TELEMETRY CHALLENGES FOR BALLISTIC MISSILE TESTING IN THE CENTRAL PACIFIC

Transcription

1 TELEMETRY CHALLENGES FOR BALLISTIC MISSILE TESTING IN THE CENTRAL PACIFIC Item Type text; Proceedings Authors Markwardt, Jack; LaPoint, Steve Publisher International Foundation for Telemetering Journal International Telemetering Conference Proceedings Rights Copyright International Foundation for Telemetering Download date 15/05/ :28:16 Link to Item

2 TELEMETRY CHALLENGES FOR BALLISTIC MISSILE TESTING IN THE CENTRAL PACIFIC Jack Markwardt and Steve LaPoint ABSTRACT The Ballistic Missile Defense Organization (BMDO) is developing new Theater Missile Defense (TMD) and National Missile Defense (NMD) weapon systems to defend against the expanding ballistic missile threat. In the arms control arena, theater ballistic missile threats have been defined to include systems with reentry velocities up to five kilometers per second and strategic ballistic missile threats have reentry velocities that exceed five kilometers per second. The development and testing of TMD systems such as the Army Theater High Altitude Area Defense (THAAD) and the Navy Area Theater Ballistic Missile Defense (TBMD) Lower Tier, and NMD systems such as the Army Exoatmospheric Kill Vehicle and the Army Ground-Based Radar, pose exceptional challenges that stem from extreme acquisition range and high telemetry data transfer rates. Potential Central Pacific range locations include U.S. Army Kwajalien Atoll/Kwajalein Missile Range (USAKA/KMR) and the Pacific Missile Range Facility (PMRF) with target launches from Vandenberg Air Force Base, Wake Island, Aur Atoll, Johnston Island, and, possibly, an airborne platform. Safety considerations for remote target launches dictate utilization of high-data-rate, on-board instrumentation; technical performance measurement dictates transmission of focal plane array data; and operational requirements dictate intercepts at exoatmospheric altitudes and long slant ranges. The high gain, high data rate, telemetry acquisition requirements, coupled with loss of the upper S-band spectrum, may require innovative approaches to minimize electronic noise, maximize telemetry system gain, and fully utilize the limited S-band telemetry spectrum. The paper will address the emerging requirements and will explore the telemetry design trade space. KEYWORDS Ballistic Missile Defense, BMD, Instrumentation, Missile Defense, National Missile Defense, NMD, Telemetry, Time-Space-Position-Information, Theater Ballistic Missile Defense, (TBMD).

3 INTRODUCTION The BMDO is developing a family of BMD weapon systems to defend against the existing and expanding ballistic missile threat. The tactical ballistic missile threat includes systems with range capabilities less than 5000 kilometers. Central Pacific testing for the PATRIOT Advanced Capability 3 (PAC-3), Theater High Altitude Area Defense (THAAD), Navy Area Theater Ballistic Missile Defense (TBMD) (Lower Tier), and NMD system require development of improved telemetry acquisition, tracking, recording, and data processing systems. The design requirements and trade space includes increased link margins, high band width receivers, high data rate recorders, receiver cooling, data compression, binary and M-ary phase shift keying, and acquisition of transportable, airborne, or additional telemetry acquisition systems. BMD CENTRAL PACIFIC TESTING Projected Pacific BMD flight tests for include testing of the PAC-3, THAAD, Navy Area TBMD (Lower Tier), TMD System Integration Tests, and NMD programs. The PAC-3 program will conduct a limited number of tests, including support for TMD System Integration Tests, at USAKA/KMRKMR. During their Engineering and Manufacturing Development (EMD) Phase, THAAD program plans to conduct the majority of their testing at USAKA/KMR. The Navy plans to conduct Area TBMD (Lower Tier) testing in the restricted areas northwest of the PMRF (on the island of Kauai, Hawaii). The NMD Deployment Readiness Program will launch targets from Western Space and Missile Center in California to USAKA/KMR and will launch interceptors from USAKA/KMR. TEST IMPLICATIONS FOR TELEMETRY SYSTEMS While the maximum intercept altitudes and slant ranges for BMD intercepts are sensitive and may be classified, prudent telemetry design must consider antenna places at set-back locations and plan for initial telemetry reception long before intercept. The designer should expect initial telemetry reception to occur at or before the target vehicle reaches apogee. Consequently, initial telemetry reception from targets for the Army PAC-3 and Navy Area TBMD Lower Tier systems (the latter will utilize the Standard Missile 2 Block IVA interceptor - SM 2 Blk IVA) may be required at slant ranges up to 400 kilometers. The Army THAAD intercept zone will extend considerably further and higher. Telemetry acquisition and tracking systems to support THAAD testing should be able to collect target telemetry prior to target apogee (at altitudes near 400 kilometers) and at slant ranges up to 1500 kilometers. NMD target apogees will exceed 1000 kilometers, acquisition ranges of 2500 kilometers are anticipated, and the intercept may occur above 500 kilometers altitude at slant ranges exceeding 1300 kilometers.

