Swedish Air Force datalink history and Gripen Link 16 integration described by Czech Air Force article


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LINK 16 - a new dimension of secret data connection for Czech Gripen
12/1/2019 Aleš Hottmar 1261 Views 21. zTL Čáslav , 211. tl , JAS-39 Gripen
At the beginning of next year, the integration and flight tests of the MIDS-LVT terminals of the secret data link of the Alliance Protocol Link 16 on the Czech JAS-39 Gripen aircraft should finally begin. Link 16 is a standard protocol used by NATO countries to transmit tactical data information from ground guidance stations, AWACS early warning aircraft and between aircraft themselves. Now the machines of the tactical air force of the Air Force of the Czech Armed Forces will join this alliance standard.

Somewhat surprisingly, Sweden was the first country in the world to introduce systems for the transmission of tactical data information from ground command and guidance posts into real operational operations. The reason for their development and practical commissioning was the requirement for the ability to effectively manage the activities of the Swedish Air Force in the event of a major war. Surprisingly, a number of states did not recognize the benefits of the possibility of transmitting important tactical information using the so-called datalinka before, and some air forces do not have this necessary operational capability even today!
The Swedish Flygvapnet command was well aware that against the main potential enemy in the form of the Soviet Union, which was supposed to be able to use Swedish territory to achieve its other strategic goals in the event of war, its air force would not be able to operate from its permanent bases. using traditional command and control procedures, using, inter alia, an unsecured radio link, which is relatively easy to disrupt in the context of strong electronic warfare.

The FMR-10 transmitters of the STRIL 60 system were strategically located on the Swedish coast. (source: Swedish Armed Forces)

This led to the implementation of a strategic plan called Bas 60 (Flygbassystem 60), which included the construction of dozens of backup airports and designated road sections with parameters of 2000m x 12m throughout Sweden, on which in the event of war would quickly disperse before a possible attack Flygvapnet type fighters. Saab J-35 Draken or Saab J-32 Lansen and thanks to a nationwide distributed system of digital command and control commands called STRIL 60(Stridsledning och Luftbevakning 60) could continue to conduct effective combat operations. This data link system enabled the internal transfer of binary data from various STRIL 60 ground devices, as well as between the ground and the aircraft itself. All the calculations of control information for guiding the fighter aircraft to the target, which were provided by humans in the previously used STRIL 50 system, have now gradually taken over the computers, which has made it possible to speed up and make the whole process significantly faster.
The basis of the whole system were long-range radars PS-08 from the English brand DECCA Radar Limited, which were selected for STRIL 60 as surveillance and guidance radars. The PS-08 had a range of less than 500 km and for its time a good detection capability of targets flying at high altitude in the relevant air defense sector. The narrow beam angle (0.28 degrees) provided good accuracy in determining the position of the target. By the end of the 1950s, four stations with special nicknames in the form of male first names began to operate, and the first PS-08 "DICK" radar was installed at Vikbolandet in Östergötland. This was followed by "HARRY" at Södertälje's, "TOM" near Emmabod and finally "FRED" at Skåne. PS-08 worked with high output power and short pulses for good resolution of the target in the S band. The radar was gradually adjusted to better handle enemy interference,
In the electronic "memory" of the STRIL 60 system, all information from PS-08 radars was further processed for distribution to other users at the Luftförsvarscentral (LFC), who needed radar yield for their activities, for example to calculate optimal flight paths for different types of attacks and capture an enemy target. The data transferred in this form in the form of digital data commands or voice commands for J-35 Draken fighters was transmitted by the Stril system from FMR-10 transmitters from the German company Rhode & Schwarz, which operated in the VHF band in the frequency range 103-156 MHz and with a maximum output power of 10 kW, in peacetime reduced to 1 kW. A total of 41 stations were strategically installed on the Swedish coast, the transmitter antennas themselves were installed on a high mast and pointed obliquely upwards to cover the high altitude above the Baltic Sea. Command messages in voice form (for J-35A) or digital form (for J-35B / D / F) came via cable or radio connection, with the "wire" connection always being chosen in a combat situation for minimal risk of interference.

Draken - top secret !! The first generation of datalinka is coming

PS-08 radar yield and STRIL 60 data transmission console operator (source: Swedish Armed Forces)

The STRIL 60 data connection in Draken was, in a way, an electronic miracle due to the time of its creation. It is worth noting that at the time when the Swedish Flygvapnet successfully put this device into service in the early sixties of the last century, the US Air Force began to experiment with similar systems.
The integration of the data connection to the Drakens was strictly secret, and the entire system of command information and commands was ingeniously hidden in a number of classic analog devices, so that a casual observer in the Draken cabin could not recognize anything at first glance. The data message from the FMR-10 transmitters was received by the Draken onboard radio. The J-35B / D machines were equipped with a pair of radios - Fr13 manufactured by AGA as the main radio and Fr 14 from Collins as a backup. Based on extensive testing, the Fr 14 radio became the main recipient of the data messaging function and the Fr 13 was used only for voice communication. In Draken, its rear antenna was usually used to receive control data, which had a large gain for signals coming from behind, which suppressed the expected radio electronic interference.

