In the Philippines, where an average of 20 tropical cyclones make landfall annually, radio detection and ranging (radar) equipment play an important role in weather observation. Priced at P500 million each, a Doppler radar system enables the country’s weather monitoring system to predict both the direction of weather disturbances and rain intensity, allowing advanced warning of possible flooding.

Though there is an ongoing rehabilitation and construction of Doppler radars in the country, these radars are actually manufactured and developed abroad. The training provided by foreign manufacturers or their local sales representatives is focused solely on mechanical operating procedures and does not include proprietary information that enables in-depth understanding of radar operation. As a result, local capability regarding maintenance and operation is limited and full radar functionality is not utilized.

According to Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), their weather radar equipment experiences prolonged downtime – mainly because the technical support they need comes from overseas. Moreover, repairs have been expensive since replacement parts were also purchased and assembled abroad.

A cost-effective approach to alleviate this situation is to use PAGASA’s decommissioned radar units to thoroughly understand radar design and operation for the benefit of local scientists and engineers.

The LADDERS project looked at opportunities for local design on both radio frequency front-end and radar signal processing blocks to promote sustainable radar systems operation in the Philippines.

The team used PAGASA’s existing radar systems – specifically the recently decommissioned equipment in Guiuan, Eastern Samar and Aparri, Cagayan. The hardware components, including the obsolete ones, were thoroughly tested and studied. This enables the researchers to recommend possible alternatives that are available in the market today.

The hardware components were dismantled and reused to build a low-power table-top Doppler radar which is currently being used as a teaching and research platform for testing radar and other radar-related research. This serves today as a test-bed for building and testing synthetic aperture radar (SAR) prototype. SAR is a radar used primarily for imaging and not necessarily for weather observation.

In addition, the decommissioned radar in Guiuan, Eastern Samar was used to gather raw radar returns to emulate its display by studying its signal processing algorithms and modifying it to fit our modern-day electronics.

Super typhoon Yolanda had disrupted the study on signal processing, but it gave the team a genuine opportunity to tear down the decommissioned radar. The team was able to handle the damaged pieces, dry them out, clean them up, and put them back together again.

Although full operation was impossible as antenna parts had been blown away by the typhoon, the team learned that the radar could still be powered up despite the damage it sustained from the typhoon. The experience turned out to be a learning opportunity, demonstrating the team’s understanding of the decommissioned unit while validating its status after the typhoon.

However, without Guiuan’s fully-functional radar for gathering signal returns, the team directed its efforts to a different (not yet decommissioned) radar model in Baguio City to continue the weather radar signal processing component of the project upon PAGASA’s approval. Despite the huge difference in hardware and software implementations from the Guiuan radar unit, the team still managed to emulate the Baguio radar display using their developed software implementation.

The information from the project has been documented in such a way that it can be accessed and understood by PAGASA engineers, students, and other interested parties. At the same time, more complex technical data is also available.

These research activities and outputs provided better collective understanding of radar technology that will soon help enable the Philippines to achieve technological independence in this area. The teaching and research platforms developed by the project support human resource development through the training of engineers in radar design and principles of operation. These efforts not only strengthened ties between university researchers and PAGASA engineers, but also spurred interest in the field of radar technology. To date, a good number of students are working on other radar technologies with a myriad of applications.

Written by:
Doreena Karmina
University of the Philippines Diliman

Published by:Department of Science and Technology-Science and Technology Information Institute (DOST-STII)