GPS receivers

From Wildsong
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This page has notes on GPS receivers that I am interested in. I own a few of them and list a few others for comparison purposes.

I list both receivers integrated into systems like the Garmin eMap handheld and modules such as the Trimble Lassen SQ.

You can get the bare modules or you can use modules that have been built up into GPS hockey pucks. (Some people call them GPS mice.) For example, you can get a Garmin 25 module and wire it directly to the low voltage serial port on a PIC processor or you can get a Garmin GPS-18 hockey puck and plug it into a USB port.

For hobbyists probably the best place to get the bare modules is Spark Fun Electronics, they have a bunch of other modules that I don't list here yet.

I got the modules I have currently on eBay.

Since I originally wrote this page I have obtained an Emtac BT-338 from Tigerdirect for about $50 and a Wintec WBT-100, $95 from Semson. Both of these have bluetooth. The Wintec has WAAS, a compass, bluetooth, and USB.

Semson and GPScity are my favorite places to shop for GPS gear. GPScity has RAM mounts.

I have gotten interesting out-of-date stuff like Trimble development boards on eBay.

Related pages

GPS Protocols
Magnavox GPS reference station


Garmin OEM information

I think the 62SC uses the STM 32 channel Cartesio GPS chip set. Same as the DeLorme PN-40 and PN-60.

Model Accuracy Channels Price Comments
Garmin 62SC 10m/3m WAAS 32? $300-500 Handheld, USB but no serial or antenna ports. (8/12)
eTrex Vista 10m/3m WAAS 12 $200-300 Handheld, USB but no serial (so no RTCM) or antenna ports. Just got an HcX. (9/07)
eMap 15m/2m RTCM 12 $60 or so on Ebay Handheld, accepts RTCM for DGPS. Apparently a bad choice for Rinex software DISCONTINUED
Garmin GLO 3 meter ??? $99 bluetooth module
GPS 10 15m/3m WAAS 12 $250 bluetooth module
GPS 12 15m/3m RTCM 12 $ 1999 Handheld, accepts RTCM, no maps
GPS 15 15m 12 about $50 bare module, several models. Tiny successor to GPS-25
GPS 16 LVS (3.3-6V),
16 HVS (6-40V),
16 A (8-40V)
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)


GPS 35 / 36 15m / 5m DGPS ? 35 = mouse style, 36 = pole mount

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

Garmin nuvi models

Garmin nuvi 855
Garmin Nuvi 1390T
Garmin Nuvi 3590LMT


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
26x26x6 mm, 5.7g
$45 (use IQ instead!) Use w/RF transition cable
Lassen IQ 5-8m,no DGPS 12 8 pin header, H-FL-R-SMT 3.3v/85mW
26x26x6 mm, 5.7g
$50 Updated more accurate version of SQ. Purchase from SparkFun
Placer 455DR 1-5m,w/DGPS 8 3 DB9 11-32v
not a module! but I have one so I listed it here
Ace II 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
cheap Discontinued but I got one from eBay for $10
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
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 $


ToppTec -- purveyors of Trimble OEM modules


(Mostly) consumer grade; Earthmates are WAAS enabled but the older Tripmates are cheap on eBay if you just need a NMEA GPS source.

DeLorme is trying to push into the pro grade world. They have post-processing software (RINEX) at least for the LT40. Their slogan for the PN40 was "Serious Tool" but mostly they seem to be promoting it for geocaching and hiking.

Model Accuracy Channels Price Comments
Tripmate 15m? 12 $20-30 on eBay rs232 (discontinued)
Earthmate WAAS 12 $100 USB
Blue logger WAAS 12 $150 bluetooth enabled
LT40 WAAS ? $50 USB mouse; available bundled with software, good deal
PN-20 WAAS ? ? Handheld (discontiued)
PN-30 WAAS 32 $300 Handheld, PN-40 w/o baro or compass (discontinued)
PN-40 WAAS 32 $150? I paid around $500 for mine!
PN-60 WAAS 32 $300? wireless version PN-60W talks to SPOT device

Other links

Thales and Magellan
U-blox I have a couple U-blox devices including an Openmoko phone.