Skau1 Approach to Scalable Parallel Processing For Space-Based Radar

Skau2 Example: SAR and GMTI Partitioning/ Mapping/Utilization

Skau3 Basic SAR Processing Flow Basic GMTI Processing Flow Basic SBR Signal Processing

Skau4 Example: SAR Processing Assumptions Assumed SAR Parameters 16 channels (12 Subarrays and 4 Auxiliary Channels) Msamples/sec ( nsec per sample 500  sec receive window (200, ,000 range cells per pulse) 1 KHZ PRI 16,384 pulses in azimuth (16.4sec collection time) The last 1/2 of the collected samples are used as the first 1/2 of the samples for the image (processed only through range pulse compression and stored) 1 beam formed for SAR image; input 16,384 ranges x 16,384 pulses 8-bits (1 Byte) per A/D sample 64-bits (8 Bytes) for internal data storage for complex data (4 Bytes real, 4 Bytes imaginary) 32-bits (2 Bytes) for internal data storage of real data 4/3 oversampling out of the Polyphase Channelizer 128 Subbands formed; only 40 processed

Skau5 Example: SAR/GMTI Partitioning on BEP System Set local memory per processing element at 128 KBytes to be able to handle 16K FFTs for SAR mode (not double buffered) For the GMTI mode, the 128 KBytes of local memory can handle pulses and 64 ranges per main memory access that can be processed in the pulse or Doppler dimension or - 8,000 ranges and 2 pulses worth of data per main memory access that can be processed in the range dimension or - any combination that maximizes throughput by “blocking,” i.e., effectively “caching”, and “striding” data for optimum performance Data can also be partitioned across beams, channels, and segments when they are independent variables relative to high level data flow processing

Skau6 SAR Processing Flow/Global Memory Accessing (1 of 2) Range Pulse Compression 16,384 ranges for each pulse Store data from each pulse in global memory 16,384 ranges for each pulse 16,384 pulses x 1 range x 8 Bytes = KBytes Extract pulse (cross-range) data Perform cross-range FFT Loop 16,384 times = 16,384 ranges/1 range/loop 128 pulses x 128 ranges x 8 Bytes = KBytes Extract 2D Polar Reformat data Perform Polar Reformatting Loop 16,908 times = x 10 6 cells/ x 10 3 cells/patch Store processed data KBytes Store processed data Small overlap to process 126 x 126 patch 16,384 KBytes 16,384 ranges x 1 pulse x 8 Bytes = 16,384 KBytes Loop 16,384 times = 16,384 pulses/1 pulse/loop 16,384 KBytes Extract range data Perform range FFT Store processed data (transposed)

Skau7 SAR Processing Flow/Global Memory Accessing (2 of 2) 16,384 pulses x 1 range x 8 Bytes = KBytes Loop 16,384 times = 16,384 ranges/1 range/loop Perform Auto Focus 16,384 MBytes Store processed data KBytes 16,384 pulses x 1 range x 8 Bytes = KBytes Loop 16,384 times = 16,384 ranges/1 range/loop 65.6 KBytes Extract pulse (cross-range) data Perform Magnitude Function Store processed data Extract pulse (cross-range) data Perform cross-range FFT Store processed data Extract pulse (cross-range) data 16,384 pulses x 1 range x 8 Bytes = KBytes Loop 1024 times = 32,768 ranges/32 ranges/loop All of this, from cross-range FFT through Magnituding, can be done with the data in place, i.e., no need to extract and restore data until all of the processing is complete. (I set it up that way because the 2nd half of the 2D FFT, AutoFocus, and Magnituding appear to be performed only in the cross-range dimension.

