Navigational system for manned lunar vehicles is intended for travel totaling 30 km within 5 km of home base, total distance traveled must be indicated with 2 percent accuracy. Hardware includes two two-degrees-of-freedom gyroscopes, odometers, tachometers, and signal processing equipment

Green, W. L.

English

NASA Technical Reports Server

April 1971	 CORRECTED COPY
	 Brief 71-10072 
S	 NASA TECH BRIEF 
Marshall Space Flight Center 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a aubscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D. f. 20546. 
Systems for Dead-Reckoning Navigation and for Simulation

of Instrumental Error: Concepts 
A dead reckoning navigational system, conceived 
for manned lunar vehicles, and a relatively simple 
test system for simulated instrumental error, devised 
in conjunction with the navigational concept, may 
have application in such diverse fields as ocean-
ography and air-traffic control. 	 - 
The navigational system is intended for travel 
totalling 30 km within 5 km of a home base, 
and the total distance traveled must be indicated 
with ±2% accuracy. At five kilometers radially from 
the home base, the heading toward the base must 
always be known within 7r/60 radians (3 deg). 
The system must always be able to return the vehicle 
to within 500 m of the base, and to effect a 
return visit to an established site. (Unless aided by 
visual cues, natural or artificial landmarks, such a 
return would need greater accuracy than within 
500 m.) The vehicle and system must be capable 
of 3-hr trips over a 3-day period. 
Hardware required by the navigational system in-
cludes two two-degrees-of-freedom gyros solidly 
mounted on the vehicle frame, odometers, and 
tachometers. For the system to be self-contained, 
some type of signal-processing equipment would 
also be required. 
A particular lunar trajectory was selected for 
evaluating the accuracy of the system. The time-
varying sequential angles were used as inputs for a 
digital simulation study of the gyro drift rates 
and vehicle misalignments. The results of. this simula-
tion study indicate that the navigational system can 
meet the requirements. If the accuracy requirement
is to be met, the gyro drift rates should be in the 
range of 7r/180 rad/hr (I deg/hr). ibility to re-
visit any point, with ±300 m accuracy, requires a 
vehicle realignment accuracy of r/36 rad. (5 deg). 
Other navigational systems that should be analyzed 
include a directional and vertical gyro system, a sun-
aspect sensor and vertical-gyro system, and a direc-
tional gyro and inclinometer system. Simulation 
studies could determine the accuracies of the sys-
tems. 
Notes: 
I. This innvoation is in the conceptual stage only 
and at the time of this publication no model or 
prototype exists. 
2. The following documentation may be obtained 
from: 
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.95) 
Reference: 
NASA-TM-X-53953 (N70-20655), A Simpli-
fied Dead Reckoning Navigation System for 
the Manned Lunar Roving Vehicle 
Patent status: 
No patent action is contemplated by NASA. 
Source: W. L. Green
Marshall Space Flight Center
(M FS-20860) 
Category 07 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19710000071 2020-03-17T02:22:39+00:00Z


Systems for dead-reckoning navigation and for simulation of instrumental error - Concepts

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