Navman GPS Sleeve i-Series Review

This review covers the Navman sleeve that is custom designed to attach to an iPAQ 3600, 3700, 3800 or 3900 pocket pc. This unit is shown on the left displaying a topo map from Maptech. The testing was performed on a iPAQ 3970 running Pocket PC 2002 operating system and used Navman driver version 3.1.1. The i-series is also known as the 3000 series and is the same hardware as 3400 and 3420 models. The difference in the various models is based on the supplied software.

The Navman hardware, shown at the right, is based on the SiRF chipset as are most of the pocket pc gps receivers and it derives its power directly from the iPAQ. It includes a built in Compact Flash (CF) card slot which is suitable for navigation programs and maps or anything else you would like to use it for. The cover for this slot can just be seen in the side view near the bottom. A microdrive is reported to work in this slot but Navman does not recommend it due to the excessive current drain. Accessories that were shipped with the unit include a vehicle 12V power cord and a vehicle suction cup mount. The power cord required that I use the iPAQ adapter that came with my AC adapter (true for 3800 and 3900 iPAQs). Be sure and wet the suction cup before using it to ensure that it sticks well. The vehicle suction cup mount uses special slots in the Navman hardware and will not work to mount the iPAQ without the Navman. Generally the mount can be used to attach to the front window of a car and is fairly secure. I would not recommend leaving the unit in the mount when you are not present since the suction cup has been known to release without warning after a few hours, particularly if you haven't cleaned the window first. I would have preferred the stem to have been a couple of inches longer as it was difficult to get clearance to remove the iPAQ when the unit is attached to the window. It is best if the bottom of the iPAQ or mount rest on the dash to cut down on vibrations. The product also ships with a cdrom containing the driver software (V3.1.1) and a test program.

The Navman always comes with software. Which software depends on how it was purchased. For example buying a Navman from Navman themselves will get you a set of street level maps for your country or perhaps several countries. In my case the Navman came with Maptech Pocket Navigator and a set of California topo maps. There are many other configurations that will net you a Navman and some choices will include multiple software bundles, so you will need to factor in the correct software with the hardware purchase decision. However, once you own the unit you will likely find that you will use it with different software packages as well as the one you purchased with it. For my review I used MapTech Pocket Navigator, Memory-map Pocket Navigator (3.0), NMEAMon, Some Tom-Tom mapping products, National Geographic Topo! sync, Pocket Streets and Trips, and a few others. I found that my Navman could be made to work with all of them, although I sometimes have problems with a program utility from Tom-Tom called GPS. I even had it working with a TTY program just to look at the NMEA data.

Installation

To install the unit you simply plug it into the iPAQ and place the whole thing in the cradle. Then install the software following the installation instructions that came with the software, which is generally just to click on the executable. You will need to install the driver as well. If the software doesn't do this or the software driver is not the latest then install the driver from the Navman cdrom. It installs automatically and leaves you with a small utility program called GPS-Info that can be used to verify the installation. I wouldn't bother with this program unless you have trouble. It doesn't tell you very much about what is going on and is really only valuable in that it can verify the hookup and display some internal version numbers which might be useful to Navman technical support. The best bet is to just try your application and see what happens. Each program will have a slightly different setup procedure so check the manual. I found that the Navman uses its own serial port which is usually the last one in the list. On my 3970 that meant that it was hooked to com 6. Generally it is likely to be com 5 on units without BlueTooth support. There are no controls on the Navman gps. Once it is plugged in it will be turned on automatically by any program attempting to access the serial port and will be turned off automatically when the port is freed.

Operation

When you first use this gps it may require an exceptionally long period of time to get a lock on the satellites. Part of this reason is that you cannot tell it where you are so it will have to search the sky to find all of the gps satellites. This is called an auto-locate since the unit is automatically figuring out its location without any prior knowledge. Once it knows its approximate location it will know the approximate location of the satellites with respect to its current location and current time which will allow it to find them much quicker. This initial lock period could be as long as 15 minutes. If you would like to understand what is going on please read my article on gps fix. It was originally written for Garmin gps receivers but the principles are the same for any receiver. Understanding how a gps works will help considerably in understanding its limitations and will help you in troubleshooting any problems so it may also be useful to read my article the theory behind the gps system. In my case the unit was able to find itself in much less that the 15 minutes the specifications allowed for, however just finding yourself once does not ensure that a full almanac is present so it would be better to leave it on for a while the first time you use it.

The much more important specification is how long will it take to get a fix first thing in the morning, the so called TTFF, time to first fix. Quite frankly the Navman 3000 doesn't have a very good reputation when it comes to TTFF. The specification itself allows for two minutes to achieve a first fix which is twice as long as any good handheld receiver and even as much as 3 times what some can do but I have heard reports that it could take even longer. I decided to try and get to the bottom of this with some testing and some research. My conclusion is that some of the problems are part of the design of the Navman and some are an artifact of the pocketpc. First of all the Navman is mounted in very close proximity to the iPAQ itself and it seems the iPAQ emits a lots of RF noise. I don't mean the kind of noise you can hear but the kind of noise that you sometimes find on your radio where static interferes with the morning news. Don't forget that a gps is like a radio and it receive signals as well only they are much less powerful than the ones your radio gets. Every electronic device generates some noise and digital devices are at least as bad as other electronic devices. This is the reason that airlines make you turn off electronic devices before they enter the critical landing stage. Part of the design of an electronic device should be to try and shield it so that the noise emission level is minimal and the susceptibility to outside noise is minimized. Somewhere along the way it seems that the Navman and the iPAQ have a shaky relationship, and the 3900 series with its higher clock rate is worse than its predecessors. So the question is, what can be done about it? Here is what I have found if you want a short TTFF.