Skau8 SAR Processing Flow/Global Memory Utilization 16, 384 pulses 2.2 GBytes complex data Storage of pulse compressed range data for further processing 1.1 GBytes of new data from current CPI collection Storage of cross-range FFT processed data through through polar reformatting Storage of 1st half of 2D FFT result transposed (corner-turned) through Magnituding 2.2 GBytes complex data 2.2 GBytes complex data Total global memory required for SAR (worst case) = 9.9 GBytes * * This might be able to be reduced to 7.8 GBytes if 2D FFT can be done “in place.” ** 2.1 GBytes available for storing training samples for AWC (Adaptive Weight Computation) for ECCM CPI N-1 CPI N CPI N+1 Platform Motion Notes: 1) For continuous map, the last half of the previous CPI can be used as the first half of the data for the next CPI 2) Not exactly sure how this works with ECCM, collecting training samples, etc. Obviously, you do not want a big jammer to mess up the formation of the SAR image. How to null a big jammer out without affecting the image is a major consideration. 3) For onboard DTED processing, I assume the global memory requirements would double because two (2) beams would be formed, an upper beam and a lower beam with slightly different look-down angles that could be used to form the elevation differential ISAR image 4) Historically, SAR processing hasn’t required the arithmetic precision of GMTI, e.g., 4-bit A/D converters and 8-16 bit data representation in the processing chain. The memory requirement is a function of the arithmetic precision.

Skau9 Possible SAR Partitioning/Mapping/Utilization (32K x 32K Image)

Skau10 SAR Processing - Assumptions Assumed SAR Parameters 16 channels (12 Subarrays and 4 Auxiliary Channels) Msamples/sec ( nsec per sample 500  sec receive window (200, ,000 range cells per pulse) 1 KHZ PRI 32,768 pulses in azimuth (32.8 sec collection time) The last 1/2 of the collected samples are used as the first 1/2 of the samples for the image (processed only through range pulse compression and stored) 1 beam formed for SAR image; input 32,768 ranges x 32, 768 pulses 8-bits (1 Byte) per A/D sample 64-bits (8 Bytes) for internal data storage for complex data (4 Bytes real, 4 Bytes imaginary) 32-bits (2 Bytes) for internal data storage of real data 4/3 oversampling out of the Polyphase Channelizer 128 Subbands formed; only 40 processed Assumed Processing Resources 32 processing nodes per board 64 GFLOPS peak throughput per board 48 GFLOPS sustained throughput per board 75% execution efficiency) 32 MBytes local data memory per board - 8 MBytes local data memory per processing cluster per board -- 2 MBytes local data memory per processing node 256 KBytes local memory per processor 32 GBytes Global Memory (worst case SAR requirement)

Skau11 SAR Processing Flow/Global Memory Accessing (1 of 2) Range Pulse Compression 32,768 ranges for each pulse Store data from each pulse in global memory 32,768 ranges for each pulse 32,768 pulses x 32 ranges x 8 Bytes = 8.4 MBytes Extract pulse (cross-range) data Perform cross-range FFT Loop 1024 times = 32,768 ranges/32 ranges/loop 1012 pulses x 1012 ranges x 8 Bytes = 8.2 MBytes Extract 2D Polar Reformat data Perform Polar Reformatting Loop 1060 times = x 10 6 cells/1.012 x 10 6 cells/patch Store processed data 8.4 MBytes Store processed data Small overlap to process 1010 x 1010 patch 8.2 MBytes 32,768 ranges x 32 pulses x 8 Bytes = 8.4 MBytes Loop 1024 times = 32,768 ranges/32 ranges/loop 8.4 MBytes Extract range data Perform range FFT Store processed data (transposed) Note: This sizing assumes that the extracted data fills the available 8 MBytes of external memory available on the Compute Cluster. It might be safer to assume only twenty-eight (28) ranges per extraction ==> more loops, but the bandwidth is about the same because the same amount of data has to be extracted and re-stored. The same thing is true for the patch size, except there is a little more bandwidth required because of the overlap needed to do the interpolation. This gets a little tricky because of the assumed in-place calculation.

