SIRS - HRPT
Satellite Infrared Reception System - (High Resolution Picture Transmission).   There is fully digital reception of the S Band signal emitted by the NOAA or Sea Star satellites.  This system is designed for more sophisticated technicians, to provide a central, generally land-based, meteorological or sea surface information source for a company, ministry or university.   Resolution ranges down to 1.1km / pixel and temperature accuracy is in the range of +/- 0.1-degree Celsius.

This system is indicated when vessels are working on less than 3 - 5 day cycles.   For fishing trips of this duration the vessels can receive new images when they unload at the dock.

For more information SIRS - HRPT

SIRS - APT
(Satellite Infrared Reception System) is the fully marinized analog VHF counterpart of SIRS-HRPT. Generally mounted aboard ship, as its omni-directional antenna is not disturbed by vessel motion. The images are loaded directly into BRIDGE for use as charts.  Its ease of use, with Spanish or English menus and  rugged construction makes it ideal for fishing vessels.  The system is designed for ships away from port on fishing trips of 5 days or longer.  For fishing trips of this duration the images received during unloading become outdated, and new images must be resupplied aboard.   This is the practical limit for receiving infrared images upon departure. 

Resolution is 4 km / pixel and temperature accuracy is in the range of +/- .75 degree Celsius, quite adequate to determine current fronts.

For more information SIRS - APT

Analog systems are particularly suited for the gathering of high quality thermal information, where that information is needed to make fishing decisions, and by the people who need to make those decisions. The intuitive simplicity of SIRS software brings the technology to the people who need to use it. System robustness, cost and portability lend themselves to shipboard installations.  Analog reception is often unsuited for installation in large cities due to interference from powerful commercial broadcasters.

Scientific and industrial users of the technology need more detail.  HRPT systems provide state of the art thermal imaging data down to very fine temperature tolerances, at a highly detailed resolution, and have 1024 bit color resolution for determining sea color differences. Trained personnel focussed on a particular objective can develop a quality of information with multi–spectral analysis that is unsurpassed. If image processing is desired for users, SIRS-HRPT satellite images can be used in virtually any of the high-end (Geographical Information System) GIS or image processing packages on the market today.

The need for large-scale operations to justify system cost, the ability to penetrate RF (Radio Frequency) interference and to be mounted in capital cities, and the need for trained operators, make this a central office technology.

The analog SIRS systems is capable of resolving objects down to 4 kilometers square, and temperature of + / - .75° C. It receives a double image, one band of visible light and one band of infrared light in the day. At night it receives two bands of infrared light. At the current time there are three satellites functioning (NOAA 12, 14 and 15) which provide a total of between four (4) and six (6) images per satellite per day, for a total of between twelve (12) and eighteen (18) images daily.  Note that the NOAA commitment is to maintain 2 functioning satellites in orbit and the oldest functioning satellite (NOAA 12) can be expected to cease transmissions at some point in the near future - although it is functioning perfectly today!

The satellites that are received are NOAA Polar orbiting satellites. Our installations principally receive these satellites because they orbit much closer to the earth’s surface, several hundred km up. The other group of satellites, the geostationary satellites, are in orbits 40.000 km above the earth. The closer perspective of polar orbiting satellites provides better resolution and detail in images, important for oceanographic and terrestrial work. The geostationary images can be quite useful for meteorological work, where a very large field of view is desired.

The other technology available for downloading the Polar Orbiting satellites "High Resolution Picture Transmission" or HRPT is purely digital reception of information. Much more information is received in each pass, up to 90 Mb, and the resolution is down to approximately squares of 1100 meters per side, temperature accuracy is 0,1° C.

These HRPT systems require tracking dish antennas, which must move to track the satellite as it goes by. With the dish they can receive the Ku band emissions and the large volumes of information in the digital satellite download. These antennas require very accurate semi-permanent mountings, while the APT systems can be easily moved for operation in various locations. Tracking and focussed parabolic antennas almost entirely bypass the interference present in large cities – they are highly directional and go right to the satellite. The analog systems with their wide reception angle suffer from strong interference in RF (radio frequency) intense places such as capital cities and busy ports.

These HRPT systems are more complicated in operation than the analog systems, and the directions and menus are in English (both menus and manuals for the APT system are in Spanish and English). The systems must be land based, unless a gyro compensated platform is placed beneath the antenna, in which case they can be marine mounted.

HRPT might very well be the best technology for the job if your need for detailed information is greater and if you have capable people to operate the terminal. Also, if you require mounting in cities with large quantities of RF and you need very detailed resolution to be able to see small rivers and bays and warm spots. Finally if you find that the greater amount of information available is cost efficient, compared to the addition in cost over SIRS - APT.

SIRS will do the job if you require easy to operate systems, use them remotely from RF interference, and the goal is to put easy to use thermal information directly in the hands of the people using it.

Either system is capable of outputting images into desktop publishing or image processing programs (either MAC or Windows).

Marine Imaging Systems S.A., from its base in Viña del Mar, Chile, is the South American leader in providing this satellite imaging technology to South America’s fishing and other temperature involved industries. We are happy to answer whatever questions you may have about this and other related satellite technologies.