Integer Ambiguity Resolution Based on Capuchin-Cuckoo Cooperative Search Algorithm and Enhanced Sharpness-Adaptive Ratio Test

Abstract

In GNSS carrier-phase observations, rapid and accurate integer ambiguity resolution is essential for centimeter-level positioning. With BeiDou-3 and Galileo operational, rising dimensionality challenges LAMBDA with exponential complexity and heavy dependence on float-solution quality. This paper proposes a Capuchin-Cuckoo Cooperative Search Algorithm (CCCSA), combining capuchin global exploration with cuckoo Levy flights to escape local optima. In simulated integer least-squares experiments, CCCSA reduces resolution time by 67% and 10% versus LAMBDA and M-LAMBDA, maintaining over 98% success in 12-dimensional scenarios; in a 42.7 km long-baseline test, its success rate reaches 77.4%, surpassing LAMBDA by 25 percentage points. To overcome the traditional Ratio test’s deficiency—a one-dimensional scalar ratio without spatial topological awareness—this paper proposes an Enhanced Sharpness-Adaptive Ratio test (ESA-Ratio) with multi-dimensional feature fusion. Full-threshold scanning shows ESA-Ratio operates safely at threshold 2.0, whereas the traditional Ratio requires 3.0 to mitigate false-peak risks, with a true fix rate of 97.55% and a false fix rate of 0.14%. CDF analysis shows a 95% confidence three-dimensional positioning error of 0.0166 m versus 0.0170 m for the traditional ratio. These results confirm that, in the tested static single-system scenarios, ESA-Ratio improves availability, integrity, and positioning accuracy simultaneously at a lower threshold.