The Draken cabin was advanced for the time of introduction into service in the early 1960s. (source: Swedish Armed Forces)

The control data message from STRIL 60 contained an introductory specific code, which had to correspond to the individual code of a particular aircraft. If all was well, the message was distributed from the radio to the FD 10 / FD 11 control data converter, which converted the data to analog signals, which were displayed on flight indicators in the cockpit. For example, commands for the Draken pilot were presented in the upper window of the AHK (Avstånd Höjd Kommando) indicator, located to the right of the radar screen. The indicator had a rotating drum that displayed all 20 predefined STRIL commands, while the input signal determined which of them would be visible through a small observation hole. Each time the command was changed, a warning tone sounded in the pilot's headphones.
The AHK indicator thus provided tactical information to the pilot, which was displayed as words, and the altitude scale showed the actual altitude of the aircraft and the arrow the target altitude set by incoming messages plus the distance to the target. The FLI-25 gyrocompass, in turn, showed the direction to the target, the speedometer displayed the speed of the target, etc. The list of commands and other data literally led the pilot to the target, which was to attack without having to turn on his own radar or start communicating in any way on open frequencies.
Each STRIL data message contained 103 bits, of which 68 bits were direct flight information and the rest was set aside for technical information such as aircraft identity, etc. In electronic storage, incoming data messages from Air Defense Center exchanges were processed into a constant data flow. at 3000 bits per second. That means about 30 control data messages per second. In reality, this meant that if there were 30 fighters in the same area, each would receive an updated message per second.
The data message for J-35 Draken aircraft contained, in addition to the administrative part consisting of the so-called "Introductory Code" and "Address" (original identity of each aircraft), the following flight orders and data:
  • Phase of flight - contained two options, phase I for approach and phase II for ambush. The phase also served to scale the distance information. In phase II, at a distance below 40 km from the target, the distance resolution increased 10 times. The flight phase is transmitted with 2 data bits.
  • Target height - the height was sent in decimal format, which consisted of three decimal places with a resolution of 200 meters. The pitch was transmitted with 2 + 4 + 3 = 9 data bits. The specified maximum height for the J-35 Draken was limited to 20,000 meters, later for the JA-37 Viggen was increased to 30,000 meters.
  • Command - this function allowed the pilot to send one of 20 predefined text commands * with tactical content from the radar operator. These commands were transmitted with 5 data bits.
  • Target course - the course was sent binary coded with 9 data bits with a technical resolution of 0.703125 degrees.
  • Direction to the goal - was sent in the same way as in the case of the goal course.
  • Distance to destination - The distance was transmitted in binary coded 9 data bits. The resolution was 1 km at a distance of 40 km to 400 km. At a distance of less than 40 km during Phase II, the distances were transmitted with ten times higher resolution.
  • Changing the angle to the target- The rising or falling angle was transmitted using 6 data bits.
  • Height change to target - height change in meters was transmitted using 6 data bits.
  • Reserve - these were another 4 data bits that were not used in the messages
In the era of digital multifunction displays and powerful computers, it was a remarkable system that gave the Swedish Flygvapnet the ability to disperse to backup areas across the country and meet any air raid using ground-based radar stations, all without a single spoken word on open frequencies. The entire first generation datalinka system was implemented in 1963, first on the J-35B and J-35D Draken aircraft, and in 1965 it began to cooperate with the latest version of the J-35F Draken. The first generation of the data plant in Draken was, of course, chargeable to its time and allowed only one-way communication from the ground guidance station to the designated aircraft and vectoring to the starting position to attack only one primary air target.
The LFC (Luftförsvarscentral) had a total of 12 operator consoles in three cabins, with four operators in each. Each operator could handle four missions in one mission with one to four aircraft. In total, the operators in the LFC center could guide from their consoles 48 to 192 aircraft, which corresponded to 6 - 24 squadrons of Flygvapnet, so that a massive enemy attack by the Soviet Union could be prevented. Really respectable at the time.
Note * - these were the following commands: FEL (error), HÖJDÄNDRING (height change), FLERA MÅL (multiple targets), JAKT (chase), REMSOR (?), NYTT MÅL (new target), OSÄKERT (unconfirmed), VARNING (warning), MÅLFART (?), MÅLKURS (destination course), O (zero), FRAM (?), TVÄRS (?), BAK (?), ÖKA (?), STIG (route), BRANT (?), KVARLIGG (?) And LANDA (ground).

