A highly sensitive 640 x 480-element flash LADAR camera will be developed that is capable of 100-Hz rates with better than 5-cm range precision. The design is based on proven readout integrated circuit (ROIC) designs, shown to have very low noise, high frame rates, and superior range resolution, and proven high gain, low noise avalanche photodiode (APD) array technology, sensitive in the 1.0- to 1.6-micron wavelength range. These technologies are integrated into a robust, compact camera with real-time processing and data transmission. In Phase I, an existing 128 x 128-element InGaAs linear-mode (Lm) APD 3D flash LADAR camera will be demonstrated. The FPA allows for readout of multiple laser pulse echo amplitude and time-of-arrival data pairs, in windowed regions, at up to 20K frames per second. The demonstration will include either or both of Voxtel's APD technologies: Deschutes APD technologies, characterized by a mean gain of M = 20 and excess noise parameterized by k = 0.2; or Siletz family of APDs (M = 75; k = 0.02). The data measured on the InGaAs Lm-APDs, along with receiver operating characteristic (ROC) analysis developed from measured data, will be used to develop a new 640 x 480-element ROIC that implements the NASA-communicated mission requirements. By completion of Phase I, the LADAR ROIC pixel circuits will be designed and simulated, and the performance of the new design will be documented.