Satellite Software: Applications Abound
By Rob Fernandez
Software has always been an important part of every satellite system. In the early years of the industry, software was written on an as-needed basis, and each program was tailor-made for the satellite system that employed it. As the industry has evolved, however, companies have stepped forward to offer commercial-off-the-shelf (COTS) software solutions that can be adapted to serve a variety of applications. The rise of this kind of software vendor has allowed the use of satellite-related software to expand to include companies without the resources to write their own programs, as well as saving valuable time, money and effort for those companies that do have the option of a custom-software solution.
Today, software applications are serving the satellite industry in a host of different applications, ranging from remote monitor and control to spectrum analysis. The following are just a few vignettes of satellite software live from the field.
Honeywell’s Datalynx subsidiary is one user of satellite software solutions, in this example Software Technology Inc.’s OS/Comet command and control solution. According to Todd Probert, program manager, “Datalynx is a fee-for-service, space ground infrastructure. We’ve got a network of antennas and a mission control center that we’re selling on a by-the- use basis to a number of commercial customers.” Datalynx’s customer base is made up of single-satellite operators looking to outsource their mission operations responsibilities.
Datalynx owns and operates a number of remote antenna sites. In fact, at the time of this interview, Probert was in Fairbanks, AK, overseeing the installation of an 11-meter remote tracking installation.
Datalynx uses OS/Comet in the mission control center for real-time command and control, as well as in the remote network architecture for the monitor and control functions of each antenna. In addition to allowing Datalynx to control both its antennas and it customers’ satellites, the software helps Probert reduce the cost of antenna operations on the network side. “Before [OS/Comet], we had to deploy large forces of folks to literally live with those assets in the field to operate them over time,” Probert says. STI’s software solution has allowed Datalynx to automate much of the operation of these antennas. “So now we’ll have maybe one person on site, and that person will be a caretaker, not an operator. The systems themselves can be controlled remotely from our control center in Columbia, but our real goal is to have them be autonomous, control themselves,” Probert says.
“OS/Comet isn’t the only product out there that can do this particular function (real time command and control),” Probert adds. “We did a pretty extensive study, looking at all the COTS products that were out there, and racked and stacked them based on their capabilities, their maturity, where our business wanted to go, and we selected OS/Comet.” The deciding factor for Probert was because OS/Comet was “a very mature product in a multi-mission environment.” Datalynx often flies a wide variety of spacecraft, from geostationary (GEO) satellites to low earth orbit (LEO) remote sensing birds. “I’ve got a very diverse set of multi-mission assets that I need to control,” he says. “And we needed a product we knew could operate in that multi-mission environment.” Probert was familiar with OS/Comet from previous experience with the military systems and Iridium. “So far, we’ve been very pleased with STI’s support and the OS/Comet product,” Probert adds.
As part of this evaluation study, Probert and Datalynx also looked into writing a custom software solution in-house, but decided against it. Datalynx did a cost analysis, and while Honeywell has a longstanding legacy of writing custom code for NASA control centers, “it’s just not cost-effective now,” Probert says. “To maintain that code for one program is very costly, versus a COTS product that’s maintained over a larger customer base.” STI’s large customer base and stability again won the day for OS/Comet, according to Probert. Honeywell did write an overarching software architecture to marry OS/Comet to a number of other COTS software products, among them Analytical Graphics’ Satellite Tool Kit, because, as he puts it, “the COTS world did not lend itself to the flexibility that we wanted for our program.”
If Probert could see one improvement with the OS/Comet product, and this applies to all COTS software solutions, it would be interoperability standards. “Standardization is certainly one thing our industry is slow to tackle,” he concedes. “If all the products could talk to one another, that would be nice.” Probert would also like to see a stronger Web-based interface for OS/Comet, “and we’re changing that so we can add a Web-based interface, working with STI.”
