GNSS receiver and external storage device system and GNSS data processing method
A GNSS system includes a receiver connected to an external mass storage device. Applications for the system, including GNSS data processing methods are also disclosed. The external storage device can comprise a flash (thumb) drive, which can be connected to the receiver via a USB interconnection.
1. A system for processing GNSS signals from multiple satellite sources received, which comprises:
a GNSS receiver including a digital signal processor (DSP) and a general purpose central processing unit (CPU);
USB host hardware connected to said CPU;
a USB serial interface connected to said CPU;
said CPU having random access memory (RAM);
nonvolatile memory connected to said receiver;
said receiver including a real-time operating system (RTOS) including a hardware abstraction layer (HAL) and upper-level USB software enabling USB host capability; said USB host hardware and the USB software interfacing with the HAL;
USB host software embedded in said CPU and including interrupt service routines (ISRs) and delayed service routines (DSRs) in said USB host software;
said ISRs handling USB activities between the upper-level USB software and the HAL;
said DSRs handling USB activities not handled by the ISRs;
said RTOS providing time slice bases for executing the DSRs;
said GNSS receiver software including a PC compatible file system and receiving raw analog GNSS ranging and timing signals;
an AD converter downconverting the raw analog GNSS signals to digital signals;
the digital signal processor (DSP) correlating the digital signals;
the CPU closing code and carrier tracking loops on a fixed time interval (interrupt) basis;
a user interface calculating a GNSS solution and communicating the GNSS solution;
the USB receiving output signals representing the GNSS positioning solution;
the external USB storage device providing compatibility for the RTOS files read from or written to the external USB storage device;
the CPU processing said output signals in real-time;
a mass storage interface transferring said output signals between said USB host hardware and said storage device;
said external USB storage device storing said output signals; and
said external computer post-processing said externally stored data.