GPS

1
GPS

• Xinwen Fu

2
Outline

• Deluo USB GPS Pro SiRFstarIII
• Introduction to gpsd
• Installation
• Collect Position Data
• sirfmon
• Convert latitude/longitude
• kismetgpsmap

3
Deluo USB GPS Pro SiRFstarIII

• Receiver Up to 20 simultaneously tracking
  channels. L1, 1575.42MHz, C/A code
• Accuracy lt 2.5m (Autonomous) lt 2.0m
  (WAAS) lt0.01 m/s (speed)
• Acquisition Hot Start 1 sec. (Min.) Warm
  Start 35 sec. (Average) Cold Start 42 sec.
  (Average)
• Dynamics Altitude 18,000m (Max.) Velocity
  500m/sec (Max.) Acceleration 4G (Max.)
• Sensitivity Acquisition -142 dBm Tracking
  -159 dBm
• Navigation update rate Once per second
• Protocol NMEA 0183 Ver.3.0
• NMEA Messages GGA, GSA, GSV, RMC, VTG
• Coordinate Datum WGS-84
• Power consumption 45mA (Average)
• Waterproof Yes
• Baud Rate 4800bps
• Operating Temperature -40ºC 80ºC
• Storage Temperature -20ºC 60ºC
• Operating Humidity 5 95
• Cable Length 5ft

4
gpsd

• Is a service daemon that monitors one or more
  GPSes attached to a host computer through serial
  or USB ports
• Makes all data on the location/course/velocity of
  the sensors available to be queried on TCP port
  2947 of the host computer
• Responds to queries with a format that is
  substantially easier to parse than the NMEA 0183
  emitted by most GPSes
• Includes a linkable C service library, a C
  wrapper class, and a Python module that
  developers of gpsd-aware applications can use to
  encapsulate all communication with gpsd

5
gpsd Auxiliary Tools

• Diagnostic monitoring
• Profiling of GPSes
• Feeding GPS-aware applications specified track
  data for diagnostic purposes

6
Installation

• Plug Deluo USB GPS Pro SiRFstarIII into the usb
  port
• Download the source of version 2.37
• Compile it
• tar zxvf gpsd-2.37.tar.gz
• cd gpsd-2.37
• ./configure
• make
• make install
• (Note I cannot compile xgps and a few other
  tools needs dbus installed and configured)
• Start gpsd the GPS device is nased ttyUSB0
• gpsd /dev/ttyUSB0
• gpsd /dev/ttyS0
• Test gpsd
• cgps

7
Collect Position Data

• Log the position data into a file
• cgpxlogger gt position-data-file.xml
• ctrl-c to stop the data collection
• Load the xml data into excel
• Open the xml file with excel
• Ok the default choices

8
Sample Imported Data in Excel
9
sirfmon

• Monitor and control a SiRF GPS in binary mode
• Start sirfmon via the serial port in the binary
  mode
• sirfmon /dev/ttyUSB0
• When the GPS is in the binary mode, it outputs
  all the messages except those poll/response
  message
• We can program to send a poll message
• Under sirfmon, we can use the s command to send
  a poll command. Note there is no space between a
  sirfmon command and the payload

10
Sirmon (Continued)

• The function that decode the binary output
  messages
• static void decode_sirf(unsigned char buf, int
  len) / buf has the whole binary data /
• Code is changed by Fu to process Messages 7, 28
  (0x1C), 30 (0x1E). Search XINWENFU for the
  changed code
• Added functions to convert the data to be
  properly interpreted on a PC
• static double getdbl(unsigned char buf, int off)
  / this function is for converting
  double-precision value and may need to be changed
  if another GPS product is used. Refer to sirf
  binary protocol manual p. 3-33/
• static float getsgl(unsigned char buf, int off)
  / this function is for converting
  single-precision value /
• Example to send a poll to the device
• / probe for version /
• putbyte(buf, 0, 0x84)
• putbyte(buf, 1, 0x0)
• /_at_ -compdef _at_/
• (void)sendpkt(buf, 2, device)
• /_at_ compdef _at_/

11
Converting Addresses to/from Latitude/Longitude
in One Step

• Convert

http//www.worldatlas.com/aatlas/imageg.htm
12
Wardriving by kismetgpsmap
13
Use gpsmap

• Installation
• yum install ImageMagick
• yum install ImageMagick-devel
• yum update dbus
• Download, compile, and install kismet
• Run gpsmap
• gpsmap S 3 t p o test.jpg e
  Kismet-Oct-Oct-15-2007-1.gps

14
References

• Deluo USB GPS Pro SiRFstarIII, 2007
• gpsd, 2007
• Stephen P. Morse, Converting Addresses to/from
  Latitude/Longitude in One Step, 2004
• Mike Shannon, Linux Wireless, 2007
• Kismet Installation, 2006
• FC6 Wireless Auditing Laptop HOWTO, February 07
• Kismet - Google Maps, 2007
• PRODUCING WIRELESS MAPPING WITH KISMET, 2006
• Kismet, 2007