1. A multimode passive detection system responsive to naturally occurring ambient charged particles, comprising: a detector assembly including an array of drift tubes arranged as detector modules to generate detector signal data from respective detector modules, the detector signal data representing electrical responses to cosmic ray charged particles passing through the respective detector modules and traversing through a volume of interest; detector circuitry communicatively coupled to the detector assembly, wherein the detector circuitry is configured to measure the generated detector signal data of respective detector modules and output the measured detector signal data as spatially segregated data streams corresponding to respective detector modules; a clock system communicatively coupled to the detector circuitry, wherein the clock system distributes a master clock signal throughout the detector circuitry; and a computer cluster including nodes of computing devices communicatively coupled to the detector circuitry, the computer cluster configured to merge the spatially segregated data streams into temporally segregated data, obtain information on tracks of the cosmic ray charged particles traversing the volume of interest based on the temporally segregated data, reconstruct an image of the volume of interest based on the obtained information on the tracks of the cosmic ray charged particles traversing the volume of interest, and identify an object in the volume of interest based on the reconstructed image.