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RF Solutions GPS1513R / Cyber i-tech SIRIUS-1513R test Test of the RF Solutions GPS1513R / Cyber i-tech SIRIUS-1513R GPS receiver (SkyTraq Venus 624 based module). "How precise, how accurate?"
Equipment list: Trimble Thunderbolt tc=300, damp=0.700, Trimble OCXO Dly=-84.54: cable=52.8 ns (measured), ant=31.74 ns (specified) PPS=UTC, measured on face of connector unit is in a thermally slow environment S1513R #1 31.74 ns outdoor reference antenna. Matching to Tbolt antenna <5ns 6.0m RG174 (30 ns) 2cm to front of antenna connector (100ps) PPS is measured 3cm from the the receiver (~200ps) Scope LeCroy 9304A 1.0m RG58 from tbolt to channel 1 (5ns) probe on channel 2 matching between probe and RG58 on face of tbolt is better than 1ns   Summed propagation delay, antenna to receiver input = 31.74ns (antenna) + 30ns (feedline) + 300ps (board wiring) = 62 ns. Receiver delay = 17ns(ref to out) -62ns (ant to out) = -45ns measurement tolerance: -15ns(tbolt) + -5ns (ant) = -20ns / +15ns (tbolt) + +5ns (ant) =+20ns. So S1513R is [-65 ns .. -25 ns] slow (the number is negative, so S1513R is 'fast'.) |