So the Pentagon solved the main problem of military space communication.
The Pentagon is looking for an easier way to protect military satellite communications from jamming. Engineers MIT Lincoln Laboratory have developed a prototype HoNi BAJR antenna for low-orbit satellite constipations, where not several large devices operate in orbit, but many small satellites. Such an architecture requires compact equipment that does not eat energy on board.
Military satellites are increasingly using adaptive antenna arrays. They can quickly change the direction of the signal, strengthen communication with the right subscriber and inhibit the interference if the enemy tries to muffle the channel. The problem is that conventional phased antenna arrays are complex, roads and consume a lot of energy: they control the signal is controlled by many active elements, amplifiers and control circuits.
MIT Lincoln Laboratory offers another option. Honi BAJR stands for Hosted Nimble Beamforming Anti-Jam Reflectarray. In meaning, it is a reflective antenna array with fast beam formation and interference protection. Instead of putting amplifiers on each element, engineers use a controlled reflective surface. The radio signal falls on it, reflects, changes the phase in certain areas and goes to a separate feeding antenna with the desired shape of the beam.
This principle is similar to a mirror, which does not just reflect the signal, but changes its direction and shape. Due to controlled elements, the antenna can point a beam at the desired user, divide it between several subscribers and weaken the signal coming from the source of the interference. According to the laboratory, reflectarray reduces power consumption by about 95% compared to traditional antenna gratings.
For small satellites, the difference is critical. In low orbit, the device is limited to the size, mass, area of solar panels and a supply of energy. If protection against jamming can be obtained without a heavy and voracious phased array, the military will be able to put such antennas on more compact satellites and deploy large constellations cheaper.
The main task of HoNi BAJR is to keep the connection during active jamming. Typically, an adaptive antenna system is terrified by hindrance through dill in a directional chart. Simply put, the antenna tries to receive a signal worse from the direction where the source of interference is located, and at the same time hold a useful channel. This approach is especially important for tactical satellite communications, where subscribers can work in the combat zone.
The prototype was checked on the RF Systems Testing Facility. Engineers have shown that the antenna can scan a wide sector and receive signals from a large corner area. Also confirmed the work with several beams: the system shared the signal between several users with small losses. For a satellite constellation, this is important because one device must serve not one fixed point, but several subscribers or coverage zones.
The team also tried to suppress not one point interference, but a wider area. To do this, engineers changed the side petals of the directional chart. The side petals are additional directions where the antenna inadvertently emits or from which it takes part of the energy. If they are more precise, you can relax interference not only from one direction, but also from the whole sector.
So far, there are difficulties with that. The first tests gave a mixed result: small deviations of the signal interfered with exactly control the lateral petals. Researchers believe that the problem can be reduced by more accurate calibration. For reflective gratings of the military satellite class, such experience is still limited, so engineers still need to learn how to accurately measure and compensate for distortions over the entire surface of the antenna.
Calibration remains the main technical barrier. It depends on how accurately the system will direct the beam, how deeply the hindrance will be and how stable it will work after launching into orbit. Conventional phased lattices have long been studied and used in different systems, and scanners of the missile reflectant antennas for secure satellite communication only go from the laboratory prototype to possible use.
According to MIT Lincoln Laboratory, the technology is best suited for cases where the satellite operates on pre-planned rays, is limited in energy and collides with constant, but not changing interference. The following steps are associated with improved beam formation, calibration and search for specific military tasks, where a light antenna will give an advantage over heavier classical systems.
The Pentagon is looking for an easier way to protect military satellite communications from jamming. Engineers MIT Lincoln Laboratory have developed a prototype HoNi BAJR antenna for low-orbit satellite constipations, where not several large devices operate in orbit, but many small satellites. Such an architecture requires compact equipment that does not eat energy on board.
Military satellites are increasingly using adaptive antenna arrays. They can quickly change the direction of the signal, strengthen communication with the right subscriber and inhibit the interference if the enemy tries to muffle the channel. The problem is that conventional phased antenna arrays are complex, roads and consume a lot of energy: they control the signal is controlled by many active elements, amplifiers and control circuits.
MIT Lincoln Laboratory offers another option. Honi BAJR stands for Hosted Nimble Beamforming Anti-Jam Reflectarray. In meaning, it is a reflective antenna array with fast beam formation and interference protection. Instead of putting amplifiers on each element, engineers use a controlled reflective surface. The radio signal falls on it, reflects, changes the phase in certain areas and goes to a separate feeding antenna with the desired shape of the beam.
This principle is similar to a mirror, which does not just reflect the signal, but changes its direction and shape. Due to controlled elements, the antenna can point a beam at the desired user, divide it between several subscribers and weaken the signal coming from the source of the interference. According to the laboratory, reflectarray reduces power consumption by about 95% compared to traditional antenna gratings.
For small satellites, the difference is critical. In low orbit, the device is limited to the size, mass, area of solar panels and a supply of energy. If protection against jamming can be obtained without a heavy and voracious phased array, the military will be able to put such antennas on more compact satellites and deploy large constellations cheaper.
The main task of HoNi BAJR is to keep the connection during active jamming. Typically, an adaptive antenna system is terrified by hindrance through dill in a directional chart. Simply put, the antenna tries to receive a signal worse from the direction where the source of interference is located, and at the same time hold a useful channel. This approach is especially important for tactical satellite communications, where subscribers can work in the combat zone.
The prototype was checked on the RF Systems Testing Facility. Engineers have shown that the antenna can scan a wide sector and receive signals from a large corner area. Also confirmed the work with several beams: the system shared the signal between several users with small losses. For a satellite constellation, this is important because one device must serve not one fixed point, but several subscribers or coverage zones.
The team also tried to suppress not one point interference, but a wider area. To do this, engineers changed the side petals of the directional chart. The side petals are additional directions where the antenna inadvertently emits or from which it takes part of the energy. If they are more precise, you can relax interference not only from one direction, but also from the whole sector.
So far, there are difficulties with that. The first tests gave a mixed result: small deviations of the signal interfered with exactly control the lateral petals. Researchers believe that the problem can be reduced by more accurate calibration. For reflective gratings of the military satellite class, such experience is still limited, so engineers still need to learn how to accurately measure and compensate for distortions over the entire surface of the antenna.
Calibration remains the main technical barrier. It depends on how accurately the system will direct the beam, how deeply the hindrance will be and how stable it will work after launching into orbit. Conventional phased lattices have long been studied and used in different systems, and scanners of the missile reflectant antennas for secure satellite communication only go from the laboratory prototype to possible use.
According to MIT Lincoln Laboratory, the technology is best suited for cases where the satellite operates on pre-planned rays, is limited in energy and collides with constant, but not changing interference. The following steps are associated with improved beam formation, calibration and search for specific military tasks, where a light antenna will give an advantage over heavier classical systems.