Skau12 SAR Processing Flow/Global Memory Accessing (2 of 2) 32,768 pulses x 32 ranges x 8 Bytes = 8.4 MBytes Loop 1024 times = 32,768 ranges/32 ranges/loop Perform Auto Focus 8.4 MBytes Store processed data 8.4 MBytes 32,768 pulses x 32 ranges x 8 Bytes = 8.4 MBytes Loop 1024 times = 32,768 ranges/32 ranges/loop 4.2 MBytes Extract pulse (cross-range) data Perform Magnitude Function Store processed data Extract pulse (cross-range) data Perform cross-range FFT Store processed data Extract pulse (cross-range) data 32,768 pulses x 32 ranges x 8 Bytes = 8.4 MBytes Loop 1024 times = 32,768 ranges/32 ranges/loop All of this, from cross-range FFT through Magnituding, can be done with the data in place, i.e., no need to extract and restore data until all of the processing is complete. (I set it up that way because the 2nd half of the 2D FFT, AutoFocus, and Magnituding appear to be performed only in the cross-range dimension. Note: This sizing assumes that the extracted data fills the available 2MBytes of external memory available on the Compute Cluster. It might be safer to assume only twenty-eight (28) ranges per extraction ==> more loops, but the bandwidth is about the same because the same amount of data has to be extracted and re-stored.

Skau13 SAR Processing Flow/Global Memory Utilization 32, 768 pulses 8.6 GBytes complex data Storage of pulse compressed range data for further processing 4.3 GBytes of new data from current CPI collection Storage of cross-range FFT processed data through through polar reformatting Storage of 1st half of 2D FFT result transposed (corner-turned) through Magnituding 8.6 GBytes complex data 8.6 GBytes complex data Total global memory required for SAR (worst case) = 30.1 GBytes * * This might be able to be reduced to 21.4 GBytes if 2D FFT can be done “in place.” ** 2.9 GBytes available for storing training samples for AWC (Adaptive Weight Computation) for ECCM CPI N-1 CPI N CPI N+1 Platform Motion Notes: 1) For continuous map, the last half of the previous CPI can be used as the first half of the data for the next CPI 2) I am not sure how this works with ECCM, collecting training samples, etc. Obviously, you wouldn’t want a big jammer to mess up the formation of the SAR image, but I am not sure how you null a big jammer out without affecting the image 3) For onboard DTED processing, I assume the global memory requirements would double because two (2) beams would be formed, an upper beam and a lower beam with slightly different look-down angles that could be used to form the elevation differential ISAR image 4) Historically, SAR processing hasn’t required the arithmetic precision of GMTI, e.g., 4-bit A/D converters and 8-16 bit data representation in the processing chain. The memory requirement is a function of the arithmetic precision.

Skau14 SAR Processing Flow/Board-Level Partitioning/Utilization Polyphase Channelizer Board #1 Polyphase Channelizer Board #2 Polyphase Channelizer Board #3 Polyphase Channelizer Board #4 ECCM, AWC, & PP Combination Board #1 ECCM, AWC, & PP Combination Board #2 ECCM, AWC, & PP Combination Board #4 ECCM, AWC, & PP Combination Board #3 Range PC, Freq. Conv, Polar Reform, 2D FFT, Auto Focus, & Mag. Board #1 Range PC, Freq. Conv, Polar Reform, 2D FFT, Auto Focus, & Mag. Board #2 Range PC, Freq. Conv, Polar Reform, 2D FFT, Auto Focus, & Mag. Board #3 Range PC, Freq. Conv, Polar Reform, 2D FFT, Auto Focus, & Mag. Board #4 Max. Sustained T-put per Stage = 192 GOPS Used T-put per Stage = 144 GOPS Max. Sustained T-put per Stage = 192 GOPS Used T-put per Stage = 96 GOPS Each ECCM/AWC/PP Combo Board processes 16 radar channels with 750 range cells per pulse and 40 subbands per channel; forms 1 beam; combines 40 subbands; each ECCM node outputs 8192 ranges to each of the next stage receiving nodes Each Range PC - Mag node performs range compression on a pulse by pulse basis; sends processed data to global memory; frequency conversion, polar reformatting, 2D FFT, Auto Focus, and Magnituding are performed working out of global memory, and restoring processed data in global memory on a function by function basis 1.15 GBytes/sec input to each PPC board 1 beam x 8192 ranges x 8 Bytes input to each Range PC board from each ECCM board every PRI = 65.5 MBytes/sec; Aggregate BW = 1.05 GBytes/sec Global Memory Max. Memory = 32 GBytes Used Memory = 30.1 GBytes Output MBytes/sec between each board and global memory Aggregate BW = 2.1 GBytes/sec Training Samples & Adaptive Weights 16 ch x 256 pulses x 288,000 ranges x 4 Bytes every CPI (0.256 sec) = 18.4 GBytes/sec 4 ch x 40 subbands x 1 pulse x 750 ranges x 8 Bytes output from each PPC board and input to each ECCM board every PRI (1 msec) = 0.96 GBytes/sec; Aggregate BW = 15.4 GBytes/sec Each PPC Channelizer Board processes 4 radar channels with 288,000 range cells per pulse; generates 128 subbands; 40 subbands are output to the Global Memory for prcessing in the ECCM nodes

