Telemetry
Telemetry & Data Logging
AXYS Technologies Inc. (AXYS) offers products that feature wireless transmission and reception of data via a variety of standard telemetry options. Collected information can be processed and broadcast in real time (or near real time) to data collection centres via telemetry options such as VHF radio, UHF radio, InmarsatD+/C, ARGOS, ORBCOMM, IRIDIUM, GOES, and Cellular phone (GSM or CDMA).
Direct Radio (VHF and UHF)
Radio telemetry is one of the most common methods of transmitting data from remote inaccessible installations, (water or land). Radio telemetry requires a clear line-of-sight between the monitoring system and the base station for distances up to 20 km. While antenna positioning, gain, tuning, and ambient noise can adversely affect range, our systems can be configured to send multiple transmissions to ensure a consistently high data throughput.
Inmarsat (International Maritime Satellite)
Inmarsat is a high orbit geostationary satellite telemetry system. Since Inmarsat satellites are in high stationary orbits, seldom does a terminal have to switch from one regional satellite to another. The Inmarsat system consists of four communications satellites backed up by an additional five satellites that can be brought into use in the event of technical difficulties or high traffic. By using four overlapping beams from the satellites, Inmarsat provides global coverage everywhere except the poles. There are a number of different bandwidth telemetry services available through Inmarsat.
AXYS in a service solution provider for InmarsatD+ data service, which enables short data messages to be sent and received from small, low-power terminals. The system transmits data in 8-byte packets, with the number of packets sent restricted only by the system-sampling regime and power budget. There is a low cost per message, data is posted on a secure website in near real time, and there is no restriction on users or applications. InmarsatD+ is now available on the TRIAXYS™ Directional Wave Buoy for transmission of position and data. When TRIAXYS™ is only reporting position, one data packet is sent. When wave data is transmitted, two packets are sent. The data parameters available via InmarsatD+ from a TRIAXYS™ buoy are as follows: Mean Dir (single point), Mean Spread (single point), HMAX, T1/3, HMO, Tp, Position, Boot Times, and Sample Start Time.
Inmarsat C is a higher bandwidth transmission medium for longer messages,
however its higher power consumption is not ideal for all applications.
Argos (Advanced Research and Global Observation Satellite)
The Argos satellite system is comprised of low orbit, non-geostationary satellites. Argos satellite telemetry is a limited data communications solution for use in remote locations where VHF or cellular telemetry are intermittent or unfeasible. This telemetry option is controlled through NOAA and there are some restrictions to applications and users; users need to apply for the service. Argos satellites are polar orbiting and the transmission window increases with latitude. The Argos transmitter can transmit a 32-byte binary data string every 90-200 seconds, depending on the transmission options selected. Most transmissions are repeated to ensure complete data transfer, as satellites are not always within range. There can be data gaps depending on location.
ORBCOMM (Low-Earth Orbit Satellite)
The ORBCOMM satellite system uses a network of low-Earth, near-polar orbital satellites for data and messaging communications services. ORBCOMM provides tracking, monitoring, and messaging capabilities to and from anywhere in the world, and there are no restrictions to applications or users. The system operates by transmitting the data packet to the ORBCOMM satellite, which then relays the message through one of four U.S. Gateway Earth Stations (GES). The data is then sent to the Network Control Center (NCC) via satellite link or dedicated terrestrial line. The NCC routes the message to the final addressee via e-mail, dedicated telephone line, or facsimile. Messages originating outside the U.S. are routed through international Gateway Control Centers (GCC) in the same manner.
IRIDIUM (Low-Earth Orbit Satellite)
The Iridium uses a dedicated constellation of 66 operational satellites and 14 spares in low-earth orbit (LEO), which provides global coverage without restrictions to users or applications. Iridium systems are primarily focused on remote phone and digital data service. This system is readily available to private industry and is best applied to situations where large amounts of data need to be transmitted, as airtime is charged by the minute.
GOES (Geostationary Operational Environmental Satellite)
GOES is a geostationary satellite system that provides 24-hour coverage and is generally used by governments and institutions. Interested persons must apply for its use, as there is limited access to this system. There is a cost associated with the purchase of the transmitters but the data collection is free, provided that the data is distributed on the Global Telecommunications System (GTS). GOES communications is one-way only.
Cellular (GSM and CDMA)
GSM telemetry uses a circuit switched technology that allows data to be transmitted over a GSM link at speeds of 9.6 kbps (9600 baud). For more information on this technology, consider visiting the website www.gsmworld.com or contact your cellular service provider. AXYS can also offer a CDMA (Code Division Multiple Access) cellular module for clients that do not have GSM coverage, but still want to take advantage of the benefits of cellular data transfer. AXYS can offer a 800 MHz CDMA, 800 MHZ analog, and a 1900 MHz CDMA cellular module. CDMA is described as a "spread spectrum" technology, meaning it spreads the information contained in a particular signal over a much greater bandwidth than the original signal. For more information on this type of telemetry, see www.cdg.org. This telemetry option is limited to areas where there is a local cell network installed.
Data Logging
AXYS' products come with an optional internal data logging option. This can be used as either a backup system in the event of marginal telemetry conditions or as a stand-alone feature. Data sampled by the system is logged onto a flash microdrive that can store up to one gigabyte of collected data.
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