Revised Edition: 2016 ISBN 978-1-283-49605-6 © All rights reserved. Published by: Research World 48 West 48 Street, Suite 1116, New York, NY 10036, United States Email: [email protected] Table of Contents Chapter 1 - AN/FPS-16 Chapter 2 - AN/FPS-17 Chapter 3 - AN/FPQ-6 and Airport Surveillance Radar Chapter 4 - EL/M-2080 Green Pine and GIRAFFE Radar Chapter 5 - Chain Home Chapter 6 - Counter-battery Radar and SLC-2 Radar Chapter 7 - Joint Surveillance System WT Chapter 8 - Wave Radar Chapter 9 - Active Phased Array Radar Chapter 10 - AN/SPS-67 and AN/SPY-1 Chapter 11 - AN/SPS-49 and AN/SPS-48 Chapter 12 - Kashtan CIWS and CXAM Radar ____________________WORLD TECHNOLOGIES____________________ Chapter-1 AN/FPS-16 WT The FPS-16 radar sits atop Tranquillon Peak overlooking all of Vandenberg Air Force Base in California, including Space Launch Complex-6, and the shoreline. Tranquillon Peak's elevation of 2,126 feet (648 m) is the highest point on Vandenberg AFB. The radar provides data and range safety for missile launches. This radar, along with its data system, is used for tracking the Minuteman III ICBM. The AN/FPS-16 is a highly accurate ground-based monopulse single object tracking radar (SOTR), used extensively by the NASA manned space program and the U.S. Air Force. The accuracy of Radar Set AN/FPS-16 is such that the position data obtained from point-source targets has azimuth and elevation angular errors of less than 0.1 milliradian ____________________WORLD TECHNOLOGIES____________________ (approximately 0.006 degree) and range errors of less than 5 yards (5 m) with a signal-to- noise ratio of 20 decibels or greater. FPS-16 Monopulse Tracking Radar The first monopulse radar was developed at the Naval Research Laboratory (NRL) in 1943 to overcome the angular limitations of existing designs. The monopulse technique makes angular determinations simultaneously on each individual received pulse. This improvement in radar technology provides a tenfold increase in angular accuracy over previous fire and missile control radars at longer ranges. The monopulse radar is now the basis for all modern tracking and missile control radars. Although monopulse radar was developed independently and secretly in several countries, Robert Morris Page at the NRL is generally credited with the invention and holds the U.S. patent on this technique. The monopulse technique was first applied to the Nike-Ajax missile system, an early U.S. continental air defense weapon. Many improvements were made to provide a more compact and efficient monopulse antenna feed and lobe comparison waveguide circuitry, such that monopulse tracking radar became the generally accepted tracking radar system for military and civilian agencies, such as NASA and the FAA. WT The NRL's work on monopulse radars eventually led to the AN/FPS-16, developed jointly by NRL and RCA as the first radar designed especially for missile ranges. The AN/FPS-16 was used to guide the first U.S. space satellite launches, Explorer 1 and Vanguard 1, at Cape Canaveral in 1958. ____________________WORLD TECHNOLOGIES____________________ FPS-16 and Project Mercury WT The FPS-16 radar at Vandenberg AFB, California has been used for tracking NASA space vehicles since the 1960s. The C-band monopulse tracking radar (AN/FPS-16) used in the Project Mercury was inherently more accurate than its S-band conically-scanned counterpart, the Very Long Range Tracking (VERLORT) radar system. The AN/FPS-16 radar system was introduced at the Atlantic Missile Test Range with installations including Cape Canaveral, Grand Bahama, San Salvador, Ascension and East Grand Bahama Island between 1958 and 1961. The FPS-16 located on the Australian Weapons Research Establisnment Range at Woomera, in South Australia was also linked to the NASA network for Mercury and later missions. NASA Acq aid and telelmetry systems were co-located with the Australian radar. To obtain reliability in providing accurate trajectory data, the Mercury spacecraft was equipped with C-band and S-band cooperative beacons. The ground radar systems had to be compatible with the spacecraft radar beacons. The FPS-16 radar in use at most national missile ranges was selected to meet the C-band requirement. Although it originally had a range capability of only 250 nautical miles (460 km), most of the FPS-16 radar units selected for the project had been modified for operation up to 500 nautical miles (900 km), a NASA requirement, and modification kits were obtained for the remaining systems. In addition to the basic radar system, it was also necessary to provide the required data-handling equipment to allow data to be transmitted from all sites to the computers. ____________________WORLD TECHNOLOGIES____________________ The FPS-16 system originally planned for the Project Mercury tracking network did not have adequate displays and controls for reliably acquiring the spacecraft in the acquisition time available. Consequently, a contract was negotiated with a manufacturer to provide the instrumentation radar acquisition (IRACQ)[Increased RAnge Acquisition] modifications. For the near earth spacecraft involved a major limitation of the FPS-16 was its mechanical range gear box, a wonderful piece of engineering. However, for a target at a range typically, say, 700 nautical miles (1,300 km; 810 mi) at acquisition of signal [AOS], the radar was tracking second time around, that is, the pulse received in this interpulse period was that due to the previously transmitted pulse, and it would be indicating a range of 700 nmi (1,300 km; 810 mi). As the range closed the return pulse became closer and closer to the time at which the next transmitter pulse should occur. If they were allowed to coincide, remembering that the transmit-receive switch disconnected the receive (Rx) and connected the transmit (Tx) to the antenna at that instant, track would be lost. So, IRACQ provided an electronic ranging system, the function of which was to provide the necessary gating pulses to the Az and El receiver channels so that the system would maintain angle track. The system utilized a voltage controlled crystal oscillator [VCXO] as the clock generator for the range counters. An early/late gate system derived an error voltage which either increased [for a closing target] or decreased [for an opening target] the clock frequency, thus causing the gates to WT be generated so as to track the target. It also, when the target reached an indicated range of less than 16,000 yd (15 km), took over the generation of transmitter trigger pulses and delayed these by 16,000 yd (15 km), thus enabling the received pulses to pass through the Big Bang, as it was called, of normally timed Tx pulses. The radar operator, would, while IRACQ maintained angle track be slewing the range system from minimum range to maximum so as to regain track of the target at its true range of <500 nmi (900 km). As the target passed through point of closest approach (PCA) and increased in range the process was repeated at maximum range indication. The most difficult passses were those in which the orbit was such that the target came to PCA at a range of, say 470 nmi. That pass required the radar operator to work very hard as the radar closed, and then opened in range through the Big Bang in short order. The IRACQ Console contained a C-scope associated with which was a small joy stick which gave C-scope operator control of the antenna angle servo systems so that he could adjust the pointing angle to acquire the signal. IRACQ included a scan generator which drove the antenna in one of several pre- determined search patterns around the nominal pointing position, it being desirable that IRACQ acquire the target as early as possible. An essential feature of this modification is that it allows examination of all incoming video signals and allows establishment of angle-only track. Once the spacecraft has been acquired, in angle range. Other features of the IRACQ system included additional angle scan modes and radar phasing controls to permit multiple radar interrogation of the spacecraft beacon. The addition of a beacon local oscillator wave meter permitted the determination of spacecraft-transmitter fre- quency drift. Early in the installation program, it was realized that the range of the Bermuda FPS-16 should be increased beyond 500 miles (800 km). With the 500-mile (800 km)-range limitation, it was possible to track the spacecraft for only 30 seconds prior to launch- vehicle sustainer engine cut-off (SECO) during the critical insertion phase. By extending ____________________WORLD TECHNOLOGIES____________________ the range capability to 1,000 miles (2,000 km), the spacecraft could be acquired earlier, and additional data could be provided to the Bermuda computer and flight dynamics consort This modification also increased the probability of having valid data available to make a go/no-go decision after SECO. The VERLORT radar fulfilled the S-band requirement with only a few modifications. Significant ones were the addition of specific angle-track capability and additional angular scan modes. At Eglin Air Force Base in Florida, the MPQ-31 radar was used for S-band tracking by extending its range capability to meet Project Mercury requirements. The data-handling equipment was essentially the same as for the FPS-16. Coordinate conversion and transmitting equipment was installed at Eglin to allow both the MPQ-31 and the FPS-16 to supply three-coordinate