The traditional one-bit direct position determination (DPD) based on zero-thresholding quantization (ZQ) scheme suffers from remarkable performance degradation. To solve this problem, this paper proposes a Rao-test-based method for the one-bit signal based on time-varying quantization (TQ) scheme (TQ-one-bit Rao test, TQ-OBRT) to detect and locate the target simultaneously. We derive the one-bit Cramér-Rao Lower bound (CRLB) based on TQ scheme. Then, we obtain the optimal quantization (OQ) scheme by the minimizing the one-bit CRLB, and introduce a random quantization (RQ) scheme without iterative processing. Simulation results show that the performance of the proposed OQ and RQ schemes is superior to that of the conventional ZQ scheme.