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milstar: 8 The mono-pulse or sum-difference RDF technique uses two antennas. The antennas are connected to a four-port combiner 180° hybrid that generates a sum and difference signal. Such sum and difference patterns are generated by means of closely spaced overlapping radiation patterns at boresight. These signals form sum and difference radiation patterns. The ratio of the sum and difference signals and knowledge of the sum and difference patterns are used to determine the direction of the transmitter. Phase information is used to determine on which side of the sum pattern the transmitter is. An advantage of this system is in its capability to determine the direction of a transmitter after receiving one pulse. Such pulse could be a mere few microseconds. Accuracies of 10meter over a 100Km distance has been reported. ------------------------------------------------------------- https://www.alarisantennas.com/wp-content/uploads/2020/12/An-Introduction-to-Radio-Direction-Finding.pdf https://www.alarisantennas.com/blog/an-introduction-to-radio-direction-finding/ --------------------------------------------------------------------------- Precision Receiver Inc. Precision Receivers Incorporated (PRI) New technology PRI has introduced proprietary technology to reduce spurious responses in analog to digital converter systems. All ADCs have quantization and timing errors creating spurs in the outputs of ADCs. These spurs degrade the sensitivity of Cellular, SIGINT, COMINT, ELINT and EW systems. Many schemes have been implemented to mitigate these problems such as clock dithering, but the schemes have tradeoffs and consequences including a reduction in the dynamic range of a system. PRI’s technology reduces the magnitude of all the spurs across the IF bandwidth and over the entire RF input bandwidth, nearly the entire Fs/2 as well as all the Nyquist zones. Figure 2 (next page) shows the ENOB performance of PRI’s new technology, current ADC chips and a competitor’s digitizer board. Figure 3 shows the SNR performance of PRI’s new technology. Existing competitive 2.5 GSPS systems struggles to achieve 10 effective bits or ENOB. PRIs technology achieves almost 11.5 bits of ENOB. Increased performance will serve to enhance future systems and PRI’s technology allows for an easy upgrade to existing platforms. Other BW’s are available as well as other clock rates and more ruggedized formfactors are being developed. Precision Receivers Incorporated Introduces 1st HDRR Receiver The HDRR-3.6G-12B is a single-channel signal collection and recording system incorporating PRI proprietary technology to reduce spurious responses in the analog to digital converter. The system collects and records signals across a large (>1GHz) BW. HDRR technology is described as the industry’s most effective way to improve the performance of direct-sampled receivers employed in electronic warfare, radar, signals and communications intelligence, spectrum monitoring, and wireless communications systems. HDRR technology provides an order-of- magnitude improvement in reducing unwanted spurious signals to levels previously unachievable using other methods and increases spurious-free dynamic range (SFDR) by up to 16 dB. HDRR-3.6G-12B PRI Inc 4111 Rutledge Ln, Marshall, VA 20115 Phone (202) 773-4252 info@precisionreceivers.com www.precisionreceivers.com Precision Receiver Inc. Precision Receivers Incorporated (PRI) New technology PRI has introduced proprietary technology to reduce spurious responses in analog to digital converter systems. All ADCs have quantization and timing errors creating spurs in the outputs of ADCs. These spurs degrade the sensitivity of Cellular, SIGINT, COMINT, ELINT and EW systems. Many schemes have been implemented to mitigate these problems such as clock dithering, but the schemes have tradeoffs and consequences including a reduction in the dynamic range of a system. PRI’s technology reduces the magnitude of all the spurs across the IF bandwidth and over the entire RF input bandwidth, nearly the entire Fs/2 as well as all the Nyquist zones. Figure 2 (next page) shows the ENOB performance of PRI’s new technology, current ADC chips and a competitor’s digitizer board. Figure 3 shows the SNR performance of PRI’s new technology. Existing competitive 2.5 GSPS systems struggles to achieve 10 effective bits or ENOB. PRIs technology achieves almost 11.5 bits of ENOB. Increased performance will serve to enhance future systems and PRI’s technology allows for an easy upgrade to existing platforms. Other BW’s are available as well as other clock rates and more ruggedized formfactors are being develop https://precisionreceivers.com/wp-content/uploads/2021/04/HDRR-3.6G-12B-Product-Sheet.pdf ############# SIGINT Direction finding comparsion Time Difference of Very High Precision, Very Complex, At Least 3 Aircraft; High Quality Arrival (Pulsed Signals) https://www.phys.hawaii.edu/~anita/new/papers/militaryHandbook/sig-sort.pdf WPI MQP Group: Daniel Guerin - ECE Shane Jackson - Physics Jonathan Kelly - CS/ECE Phase Interferometry Direction Finding Lincoln Laboratory https://web.wpi.edu/Pubs/E-project/Available/E-project-101012-211424/unrestricted/DirectionFindingPresentation.pdf Passive Direction Finding [DF] Techniques – DTOA (Difference Time of Arrival) Comparison Written By Riccardo Ardoino The Time-Of-Arrival (TOA) comparison measurement can be done with a two antennas receiver, a third antenna is used to eliminate ambiguity, and four antennas are used to cover 360° in Azimuth. Assuming two antennas at distance “B” between them (order 10m). Assuming incident radiation from the emitter >> B (≈ Infinite). The difference in Time of Arrival observed at the two antennas is ∆TOA, with ∆R = B x sin (DOA) equal to the optical path difference. https://www.emsopedia.org/entries/passive-direction-finding-df-techniques-dtoa-difference-time-of-arrival-comparison/
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