Why Turkish Army hasn't ordered Turkish Passive Radars which created almost 6 years ago?
İ always though passive radars with IIR guided Hisar A/O would work together.
İ might have exegarated ?
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PARS Project and Passive Radar Studies in Turkey
by İbrahim Sünnetçi
About the radar activities completed and ongoing by the ASELSAN Radar, Electronic Warfare and Intelligence Systems (REHİS) Sector Presidency on 24 March within the scope of the Defense Technologies Days '21 event held by the Istanbul Technical University Defense Technologies Club (ITU SAVTEK) between 24-26 March 2021. ASELSAN Radar Systems Engineering Director Muhammet Mustafa AKKUL, who made a comprehensive presentation, also shared important information on PYAS and PBAS type Passive Radar Systems, which ASELSAN is working on within the scope of PARS Project.
AKKUL, ASELSAN Radar Systems Engineering Director, spoke as follows regarding the ongoing Passive Radar studies:
“Studies on Passive Radars have been carried out in Turkey. Two types of passive radar are mentioned. One of them is the structures we call PYAS, which works more like an electronic warfare (EW) system by listening to the broadcasts emitted from the avionics devices used for navigation on the air elements. Another is PBAS, structures that detect targets with the help of broadcasts created by mobile transmitter sources (in this respect, similar to multi-static radar) as a result of broadcasts from radio or television stations hitting the target and arriving at our receiving antennas, or if there is no broadcast. Work continues on passive radar. A number of prototypes were also made. These are the issues we need to explore. Communication problems such as working in a network here, fusion of the created data in a single center and removing traces from there, as well as the transmission of that data and that high data to a single center, need to be resolved.”
AKKUL, in the Passive Radar System solution for the PARS Project, which consists of 16 tools shared during the presentation (also 2 Mobile Data Source Tool and Role Tool are included in the system as Optional Vehicle) and the PARS Remote Radar Control Terminal (PURKT) connected to these vehicles via TSK-NET. He did not mention the PEAS system, which is among the passive radars in the field and consists of 3 Detection Tools and 1 Data Integration and Control Tool. According to the information I received from Mr. AKKUL, PEAS is a subsystem of the PARS Project equipped with optical sensors and is included in the slide in the presentation to show the whole of the PARS Project.
As you may remember, an Information Request Document (BID/RFI) was published by the Presidency of Defense Industries (SSB) on April 20, 2020, within the scope of the Passive Radar Systems Procurement (PARS) Project. Responses to the BID, which was stated to be available only to domestic companies/institutions/organizations with National Secret or NATO Secret facility security certificate, were requested to be submitted by 17 June 2020.
A Look at Passive Radar Studies in Turkey
In the field of Passive Radar Systems in Turkey, the Passive Compound Detection System (PBAS) product of Havelsan EHSİM, the Passive Sensor System (PASIS), which is expected to be developed with the cooperation of Havelsan and Ukroboronprom, the first system/prototype delivered to HvKK, TÜBİTAK BİLGEM product PYAS and The Low Air Defense and Analysis System Project, a network-based early warning system that is thought to consist of multiple antennas and passive radars, was launched.
Under the Passive Broadcast Detection System (PYAS) Project, the system developed and prototyped by national means is actually a Passive Emitter Tracking/PET type Passive Radar System that can detect in the Lower Frequency and Upper Frequency Bands.
As we know Passive Radars are a subset of Bi-Static/Multi-Static Radars. Because in Passive Radars, transmitter and receiver can be placed in separate/different positions as in Bi-Static/Multi-Static Radars. In passive radars, the transmitter is not under user control.
The first radar systems had to work in Bi-Static mode due to the technological difficulties at that time. Radars used in World War II are an example of this. Bi-Static Radar is actually the most primitive and most modern radars in a way. Bi-Static/Multi-Static Radars can offer better detection performance compared to conventional radars for targets with low RKA/RCS values of the “stealth” type (low radar visibility provided by geometry).
In Bi-Static Radars, the receivers actually have the advantage of invisibility as they do not emit any signals, because the enemy cannot easily detect where your receivers are deployed (with Satellite and EO/IR/SAR/GMTI systems, reconnaissance is required for the location determination of the receiver units).