designate data to the Atlantic Missile Range (AMR) radars via central analog data distributing and computing (CADDAC) . C-Band Radar Transponder The C-Band Radar Transponder (Model SST-135C) is intended to increase the range and accuracy of the radar ground stations equipped with AN/FPS-16, and AN/FPQ-6 Radar Systems. C-band radar stations at the Kennedy Space Center, along the Atlantic Missile WT Range, and at many other locations around the world, provide global tracking capabilities. Beginning with Vehicles 204 and 501, two C-band radar transponders will be carried in the instrumentation unit (IU) to provide radar tracking capabilities independent of the vehicle attitude. This arrangement is more reliable than the antenna switching circuits necessary if only one transponder would be used. Transponder operation The transponder receives coded or single pulse interrogation from ground stations and transmits a single-pulse reply in the same frequency band. A common antenna is used for receiving and transmitting. The transponder consists of five functional systems: superheterodyne receiver, decoder, modulator, transmitter, and power supply. The duplexer (a 4-port ferromagnetic circulator) provides isolation between receiver and transmitter. Interrogating pulses are directed from the antenna to the receiver, and reply pulses are directed from the transmitter to the antenna. The preselector, consisting of three coaxial cavities, attenuates all RF signals outside the receiving band. The received signal is heterodyned to a 50 MHz intermediate frequency in the mixer and amplified in the IF amplifier which also contains the detector. In case of coded transmission, the decoder module provides a pulse output only if the correct spacing exists between pulse pairs received. The shaped-pulse output of the decoder is directed to the modulator which converts it into a high-power, precisely shaped and precisely delayed pulse which is applied to the magnetron to produce the reply pulse. Six telemetry outputs are provided: input signal level, input pulse repetition frequency (PRF), temperature, incident power, reflected power, and reply PRF. Semiconductors are used in all circuitry, with the exception of the local oscillator and magnetron. ____________________WORLD TECHNOLOGIES____________________ Radar ground station operation The radar ground stations determine the position of the vehicle C-band transponder by measuring range, azimuth angle, and elevation angle. Range is derived from pulse travel time, and angle tracking is accomplished by amplitude-comparison monopulse techniques. As many as four radar stations may track the beacon simultaneously. NASA Manned Space Flight Network (MSFN) C-band Radar The NASA Manned Space Flight Network (MSFN) land based C-band pulse radar types consist of the AN/FPS-16, AN/MPS-39, AN/FPQ-6 and the AN/TPQ-18. The MPS-39 is a transportable instrument using space-fed-phased-array technology; the TPQ-18, a transportable version of the FPQ-6. The indicator AN (originally "Army–Navy") does not necessarily mean that the Army, Navy or Air Force use the equipment, but simply that the type nomenclature was assigned according to the military nomenclature system. The meaning of the three letter prefixes; FPS, MPS, FPQ and TPQ are: • FPS - fixed; radar; detecting and/or range and bearing • WMPS - ground, mobile; radar; detectinTg and/or range and bearing • FPQ - fixed; radar; special, or combination of purposes • TPQ - ground, transportable; radar; special, or combination of purposes. AN/FPS-16 RADAR SET TYPICAL TECHNICAL SPECIFICATIONS ------------------------ Type of presentation: Dual-trace CRT, A/R and R type displays. Transmitter data - Nominal Power: 1 MW peak (fixed-frequency magnetron); 250 kW peak (tunable magnetron). Frequency Fixed: 5480 plus or minus 30 MHz Tunable: 5450 to 5825 MHz Pulse repetition frequency (internal): 341, 366, 394, 467, 569, 682, 732, 853, 1024, 1280, 1364 or 1707 pulses per second Pulse width: 0.25, 0.50, 1.0 µs Code groups: 5 pulses max, within 0.001 duty cycle limitation of transmitter. Radar receiver data - Noise Figure: 11 dB Intermediate Frequency: 30 MHz Bandwidth: 8 MHz Narrow Bandwidth: 2 MHz ____________________WORLD TECHNOLOGIES____________________ Dynamic Range of Gain Control: 93 dB Gate width Tracking: 0.5 µs, 0.75 µs, 1.25 µs Acquisition: 1.0 µs, 1.25 µs, 1.75 µs Coverage Range: 500 to {{convert|400000|yd|m|-5|abbr=on}} Azimuth: 360° continuous Elevation: minus 10 to plus 190 degrees Servo bandwidth Range: 1 to 10 Hz (var) Angle: 0.25 to 5 Hz (var) Operating power requirements: 115 V AC, 60 Hz, 50 kV·A, 3 phase Principles of operation WT AN/FPS-16 Radar Set block diagram. ____________________WORLD TECHNOLOGIES____________________