Skau15 SAR Processing Flow/Node-Level Partitioning/Utilization Global Memory Compute Board #N 8 MByte Local Data Memory 8 MByte Local Data Memory 8 MByte Local Data Memory 8 MByte Local Data Memory Compute Cluster #1 Compute Cluster #2 Compute Cluster #3 Compute Cluster #4 CNA #1 CNA #2 CNA #3 CNA #4 CNA #1 CNA #2 CNA #3 CNA #4 CNA #1 CNA #2 CNA #3 CNA #4 CNA #1 CNA #2 CNA #3 CNA #4 Possible Partitioning/Utilization for Range Pulse Compression, Frequency Conversion in Range, 2D FFT, Auto Focus, and Magnituding: Ranges or Cross-Ranges M+1 to M+32 => Compute Cluster #1 Ranges or Cross-Ranges M+1 to M+8 => CNA #1 Ranges or Cross-Ranges M+9 to M+16 => CNA #2 Ranges or Cross-Ranges M+17 to M+24 => CNA #3 Ranges or Cross-Ranges M+25 to M+32 => CNA #4 Ranges or Cross-Ranges M+33 to M+64 => Compute Cluster #2 Ranges or Cross-Ranges M+33 to M+40 => CNA #1 Ranges or Cross-Ranges M+41 to M+48 => CNA #2 Ranges or Cross-Ranges M+49 to M+56 => CNA #3 Ranges or Cross-Ranges M+57 to M+64 => CNA #4 Ranges or Cross-Ranges M+65 to M+96 => Compute Cluster #3 Ranges or Cross-Ranges M+65 to M+72 => CNA #1 Ranges or Cross-Ranges M+73 to M+80 => CNA #2 Ranges or Cross-Ranges M+81 to M+88 => CNA #3 Ranges or Cross-Ranges M+89 to M+96 => CNA #4 Ranges or Cross-Ranges M+96 to M+128 => Compute Cluster #4 Ranges or Cross-Ranges M+97 to M+104 => CNA #1 Ranges or Cross-Ranges M+105 to M+112 => CNA #2 Ranges or Cross-Ranges M+113 to M+120 => CNA #3 Ranges or Cross-Ranges M+121 to M+138 => CNA #4 for 1 < M < 128 Similarly across all four (4) Compute boards with the associated change in indexing. (Polar Reformatting is similar except data is in Rng-XRng patches Input to Board from ECCM nodes = 65.6 MBytes/sec/ECCM board x 4 ECCM boards = 262 MBytes/sec => perform range compression Range Compression Output to Global Memory = 262 MBytes/sec Post-Range Compression Processing out of global memory: Input to Board 33.6 MBytes per fetch x 128 fetches per function per board every 65.5 sec = 4.3 GBytes/65.5 sec = 65.6 MBytes/sec per function per bd. Output from Board 33.6 MBytes per store x 128 stores per function per board every 65.5 sec = 4.3 GBytes/65.5 sec = 65.6 MBytes/sec per function per bd. Aggregate Bandwidth per board= MBytes/sec x 4 functions = MBytes/sec