Passive Radars also have two separate subsets, PCL and PET. PCL (Passive Coherent Locator/PCL) type systems are passive receiver systems that use opportunity signals in the environment as illuminating. PCL type passive radars, which can use broadcasts such as Analog FM, Digital Terrestrial Radio, Analog TV, Digital Terrestrial TV, GSM, Satellite Broadcasts and WiFi Systems, are a lower cost system than normal radars. However, the system cannot show the same tray performance in all of the above-mentioned opportunity signals. Because the higher the bandwidth of the broadcast signal, the better the resolution can be obtained. PCL type Passive Radars, which are easy to carry, are invisible because they do not transmit any broadcast (cannot be detected with SIGINT/ELINT), and they are difficult to deceive and their power consumption is very low. Although detection performances are high, it is dependent on the signal in the environment (bandwidth must be high), and it is a very geography dependent system. A system that can work at one point may not work at another (due to dependency on opportunity signals in the environment). In addition, in PCL type systems, a signal comes directly from the transmitter while the signal comes from the target, so this signal and the clutter/interferences in the environment must be suppressed. Therefore, if there is no opportunity signal in the environment, the detection performance is lower than normal radars.
As examples of PCL type Passive Radar Systems, we can give the Hensoldt Company product 'TwInvis' and Havelsan EHSİM a Passive Compound Detection System (PBAS). As it will be remembered, Hensoldt Company announced in September 2019 that it was able to track two F-35 Lightning II JSF Aircraft, which participated in the ILA Air Show in Berlin in April 2018, for 150 km with the TwInvis Passive Radar System. It is considered that the tracking process started when two F-35s started approaching Berlin, taking off from Luke Air Base and landing at Schönefeld Airport in Berlin with a trans-Atlantic flight of over 11 hours without a break. Due to the strong radio broadcasts in the region, it is thought that the TwInvis Passive Radar System has no difficulty in detecting and tracking the F-35s (Luneburg radar reflectors attached) with known flight path/approach path. TwInvis, which has digital receiver technology and special algorithms, can simultaneously evaluate 16 FM transmitters (analog radio) and 5 different frequencies (such as DAB, DAB+, DVB-T and DVB-T2 [digital terrestrial TV]) to produce a comprehensive aerial picture. In the tests carried out with the Passive Radar System on the Baltic Sea coast in Poland, it was observed that different types of sea and air targets could be detected at a distance of up to 300 km.
Passive Emitter Tracking/PET type systems, which are another subset of Passive Radar, are passive receiver systems that can detect the signals broadcast by target platforms and perform target positioning. Unlike PCL, instead of using the reflected signals in PET, a detection is made by using the signals emitted by the target platform itself and the target is tried to be positioned. PET looks more like an EDT/ESM System compared to PCL. Like the EDT System, it receives the transmitted signal, detects it, perhaps classifies it, and can position the target in different ways, unlike an EDT System.
PET, located on the target platform;
· Communication Signals (Can be in different bands, such as HF/VHF/UHF radio and data link),
· Identification Systems (IFF, TCAS etc.)
· Approach Systems (such as TACAN and DME)
Radar Systems (such as aircraft radar and terrain tracking radar) and
Mixing Systems (such as EH Self Defense Pods, internal EH Systems)
It detects the signals emitted from such systems and detects the target and passively positions the target.
Its main advantages are; stealth (because there is no broadcast), very low cost compared to normal radars, hard to cheat, low power consumption and higher detection performance compared to radars.
The main disadvantages are; Dependent on the signals emitted from the target, if there is no broadcast from the target, the system cannot operate and cannot be detected. The higher the bandwidth of the broadcast signal, the better the resolution of the system. However, since most of the signals broadcast from the systems, except for the low-frequency radio sets in the aircraft, have sufficient bandwidth, it is possible to detect them with PET type passive radars. The geographical location of the system directly affects the detection performance. Because if the target falls right in the middle of the receivers, an excellent result can be achieved in terms of detection. Target positioning can be done by detecting the signal broadcast from the target aircraft by 2 receivers.
Kolchuga Passive Radar System
The target detection range to be obtained with a PET type Passive Radar is directly related to the strength of the signal broadcast from the aircraft. Radar is a device that can determine its own output power. For example, if the radar on the target aircraft has enough power to reach the highest detection range, a PET type Passive Radar on the ground can detect from a distance of 300-500km depending on the location of the receivers. However, if the radar on the aircraft presses a lower power for low range detection, the detection range with passive radar may be less than 50 km. Passive radar detection of LPI and AESA type weather radars will be performed at shorter distances compared to conventional radars.
... HvKK PYAS Project
Under the Passive Broadcast Detection System (PYAS) Project implemented in cooperation with TÜBiTAK BİLGEM Information Technologies Institute (BTE) Radar Systems Department, Istanbul Medipol University and Gebze University, a unique passive radar system has been developed for HvKK with national resources.