Telemetry And Data Acquisition
Another example of software in action is Orbital Network Engineering (ONE), a company that uses a system and support tool called Netacquire, provided by Real Time Integration (RTI), as the core to several solutions it offers its own customers for real-time data processing, acquisition and control. For example, ONE has recently provided Panamsat with a product called ONE-UP (universal portal) for telemetry and data acquisition, based around the Netacquire solution combined with value-added hardware and software from ONE.
Tom Leisgang, ONE’s vice president of systems development, says that he made the decision to adopt Netacquire based upon “the system architecture and approach to the problem, if you will. It’s an open architecture, based upon current Internet-type technology for getting the job done.” For example, Leisgang points out that today’s data acquisition products commonly come in two pieces: the hardware itself, and a software solution that must be installed on a PC in order to interface with the product. Netacquire comes with a built-in Web server, allowing control of the unit and all the value-added functionality via a simple Web browser. “The trade-off is whether you have to have custom vendor software installed on your computer, or a standard Web browser,” he explains.
Another advantage to employing RTI’s solution in ONE’s products is that it allows the final product to simulate other device drivers and interfaces. Thus a customer of ONE can replace and upgrade a system employing discontinued, obsolete software interfaces from another provider without changing from the familiar front-end “look and feel,” and with the added benefit of a Web interface as well.
“Using the Web interface you download the Java-based software to control the device, so there’s nothing you need loaded on the computer but the browser. It ends up being quite powerful, because you can make it end up looking like anything you want it to look like,” Leisgang explains. In addition, the ability of ONE-UP to distribute its own interface software to any computer that needs it means that “the paradigm shift is you don’t need to buy site licenses or seat licenses for software.
“It takes a consumer-level approach to configuration and makes it available to specialty products,” Leisgang says. “It’s a very COTS approach to specialized data applications.”
According to Leisgang, ONE is currently working with RTI to implement dynamic reconfiguration in the software, thus allowing users to change the settings and parameters of the software without requiring a system reboot.
When it comes to satellite software, few would immediately think of digital topographical data. But on closer examination, companies like Softwright are providing their TAP (Terrain Analysis Package) radio engineering software to customers active in the communications and satellite field.
One such customer is Mark Hutchins, a radio engineering consultant who performs predictive work for a variety of clients utilizing both satellite and terrestrial communications. While TAP’s primary utility lies in displaying terrain elevation data and other man-made boundaries, such as municipal borders and zoning information–information that is crucial to planning line-of-sight terrestrial systems–Hutchins points out that satellite communications are also line-of-sight. Even if his customer is only using satellites in a receive-only capacity, the dishes must still be positioned and pointed at the satellite in question.
That’s where TAP comes in to play. “We don’t always have a clean shot,” Hutchins says. “We don’t always have the ability to look directly at the satellite.” This is because Hutchins is based in Vermont, necessitating lower look angles to see the geostationary arc. Added to this is the fact that the population centers tend to be in the valleys and low-lying terrain, with mountains and trees frequently obscuring the line to the satellite. “TAP gives me good data that I can trust on ground elevations, the ability to put in vegetation information, like the trees, so that I can see what the effect is on my signal path, plus likely terrestrial interference.”
Prior to using TAP, Hutchins was forced to use trial and error, panning the dish until it picked up the desired signal. Even with this method, some sort of software or other calculation needed to be employed to select the dish site. “Often we’re dealing with pouring concrete, so before we start putting in footers, foundations and so on, we want to make sure we’re at least in the ballpark,” Hutchins explains. What Hutchins likes about TAP is the ability to quickly examine a variety of different site locations and configurations to find the best solution. Oftentimes he can enter into TAP the desired reliability and other parameters, and TAP will tell him at which elevation he needs to place the dish.
Hutchins has been using TAP for over 10 years now, and he was originally drawn to the earlier versions of the product because the software package did not demand a high-end computer. “The whole thing of using computers to do your calculations was fairly new, even 10 years ago,” he says.