Although Draken structurally dates back to the end of the 50s of the last century, its first versions already had on-board RL and a number of relatively sophisticated systems at the time. The picture shows the latest version of the J-35J Draken, which was modified in the number of 66 pieces of stored J-35F2 and all served in the years 1987-1998 at the F10 wing in Ängelholm. The "Johan" version was created due to delays in the supply of JA-37 fighters and the development of the new JAS-39, while it had the ability to capture low-flying targets such as Su-24 bombers, which began to come to the USSR Air Force and Naval Air Force. (photo: Aleš Hottmar)

The second generation of the datalink in Viggen - the possibilities are expanding
The introduction of the fighter version of the new JA-37 Viggen aircraft in the early 80's into the Flygvapnet armament moved the STRIL 60 system to a completely different level of capabilities. Viggen was the first aircraft in the history of aviation to use a modern on-board computer CK37 (Centralkalkylator 37) with integrated circuits as early as the early 1970s. This computer controlled, for example, on-board navigation, control of Radar PS-46 radar functions, displaying information about flight mode, orientation in space, engine control, fuel management, etc.

The original form of the dashboard of the fighter JA-37 Viggen, which was dominated by the EP-12 imaging system, which consisted of three indicators in the form of a transparent Sight Line Indicator SI (HUD), Target Indicator MI, which displayed all target data from the PS-46 radar and Tactical Indicator TI with a size of 5 x 4 “for the presentation of flight data, navigation and radar information plus a data link. (source: www.aef.se/ )

The fighter JA37 in its final serial version flew for the first time on November 4, 1977, and this version already had a more modern and powerful on-board computer CD107. The first series of Viggen fighters was delivered to a squadron of the F13 wing "Bråvalla" in Norrköping on June 25, 1980. Deliveries to the F13 were not completed until January 1982 due to delays due to engine problems. Another unit that acquired the Vigenny fighter was one of the squadrons of the F17 "Blekinge" wing in Ronneby, which received its first JA-37 in December 1981 and deliveries were completed in September 1982. In October 1982, deliveries to the third squadron of the F21 " Norrbottens' in Luleå, the last arriving in May 1983. Subsequently, the JA-37 was included in the armament of two squadrons of the F4 wing "Jämtlands" in Östersund in the period from August 1983 to April 1985.
In the mid-1990s, a major modernization of part of the Viggen fighters began, during which about 30 selected JA-37 machines from the F16 and F4 wings were upgraded to use new guided missiles and electronic warfare systems for deployment in international operations. The designation of such modernized Viggenes was changed to JA-37D. In addition to the upgraded cockpit, this version also received a new central computer CD-207. Otherwise, the original computer CD107 fighter versions of the JA-37, of course, cooperated with the STRIL 60 system. This meant that although he still received the same basic 103-bit message format as the J-35 Draken, he was able to work on the necessary calculations thanks to a more powerful computer and radar,

Display of information on a tactical indicator with CRT technology.

The cabin of the Viggen fighter was modernly equipped for its time and had both a Head-Up Display (HUD) and a pair of displays based on CRT technology. For example, the tactical display was already able to show the pilot much more data such as information about the attacked target, fuel and weapon status plus other information. The datalink itself enabled guidance to one main destination, or four backup destinations. Data messages were received via the FR-29 on-board radio, which converted the received analog information via digital transceiver into digital format, which was then transferred to the CD107 on-board computer on bus No. 3. The computer decrypted and analyzed received messages, error correction, importance assessment and was responsible for presenting this data on TI's tactical information display.
The development of the data line in Viggen, of course, continued, and in 1982 it already made it possible to connect two Viggen data to each other. Since 1984, even four machines, and in 1985 a two-way datalink was introduced. One aircraft could thus, among other things, automatically mediate the position of the target from its own radar, its own position of the aircraft and the state of armament for display on the tactical display (TI). This provided JA37 pilots with much greater situational awareness and enabled the use of a completely new air combat tactic. For example, it was possible to increase the distances between aircraft and cover a much larger tracking area, and at the same time it allowed to fly in a group in bad weather and at night much safer, and at the same time track the position of other machines in "combat". It was really a generational leap from the existing system, because for the first time, Viggen could share tactical data not only with each other, but also with ground systems, in real time. In 1995, the ability to transmit short text messages was launched.

