RF Communications for Oceanographic Applications Workshop on Universal Undersea Navigation/Communication Gateway Platforms Woods Oceanographic Institute Woods Hole, Ma January 17th & 18th, 2001 ViaSat, Inc. 125 Nagog Park Acton, Ma

January 17th, 2001 ViaSat, Inc. Page 2Introduction 1.)Telemetry is typically the system bottleneck!  Advances in sensors, platforms, and systems easily out pace telemetry development. 2.)Performance is location dependent.  Remote operation limits telemetry performance and options. Silver Bullets 3.) Lots of advances, but no “Silver Bullets”  LEOs appeared to be the salvation, but suffer practical limitations for most oceanographic applications.

January 17th, 2001 ViaSat, Inc. Page 3 Telemetry- the Bottleneck Data needs have increased.  There are more sensors, platforms and systems and they are more complex. Monitoring is increasingly “remote”.  Deep Ocean  Global contingencies Telemetry advances are being made.  Higher throughput, two way systems are coming online. However, these advances have not kept pace.  Throughputs 10 to 100 times ARGOS can be expected for most remote applications. Therefore, telemetry remains a limitation.

January 17th, 2001 ViaSat, Inc. Page 4Classification From a telemetry perspective, oceanographic systems can be classified as follows: Short Range Coastal Deep Ocean Polar Options Throughput

January 17th, 2001 ViaSat, Inc. Page 5 Short Range Typically Line-Of-Sight (LOS). Between miles from receiver. Options include:  LOS radio.  Cellular (CDPD).  Cellemetry. LOS radio typically the best option.  Highest throughput (burst rates to 115 kbps).  Low power (10W transmit power).  Small size.  No recurring cost. Useful only near shore or from a ship.

January 17th, 2001 ViaSat, Inc. Page 6Coastal Between roughly miles offshore. Options are Beyond Line of Sight (BLOS).  GEOs  LEOs  Wideband HF RegionalLittle GlobalBig MilitaryMilitary Military satellites are nice options, but rarely available and have limited access. Wideband HF is an option, but requires significant infrastructure and has limited capacity.

January 17th, 2001 ViaSat, Inc. Page 7Coastal Big LEOs - not a realistic option.  Limited coverage.  Poor voice performance, no data support.  Poor sales performance, uncertain future. Little LEOs are attractive, but lack capacity and real time coverage. Regional GEOs are attractive in specific regions, specifically L-band GEOs. Global GEOs are attractive, specifically C-band GEOs.

January 17th, 2001 ViaSat, Inc. Page 8Coastal

January 17th, 2001 ViaSat, Inc. Page 9 Deep Ocean > 200 miles offshore. Options are limited.  INMARSAT C&D  C-band GEOs (ODL)  ARGOS  Little LEOs INMARSAT C equipment is  big, power hungry and service fees are expensive. ARGOS is  small & low power, but  has limited capacity, is one-way & is non real time. Little LEOs equipment  is small, very low power, low cost, and two way, but  has capacity similar to ARGOS and is non real time.

January 17th, 2001 ViaSat, Inc. Page 10 Deep Ocean INMARSAT D is  small, low power, two way, and near real time, but  capacity is very limited. C-band GEO equipment is  small, low power, two way, near real time and has 10 to 100 times the capacity of ARGOS.  In addition, service fees are a fraction of competing systems including ARGOS.  but, equipment costs are greater than ARGOS. C-band equipment is the clear alternative in all but the most power critical applications.

January 17th, 2001 ViaSat, Inc. Page 11 Deep Ocean

January 17th, 2001 ViaSat, Inc. Page 12Polar Polar coverage Little LEO & LOS radio are the options.  GEO satellites cover between 70-75º N and 70-75º S. LOS radio is the preferred option.  Requires a LOS link of miles or less. Little LEO constellation such as ORBCOMM is the next best option.  Provides similar capacity to ARGOS, at lower power, with a two way capability. ARGOS is the final choice.  Higher throughput, reduced power consumption at the poles, but still one way.

January 17th, 2001 ViaSat, Inc. Page 13Summary A variety of RF telemetry options exist for oceanographic platforms depending on the application. But, as the application demands more remote operation, RF options and telemetry capacity is reduced. Therefore, telemetry should be a primary consideration in the design of an oceanographic gateway platform.