Expect a new TTFF whenever the unit has been shut down for an hour or two, but with shorter shutdowns the Navman will get a new fix in a much shorter time varying from about 10 seconds to a bit longer. It is always a good idea to check the satellite status when starting up your gps. Many of the better mapping programs provide some way to monitor this data without even leaving the program.

Performance

Once the gps receiver has a reasonable fix then the testing can begin. My evaluation involved several programs and several conditions including hiking and car use in the wide open spaces and in tree lined mountain roads and trails. I compared the unit to my trusty Garmin emap or in some cases my Vista. I found that, in general the performance matched the emap, horizontal accuracy was similar and its reception under tree cover was about the same, sometimes edging out the emap and sometimes a bit worse. A few things that I did note include:

NMEA mode

The navman always works in NMEA mode and the new drivers are very successful at negotiating the baud rate with the application. This means that the 57600 baud rate no longer limits the availability of application programs since the driver will accommodate lower rates clear down to the standard 4800 baud. The result is that if the program can support the com channel it will likely work with the navman even if it does not have adjustable baud rates. Just set it to NMEA, pick the com channel, and fire up the gps connection.

The navman will output GGA, GLL, RMC, VTG, GSA and GSV sentences. My tests found that the first four were output every second and the satellite status sentences GSA and GSV once every 4 seconds making the display quite responsive. The documentation indicates that the updates were only every 2 seconds. Either would satisfy the needs of any mapping program. Of course different applications may chose to sample the data less often. The navman will respond to the proprietary NMEA input commands available for SiRF devices so it is possible that an application could modify these values and some others. These are not intended to be changed by the user and could cause the gps to quit working properly if misused. For my testing I used the defaults.

The CF card

The Type II CF card slot is a nice bonus. I didn't have any problems using a standard CF card in the slot either for programs or for data. It is found automatically by PocketPC 2002 and reports itself as 'Storage Card2' while the SD card slot on my 3970 reports 'Storage Card'. Note that the storage card is only recognized if the Navman driver is present.

What about the iPAQ?

The truth is that the Navman is worthless without the iPAQ. They are married to produce the full GPS receiver. Thus it is a fair question to ask how well the marriage stacks up to a stand alone gps. In general the combination can replace a standalone gps under many conditions.

For hiking the map display on the iPAQ is great. Good resolution and color makes topo maps a pleasure to use. The iPAQ is not very rugged however, so it is good for day hikes, but not where it could be dropped or get wet. It has a glass screen that could break and the unit is not water proof. A protective case or waterproof bag is advised. The combined unit is a little bulky but still fits ok in your hand. It should also work well on a bicycle with a suitable mount and protection.

The Navman gets its power from the iPAQ and will shorten the battery life. With minimal use of the backlight I was able to achieve more than 3 hours of use on a charge without getting a low battery warning. For maximum battery life lower the standby period to as low as you dare and lower the backlight setting to the minimum you can get by with. I suspect more than 4 hours of continuous operation is possible. An external battery pack with a set of 4 AA NiMH batteries could extend the usage to a full day.

For vehicle use it should be run on the external power and the backlight set to maximum in the daytime and less at night. The varying sunlight conditions during the day preclude trying to get by with a lower backlight setting. Even so the glass screen will often have reflections making the display difficult to see so placement is critical to minimize this. A screen protector can help tremendously in the reflection problem. The iPAQ OS typically has too high a dependency on the the stylus making program operation while driving potentially dangerous.

The unit should be equally comfortable in a marine or aircraft environment but try and place it where it won't get wet or use a protective waterproof bag. I am not sure the iPAQ can take the abuse of the constant pounding of a speed boat.

For gps use I recommend the use of a free program called WIS Bar. It modifies the behavior to the top banner making the iPAQ easier to use. The program makes the battery status settings easier to get to and change. It also provides an easy way to see and kill other applications. In addition you can move the ok button on the top bar away from the corner so you have at least a chance of hitting it with your finger nail.

The NavMan can be left connected to the unit even when hotsyncing or running other programs and does not interfere with other uses for the iPAQ. The CF slot can be used totally independently from the gps.

Conclusions

In addition to the comments already presented in the text above I have the following observations.

The Navman plus an iPAQ makes a very convenient GPS system. There are no wires to worry about and the attachment is solid. It can be used as needed without much fuss. This is one of its strengths and should appeal to many users.

The antenna is attached well with no danger in breaking it off. It is of quad-helix design which has maximum reception when held vertically but works well down to about 45 degrees from vertical. Holding the unit horizontal will result in a significant drop in sensitivity.

The hardware is a bit bulky and may not fit it the standard case you use for your iPAQ. The screen cover that came with the iPAQ will not work with this unit.

With a little care in obtaining the first fix of the day this unit could easily be your favorite gps system.

Final Notes

The opinions expressed in this review are mine alone. All rights are reserved by Dale DePriest.

revisions
Released on Oct 15, 2002.
Updated in 11/27/2002
Minor updates in Mar 2003.