Vectornav VN-200 User Manual download pdf (Page 17)

random data for testing. Thus, it makes me hard to compare this driver with other mature platforms.

The only other actual driver that we can compare with is Novatel. Since we do not have the

hardware, we can only compare them by their source codes. In the novatel folder, we can see there

is only one cpp ﬁle for CRC32 checking, and the ﬁnal library ﬁle l ib novatel.a only contains functions

for this. Other functions deﬁned in other header ﬁles for command speciﬁcation an d logging are not

included as part of the binary library. In the vn200 folder, the library gives us an easy access to

each of the command listed in its user manual, so we only need to ﬁrst initialize a vn200 str uc t and

then pass necessar y arguments as in the user manual.

The diﬀerence between novatel and vn200 makes the code of novatelspan and vn200span very

distinct from each other. I n novatelspan, it is clear that the driver programs does much work in

detail, like setting baud rate, deﬁning the serial port access and the format of commands. Therefore,

the pr ogr am looks complicated as it has to deal with so many details like mode switching, sensor

disconnection, etc. For vn200span, the driver program is simpler as vn200 has a good encapsulation

ready for development. My driver program only needs a direct fu nc ti on call when it needs to read

data from the sensor. Other sections of the source code are only designed for maintaining the state

of the state of the sensor, like open, close, reset and read.

Besides, the hardware design of VN200 is more advanced so that it has more functionalities than

that of Novatel. For example, VN200 has an on-board chip to calc ul ate calib r ated coordinates of

the GPS sensor and the IMU sensor. This can give us a better accuracy and we do not need to get

these two results separately and calculate calibration on our platform. This functionality will help

us to make the development even much easier.

5.2 Motor Encoder Driver

The motor encoder driver is much si mple r , which only gives the current speed to the Orca system.

This driver is simpliﬁed and modiﬁed from the laser2d component. The driver can display the speed

of the motor correctly (Figure 6). Both laser2d and th is arduino

enc components are just simpl e

modules to get data from devices. They are well designed for the Orca system to cooperate with

other depending components.

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Vectornav VN-200 User Manual Page 17