In the mid-1990s, the JA-37D Viggen cockpit was modernized, replacing the original TI monochrome tactical indicator with a completely new 6 x 8 ”color TI 237 display, which was later used in the JAS-39C / D aircraft. The twenty-four-button MFD made it possible to display tactical data from the datalink much better. (source: www.aef.se/ )

Flygvapnet tested a new guidance tactic using a datalink, for example, against the US strategic reconnaissance aircraft SR-71 Blackbird. He flew through the edge of Swedish airspace about once a week, flying "Baltic Express" reconnaissance missions along the Soviet coast, and on his way back to his home base in Fairford, UK, he flew the narrow 3 km wide corridor of international airspace between the Swedish mainland and Gotland at 21,000m (70,000 ft) and Mach 3 speed.
As soon as the ground radar stations detected the incoming SR-71, the cash Viggen first reached an altitude of 8,000m (26,000 ft) and from Mach 1.35 the pilots swept to maximum speed and climbed at an angle of three to five degrees up to an altitude of 18,000m (60 000 ft), directly to the support course of the flying SR-71 and to the best shooting position for simulated firing of Skyflash missiles. During the raid, Viggen's pilots had a full tactical picture of the situation on their display, combining information from ground-based radars and their own radar to provide the precision needed to correctly capture the target at Mach 4-5.
The Swedish Air Force recorded over 50 successful interceptions of Blackbird, which were evaluated as those in which a simulated launch of Skyflash missiles would probably achieve a direct hit. It is difficult to imagine that Viggen pilots would have achieved the same success without the accuracy of guidance and data provided by the Stril 60 system. in the form of types MiG-23ML or Su-15TM, which in the 80s began to appear more and more often near Swedish airspace.

Viggen was the backbone of Flygvapnet throughout the 1980s and 1990s until the arrival of the Gripen. Again, a relatively underappreciated aircraft, with an effective weapon system, including medium-range missiles RB71 Skyflash and very decent flight characteristics and performance. The picture shows the AJS37 version, modified due to the delay of the entire JAS-39 Gripen program. Between 1992 and 1997, SAAB upgraded a total of 48 AJ37s, which acquired new avionics and a central computer, including 1553 data buses. This allowed the AJS37 version to use Gripen weapons, such as the AIM-120B AMRAAM or anti-ship RBs. -15F. (photo: Aleš Hottmar)

Very interesting two-seater version of the SK37E (Electronic), designed for REB lines and equipped with various jamming systems, which were controlled by the operator in the rear cabin. A total of 10 machines were converted to this version, serving in the years 1998 - 2002 at the wing of the F4 Jämtlands at the base of Frösön. The chosen camouflage coating was ideal for dispersion on the BAS 90 reserve areas in the summer months, and the ability to take off and land shortly was also phenomenal. (photo: Aleš Hottmar)

TIDLS - new capabilities of the third generation datalinka in the Gripen aircraft
The 4th generation JAS-39 Gripen machines have a completely new third generation CelsiusTech CDL39 (Communication and Datalink 39) with hardware from Rockwell Collins, better known as TIDLS (Tactical Information Data Link System), or "TAU-link “(Tactical Air Unit).
TIDLS is a high-speed two-way UHF datalink based on TDMA (Time Division Multiple Access) technology, which significantly expands the possibilities of data communication compared to the original system in Viggen. The Gripen system consists of two analogue Fr41 radios and a Rockwell Collins Fr90 digital radio, which operates in the 960-1215 MHz band and uses countermeasures based on frequency hopping and encryption. TIDLS was fully integrated into the new Swedish tactical radio system TARAS (Tactical Radio System), connected to the updated STRIL 90 systemand which provided radio networks for JAS-39 Gripen and JA-37D Viggen fighters, S100D Argus early warning aircraft, S102B Korpen machines designed for SIGINT and Stridslednings - StriC ground guidance centers. The Gripen concept already corresponded to the new BAS 90 system , which assumed the dispersion of groups of 4-6 aircraft on a large number of reserve areas and road sections with minimum dimensions of 800m x 9m.

Display of information from TIDLS on the center display of the horizontal situation HSD (left) and the right multi-sensor display MSD. Green symbols indicate own forces, red enemy and yellow are unidentified targets. (source: Saab, https://saabgroup.com )

