| Photoelectric theodolite is a high-precision equipment for tracking and positioningthe moving target. It is one of the most important equipments in range. With thedevelopment of the photoelectric theodolite and image sensors, measure systemrequires the image storage device to have faster storage rate, larger storage capability,meanwhile higher reliability stability and excellent portability.In order to observe and record the flying target real-time, the correspondinghigh-speed storage device must be able to store the image datum and additionalinformation correctly, and replay the recorded image to determine whether the resultis right or not, analysis the problems, evaluate the system’s performance. According tothe characteristics of range application a storage system based on flash memory andFPGA with high speed and huge capacity is designed. In this system, flash memory isused for storage medium is which controlled by FPGA. USB2.0interface is used forsystem’s replay interface, CAN bus is used for the system’s command and statusinterface. The storage system has high storage rate and huge capacity, also can writeand erase repeatedly and replay the image expediently.The access rate of the flash memory is too slow to meet the requirement of theimage storage system. To resolve this problem, High-Band-Buses and Pipeline techniqueare applied in order to improve the storage rate. Flash memory’s reliability can not beguaranteed because of invalid blocks, therefore redundant design is adopted toimprove the reliability. In addition, the ECC method is used to improve the accuracy ofimage datum.The whole system’s storage capacity is up to80GB, and extend storage capacitycan be attained through only changing the hardware circuit slightly. The theoreticalstorage rate is up to160MB/s, and it meets the speed requirement of the system. Theimage replay speed approached to20MB/s through USB2.0interface. The storagesystem is all-purpose, and can be applied to other datum acquisition and storage field. |
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