across the radar detection zone, these combined calculations will result in a range
reading that will vary materially more than the specified resolution of the radar.
That said, the range resolution enhancement algorithm is able to achieve
significantly better effective range measurement as compared to competing
products. In many cases as much as 5 to 10x better performance can be expected.
Radar Configuration and Data Variables
The radar firmware provides uniform access method for the configuration parameters and
generated data via internal variables. Each variable is identified by a combination of its
domain and a two letter name. Persistent variables that are preserved over reboots and
power cycles belong to domain 0 while volatile variables belong to domain 2. Each
variable stores a 16-bit value. Variables with names that begin with an upper case letter
are user settable. Variables with names that begin with a lower case letter are protected
and cannot be modified by user.
Configuration parameters are stored in persistent variables. The easiest way to configure
the radar is to use supplied Houston Radar Windows Configuration Utility. It will present
you with a set of easy to understand configuration options. Once the user makes his
selection, the Configuration Utility converts user specified options into a set of
configuration variables and stores them in the radar.
Persistent variables are written to radar FLASH memory. Do NOT update settings on a
periodic basis, e.g. every second or every minute. Only change settings when the user
needs it. The FLASH memory has a limited number of write cycles and will wear out
with excessive (>20,000) number of writes. On the other hand, setting a persistent
variable to the
same value
repeatedly is OK because the radar recognizes that the variable
has not changed and does not update it in FLASH.
The same mechanism as used for configuring the radar is used for retrieving some of the
measurement data. Measurement data is stored in volatile variables. For example
per-lane
occupancy
can be retrieved from the radar as a set of six variables.
In some case an advanced user may choose to bypass Configuration Utility and access
variables directly. Radar supports both ASCII protocol for interfacing with a human
operator and binary protocol for interfacing with a computer. ASCII command interface
can be accessed via a terminal program such as Hyperterminal and is described in
Appendix E
. Binary interface requires implementation of a custom software that takes
advantage of Houston Radar binary protocol SDK. An example where this may be
desired is a situation where the radar is connected to a custom controller card that cannot
run Windows applications.