4 BMD PROGRAM INSTRUMENTATION REQUIREMENTS Many TMD targets will carry two independent inertial measurement units (IMUs) to provide cooperative time-space-position-information data to range safety systems and a fiber-optic-mesh impact detection system called the Photonic Hit Indicator (PHI). The IMU and PHI data will be relayed via S-band telemetry. Some TMD targets will also carry a RF miss distance indicator (MDI) and a Global Positioning System (GPS) translator to receive and relay GPS signals via S-band telemetry to ground-based translator processors. The NMD targets will carry a GPS translator and may also carry the PHI and MDI. NMD target vehicles will deploy reentry vehicles and may also deploy reentry vehicle replicas, penaids, and other target decoys. Instrumentation for the replicas, penaids, and decoys may include a instrumentation and S-band telemetry system called the Light Weight Instrumentation System (LWIS). The interceptor vehicles will transmit IMU and vehicle health/status (H&S) telemetry signals. The Navy SM-2 Blk IVA, THAAD, and NMD interceptor will also transmit focal plane array (FPA) data. The NMD interceptor will carry and the THAAD EMD interceptor may carry a GPS translator. Table 1 describes the anticipated target and interceptor instrumentation and provides estimates for the associated S-band telemetry data rates and bandwidth requirements. Table 1: TMD and NMD Telemetry Requirements TLM Data TLM Bandwidth Channel Rate (with overhead) TMD Target Instrumentation: 2 IMUs 4 MB/s 2.6 MHz 1 MDI 0.1 MB/s 60 KHz 1 PHI 6 MB/s 4.0 MHz 1 GPS Translator 6 MB/s 4.0 MHz NMD Target Instrumentation: 1 LWIS TBD 1.5 MHz 1 MDI 0.1 MB/s 60 KHz 1 PHI 6 MB/s 4.0 MHz 1 GPS Translator 6 MB/s 4.0 MHz PAC-3 Interceptor Instrumentation: 1 IMU 2 MB/s 1.3 MHz 1 H&S 2 KB/s 3.0 KHz

5 SM BLK IV A Interceptor Instrumentation: 1 FPA 10 MB/s 7.5 MHz 1 IMU 2 MB/s 1.3 MHz 1 H&S 2 KB/s 3.0 KHz THAAD Interceptor Instrumentation: 1 FPA 10 MB/s 7.5 MHz 1 IMU 2 MB/s 1.3 MHz 1 H&S 2 KB/s 3.0 KHz 1 GPS Translator 6 MB/s 4.0 MHz NMD Interceptor Instrumentation: 1 FPA 10 MB/s 7.5 MHz 1 IMU 2 MB/s 1.3 MHz 1 H&S 2 KB/s 3.0 KHz 1 GPS Translator 6 MB/s 4.0 MHz Table 2 describes the most stressing telemetry citation for potential BMD instrumentation: Dual frequency (L1/L2 - Precision Code) translators with ground-based carrier cycle and ambiquity processing have been proposed to provide interceptor-to-target relative range with 2-3 centimeter accuracy. The higher focal plane array data rate has been cited as an upper limit for SM-2 BLK IVA telemetry. Table 2: Most Stressing Future Telemetry Demands Instrumentation Data Rate Bandwidth Dual Frequency Translators 25 MB/s 20 MHz SM-2 BLK IVA FPA Data 40 MB/s 30 MHz EXISTING S-BAND TELEMETRY SYSTEM CAPABILITIES USAKA/KMR: The most capable USAKA/KMR telemetry tracking, receiver, and recorder system can support long range acquisition of narrow-band reentry vehicle and some wide-band TMD telemetry channels. At the present time, USAKA/KMR wide-band receiver and high data rate recorders are limited in number. USAKA/KMR assets are summarized below:

6 USAKA/KMR Antenna Systems: Carlos 9 meter telemetry tracking antenna, 43.6 db gain, noise temp 350 K Carlos 7 meter telemetry tracking antenna, 42.3 db gain, noise temp 350 K Roi-Namur 5.5 meter telemetry tracking antenna, db gain, noise temp 350 K 4 Carlos 3 meter telemetry tracking antennas, 34.6 db gain, noise temp 400 K Gagan 3 meter telemetry tracking antenna, 34.6 db gain, noise temp 400 K Roi-Namur 3 meter telemetry tracking antenna, 34.6 db gain, noise temp 400 K Carlos Multi-couplers, Receivers, Combiners, Synchronizers, and Recorders: 14 Multi-couplers S-band ( ) 5 Multi-couplers L-band ( ) Narrow-band receivers: Of the 28 receivers, 8 convertable to wide-band 14 Narrow-Band Combiners: Of the 14 combiners, 4 convertable to wideband 23 bit synchronizers 6 Narrow/wide band receivers 6 Narrow-band combiners 4 Narrow/wide band combiners 23 Bit synchronizers 8 Narrow-band analog recorders 4 MHz direct (1 Mhz FM) Roi-Namur Multi-couplers, Receivers, Combiners, Synchronizers, and Recorders: 67 Multi-couplers S-band 2 Multi-couplers L-band 16 Narrow-band receivers, S-band 4 Wide band receivers, L-band 8 Narrow band combiners, S-band 2 Wide band combiners, L-band 9 Bit synchronizers 4 Narrow-band analog recorders 4 MHz direct (1 MHz FM) Gagan Multi-couplers, Receivers, Combiners, Synchronizers, and Recorders: 34 Multi-couplers 8 Narrow-band receivers 4 Narrow-band combiners 2 Bit synchronizers 2 Narrow-band analog recorders 4 MHz direct (1 MHz FM) Notes: 1. The 8 Carlos analog recorders can be linked to 4 high density digital formatters to record up to 32 MB/s (for 15 seconds) 2. Of the 4 analog recorders at Roi, 2 can be converted to High Density Digital Recorders (HDDR) to record up to 11.7 Mbps.

7 PMRF: The most capable PMRF telemetry systems can reliably acquire telemetry signals at TMD acquisition ranges. The existing receivers and recorders are relatively narrowband, lower data rate equipment: PMRF telemetry acquisition assets are summarized below: Kauai/Barking Sands Antenna Systems 3 GKR-8A 30 ft automatic telemetry tracking antennas, 41 db gain 2 GKR-9A 8 ft automatic telemetry tracking antennas, 30 db gain 1 GKR-9 7 ft automatic telemetry tracking antenna, 27 db gain Kauai Multi-couplers, Receivers, Combiners, Synchronizers, and Recorders: 16 TR-109B dual channel receivers MRA single channel receivers 8 FR track tape recorders, 400 Hz MHz 4 VR track tape recorders, 400 Hz MHz 4 Telemetry processing and display systems, data rate 5.6 MB/s TELEMETRY DESIGN CONSIDERATIONS AND ASSUMPTIONS The telemetry loads of ballistic missile defense testing will tax the remaining S-band telemetry spectrum. With sale of the upper S-band spectrum, S-band telemetry is now limited to the spectrum between MHz. Practical target and interceptor transmitters are limited to 10 watts; imposing a transmit limit on telemetry design. Atmospheric losses, albeit small, can be expected for long range telemetry acquisition. Connector and cable losses must be anticipated at the transmitter and receiver. Free space losses, FSL, are given by Eq 1: FSL = 20 log10 ( C/4πfR) (1) where C f R = the speed of light (3.0 x 108 meters/sec), = S-band carrier frequency (Hz), and = slant range from transmitter to receiver (meters) Telemetry receiver noise is given by Eq 2: RN = 10 log10 ( 1/kBTsF) (2) where k = Boltzmans constant (1.38 x 1023 joules/k), B = Receiver intermediate frequency bandwidth (Hz), To = Receiver noise operating temperature (K), Ts = Receiver noise standard temperature (270 K), and F = Receiver noise figure = To/Ts