The Gripen datalink has two basic elements - air-to-ground and air-to-air connections with other aircraft. TIDLS can connect up to four aircraft in real time in both directions (some sources even state 8), the number of recipients of data information is not limited. The range is about 500 km and is highly resistant to interference, transmitted in short time intervals. Each of the four participants uses 25% of their transmission time. Data is transmitted via pre-programmed broadcast channels. The Swedish manufacturer claims that the only way to disrupt the data connection is to place an active jammer directly between the two communicating aircraft.
TIDLS basic modes include the ability to display the position, direction, altitude and speed of all four aircraft in formation, including basic information such as fuel status, weapons, countermeasures, and even the cursor position on the multifunction display to allow pilots to highlight important targets for other aircraft. TIDLS differs in part from a similar alliance system, the Link 16. It provides connections to fewer users over shorter distances, but connects them more closely together, exchanges much more data, and works in near real time. The Swedish datalink is updated every second compared to Link16, which is updated every twelve seconds. TIDLS allows up to four aircraft to be connected in both directions over a distance of 500 km and at the same time allows access to data from the SAAB 340 Erieye early warning aircraft,
Information from the TIDLS data plant, together with the output from the radar, the EWS39 electronic warfare system and a moving map, is displayed on the central HSD (Horizontal Situation Display) display, designed to visualize the tactical situation on the battlefield. Colored symbols distinguish between their own, enemy and unidentified targets and show who "targeted" whom. Similar data are displayed on the HUD viewfinder, where the symbolism again distinguishes between own, enemy and unidentified aircraft. If two pilots choose the same target, the system will show which of them is more effective to attack. The whole system is also optimized to prevent two Gripen from attacking the same aircraft, etc.
In combat beyond the visual reach of BVR, where information and situational awareness are the key to success, datalink provides an unrivaled advantage and a significant overview of the battlefield. It is no exaggeration to say that in a formation of four Gripen aircraft, each pilot immediately knows what the others see, do - and what they will do next. Each aircraft has access to the radar and sensory data of the others, allowing a small number of machines to defend a wide area. For example, in one Flygvapnet exercise, six JAS-39s were able to defend almost half of Sweden when three "pairs" of Gripen Combat Air Patrol missions were able to patrol the entire Swedish east coast, from the northern edge of the Baltic Sea island of Gotland to Ronneby Air Force Base. , and further to the southern tip of the country.

The STRIL 90 system also includes S100D Argus early warning aircraft, equipped with Erieye radar, which can use TIDLS to send their radar image data to long-range Gripen fighters. (photo: Aleš Hottmar)

Data can be exchanged with S100D "Argus" early warning aircraft (SAAB 340 AEW), and with the help of their Erieye radar, the Gripen formation can obtain a picture of the tactical situation at a much greater distance using a datalink, which significantly increases their combat range. Datalink TIDLS is also fully functional even when the aircraft is on the ground. The condition is, of course, all running systems and running APU (Auxiliari power Unit). This function is advantageous if the pilot is just getting ready to take off and has a perfect overview of the tactical situation in the air before takeoff.
Probably the biggest benefit of the TIDLS datalink is the ability to perform new covert air combat tactics out of sight of the target. Flygvapnet refers to them as "Samverkan", which could be loosely translated as "joint attack". One Gripen can provide radar data to other machines, allowing one fighter to track a target at a greater distance, while others in passive mode use this data for covert attack. Without an emitting radar, other Gripen aircraft are much less likely to be detected by enemy aircraft, giving them some surprise advantage.
An even more sophisticated tactic is to use the Gripen to upgrade the target for a medium-range AIM-120B AMRAAM missile. This tactic is used, for example, when one of the Gripen captures a target at a great distance, passes its data with TIDLS to another machine, which with the radar off can get much closer to the target and which fires an Amraam missile. It then makes a turn and escapes from the enemy's range, while the missile fired is updated with data from the first machine. This allows the activation of the missile guidance radar much later and thus shortens the reaction time for possible countermeasures of the target.
TIDLS also allows multiple fighters to determine the position of the target faster and more accurately using triangulation from several radars and RWR. The PS-05 / A radar of the Gripen aircraft itself can operate in passive mode as a sensitive receiver with high directional accuracy. Two PS-05 radars can exchange information over a data link and locate a target using triangulation. Datalink also helps to track the target more accurately. Typically, three "echoes" are required to capture and track a target in track while scan (TWS) mode. Datalink allows aircraft and their radars to share these echoes, so even if none of the aircraft in the formation have enough "echoes" to track the target, they can do so together.** or Thai Air Force.

Note ** - The South African datalink called Link-ZA is again a data connection based mainly on the TDMA method, which can operate on HF, VHF or UHF bands at speeds of up to 16,000 bits / s, with up to 16 platforms per network and at least three concurrent networks in operation. Through Link-ZA, the South African Air Force has adapted the Swedish TIDLS concept to share data on the radar situation between JAS-39 Gripen aircraft and Hawk Mk.120 subsonic machines, which do not have their own on-board radar.