Skau16 Example GMTI Partitioning/Mapping/Utilization

Skau17 GMTI Processing - Assumptions Assumed GMTI Parameters 16 channels (12 Subarrays and 4 Auxiliary Channels) Msamples/sec ( nsec per sample) 256 pulses per CPI 1 KHZ PRI 500  sec receive window; (200, ,000 range cells per pulse) into the polyphase channelizer 4/3 oversampling out of the Polyphase Channelizer 128 Subbands formed; only 40 processed 6 beams formed 10-bits (2 Bytes) per A/D sample 64-bits (8 Bytes) for internal data storage for complex data (4 Bytes real, 4 Bytes imaginary) 32-bits (2 Bytes) for internal data storage of real data Assumed Processing Resources 32 processing nodes per board 64 GFLOPS peak throughput per board 48 GFLOPS sustained throughput per board 75% execution efficiency) 32 MBytes local data memory per board - 8 MBytes local data memory per processing cluster per board -- 2 MBytes local data memory per processing node 256 KBytes local memory per processor 32 GBytes Global Memory (worst case SAR requirement)

Skau18 GMTI Processing Flow/Board-Level Partitioning/Utilization #1 Polyphase Channelizer Board #1 Polyphase Channelizer Board #2 Polyphase Channelizer Board #3 Polyphase Channelizer Board #4 ECCM, AWC, & PP Combination Board #1 ECCM, AWC, & PP Combination Board #2 ECCM, AWC, & PP Combination Board #3 Max. Sustained T-put per Stage = 144 GOPS Used T-put per Stage = 100.3GOPS Each PPC Channelizer Board processes 4 radar channels with 288,000 range cells per pulse; generates 128 subbands; 40 subbands are output to the Global Memory for prcessing in the ECCM nodes Each ECCM/AWC/PP Combo Board processes 16 radar channels with 1000 range cells per pulse and 40 subbands per channel; forms 6 beams; & combines 40 subbands; each ECCM node outputs 30,000 ranges to global memory for Pulse Compression processing Each Pulse Compression board outputs 2 beams with 256 pulses and 72,000 ranges; Doppler board receives 6 beams with 256 pulses and 72,000 ranges and outputs 12 beams with 256 Doppler cells and 72,000 ranges (staggered); STAP outputs 3 beams with 256 Doppler cells and 72,000 ranges; CFAR outputs target detections 16 ch x 256 pulses x 288,000 ranges x 4 Bytes every CPI (0.256 sec) = 18.4 GBytes/sec 4.61 GBytes/sec input to each PPC board 4 ch x 40 subbands x 1 pulse x 3000 ranges x 8 Bytes output from each PPC board and input to global memory every PRI (1 msec) = 3.85 GBytes/sec ; Aggregate BW = 15.4 GBytes/sec 6 beams x 256 pulses x 30,000 ranges x 8 Bytes output to global memory from each ECCM board every CPI = 1.44 GBytes/sec; Aggregate BW = 4.32 GBytes/sec Global Memory Max. Memory = 32 GBytes Used Memory = 21 GBytes Output Pulse Comp. Board #1 Pulse Comp. Board #2 Pulse Comp. Board #3 Max. Sustained T-put per Stage = 144 GOPS Used T-put per Stage = 101 GOPS Doppler, STAP, & CFAR Board #1 Max. Sustained T-put per Stage = 48 GOPS Used T-put per Stage = 34 GOPS 16 ch x 256 pulses x 1000 ranges x 40 subbands x 8 Bytes input to each each ECCM board from global memory every CPI = 5.1 GBytes/sec; Aggregate BW = 15.4 GBytes/sec 2 beams x 256 pulses x 90,000 ranges x 8 Bytes input to each Pulse Compression board from global memory each CPI = 1.44 GBytes/sec; Aggregate BW = 4.32 GBytes/sec 2 beams x 256 pulses x 72,000 ranges x 8 Bytes output from each Pulse Compression board to global memory every CPI = 1.15 GBytes/sec; Aggregate BW = 3.46 GBytes/sec 6 beams x 256 pulses x 72,000 ranges x 8 Bytes input to Doppler board from global memory every CPI = 3.46 GBytes/sec Doppler 6.92 GBytes/sec STAP 6.92 GBytes/sec STAP 1.73 GBytes/sec CFAR 1.73 GBytes/sec

