GPS receivers

Software

The FreeGIS site http://www.freegis.org/ has the largest collection of freely available GIS/CGPS software. But the collection is not inclusive because policy prohibits them from listing free but protected commercial software.

GISuser has a collection of free tools.

So for example, Trimble's free mission planning program is not available there.

From email: Since 1997, I have implemented sets of Java, Web & Wireless GIS tools. Most of them are free to use. If you are interested, please visit http://www.jshape.com for more information. -- Shiuh-Lin Lee

ERmapper MapWindow GIS JUMP
Thuban
Quantum GIS QGIS

Mobile GIS Software

BBBike
ESRI ArcPad
GiMoDig
GPSDrive
Hoko

GPS

Data formats and protocols

RINEX = Receiver Independent Exchange Format

RINEX 1 RINEX 2

Using RINEX to do differential postprocessing on your GIS data.

1. Collect raw data using Garmin equipment
2. Conversion of Raw Observation Data and Navigation Message Data to RINEX See TEQC software and GRINGO software
3. Download CORS data
4. Postprocess; using P4 (companion to Gringo)

Prairie has an intersting collection of information on using Garmin and Rhino products for DGPS. Rhino is a product of US Positioning.

"Proven Success With Rhino" (and therefore probably with RINEX conversion software?)

eTrex, eTrex Summit, eTrex Vista, eTrex Legend, GPS 12, GPS II +, GPS III, GPS III +, GPS V, GPS 16, GPS 16A, GPS 17N, GPS MAP 76, GPS MAP 76S, GPS MAP 176, GPS MAP 176C

NMEA

NMEA = National Maritime Electronics Association

NMEA 0183 standard is the ASCII format for (among many other things) GPS spatial data. You have to pay $250 to get a copy of the 0183 standard, these people don't know about the Internet and open standards yet. (The NMEA 2000 standard is $3800, ha ha ha.) If you are designing a new device and you have the bucks, you have to pony up. If all you want to do is grab data from your handheld and process it, the manufacturer manuals from both Garmin and Trimble are good. (Probably others too, these are just the ones I have read.)

RTCM

RTCM = Radio and Telephony Communications Maritime or something like that.

RTCM is another standards body in the business of selling information that really probably should be distributed for free. The publication set on differential GPS is $100. NTRIP which is the standard for distribution of the data over IP networks (via HTTP) is $50.

Trimble TSIP, proprietary binary format

Selected GPS Hardware

My interest is in learning as much as possible for the least cost. I already own a Garmin eMap and a Garmin GPS 25 LVC. I am interested in finding a Trimble or maybe an Ashtech receiver.

Garmin OEM information

Model	Accuracy	Channels	Price	Comments
eMap	15m/2m	12	$200 or so	Handheld, accepts RTCM for DGPS. Apparently a bad choice for Rinex software
GPS 15	15m	12		bare module
GPS 16 LVS, 16 HVS, 16A 3.3-6V / 6-40V / 8-40 V	15m / <3m WAAS / 3-5 USCG RTCM	12 channel		2 serial ports, deck mount
GPS 17			$200	basically the same as a GPS 16 but in a white, pole mount case
GPS 18	15m / 3m WAAS	12	$130	CMOS serial or RS232 or USB hockey puck
GPS 25-LVC (3.6-6V), -LVS(3.6-6V RS232), -HVS(6-40V RS232)	15m / 5m DGPS	?		bare module; capable of raw data output (pseudorange and phase) [1]
GPS 35 / 36	15m / 5m DGPS	?		35 = mouse style, 36 = pole mount

The GPS 17 is designed for marine applications but is often pressed into service in backpack style data collectors.

Trimble GPS modules

Model	Accuracy	Channels	Connectors		Price (est)	Comments
Pathfinder Pocket	10m/2m DGPS	8	2 RS232 via one DB9, SMB 3.3v, power		$500	includes an external antenna.
M-Loc	10m (no DGPS)	12		3.3v 35mW(68mW) 25 x 25 x 6.9 mm	$45	FirstGPS software runs on host processor
Lassen SQ	6-9m,no DGPS	8	8 pin header, H-FL-R-SMT	3.3v/100mW(133) 26x26x6 mm, 5.7g	$45	Use w/RF transition cable
Ace III	25m/2m DGPS	8	8 pin (2 CMOS TTL serial) SMB 5v/25mA	5v / 95mA / .47W 82.6 x 46.5 x 11.5 mm	$80
Lassen SK-8	25m/2m DGPS	8	8 pin (2 CMOS TTL serial) SMB 5v/25mA		$	Discontinued; use SKII
Lassen SKII	25m/2m DGPS	8	8 pin (2 CMOS TTL serial) SMB 5v/25mA	5V / 95mA(120mA)/ .47W(.60W)	$80
Lassen LP	25m/2m DGPS	8	2 serial and power via 8 pin header, MCX/3.3v 12mA	3.3V / 55mA(67mA)/ .182W(.221W) 66.167 x 31.75 x 12	$55	Low power; can be programmed to power up/down on schedule

Style	Gain	Connector	Price
Micropatch	26dB	5m cable with MCX	$17
Hardmount micropatch	26dB	TNC	$
Bullet	35dB	22m cable with SMB adapter	$

GPS simulators

People make boxes that simulate NMEA-capable devices to allow testing when the actual data stream is not available and to enable regression testing.

NMEA data stream
The virtual serial port idea
Can I make a virtual serial port driver under Linux and fool VMware into using it??? Hmmm... Yes. It's quite doable. You can hook a named pipe up as the serial port in the VMWare configuration settings and then write a program to read and write data on the pipe.

Another project, damn.

GPS mission planning software

A GPS mission consists of three phases. planning, execution, and post-processing. Mission planning software packages run on a desktop system at your office and assist with planning and post-processing phases.

The two commercial programs that I know of are tightly integrated with the field software so they are not all that useful unless you buy in to the whole enchilada -- data collector, proprietary data collector software, and "office" software.

The two programs are Trimble GPS Pathfinder Office for use with Trimble data collectors and TDS SoloOffice which works with TDS SoloField.

Planning for a GPS mission should include checking for suitable conditions. This includes knowing that the satellites will be positioned propitiously when you will be in the field.

I use Trimble's free planning program for this. You can download it from [insert Trimbles download site]. The bad part is that it is available only for Windows systems but it's handy enough that I use it anyway.