The one thing Hutchins would like to see added to the Softwright’s product line is a module to calculate dish position. Currently, Hutchins must independently calculate the azimuth and elevation needed by the dish to receive the satellite signal, and then TAP analyzes the signal path for obstructions and terrestrial interference. Since the position of a GEO satellite is not an element over which Hutchins has any control, a database module with commonly used satellite positions would be a great help.
Air Traffic Control
Worldcom’s government markets division is another user of satellite software, this time the Mercury product offering from Newpoint. In 1996, Worldcom received a contract award from the Federal Aviation Administration’s (FAA) Telecommunications and Satellite program (Faatsat). According to John Bolton, senior engineer with the Faatsat program management office, “This program was to provide satellite and telecommunications services for use by air traffic control to critical FAA radar and radio sites.”
In carrying out this contract, MCI Worldcom maintains 21 ARTCC (air radio traffic control center) hub earth stations around the nation. “Each one of those hubs has remote connectivity to the various remote sites,” of which there are 87, Bolton says. The ARTCC sites are located near airports, but the remote sites are radar installations in such out- of-the-way locations as Rainbow Ridge, CA, Lake View, OR, and the like.
According to Bolton, “We are in the process of replacing our remote interface controllers with the Mercury product. This Mercury controller interfaces the FAA satellite equipment with our own monitor and control system.” Mercury is a self-contained remote site manager that contains a full-function version of Newpoint’s Compass server software. He says Worldcom is removing the previous vendor’s solution due to poor software support and unreliable hardware. “We had bugs in the software, and couldn’t get them fixed. The hardware is at remote sights, and sometimes it takes a day to get to these sites when they hang up.”
MCI Worldcom chose Newpoint because of its length of experience in the satellite industry, and the many software drivers the company has developed, Bolton says. “We didn’t want to re-invent the wheel when we went to a new software vendor,” he says. “We asked them to come in, and look at the old controller we had, and they came in and customized some software in a very short time. In fact, they came in for two weeks and developed an interface to our M&C system.”
In addition, the controllers were able to work with MCI’s existing maintenance program, “and it could interface with this maintenance program simultaneously. Previously, if we wanted to run the maintenance program, we would lose connectivity to the existing M&C system.” Bolton also likes the fact that the Mercury product comes with an Ethernet port. Bolton would like to see a Web interface added as well.
“They’ve been very responsive,” says Bolton, referring to Newpoint’s support of the Mercury system.
The W. L. Pritchard and Co. (WLP) consulting firm provides its clients with telecommunications consulting services including satellite system design and interference assessment. WLP uses Transfinite’s Visualyse software tool to assist in these tasks. According to Ellen Hoff, president, “Some of the issues we’ve used it for have been to analyze interference between GEO and non-geostationary (NGSO) satellite systems, NGSO to NGSO, and fixed terrestrial services and NGSO.” Jack Dicks, vice president of engineering, also adds that the software is good for studying NGSO performance over time, “to make sure that I’m always getting the right interference and signal performance over time.”
WLP originally selected Visualyse when the issue of GEO and NGSO interference first arose, four or five years ago. “The GEO arc avoidance issue became a question,” Dicks recalls. “There really was a very limited selection of software around that allows you to run the simulation. Visualyse is, in my view, more ‘communications engineering favorable.’ In other words, the communications package that comes with Visualyse really gives you the answers that a communications engineer wants to see.” Dicks wanted to see such calculations as Io/No ratio versus percentage of time printed out as a graph, straight from the software, and only Visualyse had this capability at that time.
WLP had previously used some internally-designed, proprietary software to look at constellation design, but the LEO constellations introduced a complexity heretofore unseen. Needing results to meet a deadline for a LEO/GEO analysis for a client in only three weeks, WLP turned to Transfinite’s COTS solution. Transfinite was able to provide the software solution in time to meet this stringent schedule. “It was also an advantage to us that Visualyse had been reviewed in different international fora,” Hoff adds, “and was understood by people so that we weren’t coming in with a proprietary product that people would have to evaluate before they agreed with the results. The fact that it had some international recognition and credibility was of use to us in what we were doing with it.”