In the TÜBİTAK 2019 Annual Report, the following information was shared regarding the latest situation in the Project: “The Factory Acceptance Tests (FAT) of the Passive Broadcasting Detection System (PYAS), developed for HvKK, which performs long-range target positioning and tracking via signals broadcast from air targets, have been successfully completed. carried out.” In the light of this information, I evaluated that the Site Acceptance Tests were carried out after the PYAS FAT process was completed in 2019, and since no information regarding the delivery of PIAS to HvKK was shared in the Activity Report, I thought that it would be possible to carry out the delivery in the first half of 2020 after the Site Acceptance Activities. However, according to the TÜBİTAK 2020 Annual Report published recently, PIAS has been placed in 4 locations (the system has 4 passive receivers in sheltered structure) and the System has been activated actively. In the report, it was stated that PYAS was made ready for Site Acceptance Tests by 2020. Based on this information, I think it would not be wrong to make an assessment that the PIAS Field Acceptance Tests will be held in 2021 and if successful, the acceptance process will be completed in 2021.
However, at the Military Radar and Border Security Summit held in Ankara on October 2-3, 2018, striking information was shared about the Passive Broadcasting Detection System (PYAS), developed by TÜBiTAK BİLGEM for the Turkish Air Force and the first field trials were carried out in 2018 at the TÜBiTAK Gebze campus. It was stated that the project, which started on December 15, 2015, is planned to be completed on December 17, 2018.
The Call Document under the Scientific and Technological Research Council of Turkey (TÜBiTAK) Public Institutions Research and Development Projects Support Program (SAVTAG 1007 Project) was developed within the scope of the Passive Broadcast Detection System Development Project, which was published on 13 March 2015 and the call was closed on 29 May 2015. System (PYAS) is a passive broadcast detection system that can detect and track targets by detecting and processing air target signal broadcasts from different points in order to meet the need for HvKK. In this framework, PYAS captures the broadcasts/signals of various electromagnetic energy sources (lower frequency band and upper frequency band) on air targets with receivers located at different locations and performs target positioning in three-dimensional space. Signals in the Lower Frequency Band broadcast from air targets Mod 1, 2, 3AC, Mod-S, TDL (Link 16) and TACAN. Signals in the Upper Frequency Band originate from Radar and RF Jammers.
The main disadvantage of passive radar systems, which are difficult to see and deceive, is that they are signal dependent, that is, if the threat aircraft does not emit a signal, it is not possible to detect it. The higher the bandwidth of the broadcasted signal, the stronger the resolution and detection range of the system will be. Since there are too many disturbing effects and signals in the environment, target positioning and screen display in passive radars are not as clear as in normal radars, so the probability of false alarms is much higher. In order to prevent this, an advanced tracking algorithm and trace merging algorithm were used in PYAS.
Since passive systems are highly dependent on geography, sensors must be optimally positioned in the field and perfectly synchronized with each other in order to maximize system performance. A special tool/software has been developed to ensure that the PIAS sensors can be optimally positioned in the field. Thanks to this software, which is stated to be delivered to HvKK with the system, the user can see which regions are covered and in which regions blind spots occur when the sensors are positioned on the 3D map. Thanks to the special algorithm/software, the most suitable geographical positions for the 3D placement of the PYAS sensors can be calculated and optimum settlement locations can be suggested on the map.
One of the 4 sensors developed for HvKK under the PYAS Project acts as the main center. Although it looks the same from the outside, the sensor in the center has additional equipment unlike the others. There is an 8m collapsible mast and electronic cabinet on the PIAS sensor, which is a 5m long shelter placed on a towable trailer. There are antennas and RF conditioner circuits serving different bands in the radome on the mast. PYAS sensors in sheltered structure with two personnel inside can communicate with each other via radio link (there are radio link antennas on the shelter) or with a network network, if any. The first field trials of PYAS were carried out in 2018 at the TÜBiTAK Gebze campus. In this context, the PYAS receiver, which served as the center for PYAS field trials, was located at the Gebze campus (right next to the MGR radar), while the other three (one at the military airport in Yalova, the other two were placed on two separate hills at different points) were located 15-20 km away from the center. In the first field tests carried out in a small geography (the distance between the receivers was 5 km) with the PIAS System, which is not yet fully completed and has not reached its final performance, signal detections could be made from ranges up to 90 km.
In the TDOA and target detection method, the farther the distance between the receiver/sensors is from each other, the better the system performance. Therefore, when the distance between the receivers is increased from 5km to 20km, it is evaluated that signal detection can be made from ranges much longer than 90km. The power of the transmitter on the threat air platform is also an important factor in the target detection range. The stronger the transmitter transmits, the longer the detection range with passive radar. Since the radar is a device that can determine its own output power, it can print the signal low or print the signal high to reach the maximum range. When it sends a signal at the highest power, the radar broadcast can be detected at a distance of 300 or even 500 km, but if the power is low (for example, an LPI type radar), it cannot be heard even 50 km away.
