-time soil moisture monitoring system for the three Phormium collections is of great significance. The beneficial effects of ideal soil moisture in all three collections will translate into an increased yield of leaves per plant for weavers to harvest, greater length and higher quality of fibre extracted from the leaves, a smaller environmental footprint (through saving water), and the ability to monitor the effect of rainfall and the capability of the different soils to retain water. 
The three locations of the Swarm satellite gateways:

1. Māori Weaving Collection:
   This is a culturally significant collection used by weavers throughout New Zealand for harvesting leaves and accessing traditionally valued plants.
 2. Provenance Collection:
  These plants are from wild stands throughout New Zealand and from offshore islands such as Auckland Island, the Chatham Islands, and Manawatāwhi / Three King Islands. This collection is ideal for taxonomic work and DNA         research carried out in partnership with iwi/hapū. 
 3.Plant Variety Rights Reference Collection: 
    This collection displays the Phormium cultivars used by the horticultural trade over the last 30-plus years. It is a valued resource for national and international plant propagators

The Swarm SpaceBEE and Iridium satellites.  The Swarm satellite (left) is slightly larger than a packed lunch and weighs around 400 g, compared to the 850 kg, 9.2 m-wide Iridium satellite (right). 

Swarm is a satellite network system comprising low-cost satellites called SpaceBEEs. It was founded by one of the lead system engineers at NASA’s jet Propulsion Laboratory Dr Sara Spangelo. She had previously been working with small satellites and autonomous aircraft at the University of Michigan.[1] Recently the Swarm company was acquired by Elon Musk, who owns the SpaceX and Tesla companies. Swarm has regulatory approval for operations in New Zealand, the US, UK, and Germany, and over international waters. SpaceBEE satellites operate a network of 150 satellites (as at October 2022) in low Earth orbit of about 450–600 km, so they need to move fast (c. 7.5 km/sec) to maintain this low earth orbit, and they can complete a round-Earth trip in just c. 90 minutes. Swarm is planning to put more satellites into space in the future to cover the entire globe, 24/7. A modem is an electronic device that interfaces the data-measuring electronics and the satellite. The ground data node is equipped with a data-measuring electronic board such as CircuitPython or Arduino, a compatible microcontroller, and a Swarm 138 modem. Measured data are queued in the modem for transmitting to the SpaceBEEs when they are visible to the ground data node.
[1] https://www.crunchbase.com/person/dr-sara-spangelo

The communication systems tested: (a) a readily available, low-cost USB cellular 3G and 4G modem; (b) an Iridium RockBlock modem; (c) a Swarm 138 modem. 

The Swarm 138 modem is allowed to upload a maximum of 750 data packets per month. The maximum size of a data packet is 192 bytes. This is more than enough for remote environmental
 data collection for most of the MWLR remote data logging tasks, including precision irrigation scheduling and pest management (the Swarm system is very handy for animal trap monitoring
 in rural areas where there are no cellular services available).  The size of the data packet is sufficient for environmental data monitoring for precision agriculture on a commercial scale. It also allows data download to the modem, which can be used for remote operations such as irrigation control. Although the current Swarm satellite system covers the entire Earth, they are not visible to ground data nodes 24/7 (as of October 2022) because there are not sufficient satellites. This means there is a data delivery latency. A swarm of SpaceBEEs passes New Zealand about 8 to 10 times a day, but the actual communication strength depends on the elevation angle. Swarm provides a tool, called a ‘Pass checker’ (Figure 7, to provide the times the satellites pass a given location.[1] Elon Mask is planning to upload sufficient satellites to cover the entire globe 24/7.
[1] Swarm Pass Checker.       

(a) Cellular gateway  (b) Iridium gateway   (c) Swarm gateway.


The Pass checker tool enables you to select the most suitable time to upload the data queued in the modem to the SpaceBEEs. The driving force of two-way communication between SpaceBEE and Swarm modems on the ground is Semtech’s LoRa (long range radio) technology.[1] LoRa has proven its ability to communicate very long distances using low power and wide area coverage applications. Typical data visualization on web enabled devices (below).
[1] www.semtech.com

Global coverage by Iridium (a) and Swarm (b)