Function solve_ppp_fixed 

pub fn solve_ppp_fixed(
    source: &dyn ObservableEphemerisSource,
    epochs: &[FloatEpoch],
    float_solution: FloatSolution,
    config: FixedSolveConfig,
) -> Result<FixedSolution>

Lower-level positional form for static integer-fixed PPP.

New Rust callers should prefer solve_ppp_fixed_with with PppFixedConfig so units and frame semantics are attached to named fields. source and epochs must describe the same static ECEF/ITRF arc used to produce float_solution. Ambiguity wavelengths and offsets in config are metres; integer decisions in the returned solution are reported in carrier cycles and converted metres.

This function is kept for existing bindings and delegates to sidereon_core::precise_positioning::solve_fixed_from_float, returning its FixedSolution and mapping any failure to Error::PppFixed.