8 Table 3: Telemetry Link Assumptions Vehicle telemetry transmitter power: 10.0 watts Vehicle transmitter connector losses: db Vehicle transmitter antenna gain: db Carrier Frequency: GHz Atmospheric propagation losses: db Telemetry radome losses -1.5 db Receiver connection/cables losses: -2.0 db Signal/Noise ratio for acceptable bit error rates 14.0 db TELEMETRY DESIGN IMPLICATIONS One-on-One TMD Intercept Scenarios: Given the high gain telemetry reception capabilities of USAKA/KMR and PMRF, no serious telemetry acquisition problems arise for scenarios involving the launch of a single TMD target and interceptor. However, the existing receiver equipment is bandwidth-limited and data record rates are insufficient. Investments will be required to augment the existing receiver and recorder capabilities at USAKA/KMR and PMRF. One-on-One NMD Intercept Scenarios: The NMD intercept scenarios generate demanding telemetry gain requirements. The results in the table below indicate that the best available KMR and PMRF telemetry acquisition systems (nine meter antennas, receiver noise temperature of 350 K) have insufficient gain to ensure reliable telemetry acquisition and tracking of some NMD target telemetry, specifically the focal plane array data. Required Acquisition Gain (db) Intermediate Frequency BW (MHz) Slant Range (km) NOTE: Requirements in italics exceed best PMRF capabilities and those in bold print exceed the best USKAK/KMR capabilities.

9 NMD One-On-One Scenario Design Trades: Reliable FPA telemetry reception can not be assured, from the fixed nine meter system. A mobile, 9 meter, telemetry acquisition platform, stationed beneath the intercept point, would suffice. Receiver cooling for the current fixed systems appears to be one solution to the NMD gain requirements. The design trade space reveals that receivers with liquid nitrogen cooling (@ 177 K) could easily provide acceptable gain margins for the long range NMD intercept scenario. Data compression offers another alternative to address the high acquisition gain of the NMD FPA data channels. A 256 x 256 pixel FPA, sampled at 40 Hz, with 4 bits per pixel produces the cited 10 MB/s. Intelligent data compression would transmit only active pixels. Compression that utilized a 32 bit pixel address (16 across by 16 down), sampling at 40 Hz, with 4 data bits per pixel, could relay data on as many as 360 active pixels while requiring no more telemetry gain than the IMU data channel (a 2 MB/s channel). Data compression of GPS translator channels would be a more difficult proposition. Data compression would shift the demand from range telemetry assets to the BMD interceptor vehicle. An application specific integrated circuit (ASIC) would be required to provide interceptor FPA data compression. Error detection and correction offers a third alternative for NMD FPA data channels. Current digital error detection and correction coding techniques adds error correction coding to the transmitted message format at the expense of a slightly increased data transmission rate. Insertion of automatic error detection and correction circuitry at the receiver will increase the effective signal-to-noise ratio and will have the equivalent effect as an additional acquisition gain of 3 to 6 db, thereby reducing the total required acqusition gain. Multiple Shot TMD Intercept Scenarios: Congress has mandated multiple shot engagements for TMD systems during their EMD phase. These scenarios would involve more than two interceptors and more than two targets. The scenarios do not generate overly demanding gain margins at TMD telemetry acquisition ranges; however, all existing USAKA/KMR telemetry assets would be required to provide one-on-one tracking without backup. Existing PMRF assets would not be able to provide one-on-one coverage for a three-on-three scenario. Transportable, airborne, or additional range telemetry systems will be required to backup coverage at USAKA/KMR and one-on-one coverage at PMRF. TMD Multiple Shot Scenario Design Trades: TMD scenarios are not faced with the telemetry link margins of concern for NMD testing, as telemetry acquisition will occur at much reduced ranges. As a result, an additional trade space is available for TMD telemetry acquisition. The pulse code modulation that is prevalent in S-band telemetry could be replaced with binary or multiple (m-ary) phase shift keying. A shift to binary phase shift keying, with the loss of 3 db signal margin, would double the number of receivable channels with the available S-band spectrum. Each doubling would incur another 3 db

