1. DURO UAS – AUV RF Research
Farhanmadar Diwan

2. Transmitter
(Tx)
Channel
Receiver
(Rx)
Types of
channel
wireline
Copper,
coaxial
Optical
fiber
Wireless
RF
channel
Optical
Acoustic

3.  Ragnarok is an AUV developed by a team of undergraduate
students from Cornell University in 2013.
 Gemini is an AUV developed by a team of undergraduate
students from Cornell University in 2014.
 The Unified Serial Daemon (USD) was used for communication
between AUV’s on-board computer and the internal electrical
boards by implementing a standardized serial protocol. The
data is transferred by using RS-485 or RS-232.
 A variety of functionality is built into the USD protocol, such as
board identification and microcontroller monitoring.
Ragnarok
Gemini

4.  Matsya 3.0 was developed by students from IIT-Bombay.
 The communication stack enables data and command transfer
between six different boards on the vehicle.
 The boards are connected via a RS-232/UART or Ethernet in a
tree like structure.
 The communication between any two boards is based upon a
”ping & reply” system. A board close to the root of the tree
initiates communication between any set of two boards.

5.  Barracuda Mark XIV was developed by students from Amador
Valley High School RoboSub Team in 2015.
 Barracuda uses Wifi Tether Net Gear router for communication.
The access point is wired to the main computer via an ethernet
cable that passes through the rear endcap.
 The tether allowed to upload the code to the main computer
and control board while it was still underwater.
 By this they save time by having the operators debug while the
vehicle is still in the water.
Barracuda Mark XIV

6.  Experiments were conducted by the University of Southern
California in the coastal regions near Pt. Fermin in January
and February 2009.
 These experiments were conducted by Arvind Pereira, Hordur
Heidarsson, Carl Oberg, David A. Caron, Burton Jones and
Gaurav S. Sukhatme.

7.  These measurement of communication performance
were sparse and collected at four surfacing
locations.
 High throughputs were possible close to the base-
station (<4km), with a fairly sharp bit-rate drop from
1.46KB/s to approximately 154bytes/sec.
 This significant drop is due to the links becoming
more intermittent as carrier detect on the radio is
only available 65% of the time at a distance of
9.2km, while it is more than 86.7% at 3.5km.
 Field tests have shown that the system allows status
packets to be reliably transmitted from distances up
to 20km.

8.  Isurus is a REMUS (Remote Environment
Measuring UnitS) class AUV, built by the
Woods Hole Oceanographic Institution.
 The vehicle is equipped with a Wi-Fi
interface for surface communications, and
an acoustic modem for underwater
communications.
 The ARIES (Acoustic Radio Interactive
Exploratory Server) AUV [2] was designed
and built at NPS (Naval Postgraduate
School).
 ARIES carries radio and acoustic modems for
inter-vehicle communications and can
function as a node on a wireless network.
ISURUS ARIES

9. ω is frequency, ε is permittivity, µ is the permeability
of water, σ is electrical conductivity.

11.  The ISM radio bands were originally set aside for electromagnetic radiation
produced by industrial, scientific and medical (ISM) equipment. In the early 1990's
the Federal Communications Commission (FCC) allowed using three of the ISM bands
for unlicensed communication equipment.
 These three ISM bands are:
 902 to 928 MHz
 2.400 to 2.4835 GHz
 5.725 to 5.875 GHz
Allowed transmit power / antenna gain
and the resulting EIRP

12.  The attenuation over distance favors 900 MHz over 2.4 GHz. At any given distance the
free space loss at 2.4 GHz is 8.5 dB larger than at 900 MHz.
 The antenna gain at 2.4 GHz is significantly higher than an antenna at 900 MHz.
 As per gain perspective, 2.4 GHz has an advantage of 18 dB in a point to point link and
9 dB in a point to multipoint link.
 The total atmospheric attenuation is fairly negligible and rarely loss of 0.02 dB/Km.
For a distance of 50 Km link, we have additional attenuation of 1dB.

13.  The available channel bandwidth is subdivided into a large number of contiguous
frequency slots.
 In any signaling interval, the transmitted signal occupies one of the available
frequency slots. Selecting the frequency slots during each signaling interval is made
pseudo-randomly. User-defined protocols can determine the hopping sequence.
 The time the transceiver is transmitting or receiving is called the dwell time. The time
when the transceiver is configuring its registers to transmit or receive at another
frequency is called the blank time.
 During dwell time is the transmit (or receive) preamble, start bit, data sequence, post-
amble at a particular frequency in the hopping sequence.
 Actions during blank time are pseudo-random frequency generation, configuring the
transceiver registers to operate at the randomly generated frequency, and waiting for
the PLL to lock.

14.  MAXIM
 Web- www.maxim-ic.com
WLAN RF Transceiver with PA frequency band 2.5 GHz from MAXIM.
Also available RF Transceiver for WiMAX.
 Fujitsu
 Web- jp.fujitsu.com
Fujitsu's LTE RF Transceiver. Model-MB86L01A, supports multiple RF frequency bands.
 Hittite
 Web- www.hittite.com
IEEE 802.11ad or WiGig RF Transceiver.
 Kantronics-www.kantronics.com
 High Frequency Radio modem or HF radio modem, wireless modem.
 HAL Communications Corp. USA.- www.halcomm.com
 HF data modem Model-DSP4100/2K and more other products.