The Thai Air Force uses its national Link-T data link system, which is based on the Swedish TIDLS. Thai Gripen can thus obtain data information not only from ground stations, but also from the Thai mini-AWACS Saab 340 with Erieye radar. Link-T is also installed on Thai Northrop F-5E aircraft. (photo: Peter Liander, SAAB, https://saabgroup.com)

Alliance standard Link 16 on the Swedish Gripen and in Operation Karakal
The Swedish datalink TIDLS is undoubtedly a top system, but it has one significant flaw in its beauty. It is incompatible with a similar Link 16 device, standardly used in NATO. Of course, the Swedish side was fully aware of this problem and, due to the planned involvement of the Swedish Air Force in a number of international exercises and alliance operations, planned the implementation and full certification of Link 16 in Flygvapnet in 2008. Swedish Flygvapnet was made possible by upgrading their operating software MS19, which was announced in 2006.
The Swedish FMV (Försvarets materielverk) subsequently concluded a contract for the purchase of MIDS-LVT terminals worth USD 29.6 million, which was acquired by Data Link Solutions (DLS). Deliveries took place in 2011-2012 and the terminals were installed on JAS-39C / D Gripen fighters, S100D “Argus” early warning aircraft (SAAB 340 AEW) and various land and sea platforms.

MIDS-LVT terminal for distributed sharing of encrypted digital location information using the Link 16 alliance protocol (photo: www.viasat.com )

MIDS-LVT is a compact terminal for distributed sharing of encrypted digital position information, which works on the principle of time division multiplexing. It provides data links to air, land and naval platforms, enabling simultaneous coordination of forces and situational awareness in battlefield operations. Individual users involved in the Link 16 alliance information network thus share very similar information as in the case of the Swedish datalink TIDLS, such as the flight parameters of each specific aircraft, including the rest of the fuel or the current amount of ammunition carried and the like.
The pilot of an aircraft equipped with a MIDS-LVT terminal again sees on his MFD display all air targets in his vicinity, including their identification and description, without using his own radar or other sensors. Link 16 also enables direct control of network subscribers, or mutual communication by means of short text messages. If necessary, it can also be used to transmit smaller amounts of image data and voice communication.
The Link 16 protocol itself uses the UHF frequency band for its operation, in the range of 969 to 1,206 MHz, and the connection can be implemented up to a distance of around 900 km. To enable simultaneous access of a large number of subscribers to the network, a method called TDMA (Time Division Multiple Access) is used, in which the transmission is divided into short time slots, which are allocated to individual terminals. In the case of the Link 16 system, the length of one time slot is 7.8125 ms, with the basic unit used in network planning being a 12-second cycle containing a total of 1,536 slots.

The specialist of the Swedish contingent FL01 uploads a cryptographic key to the MIDS-LVT terminal of the JAS-39C Gripen aircraft via a data cable. (photo: Försvarsmakten)

This is probably the biggest difference from the Swedish TIDLS system, which does not allow the connection of such a large number of participants to the network, on the other hand, it paints a picture of the situation in almost real time under 1 sec. The transmitted information is of course encrypted and the transmission is also highly resistant to interference, thanks to the technology of so-called frequency hopping, where individual terminals "retune" frequencies when transmitting according to a preset and coordinated scheme at a dizzying rate of 77,000 changes per second. MIDS-LVT terminals have their own antenna and are themselves capable of transmitting with a power of 200 or 25 W (depending on the mode). When transmitting image data, the data throughput is 26.8 to 1102 kbps, while the throughput of voice communication is 2.4 kbps (LPC-10 codec) and 16 kbps (CVSD codec).
A major challenge for the Swedish Flygvapnet was the integration of the Link 16 system on the JAS-39 Gripen aircraft before deployment in the Libyan operation Karakal. The technical side of the case and the installation of "hardware" in the form of MIDS-LVT terminals in the Gripen was practically problem-free and the first testing took place during a joint exercise with the Norwegian and Finnish air forces in northern Sweden in March 2011. to access the Link 16 secret network during Operation Unified Protector, as Sweden, as a non-member country of the Alliance, of course did not have access to the secret network at the start of the operation. The licensing process itself was very difficult and was not resolved until Operation Unified Protector.

Implementation of Link 16 in the Czech Republic and its integration into Czech Gripen
As in Sweden, the officials in the Czech Republic were clearly aware that the introduction of a distributed data link of the Alliance Protocol Link 16 in the Czech Army is an absolutely necessary necessity in the future. After all, Čáslav fighters with Gripen aircraft in recent years have already significantly reduced the absence of the Link16 system to a number of large alliance exercises, during which they could not receive an image of the air situation from the ground control station GCI (Ground Control Intercept) or AWACS aircraft via datalink, which was of course relatively large handicap.
The implementation of MIDS LVT (4) (Multifunctional Information Distribution System - Low Volume Terminal) ground terminals was first started, with the 261st control and awareness centers in Stará Boleslav being acquired by the first two terminals in 2010, but they were not put into trial operation until Subsequently, they were integrated into the computer system CSI (CRC System Interface), whose monitors can display all data obtained through the Link 16 network. Airmen in the rugged Old Brno CRC can share data with, for example, AWACS aircraft or other machines connected to the relevant networks. This network was created jointly for AWACS aircraft and air force machines of Germany, the Netherlands and Belgium. Subsequently, the Czech Republic was also allowed to enter it.

