Rainbuoys - Acoustic Rain Gauges

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

Hydrophone

Mast Design

CFAV Quest(Canadian Forces Auxiliary Vessel)

Passing traffic..

Deployment

Dan Hutt

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

Land Station Rain Gauge

• 12 months at SOC• Sends 2 messages/hour• 294 bytes total per hour• Samples rain level and

temperature every minute

Land Station Messages

SOC Orbcomm Message Delays (rainb3)

0

5

10

15

20

25

30

12-Oct 19-Oct 26-Oct 02-Nov 09-Nov 16-Nov 23-Nov 30-Nov 07-Dec

Saturdays

Ho

urs

/ N

um

ber

of m

essa

ges

in b

uff

er

msg buffer

Delay

Expanded View – 1 week

SOC Orbcomm Message Delays (rainb3)

0

2

4

6

8

10

12

23-Nov 24-Nov 25-Nov 26-Nov 27-Nov 28-Nov 29-Nov 30-Nov

Saturdays

Ho

urs

/ N

um

be

r o

f m

es

sa

ge

s in

bu

ffe

r

msg buffer

Delay

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

Comparative costs

Orbcomm Iridium

• Receiver + antenna €1000

• Airtime €65 per month flat rate

• (Same as Iridium with 1 minute per day)

• Receiver + antenna €2000

• Airtime €18 per month plus €1.6 per minute

TriAxys Buoy

Dan Hutt

Dan Hutt