Skau19 GMTI Processing Flow/Board-Level Partitioning/Utilization #2 Polyphase Channelizer Board #1 Polyphase Channelizer Board #2 Polyphase Channelizer Board #3 Polyphase Channelizer Board #4 ECCM, AWC, & PP Combination Board #1 ECCM, AWC, & PP Combination Board #2 ECCM, AWC, & PP Combination Board #3 Max. Sustained T-put per Stage = 144 GOPS Used T-put per Stage = 100.3GOPS Each PPC Channelizer Board processes 4 radar channels with 288,000 range cells per pulse; generates 128 subbands; 40 subbands are output to the ECCM boards Each ECCM/AWC/PP Combo Board processes 16 radar channels with 1000 range cells per pulse and 40 subbands per channel; forms 6 beams; & combines 40 subbands; each ECCM node outputs 30,000 ranges to global memory for Pulse Compression processing Each Pulse Compression board outputs 2 beams with 256 pulses and 72,000 ranges; Doppler board receives 6 beams with 256 pulses and 72,000 ranges and outputs 12 beams with 256 Doppler cells and 72,000 ranges (staggered); STAP outputs 3 beams with 256 Doppler cells and 72,000 ranges; CFAR outputs target detections 16 ch x 256 pulses x 288,000 ranges x 4 Bytes every seconds = 18.4 GBytes/sec 4.61 GBytes/sec input to each PPC board 4 ch x 40 subbands x 1 pulses x 1000 ranges x 8 Bytes output from each PPC board to each ECCM boards every PRI (1 msec)= 5.12 GBytes/sec; Aggregate BW = 15.4 GBytes/sec 6 beams x 256 pulses x 30,000 ranges x 8 Bytes output to global memory from each ECCM board every PRI (1 msec) = 1.44 GBytes/sec; Aggregate BW = 4.32 GBytes/sec Global Memory Max. Memory = 32 GBytes Used Memory = 13.1 GBytes Output Pulse Comp. Board #1 Pulse Comp. Board #2 Pulse Comp. Board #3 Max. Sustained T-put per Stage = 144 GOPS Used T-put per Stage = 101 GOPS Doppler, STAP, & CFAR Board #1 Max. Sustained T-put per Stage = 48 GOPS Used T-put per Stage = 34 GOPS 2 beams x 256 pulses x 90,000 ranges x 8 Bytes from global memory input to each Pulse Compression board every CPI (0.256 sec) = 1.44 GBytes/sec; Aggregate BW = 4.32 GBytes/sec 2 beams x 256 pulses x 72,000 ranges x 8 Bytes output to global memory from each Pulse Comp. board every CPI (0.256 sec)= 1.15 GBytes/sec; Aggregate BW = 3.46 GBytes/sec 6 beams x 256 pulses x 72,000 ranges x 8 Bytes input to Doppler board from global memory every CPI (0.256 sec) = 3.46 GBytes/sec Doppler 6.92 GBytes/sec STAP 6.92 GBytes/sec STAP 1.73 GBytes/sec CFAR 1.73 GBytes/sec

