| Περίληψη: | In the optical fiber time transfer system, fiber optic time transfer is limited by the pulse signal time delay measurement precision, and cannot benefit from a higher precision of the carrier phase information. Its transfer precision compared to the frequency transfer exists in a larger gap transfer. This paper proposes a time delay measurement method based on carrier phase and pseudo-code ranging for optical time transfer. The time signal is modulated with pseudo-random code and carrier at the transmitter, and the time delay is measured at the receiver by the methods of pseudo-code ranging and carrier phase measurement. The time transfer is achieved by eliminating the transmission link delay through a two-way method. The first-order difference value of the carrier phase measurement and the pseudo-code ranging measurement are used as the observation quantities, and they are fused through a Kalman filtering method to finally obtain the high-precision time difference measurement. We validate the theory on the common-clock experimental platform over a 50 km fiber link, The time transfer stabilities of the systems are <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>5.2254</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>14</mn></mrow></msup></mrow></semantics></math></inline-formula>/s and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2.146</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>16</mn></mrow></msup></mrow></semantics></math></inline-formula>/<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>4</mn></msup></semantics></math></inline-formula> s (modified Allan deviation), <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>3.0169</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>14</mn></mrow></msup></mrow></semantics></math></inline-formula>/s and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1.2392</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>12</mn></mrow></msup></mrow></semantics></math></inline-formula>/<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>10</mn><mn>4</mn></msup></semantics></math></inline-formula> s (time deviation). The standard deviation of the time transfer system after fusion can reach 2.4255 ps.
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