10 signal margin loss. The original signals would be recovered via matched filters inserted between the existing antennas and receivers. CONCLUSION The BMDO, the U.S. Army, and the U.S. Navy will jointly fund the development of telemetry systems to meet critical telemetry instrumentation requirements for testing ballistic missile defenses in the Central Pacific. Ballistic missile defense testing demands will spur procurement of high-gain telemetry systems with broad bandwidth receivers and high data rate recording systems. The design solution space includes the following options: For all BMD Testing Scenarios: High Bandwidth Receivers (required) High Data Rate Recorders (required) For NMD One-on-One Scenarios (long range telemetry reception): Receiver Cooling Data Compression Automatic error detection and correction coding/receivers For TMD Multiple Shot Engagement Scenarios: Binary and M-ary Phase Shift Keying and Matched Filters Transportable, Airborne, or Additional Range Telemetry Assets ACKNOWLEDGMENTS The authors would like to acknowledge the assistance from Messrs. Dave Nekomoto and Jack McCreary. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of Defense or the U.S. Government. REFERENCES U.S. Army Space and Strategic Defense Command, "USAKA/KMRKMR Instrumentation and Support Facilities Manual, Kwajalein Missile Range," United States Army Kwajalein Atoll, July 1, U.S. Army Space and Strategic Defense Command, "Kwajalein Missile Range Safety Support Systems Description," October 15, 1994.

11 Pacific Missile Range Facility, "Range User's Handbook," Barking Sands, Kekaha, Hawaii, revised February 5, U.S. Army Space and Strategic Defense Command, "Range Users Manual, Kwajalein Missile Range, U.S. Army Kwajalein Atoll, May NOMENCLATURE BMD Ballistic Missile Defense BMDO Ballistic Missile Defense Organization B Receiver Intermediate Frequency Bandwidth C Speed of Light db Decibels EMD Engineering and Manufacturing Development f S-band Carrier Frequency F Receiver Noise Figure FPA Focal Plane Array FSL Free Space Loss GHz Giga Hertz GPS Global Positioning System H&S Health and Status IMU Inertial Measurement Unit k Boltzmans constant K Absolute Temperature in degrees Kelvin KB/s Kilobits per second KHz Kilo-Hertz USAKA/KMR Kwajalein Missile Range LWIS Light Weight Instrumentation System MB/s Megabits per second MDI Miss Distance Indicator MHz Mega Hertz NMD National Missile Defense PAC-3 PATRIOT Advanced Capability 3 PCN Pulse Code Modulation PHI Photonic Hit Indicator PMRF Pacific Missile Range Facility R Slant Range RF Radio Frequency RN Receiver Noise SM-2 Blk IVA Standard Missile 2 Block IVA TBMD Theater Ballistic Missile Defense THAAD Theater High Altitude Area Defense TMD Theater Missile Defense To Receiver Noise Operating Temperature Ts Receiver Noise Standard Temperature