APSOH – A DREAM COME TRUE
Cmde Arogyaswami Paulraj AVSM VSM PhD(Retd)/Fox/25/BCC/Silver Medallist
Early in 1969, I was nominated to attend a selection interview for the M Tech course at IIT (Delhi). I joined IIT in July 1969 for the M Tech course, overjoyed at a chance to pursue my interests in a real university. Soon Prof Indiresan became impressed with my work and asked the IIT and NHQ to allow me to transfer to a Ph D programme. I did not have a B Tech degree and therefore normally needed to complete an M Tech before starting on a Ph D. Prof Indiresan succeeded in persuading the IIT Senate to make a concession, but had much more difficulty with NHQ. Initially Vice Admiral Krishnan (the VCNS) gave a flat no, because, as he put it, he did not need scientists in the Navy. But Prof Indiresan persisted and wrote or visited NHQ. VCNS finally relented on the condition that I get back to the Navy in the two years allowed for the M Tech.
I began my Ph D research in December 1969. After an initial start in more applied work, I was successful in developing many interesting results in filtering theory (extracting signals from noise). During early 1971, Prof Kailath from StanfordUniversity visited the IIT. Kailath was already a legend. He encouraged my theoretical research interests. Prof Indiresan with his emphasis on 'practice' and Prof Kailath on 'theory' influenced my professional interests and they remain my principal heroes and mentors. In August 1971, my two years at IIT were completed, and I was posted to Valsura (the Navy'sElectrical School). I still needed a mandatory additional year to submit my thesis.
I did have interesting results, but it required more polishing and Valsura, lacking a research library, would have killed the Ph D. Once again, Prof Indiresan lobbied NHQ for a New Delhi posting and after a great deal of anxiety; I was assigned to the Directorate of Electrical Engineering at NHQ.
One night in early December 1971, during the Indo-Pakistan War, we lost the frigate INS Khukri from submarine action. The next morning, the DEE (Director of Electrical Engineering, Commodore Chatterjee) asked me whether I knew anything about sonars. I don't remember what I told him, but later that afternoon, I accompanied him to Bombay. The next day, I became aware of Lt Jain's association with the BARC experiments. I also examined some of the hardware developed by BARC.DEE then asked me if I would take over Jain's place and pursue the work to improve Sonar 170 B. I accepted and suggested that we do the project at IIT under Prof Indiresan. I was of course happy to get back to IIT to rescue my Ph.D.
The Sonar 170B Modification
In March 1972, NHQ assigned me back to IIT Delhi to develop a modification kit to improve Sonar 170 B. NHQ allowed me to use any design approach. BARC was encouraged to continue its work. I had my misgivings about the BARC's approach, but kept quiet because of the sensitivity of the circumstances.” By March 1972, IIT had a basic prototype and the team (Prof Indiresan, myself and three Ph.D. scholars) flew down to Bombay for trials on INS Kuthar. The first trial had problems in interface to the sonar. We were back again in June 1972, with an improved prototype and this time the trials went well. NHQ was enthusiastic. A final prototype was built during September 1972 to September 1973. It was cleared for production after extensive trials. BDL Hyderabad was nominated as the production agency. IIT handed over the design to BDL in December 1973. I left for the UK to work atLoughborough University in January 1974. The ex-BDL 170 B mod kits entered fleet service in 1976/77.
Comments on the BARC Project
“Lieutenant Jain had done a course in theUK at HMS Collingwood and had picked up sonar knowledge beyond his Valsura courses. In Bombay, Jain met Dr Phadnis of BARC who had returned from Italy where his professor had developed an instrument for nuclear scintillation logging. Phadnis had learnt in Italy that this technique can also improve sonars. So Jain and Phadnis, with Dr Dastidar's blessing, began adapting this instrument for use with Sonar 170 B. Jain was then at the Naval Dockyard Bombay's Weapon Workshop WECORS and Western Naval Command had clearly encouraged his association with BARC. I don't think NHQ was aware of the BARC project. Jain never visited or worked at IIT. I became aware of his involvement only after the loss of Khukri and his death. What I recollect hearing was that the BARC equipment was attached to Sonar 170 B, which was operating when Khukri was hit and Jain was in the Sonar Control Room.
I believe that the IIT system design is much superior to the BARC design. Once, during a meeting in Scientific Adviser, Dr Ramanna's office in 1973 to discuss the IIT vs BARC technology, I tried to explain why the PI approach of BARC had a problem and suggested alternate approaches. I am not sure if anyone understood. The BARC project went on for a few more years before being shut down. This was a high visibility project at BARC and it was politically hard for BARC to wind up the project on a negative note. However, BARC and Jain deserve the credit to have taken the initiative to start improving Sonar 170 B. Clearly, there would have been no IIT project (and the improvement of 170
and perhaps even APSOH if not for the BARC-Jain initiative.