... HAVELSAN EHSİM PBAS
The Passive Compound Detection System Development Project was initiated as an R&D Project funded by TÜBiTAK SAVTAG for the needs of the Turkish Air Force Command, and Havelsan EHSİM Company won the tender. The contract signed between TÜBİTAK, the Ministry of National Defense (MSB) and Havelsan EHSİM entered into force on 15 August 2013 and the project work was started. The project aims to develop a Passive Composite Detection System (PBAS) that makes use of Analog FM Radio, Digital Radio (terrestrial) and Digital TV broadcasts. Although a 36-month calendar was defined for the Project, this calendar could not be met. In the 2016 Annual Report of the company published on February 28, 2017, it was stated that the work on the PBAS Project was continuing and the project was aimed to be completed in 2017. According to the 2016 Annual Report, system hardware and software development studies continued in parallel with the data collection, recording, testing and algorithm improvement works in the field in 2016 in the PBAS Project. Within the scope of the project, first of all, a Passive Radar Signal Acquisition and Recording System (STKS) was produced and system algorithms were developed by processing the data collected with this system. In this framework, STKS was integrated on a purchased commercial vehicle, antennas were produced for FM and DAB bands, antenna beamforming units and receivers were developed, then the receiver and antennas were placed on the STKS vehicle and field studies were conducted with the SKTS vehicle to collect signals and data. By examining the collected and recorded signals in the laboratory environment, target detection and tracking algorithms were developed. In addition, mechanical modifications of 4 STKS vehicles, which are planned to be delivered to HvKK at the end of April 2017, were made, one of which was produced to operate in the FM band, and field tests were carried out with this vehicle in 2016. With the tests carried out, the user (HvKK) and customer (MSB) authorities stated that STKS meets the need. In order to create a reliable test environment, an FM broadcasting station was also established and put into operation for tests.
A Memorandum of Understanding was signed between HAVELSAN and Ukraine's state defense industry enterprise Ukroboronprom on the joint production of the Passive Sensor System (PASIS) on April 8, 2016. During the Arms and Security 2016 Fair held in Kiev on October 11, 2016, HAVELSAN signed a cooperation agreement for passive radar production, this time with Ukrinmash, a state company under Ukroboronprom. With the project, it was aimed to increase the remote sensing capability of Turkey and Ukraine up to 600km range. According to the Interfax-Ukraine news, the development work for the new passive radar system would be financed by Turkey and the product would be different from the well-known Kolchuga passive radar in the world market (ESM/EDT System can detect up to 800km range). Israel purchased a new generation Kolchuga-M Passive Radar System from Ukraine in March 2018 through Airstom Company and the system was delivered in the same year. It is evaluated that the Kolchuga-M Passive Radar System can be used by the Israeli Air Force in tests, training and exercises to be carried out in the electronic warfare field.
Conclusion
HAVELSAN EHSİM product Passive Radar Signal Acquisition and Recording System/Passive Compound Detection System (PBAS), consisting of 4 vehicles, and PIAS, developed by TüBiTAK BİLGEM and consisting of 4 separate shelters, can function in integration or interaction with each other. PBAS/STKS and PIAS Systems are supported by the Electro-Optic System (EOS, actually an Infrared Search and Tracking [IRST] System) Tool built on the LandRover Defender TTA developed for HİSAR-O/RF, thanks to its low Radar Cross Section Area (RCA) values. An important capability gain will be achieved in the detection of stealth-featured air targets, and this capability will be enhanced with the commissioning of an OHT radar system that will operate in the unique, national VHF/UHF band. On the other hand, PYAS, PBAS and PEAS type Sensor Tools, Data Integration and Control Tools, Central Control and Integration (PARS Local Radar Control Terminal) Tool, Radio Link Tool and PARS Remote Radar Control Terminal (PURKT), which ASELSAN works within the scope of PARS Project, Since the enemy air elements posing a threat with the PARS Passive Radar System, which will consist of ) can be seen and observed from different angles in a much wider geography and from longer ranges, including air targets with low radar visibility (stealth), they can be unnoticed and observed by the enemy Electronic Support (ED) Systems. A more effective air and missile defense capability (when integrated with the SIPER System) can be established without targeting enemy Anti-Radiation Missiles (ARM).
İbrahim SÜNNETCİ İstanbul Teknik Üniversitesi Savunma Teknolojileri Kulübü (İTÜ SAVTEK) tarafından 24-26 Mart 2021 tarihleri arasında gerçekleştirilen, Savunma Teknolojileri Günleri ‘21 etkinliği kapsamında 24 Mart günü ASELSAN Radar, Elektronik Harp ve İstihbarat Sistemleri (REHİS) Sektör Başkanlığ
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