“It really is a handy tool,” Dicks says, “and well-designed to accomplish the work we want to use it for.”
The program is also being revised on an ongoing basis to reflect changes in ITU technical and regulatory provisions, and to improve user-friendliness. Hoff notes that the software is versatile and capable of being applied to a wide range of analyses, and like any complicated software system, it does take some effort to get up to speed and get the full functionality out of the program. “It’s not the sort of thing that you can take out of the box, flip on and be totally proficient within two hours.” Dicks notes that the support from Transfinite has been excellent, with a rapid response should any questions arise.
The Sky Latin America digital video platform also uses satellite monitor and control (M&C) software extensively in its operations, in this case Crystal Computer Corp.’s Crystal Vision 2000 M&C solution for it’s Miami uplink center and backup facility.
“We use this system to monitor and control all of our RF equipment at our Miami Lakes facility and our diversity facility in Port St. Lucie, FL. Miami Lakes is our primary site,” says Tony Rossell, Sky’s diversity site director. According to Rossell, Sky maintains two T1 links between the two sites, primarily carrying the control data for the Crystal system. “We give 512 kbps on each link to the Crystal System,” Rossell says. The links are redundant as well as diversely routed, and if one goes down, all traffic is immediately ported to the remaining link.
Sky takes these extreme backup measures because the Crystal system itself is part of an even larger backup system. Because weather conditions in Florida, both rain fade and hurricane damage, can interfere with Sky’s Ku-band transmissions, Sky has rigged its diversity site to be able to completely take over for the primary site, switching control via Crystal’s M&C system, at a millisecond’s notice. Thirty milliseconds, to be exact. “In Port St. Lucie, we duplicated exactly the setup in our primary facility,” Rossell explains. “It’s almost like a mirror image. In fact, from a software standpoint, it is a mirror image. What we do is, when a failure occurs in Miami Lakes, rather than going to a local backup HPA, it actually switches transmission to the primary HPA at the diversity facility. That occurs in a matter of milliseconds, as opposed to the five to 25 seconds it would take to re-tune the local backup.”
Sky has timed it so that any signal loss due to rain attenuation or failure at the primary facility will result in a switchover, one transponder at a time, until in a matter of minutes the entire uplink operation has been switched to the backup facility. This type of transfer occurs two or three times a day during the rainy season, according to Rossell, and in most cases the viewer does not even realize it, because Sky catches the degradation so early. “Since we’re getting a lot of rain right now, the demand on the system is high and the system is working quite well,” Rossell says. “The manual function of the system allows us to manually switch the individual HPAs or the entire facility to the backup site for scheduled or emergency maintenance with minimum impact to our customers.
“One of the main reasons the Crystal system was selected is because the QNX software operating system is a real-time software that allows more real-time commands,” Rossell explains. With Sky’s need for responses in 30 milliseconds, the demand for real-time M&C is acute. “Crystal is great,” Rossell says “They’re available to us when we need them, and what they’ve done for us is unique. They continue to work with us to evolve the system based on our operational needs, because it’s very new to all of us. It’s something that, to this magnitude, hasn’t been done before. There are a lot of redundant, diversity sites, but I’m not sure if any of them utilize real-time switching in this manner.
“Certainly there’s the alternative of doing a fully-manned facility for manual backup,” Rossell says. Obviously, this would require Sky to hire more personnel for their diversity site. Currently, the diversity site is manned by three personnel, whereas a minimum of 10 people would be required without the automatic function of the Crystal system, Rossell explains.
If there’s one common message to be gleaned from each of these case studies, it’s that satellite software has penetrated to all levels of the satellite industry, from flying the satellite to planning the ground infrastructure to overcoming the forces of nature. Like the computer industry itself, software is constantly growing and changing in functionality, and it’s anyone’s guess as to what tomorrow’s applications will be capable of performing.
Rob Fernandez is Via Satellite’s Senior Editor.