If we talk about major trends in the use of small satellites, then we have to talk about asset tracking. Geolocation has long been a part of our lives. When we make any kind of purchase on the Internet, we are used to knowing the status and location of our order practically in real time. If that is a reality on a small scale, with products whose value does not exceed 40 or 50 euros, then this is all the more important when the safety of hundreds of people or the protection of assets of great economic value is at stake. Think of aircraft tracking (of course, we will talk about the use of small satellites for ADS-B), ship control (AIS/VDES) or the location of logistics containers, to mention just three examples.

We are all aware that terrestrial networks have limitations in asset tracking in remote areas or in areas with low coverage. This is where nanosatellites come into play. As we have already mentioned, in this article we are going to place special emphasis on the use of small satellites for ADS-B, which makes it possible to improve air traffic control throughout the world, but we also want to pay attention to other sectors that can improve the efficiency of their services from space.

The logic of using small satellites to track assets is simple. If a moving asset cannot be controlled from Earth, because of the difficulties of orography or because it is in isolated areas, why not raise your eyes a little and look into space? In the New Space age, enterprises and start-ups seek innovative solutions in space or choose to entrust their nanosatellite-based services to third parties. Space is an inexhaustible source of new business ideas. One of the fields in which these potentialities of small satellites are being exploited the most has to do precisely with the security, location and asset tracking.

Which sectors can use small satellites for asset tracking?

Let's forget about science fiction and think exclusively about realities. What can be done right now with nanosatellites in the area of asset tracking? Let's look at some applications that have already been tested in space and which are in operation:

• Aircraft tracking. Unfortunately, in recent years there have been several cases of aircraft that have disappeared without a trace, such as the Air France flight covering the route between Rio de Janeiro and Paris in 2009, or the Malaysia Airlines plane that disappeared in 2014 on the route between Kuala Lumpur and Beijing.

  In environments close to airports, ADS-B (Automatic Dependent Surveillance - Broadcast) ground systems are very accurate and can provide information about the exact location of the aircraft in a matter of seconds. The problem is that in more remote areas there are significant shaded areas where contact with aircraft is lost. Here, nanosatellites can play an important role.

  The use of small satellites for ADS-B makes it possible to increase air traffic safety, access certain information provided by aircraft sensors, and know the exact location of each aircraft at all times.

  Today, several CubeSats constellation projects already exist to improve ADS-B system coverage and aircraft control. These initiatives come from companies and start-ups that then have the capacity to resell these services to third parties, although more and more we are seeing a growing interest in this type of solutions by some of these end customers (air traffic regulation agencies, airlines, etc.)

• Ship tracking. S-AIS (Satellite-Based Automatic Identification Systems) and VDES (VHF Data Exchange System) solutions improve vessel tracking and location. Due to the nature of their activity, it is common for transatlantic vessels, ships or fishing vessels, to mention just a few examples, to spend long periods of time at sea, in isolated areas where it is not possible to rely on land-based networks to guarantee precise control over their location at all times.

  The use of small satellites can improve the safety of all types of vessels and can be an effective measure to prevent certain common problems related to maritime traffic, such as piracy and illegal fishing.

• Logistics. E-commerce has led to an exponential increase in the number of shipments in most countries. And it has done so globally. We can all buy a particular product anywhere on the planet. In that sense, any asset of a certain value that is going to be on the move today needs real-time location systems, an important aid to improve the security, control and traceability of goods.

  Think, for example, of large logistical containers for the shipment of luxury goods or machinery of high economic value. Their movement often involves the combined use of various types of transport: air, sea, rail, road... Geolocation systems, supported by constellations of small satellites, can also help to improve the safety of these goods.

• Fleet management. Geolocation via satellite has long since become a solution in the management of vehicle fleets, with systems such as GPS, GLONASS, Galileo or BeiDou.

  Small satellites can also offer interesting functionalities in this field, as they make it possible to ensure vehicle control at all times, even in remote areas where conventional networks may have problems.

• Other uses. Any asset that is in motion and that needs a control of its location (herd tracking, for example), can take advantage of the advantages offered by the constellations of small satellites.

  The services that can now be offered are very extensive, but as they say, the sky's the limit. Every year new uses appear for small satellites, also in the field of asset tracking, and these new uses become new business opportunities.

Small satellites for ADS-B: what do you need to bear in mind?

If we are talking about nanosatellites and asset tracking, there are some questions you should ask yourself from the very first steps of the project.

To help give a practical sense to these issues, let's think about using small satellites for ADS-B. To set up an aircraft tracking project, let's look at four critical questions and how they can condition your business plan:

• Which are the target areas where you want to capture information about the location of the aircraft? It's probably the first thing you think about. It's not the same if your company wants air traffic control all over the world or if it is only interested in flights in Europe, for example. It's a decision that will determine the size of the constellation, the orbits of the nanosatellites ... and also the number and location of ground stations.

• How much time must elapse at most from the moment the aircraft emits its position until an operator has it on the ground in front of their screen? We talk about latency from the moment the data is transmitted until it reaches its destination. Technically it is possible to know the location of an airplane in a matter of seconds, but the lower the latency, the greater the size of the constellation of small satellites and the network of ground stations required to achieve it. Is it enough for the nanosatellites to store this information and transmit it afterwards? Do you want to provide a service that sends it to the ground almost in real time or with a margin of a certain number of seconds or minutes?

• What data are you going to make a priority? Think of the number of parameters that can be controlled through ADS-B systems. It may not be interesting to 'bounce' all the information that reaches the nanosatellites to the ground stations. Here it is important to prioritise the data and focus on those that are key to the service you want to provide.

• For how long are the nanosatellites going to store the information they gather? Logically, satellite memory is not infinite, and this also conditions the project. All the data sent back by the nanosatellites are stored on land, but normally not all of the information they receive is downloaded (very much related to the previous point), so from time to time we would have to erase data in order to free up memory space. Bear in mind that at a specific moment, for example, if some kind of incident occurs with a specific flight, you may need access to that other information that you do not usually need and which may be stored in the nanosatellites. Therefore, it is necessary to know if these data will be stored for a day, a week, a month or with whatever expiry date you prefer, in case it is necessary to access them at a given time. This decision also affects the size and design of the satellites.

We hope this article has helped you understand the potentialities of using small satellites for ADS-B and asset tracking. In the same way as IoT services, geolocation is an unstoppable trend in the New Space age, and one that is sure to be a major topic of conversation in the coming years.

Featured image: NASA