UK and the Seeds of APSOH
From January 1974, I spent 18 months atLoughborough University working on signal processing on an Admiralty Under-Water Establishment funded project. I used every chance to visit the sonar industry and learn whatever I could about the technology. Apart from my research into passive sonar signal processing, I had lots of fun building a minicomputer. At the end of my stay, I was given 2 months to visit sonar companies. This was a revealing experience:
Visit to Grasebys: They were, at that point, building the Solid State version of 184 M for the Indian Navy. I discovered that the design team had only minimal grasp of sonar signal processing. During my brief stay, I helped them improve some of their designs.
Visit to Plessey: I was told by Plessey that they had developed an improved Sonar 170 B. I found that they had not really improved the sonar, other than adding LFM. They had not figured how to do DODN.
Visit to Thompson CSF: This was a strong team building the Diodon sonar for the Indian Navy. However, they did not know anything new. I arrived back in India in November 1975, confident that we could develop our own major sonar. Initially DEE assigned me for sea time. But then somebody intervened and I was assigned to NPOL. NPOL did not have a billet for me and I was finally posted on a transferred billet.
When I arrived in Cochin in February 1976, NPOL was already working on a sonar project. This had a budget of Rs 14 lakhs. Initially, NPOL's Director, Dr Srinivasan, did not involve me with this project. If I recall correctly, a computer system arrived from the US badly damaged and I managed to fix it.
This impressed Dr Srinivasan and I was included in the project discussions. It soon became clear to Dr Srinivasan that I had the best grasp of system design and I slowly began to drive the project into high ground. Around this time, NHQ started looking for an advanced sonar. Dr Srinivasan and I managed to convince various people VCNS, DCPT (Captain Hiranandani) and others that we should build our own. It was a leap of faith for us all. NPOL had little track record to back up such an ambitious project. And I was a pretty green project leader. A CCPA paper was drawn up for Rs 280 lakhs. We had approval by end 1976 and APSOH was rolling. Our team grew from 10 in 1976 to about 60 by 1982. Captain Prabhala headed the Engineering team at BEL. Relations between NPOL and BEL were initially good, but as deadlines appeared, there was much finger pointing and our relations cooled. Looking back, I did a poor job in carrying BEL along and indeed also the DRDO brass. Too much of the technical leadership was centralised in me and my close relations with the Navy (innocent and indeed vital for the project) were unfortunately misread by many of my superiors in the DRDO and BEL. Serious problems cropped up in 1982 and VCNS and CNS had to intervene to keep NPOL - BEL fights in check. If not for these two senior officers, APSOH could have been stopped dead. Many heads soon rolled in the aftermath. “After a 6-month installation on Himgiri commanded by Captain (later Admiral) Shekhawat, the APSOH prototype took to sea in mid 1982. On the very first day, we saw 16 km ranges against a submarine target. It brought so many others and me great satisfaction. We had problems with the power amplifiers, which took a while to fix. But this aside, the system behaved superbly. The sonar screens were sometimes unreal in quality compared to anything known.
Thoughts on APSOH in Retrospect
Now that I lead aspects of wireless technology at a worldwide level, I have a better understanding of the technology development process in the developed countries. I sometimes compare APSOH with other achievements I see in my new field. I am always amazed as to how such an inexperienced team, with such few resources, pulled off this major project in such a short period. APSOH was an impossible dream that came true for many of us.
One day in May 1983, as the APSOH trials were concluding, Dr Arunachalam, the Scientific Adviser to the Defence Minister, asked me to leave the country on sabbatical for two or three years and to do something completely different. He made it clear that my sonar career was over and I should find wider interests. Since I was not seconded to DRDO, the CNS's (Admiral Dawson's) clearance was needed, and went along with this. I was initially a little hesitant, but was willing to be persuaded. Thus, with some surprise, my sonar period ended almost as abruptly as it had begun, more than eleven years ago on the day after we lost the Khukri.“In September 1983, I joined Stanford. It all worked out thanks to Prof Kailath who remembered my Ph D work and arranged the visiting faculty appointment. At Stanford, I returned to pure theoretical research in mostly applied mathematics, very far from sonars and mostly irrelevant to the DRDO or the Navy. However I came to enjoy Stanford a lot, and therefore in 1992, when I was at a loose end, I decided to return here to start a new activity in wireless communications for the University.
I was fortunate to have played a role in the early development of the Indian Navy's sonar capability: Sonar 170 B Mod and later APSOH and its variants - I started the variant but was out of NPOL before these were completed. I acknowledge the support and encouragement of many people. Clearly the most important person was Prof Indiresan. His perseverance and faith launched me (an ex-NDA officer without a formal university degree or for that matter any real engineering training) into a world of high technology - IIT (Delhi), sonars, parallel computers, wireless networks, Stanford University and the rest. Recalling my sonar days, I was blessed with tremendous personal support from the highest levels in the Navy including every CNS and VCNS from 1972 to 1983. There are many others drawn from Navy, DRDO and BEL, too numerous to mention here.
These memoirs have been adapted from the Indian Navy history volume ‘Transition to Eminence’ Indian Navy 1965-1975, by VAdm GM Hiranandani (Retd) .