TIDLS enabled Czech pilots to develop a tactic of greater pair spacing during BVR fights, which they then successfully used in a number of alliance exercises, where they were able to surprise and defeat even more powerful opponents by loading a picture of the tactical situation via datalink. (source: Stejsy, www.armyweb.cz )

The whole implementation of distributed data systems such as Link 16 is, of course, a long-distance run, which requires a number of very professional trainings to understand the whole issue. For example, from 5 to 9 August 2019, the Link16 Joint Interoperability Course took place at the University of Defense in Brno, which brought together mainly ACR Air Force staff supplemented by specialists from other parts of the ACR, preparing the implementation of the Link 16 communication environment in the Czech Republic.
The course is part of a comprehensive training provided through the Joint Interoperability Division, deployed in Fortt Bragg, USA, which aims at an internationally recognized Joint Interface Control Officer (JICO) qualification in an alliance environment. In the ACR conditions, the National Group of Data Line Management and Control, integrated into the structure of the 261st Control and Reporting Center (CRC), is entrusted with the planning, management, evaluation and monitoring of Link16, ie selected functional responsibilities of JICO.
With its content, the course provides basic theoretical education in the field of Link16 technology, ie a basic amount of knowledge necessary to understand the functionality of this tactical data link and its use not only in Alliance operations. This level is generally intended for operational and technical personnel. Higher follow-up courses are then intended for staff who ensure the planning and management of multiline operations. Follow-up courses use simulation technologies and in the final phase of comprehensive training, students participate directly in alliance operations in the form of exercises using a variety of tactical data lines. Each subsequent phase of this training is determined by extensive practical operational experience with the planning and management of tactical data lines,

The MS20 software also brought the so-called Digital CAS, ie the possibility of exchanging data with ground FACs.

A separate chapter is the introduction of the Alliance data link format Link 16 directly on leased Czech aircraft JAS-39C / D Gripen, which were ready for its integration during the modernization in Sweden in 2016-18 and the subsequent transition to the latest version of operating software MS20 in spring 2018. The contract itself for the purchase of 15 pcs of MIDS-LVT (Multifunctional Information Distribution System) on-board terminals from the American manufacturer Viasat Inc. in the estimated value of CZK 150 million without VAT, the army signed in August 2017, stating that their integration and installation would be carried out by its own forces. Purchased MIDS terminals will probably be in the LVT (4) version, ie without the TACAN system. A total of 14 pieces will be integrated directly into the aircraft, one will serve as a backup. MIDS terminals were acquired and introduced into the ACR as their own property.
The contract also includes the initial setup of integrated logistical support for the operation of the system, including training in 2019-2020. The logistical support of the system includes the supply of diagnostic equipment, special tools and consumables for use. As this is a special covert technology, it had to be procured exclusively under the Foreign Military Sales (FMS) regime under a contract concluded directly with the United States Government. The actual delivery and installation of MIDS on-board terminals in the JAS-39 aircraft and subsequent flight tests after installation should take place around the beginning of 2020. into alliance operations.
text author: Aleš Hottmar , czechairforce.com

The author will be very grateful for any additions or clarifications to the information contained in the text and at the same time apologizes for any errors, caused mainly by translations of Swedish materials.

The Swedish third-generation datalink TIDLS was launched on Czech Gripen in 2006 during the transition to the new version of the operating software MS18.7. However, the Czech Republic did not purchase a ground terminal for it, so the Gripen could only communicate with each other. Over the next few years, TIDLS was further upgraded with MS19 and MS20 operating software updates. Now the Czech Gripen will finally get the opportunity to join the Link 16 alliance network and, thanks to ground terminals, they will also be able to receive an image of the tactical situation from the ground CRC. (photo: Aleš Hottmar)

