1. Rainbuoys - Acoustic Rain Gauges
Why ARGs? To estimate rainfall and wind over large areas
MOD is interested in the reverse problem – if it’s raining, what will it do to the ambient underwater noise?
A hydrophone hangs under the buoy at a depth of up to 30m
These buoys use a hydrophone and matched electronics package supplied by the Canadian company Metocean.
We have added a data logger and satellite telemetry using Orbcomm
Some of you will know that the rain buoy project has been around for a few years
Why re-design the buoys?

2. Acoustic Rain Gauge
Attempt to estimate rainfall and wind strength from sound spectrum
16 frequency bins from 500 Hz to 50 kHz
Hydrophone hangs 30m under buoy
Hydrophone and acoustic processing electronics from Metocean
We added data logger and Orbcomm telemetry

3. Hydrophone A new buoy has been designed by Kev Saw and Ian Waddington
Largely plastic
Battery pack for 6 months deployment
Designed and built in around 3 months in time for Canadian cruise

4. Mast Design
The stainless steel mast holds the Orbcomm and GPS antennas,
A flashing light
Radar reflector

5. CFAV Quest (Canadian Forces Auxiliary Vessel)
A tad smaller than the Darwin
Built in 1969 but recently underwent a major refit
20 berths for scientists, mainly in 2 or 4 berth cabins
Designed for quietness
Has gas turbine on upper deck for extra quiet running
Usually drifts during night

6. Passing traffic.. MacDonald Bridge
Orbcomm worked fine in this position

7. Deployment Mooring was designed by Ian Waddington
Deployment and recovery pretty straightforward
Dan Hutt

8. ARG buoy Orbcomm 3 messages per hour 466 bytes total per hour
Panasonic is active for approx. 20 min per hour
This is programmed using KXB command
If message buffer starts to get full, Panasonic is switched to continuous mode

9. Land Station Rain Gauge
12 months at SOC
Sends 2 messages/hour
294 bytes total per hour
Samples rain level and temperature every minute

10. Land Station Messages

11. Expanded View – 1 week

12. Message delays during October-November 02
Maximum delay was 25 hours. Caused by mail server failure at SOC
Average delay – 1.22 hours
Median delay – 0.25 hours
Daily pattern probably caused by interference from Vodaphone paging system

13. Comparative costs Orbcomm Iridium
Receiver + antenna €2000
Airtime €18 per month plus €1.6 per minute
Receiver + antenna €1000
Airtime €65 per month flat rate
(Same as Iridium with 1 minute per day)

14. TriAxys Buoy
Dan Hutt

15. Dan Hutt