User's Manual Part 1

Receiver System Overview Chapter 2
OEMV Family Installation and Operation User Manual Rev 5B 31
9 32-Bit CPU 22 Input Timing Signal
10 System I/O 23 Output Timing Signal
11 AGC 24 USB Communication
12 Clock 25 CAN Communication 1
13 VCTCXO 26 CAN Communication 2
2.1 OEMV Card
NovAtel’s OEMV cards consist of a radio frequency (RF) and a digital electronics section.
2.1.1 Radio Frequency (RF) Section
The receiver obtains a filtered and amplified GNSS signal from the antenna via the coaxial cable. The
RF section performs the translation of the incoming RF signal to an Intermediate Frequency (IF)
signal usable by the digital section. It also supplies power to the active antenna’s LNA through the
coaxial cable while maintaining isolation between the DC and RF paths. The RF section can reject a
high level of potential interference (for example, MSAT, Inmarsat, cellular phone, and TV sub-
harmonic signals).
2.1.2 Digital Electronics Section
The digital section of the receiver receives a down-converted, amplified GNSS signal which it
digitizes and processes to obtain a GNSS solution (position, velocity and time). The digital section
consists of an analog-to-digital converter, a 32-bit system processor, memory, control and
configuration logic, signal processing circuitry, serial peripheral devices, and supporting circuitry.
The digital section performs the translations and calculations necessary to convert the IF analog
signals into usable position and status information. It also handles all I/O functions, including the
auxiliary strobe signals, which are described in detail in Section 3.3.1 on Page 44. For input and
output levels please see Appendix A, Table 31, OEMV-3 Strobes on Page 151, Table 29, OEMV-2
Strobes on Page 145 and Table 25, OEMV-1 Strobes on Page 133.
2.2 Enclosure and Wiring Harness
An enclosure is necessary to protect the OEMV card from environmental exposure and RF
interference. A user-supplied wiring harness is also required to provide an interface to the OEMV
card’s antenna and power inputs and data and status signals.
2.3 GNSS Antenna
The purpose of the GNSS antenna is to convert the electromagnetic waves transmitted by the GNSS
satellites into RF signals. An active GNSS antenna is required for the receiver to function properly.
NovAtel’s active antennas are recommended because of their precise phase centres and robust
enclosures.