Skau20 GMTI Processing Flow/Board-Level Partitioning/Utilization #3 Polyphase Channelizer Board #1 Polyphase Channelizer Board #2 Polyphase Channelizer Board #3 Polyphase Channelizer Board #4 ECCM, AWC, & PPC Comb. & Pulse Comp. Board #1 Max. Sustained T-put per Stage = 240 GOPS Used T-put per Stage = 202 GOPS Each PPC Channelizer Board processes 4 radar channels with 288,000 range cells per pulse; generates 128 subbands; 40 subbands are output to the ECCM nodes Each ECCM/AWC/PP Combo/Pulse Compression Board processes 16 radar channels with 90,000 range cells per pulse and 40 subbands per channel; forms 1 or beams (only 1 forms 2 beams; & combines 40 subbands; each ECCM node outputs 72,000 ranges to global memory for Doppler processing Each ECCM/Pulse Compression board outputs 6 beams with 72,000 ranges per pulse; Doppler board receives 6 beams with 256 pulses and 72,000 ranges and outputs 12 beams with 256 Doppler cells and 72,000 ranges (staggered); STAP outputs 3 beams with 256 Doppler cells and 72,000 ranges; CFAR outputs target detections 16 ch x 256 pulses x 288,000 ranges x 4 Bytes every seconds = 18.4 GBytes/sec 4.61 GBytes/sec input to each PPC board 4 ch x 40 subbands x 1 pulse x 3000 ranges x 8 Bytes input to ECCM boards from each PPC board every PRI (1 msec) = 3.07 GBytes/sec ); Aggregate BW = 15.4 GBytes/sec Global Memory Max. Memory = 128 GBytes Used Memory = 8.66 GBytes Output Doppler, STAP, & CFAR Board #1 Max. Sustained T-put per Stage = 48 GOPS Used T-put per Stage = 34 GOPS 6 beams x 72,000 ranges x 1 pulse x 8 Bytes output to global memory from the ECCM/Pulse Compression Boards every PRI (1 msec) = 3.45 GBytes/sec Aggregate BW 6 beams x 256 pulses x 72,000 ranges x 8 Bytes input to the Doppler/STAP/CFAR board from global memory every CPI = 3.46 GBytes/sec Doppler Output (12 beams x 72,000 ranges x GBytes/sec STAP Input (12 beams x 72,000 ranges x GBytes/sec STAP Output (3 beams x 72,000 ranges x GBytes/sec CFAR 1.73 GBytes/sec ECCM, AWC, & PPC Comb. & Pulse Comp. Board #2 ECCM, AWC, & PPC Comb. & Pulse Comp. Board #3 ECCM, AWC, & PPC Comb. & Pulse Comp. Board #4 ECCM, AWC, & PPC Comb. & Pulse Comp. Board #5

Skau21 Backup Charts

Skau22 Hypothetical Real-Time Adaptive Space-Based Radar Design

Skau23 Space-Based Radar Advantages - the ultimate “high ground” -- radar “horizon” > for airborne or ground radar - 24-hour all weather capability (IR sensors can’t see through clouds, optical sensors blind in dark) - less vulnerable/more survivable than airborne assets - once launched, lower logistics costs than airborne assets (fuel, ground support fighter protection, etc.) - continuous world-wide coverage with full constellation of satellites - High Range Resolution (HRR) with frequency jumped burst waveforms - SAR (Synthetic Aperture Radar) - IFSAR (Interferometric SAR) - DTED (Digital Terrain Elevation Data) - DAR (Distributed Aperture Radar) - multi-mission -- GMTI (Joint STARS) -- SAR (Joint STARS) -- AMTI (AWACS [E3-A] & E-2C) - GPIR (Ground Penetrating Imaging Radar) - foliage penetration capability - reduced downlink requirements with onboard processing in many cases Disadvantages/Issues - limited power generation and power dissipation capability in space - limited aperture size (antenna dimensions) - high altitude (R 4 losses) - ionospheric effects - steep look-down angle/Nadir Hole - clutter Doppler/clutter Doppler spread -- function of satellite-target geometry (earth background) and platform velocity - optimal waveform design for target detection performance and clutter cancellation -- frequency of operation (X,L,UHF/VHF) -- polarization (T x and R x ) -- pulse width, PRF, CPI -- range resolution/bandwidth -- Doppler resolution -- range ambiguities -- Doppler ambiguities - constellation -- altitude, inclination, number of satellites, phasing - environmental -- radiation, micro-meteorites, etc. - launch vehicle capability - initial system cost

Skau24 Considerations for Optimal Onboard Processing

Skau25 GMTI/SAR Mode Switching for SBR