Dr. Arifin Nugroho

The HAPS as Strategic Platform and Industry Focus in Indonesia

Arifin Nugroho bin SUKARMAN,

GRS/AES J Chapter, IEEE Indonesia Section

HAPS has been subject of interests for years for platforms flying aloft capable of delivering communication, or surveillance, or both, missions, in complement to either cellular or satellite system. With the altitude of 20 km it would cover an area of 150-200 km diameter, allowing wireless communications up to 10 Gbps throughput, provided that appropriate spectrum capacity can be made available. It is therefore crucial that the WRC-19 which will soon be held in Egypt, should have come up with definite allocation for spectrum for HAPS application.

Owing to the expected long endurance, missions lasting for several weeks, months or even years are possible. This property makes HAPS very attractive as carrier platforms for remote sensing instruments, as well as Multibeam Wireless communications. HAPS allow for short revisiting times or even for continuous observations, e.g., by scanning constantly targeted area from airship, or by performing circular flight tracks over the region of interest. Such an operating mode is not feasible with non-geostationary satellites and is also not realizable economically with state-of-the-art aircraft platforms over longer time frames. We understand that the main thrust of applications for the HAPS would be that of synthetic aperture radar (SAR), Multibeam wireless communications, and Localization/Navigation service, as HAPS payloads.

The SAR principle ensures high resolution down to the sub-meter range independently from the flight altitude, weather conditions and sunlight illumination. Due to the side-looking radar imaging geometry also hazard areas can be monitored safely since the platform is not only separated in altitude, but additionally separated horizontally several kilometers far away from the scene center. In 2015 from the literature we knew that the Airbus Defence and Space were to investigate if it is feasible to bring and operate a SAR sensor on their solar-powered Zephyr HAPS platform. In the study they found that the two main platform restrictions, the limited payload weight and the limited available electrical power, can be overcome. For instance, a peak transmit power of 50 W at a duty cycle of 20 % is sufficient for obtaining high-quality SAR images with resolutions <1 m at X-band with a swath width of 25 km, acquired from a flight altitude of 20 km. In this conference we would expect experts from the Industries would cover in their talk a detailed overview of the potentials and applications of HAPS-SAR.  Also, may we get some expose on the onboard navigation system, which are crucial for obtaining high-quality (circular) SAR images.

In communication applications, different initiatives have been proposed by many, such as Softbank, Googles, Facebooks, and the like. As far as the payload technology is concerned, the legacies given by communications satellites should have been at the  off-the-self status. To name a view: Multibeam antenna, RF, Filtering, HPAs in higher frequency, LNAs, etc. are all available in the markets, leading to payload integration become relatively easier and more cost effective. The same facts apply to the ground segment of HAPS, as the terrestrial cellular system and VSAT system are in its maturity.

Perhaps the most challenging efforts reside in the HAPS platform technology, either airplane or especially the airship type. Namely to make HAPS bus be quasi geostationary, control system shall be designed to cope with random forces due to winds as counter-attacked by the fuselage and wing designs as well as the mass distribution variable in the HAPS body. To my knowledge, there are still less attention being given by literature and research works in this respect.

It seems that the industry shall rely to the big players for the HAPS bus technology, leaving the payloads remains the domains that the user shall be focusing at.

Address:PT UNISAT, Bukit Gading Indah, , , Jakarta, Jawa Barat, Indonesia