(introductory illustration photo: Cpl Lee Matthews RAF, © UK MoD Crown Copyright 2019, RAF Photographer)
(source: article "Link 16 for the Czech Army", author Tomáš Soušek , A-Report 8/2005, http://www.mocr.army.cz/assets/multimedia-a-knihovna/casopisy/a-report/ar8_2015 .pdf , article "Modernization of the Air Force must continue", author Tomáš Soušek , ATM 11/2019, news of the Faculty of Military Technology of the University of Defense - "Link16 Joint Interoperability Course took place at UO", https://info.unob.cz/Stranky/2019 /08/20190809.aspx , article "Gripen coming to us about Link 16 in operations on Libya", http://www.aereo.jor.br/2011/06/02/gripen-comeca-a-usar-o -link-16-nas-operacoes-sobre-a-libia / ; article "Datalinks Suecos", http://sistemasdearmas.com.br/ge/dtl7suecia.html , article "The Gripen data link", authorDarren Olivier , https://www.flightcommagazine.com/single-post/2019/03/05/The-Gripen-data-link; article "Swedish Air Force - Gripen TIDLS Data Link - 1", by Rob Hewson , https://m.blog.naver.com/PostView.nhn?blogId=jskimadd&logNo=10103299146&categoryNo=17&proxyReferer=&proxyReferer=https%3A%2F% 2Fwww.google.com% 2F ; article "Swedish Air Force - Gripen TIDLS Data Link - 2", https://blog.naver.com/PostView.nhn?blogId=jskimadd&logNo=10103300031 ; Article "Link 16 Added to Gripen's Datalink Systems", Saab AB; http://www.defense-aerospace.com/article-view/release/83146/saab-adds-link-16-to-gripen's-datalink-systems.html; article “Sweden Awards $ 29.6 Million Contract for Multifunctional Information Distribution System Terminals to Data Link Solutions”, http://www.datalinksolutions.net/news/2010-06-15.php ; Article "JA37 Program Development and Modifications in EP-12", by Håkan Algefors , https://www.aef.se/Avionik/Artiklar/EP-12/Pres_Utr_EP-12.htm ; article Electronic Presentation EP JA37 Indicator Equipment EP-12, author Håkan Algefors , https://www.aef.se/Avionik/Artiklar/EP-12/EP-12_GH.htm ; article "Stridsledningssystemet STRIL 60", by Göran Hawée , https://www.aef.se/System/Stril_60_GH/Stril_60.htm ; article "JA37 Viggen Notis 2", author Göran Hawée, https://www.aef.se/Flygvapnet/Notiser/JA37_Notis_2.htm ; publication Svenska_Flygvapnets_Styrdatasystem, author Arne Larsson )
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Here the link to the original article in Czech (Google did the translation for the text above, there's the occasional problem but everything essential is correct):

The author did a very good job of describing the history and the key features. His open sources are listed at the bottom (but he also has profound link knowledge IMO).

He had some problems to describe the meaning of some of the Swedish short form commands of the STRIL 60 GCI data link to the J35 D, E, F Draken aircraft. Here filled in/corrected:

Note * - these were the following commands: FEL (Error), HÖJDÄNDRING (Altitude change), FLERA MÅL (Multiple targets), JAKT (Fighters), REMSOR (Chaff), NYTT MÅL (New target), OSÄKERT (Unconfirmed), VARNING (Warning), MÅLFART (Target speed), MÅLKURS (Target course), O (Zero), FRAM (Collision course), TVÄRS (Abeam), BAK (Rear) (these last three describe the type of intercept), ÖKA (Speed up), STIG (Climb), BRANT (Steep turn), KVARLIGG (Stay) and LANDA (RTB).
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The article outlines the key difference between a C3 data link like MIDS over LINK16 and TIDLS or the Swedish Fighter link.

From the article: "The Swedish datalink is updated every second compared to Link16, which is updated every twelve seconds ". This is also why the TIDLS has only four active members (and unlimited listener members). The link information is real-time, meaning it can be used for cooperative targeting/tactics/EW/Communication.

A MIDS link is tactical and enhances SA (Situational Awareness) but it can't be used for sensor sharing/targeting as target updates can take 12s. Also, communication in text or digital voice is not real-time. A "BREAK!, BREAK!" from the wingman might come when the missile has hit. A Fighter link serves such purposes.

In essence, a modern fighter shall have two links: A MIDS type link for C3/SA/GCI, then a real-time link for the Tactical unit for cooperative SA/Targeting/Tactics/EW/Com. A Gripen has both (Swedish GCI/MIDS, then TIDLS) whereas an F22 has the latter but not the former (as Link16 is Pseudorandom spread spectrum and frequency hopping but not Stealth. It serves as a beacon to the aircraft for any transmission if you have a sophisticated receiver).
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Corrections for the translated Swedish:

Note * - these were the following commands: FEL (error), HÖJDÄNDRING (height change), FLERA MÅL (multiple targets), JAKT (chase), REMSOR (strips/chaff), NYTT MÅL (new target), OSÄKERT (unconfirmed), VARNING (warning), MÅLFART (target speed), MÅLKURS (target course), O (zero), FRAM (front), TVÄRS (across), BAK (behind), ÖKA (increase), STIG (ascend), BRANT (steep), KVARLIGG (remain) And LANDA (land).

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